Regression models of viscosity and density of permeate as a function of operation parameters in ultrafiltration of milk
Volume 1, Issue 1, April 2005, Pages 1-10
https://doi.org/10.22067/ifstrj.v1i1.201
Seyed Mohammad Ali Razavi
Abstract Viscosity (µ) and density (ρ) are important physical roperties for analysis of membrane processes performance and for designing a new membrane process. In addition, the energy requirement for fluid pumping is depend on these two physical properties magnitiude. In this study, firstly, the effects of different process factors such as transmembrane pressure (51, 101, 152, 203 and 253 kPa), temperature (30,40 and 50ºC) and the effects of physico-chemical properties such as milk pH (6.67, 6.43, 6.25 and 5.97), milk fat percent (0.09, 1.19, 2.4, 3.26) on the viscosity and density of permeate have been considered. Two linear multiple regression models were then developed by Sigmastat software for prediction of µ and ρ during milk ultrafiltration. The experimental results showed that µ and ρ decreased as fat percent or temperature increased. pH had no considerable effect on µ and ρ. Furtheremore, increasing transmembrane pressure to 152 kPa led to an increase in both µ and ρ, while further increasing to 253 kPa resulted in a decrease in both µ and ρ. The statistical modeling results showed that the viscosity is only significantly depend on temperature and there was an excellent agreement between actual and predicted data (R=0.976), whereas the density is siginificantly depends on both temperature and fat percent and there was a good agreement between experimental and predicted data (R=0.904).
Investigation on the effects of different amounts of gellatin and guar on texture, organoleptic and color properties of white mulberry pastille
Volume 13, Issue 1, March and April 2017, Pages 1-13
https://doi.org/10.22067/ifstrj.v1395i0.42322
Shadi Basiri, Fakhri Shahidi
Abstract Introduction: Morus Alba, known as white mulberry, is a short-lived, fast-growing and small to medium sized mulberry tree, which grows to 10–20 meters tall. The species is native to northern China, and is widely cultivated and naturalized elsewhere. The fruit is 1–2.5 cm long in the species in the wild, it is deep purple, but in many cultivated plants it varies from white to pink, being sweet and bland. The fruits are also eaten, often dried or made into wine or vinegar. In traditional Chinese medicine, the fruit is used to treat prematurely grey hair, to tonify the blood, and treat constipation and diabetes. White mulberry is a fruit with high nutritional quality. The shelf life of mulberry is short due to its high moisture content. Dried mulberry and its molasses are popular products from mulberry fruit. Hydrocolloids are used in fruit snacks formulations to create novel texture, increase stability for their water-holding capacity, improve texture and have an impact on flavor release and other structural and sensory properties in the respective products. Hydrocolloids are also widely used in the food industry as thickeners, stabilizers and gelling agents in various products including ice cream, sauces, jellies and pastille products. Guar gam is kind of long-chain galacto-mannan with high molecular weight, obtained from endosperm of guar plant. This type of synergistic behavior among polysaccharides is commercially valuable, because it creates a novel texture and a more desirable structure. The aim of this research is to produce mulberry pastille as a novel and value added product with long shelf life. Beside it can be introduced as a healthy snack replacing sugar. Materials and methods: The materials include mulberry puree, hydrocolloids (Gelatin and guar) and citric acid. Berries were collected from the gardens around Mashhad (Iran). Guar was purchased from Sigma Chemical Company, citric acid was purchased from Merk Chemical Company, Germany. Gelatin (0, 1, and 2 %) and Guar (0, 0.5, and 1 %) were used for pastille formulations. To produce fruit pastille based on mulberry puree, the prepared puree was mixed into hydrocolloids. After measure pH and moderating to PH = 4.3 by adding acid citric in 40 % concentration and controlling the Brix degree to constant Brix of 45, the mixture was prepared. Then the prepared mixture was poured into a network framework of steel origin in the cavities with 1.2×1/2 and the molds were hold in the refrigerator for 2 hours with 4°C to fasten the gel. The obtained gel was taken out of the mold cavities and placed in a glass plate. The samples were then dried at 70° C in a hot air drier with airflow rate of 1.5 m/s for 6 hours. The samples were evicted every 30 minutes. Parameters such as color, sensory and textural characteristics of samples were investigated. Statistical design was 2 factors factorial with three replicates adopted completely randomized design. Results and Discussion: The results of texture evaluation showed that increasing guar gum improves the cohesion, elasticity and chewiness of the samples, while their adhesion were decreases. Conclusion: Mulberry pastille including 1% Guar and 1% Gelatin having the lowest amount of firmness, adhesion, chewiness and suitable color characteristics, was determined as the best formulation among the other investigated samples.
The effect of fat replacement by aloe Vera gel on physicochemical, technological and sensory properties of sausage containing 40 % red meat
Volume 15, Issue 1, March and April 2019, Pages 1-11
https://doi.org/10.22067/ifstrj.v0i0.60437
Shakiba Kianiani, Mohammad Javad Varidi, Mehdi Varidi
Abstract Introduction: Meat and meat products contribute about 20% to human fat consumption. Fat is the main source of energy and the base of fat soluble vitamins. Besides, it improves cooking yield and water holding capacity, conserves taste and flavor of products and affects the emulsion stability, juiciness, costumer acceptability and structural and rheological properties of meat products. But Animal fat contains a relatively high amount of saturated fatty acids and cholesterol, which can increase the risk of cardiovascular disease, diabetes, cancer types and obesity. Thus, the meat industry is interested in merchandising fat-reduced meat products without neglecting the positive effects of fat on flavor and texture. Various researches have shown that the substitution of fat on a polysaccharides base such as fibers, starch, gums, and gels have improved and modified the texture, residual moisture and freeze stability, and decreased the price of the products. Aloe vera leaf gel contains about 99 – 99.5 % water and 1 - 0.5 % of the total solid content. On dry matter basis aloe vera gel consists of 55% polysaccharides, 17 % sugar, 16 % mineral, 7% protein, 4% lipids and 1% phenolic compounds (Lawless et al., 2014). The most important carbohydrates of aloe vera gel are the long chain polysaccharides, comprising glucose and mannose, known as the glucomannans [β (1, 4) – linked acetylated mannan]. All the solid content of aloe vera gel are surrounded by polysaccharide mucilage layer. Literature review pointed out there have been little investigations into the functionality of aloe vera gel in the emulsion meat products. According to the importance of producing low - fat meat products from one hand as well as the nutritional values and health characteristics of aloe vera gel on the other hand, this study was designed to replace the fat with aloe vera gel in the production of low - fat German sausage. Material and Methods: Sausage samples containing 40% of red meat (German sausage) were produced based on the conventional plants formula. animal fat and vegetable oil replaced by 0, 50 and 100% aloe vera gel in the German sausage formulation. All samples were cooked at 90°C temperature to achieve the core temperature of 70° C, followed by cooling, they were kept in the refrigerator (4°C) until the subsequent experiments. The AOAC (2000) methods were used for measuring the moisture content, the amount of fat, ash and protein. The amount of carbohydrate was calculated based on the calculation of the total weight difference from the sum of ash, protein, fat and moisture (according to the method FAO / WHO). The amount of energy was computed based on the total amount of energy from fats, proteins and carbohydrates. To measure the pH of samples by pH meter, method of choe et al (2013) was followed. The color analysis was done on the surface of sausage cuts by chromometer. The parameters of color include L* (lightness), a* (redness) and b* (yellowness) were measured. Texture parameters include hardness(N), cohesiveness, springiness (cm), gumminess (N), chewiness (N.cm), adhesiveness were determined by texture analyzer as described by Bourne (1978). The sensory attributes were evaluated by 10 trained panelists. A five-point hedonic scale rating (1= very bad, 2=bad, 3= neither bad nor good, 4= good, 5= very good) was carried out. Results and Discussion: Physicochemical properties analysis indicated significant differences among meat products (p ≤.0.01). The addition of aloe vera gel resulted a decrease in fat percentage and amount of energy, an increase in moisture and carbohydrate, but the amount of pH, protein and ash content did not change. This study showed that reducing the fat content and replacing by aloe vera gel caused a significant difference in the amount of energy (p≤.0.01).With respect to the significant contribution of fat in the production of energy, the amount of energy was reduced as expected by reducing the fat of the formulation. The results indicated that the value of L * showed the negative and positive trends with animal fat and vegetable oil changes, respectively (p≤.0.01). b* decreased by reducing the amount of fat and oil (p≤0.01), but the value of a* always remained constant (p˃0.05). The presence of aloe vera gel in sausage caused a reduction in hardness, adhesiveness and gumminess (p<0.05), while it did not affect the amount of adhesiveness and cohesiveness of samples (p˃0.05). The substitution of fat with aloe vera gel had a significant effect on the sensory characteristics of German sausage (p≤.0.01). By reducing fat and oil and adding aloe gel to the German sausage formulation, color acceptance score was decreased. In terms of panelists, the blank sample had the best color and the fifth sample color had the lowest score. Juiciness of the samples was increased by increasing the amount of gel. The results also showed that the fifth sample received the maximum score of juiciness. Sausages smell acceptance negatively changed by reducing the fat content and adding aloe vera gel. Third and fourth treatments got the highest texture score. Also, the third sample had the highest scores for taste and general acceptance. Chewiness analyzing showed that by increasing the amount of fat replacement the rate of this factor decreased. as well as the maximum rate of chewiness was related to the blank sample.
Effect of oil replacement with tofu and Persian gum on physicochemical, textural and rheological properties of Mayonnaise sauce
Volume 16, Issue 1, March and April 2020, Pages 1-15
https://doi.org/10.22067/ifstrj.v16i1.75184
Maryam Mohammad Khani, Mohammad Fazel
Abstract Introduction: Increasing society's desire to consume healthy and low-calorie foods has led to the production of low-fat and healthy foods. In this study, the effect of oil replacement with tofu cheese and Persian gum on physicochemical, textural, rheological and sensory properties of Mayonnaise sauce as well as its particle size, were investigated. Tofu was replaced with fat at three concentration levels of 20, 35 and 50% and Persian gum was added to the sauce at three concentrations of 2.5, 3, and 3.5%. The control sample contained 60% fat and guzanthan gum. With increasing tofu, pH and acidity increased and with increasing Persian gum acidity decreased. With increasing tofu, histological test (hardness, adhesiveness, adhesive force, work done to hardness, apparent modulus) decreased and with increasing Persian gum, their increased. With increasing tofu, decreased particle size. With increasing gum until 3%, average of particle size decreased and with more increase of gum, average of particle size increased. The rheological behavior of all samples at a shear rate of 0.01 to 1000 (on second) showed that the viscosity decreased with increasing tofu decreased and with increasing gum, increased. In all samples, with increasing shear rate, the viscosity was decreased, and the behavior of the samples was pyseudoplastic and the parameters followed the power law model. Sample with 20% tofu cheese and 3.5% Persian gum as top samples, whose properties are closer to fatty mayonnaise and can be called Mayonnaise with reduced fat.
Materials and methods: Physical and thermal stability tests of the emulsion were performed with a centrifuge machine. PH test was performed using pH meter and acidity test in terms of acetic acid percentages. The fat percentage was performed with a Soxhlet. The texture properties were performed by back extrusion test and the parameters of hardness, adhesiveness, adhesiveness force, apparent modulus and force required to squeeze were calculated. The particle size was measured using a dynamic light dispersion apparatus, and the average particle size, mod, and D50 of the emulsion particles of oil were investigated. The rheological behavior was performed by the rheometer and sensory evaluation was conducted by the hedonic method. Statistical analysis was performed by using SPSS software and the mean comparison test at 5% probability level and in the form of factorial test.
Results & Discussion: In the physical and thermal stability test of the emulsion, no two phases were observed in the samples. This could be due to the strong structure of the emulsion and the high viscosity of the continuous phase. By increasing the tofu value, the pH increased, which can be attributed to the decrease in the concentration of hydrogen ion or the increase of the aqueous phase. With increasing amount of gum, there is no change in pH, because the Persian gum has a neutral nature. Increasing the amount of gum did not affect acidity. As the tofu increased, acidity increased, and this increase was very slight, which can be attributed to buffering mode of tofu due to high amounts of high amino acids. By increasing the tofu percentage, the percentage of fat decreases because the percentage of fat in tofu cheese is law and its protein content is much. The increase in gum did not affect the amount of fat, because Persian gum structure was made up of saccharides. The tofu increase up to 35% reduced the texture properties, because the aqueous phase increased, with increasing gum percentage, texture properties increased because it produced a strong gel structure.
With the increase in tofu content, the particle size of the oil decreased, because with increasing the amount of fat, the particle size increased. By adding gum the particle size decreased to 3% and then increased, because in the Persian gum structure, there are insoluble branches and the solubility of these branches is low. In the evaluation of rheological behavior, flow behavior test was investigated; viscosity of all samples was reported at shear rates of 0.1, 1, 10, 100/ sec. In all samples, the viscosity decreases with increasing frequency. By increasing the gum at a constant shear rate, the viscosity increased, which can be explained by the fact that the formation of a stronger structure in the presence of higher concentrations of gum. By increasing the shear rate at a constant concentration of gum, the viscosity decreased, and the increase in gum with increasing shear rate also reduced the viscosity and sauce had profit and plastic behavior that could be due to the opening of the bonds. As the tofu percentage increased in all shear rates, viscosity decreased and by increasing the tofu value at a constant shear rate, the viscosity decreased, and the increasing tofu with increasing shear rate reduced viscosity due to high moisture content of the cheese. The rheological parameters of mayonnaise sauce were checked in accordance with the power law. As the gum increased, the consistency coefficient increased , because the number of molecules with high molecular weight in the liquid phase increased, with increasing the percentage of tofu cheese, the coefficient of consistency decreased. The flow behavior coefficient does not have a clear trend, and since it is less than 1, the samples are non-Newtonian. In the strain scan test in lower strains, mayonnaise always has linear viscoelastic behavior. By increasing the gum concentration, both the elastic and viscous components are transported to higher values, which can be due to more interaction between the Persian gum and the components of the emulsion. In the sensory evaluation of the samples, the addition of gum and tofu percentage was not effective.
With regarding the data of the tests, mayonnaise sample was identified with the replacement of 20% tofu cheese and 3.5% Persian gum as a superior sample, which its properties are closer to fatty mayonnaise and can be classified as Mayonnaise with law Fat. An extensive medicinal property of Persian gum with tofu cheese in mayonnaise sauce makes it a rich and very good source.
Effect of formulation and extrusion technique on technological properties of snack containing jujube flour
Volume 17, Issue 1, March and April 2021, Pages 1-11
https://doi.org/10.22067/ifstrj.v17i1.80211
Elnaz Milani, Fakhri Shahidi, Elham Ansarifar, Mohammad KalilianMovahed, Farideh Salehipour
Abstract Introduction: Extruded snacks were among the most commercially successful extruded foods. Extrusion cooking is the process extensively used for the production of snacks which are mainly produced from cereal flour or starches. Extruded snacks are normally high in calories and fat with low content of protein, fiber, and perceived as unhealthy food to many consumers. Several attempts to improve the nutritional profile of extruded starch by using food by-products have been reported (Onwulata et al., 2001; Stojceska et al., 2008). Zizyphus jujube (Rhamnaceae) is widely distributed in Iran and the fruit of this plant has gained wide attention in native herbal medicine for the treatment of a broad range of disorders. Chemical analysis of the fruit has shown the presence of antioxidants. The high consumption of low-value meals and malnutrition among the population, especially children and adolescents, is one of the problems that exists today in society, Therefore, in this research, production of high-nutritional snack with jujube flour was studied.
Materials and methods: Extrusion: In this study, a parallel twin-screw extruder (SAIXIN, model DS56, China) was applied, screw diameter of 15 mm, die diameter of 3 mm, and extrusion temperature of 180°C. Central composite statistical design was used to study the effect of feed moisture (12, 16, 18%), jujube flour addition (5, 10, 15%) and screw speed (120, 150, 180 rpm) on physicochemical properties, texture and color of expanded extrudates based on corn-wheat flour (50-50%). Bulk density was calculated using AACC (2000). The WSI of the dry solids regained through the evaporation of the supernatant obtained from the water absorption test was calculated. Textural measurement: The hardness of the extruded snacks was measured using Texture Analyzer (TAXT plus, England). The cylinder steel probe (2 mm diameter) was set to move at a speed of 1 mm/s. The samples were punctured by the probe to a distance of 8 mm. the color of samples was measured using an image processing technique (Lotfi Shirazi et al., 2020). The color parameters L* (lightness), a*(redness), b*(yellowness) values of the samples were obtained. Response surface methodology was applied for experimental data using a commercial statistical package, Design Expert (version 8.0) for the generation of response surface plot and statistical analysis of the experimental data. The second-order polynomial model was selected to predict the optimal point of the responses.
Results & Discussion: Results showed that the addition of jujube flour independently increased the density 0.33, hardness 35.73 N, solubility 42% and redness (a*) 3.41, and reduced the color brightness parameter (L*) 89.1 of the samples. Similar fiber effects for pineapple pulp (Salani et al., 2014), a mixture of barley flour and grape pulp (Altan et al., 2009) and beet fiber (Lue et al., 1994) has been observed. The reduction of bulk density in samples with increasing screw speed is probably due to the starch gelatinization. When gelatinization of the starch material increased, the volume of extruded product also increased giving low density to the samples (Hagenimana et al., 2006). The WSI is a parameter which indicates the degradation of starch granules (Sharma et al., 2015). WSI decreased with increasing feed moisture and increased with increasing jujube flour or screw speed. Increase in solubility of extruded products under mild extrusion condition could result from dispersion of amylose and amylopectin molecules during gelatinization; while, the formation of low molecular weight compounds under severe conditions (low moisture and high temperature) is the main reason for an increase in flour solubility (Colonna et al., 1984). Color changing during extrusion process can provide important information regarding the degree of browning and Maillard reaction, and also pigment degradation. Increasing the feed moisture increased flour L* while it decreased the a* and ∆E of the final product. This is probably due to the decrease in mass residence time inside the extruder which causes shorter residence time necessary for non-enzymatic darkening (Lazou and Krokida, 2011). Texture is one of the most important sensory properties of extruded products in the development of snack products. Increasing the feed moisture and jujube flour increased hardness of samples. This can be explained by the effect of fiber on cell wall thickness. However, the simultaneous effect of two parameters of screw speed and jujube flour improved the properties of the snacks, by which the increase of the screw speed may cause a decrease of the starch viscosity and then lead to extrudates with reduced hardness 1.79 N. Optimum conditions for puffed snack production was found to be 13.19% feed moisture content, 6.30 % jujube flour, 122.2% screw speed.
Optimization of reduced-fat aerated sauce production process by response surface methodology and evaluation of its physicochemical and sensory properties
Volume 18, Issue 1, March and April 2022, Pages 1-20
https://doi.org/10.22067/ifstrj.v18i1.86882
Farinaz Saremnejad, Mohebbat Mohebbi, Arash Koocheki
Abstract
Introduction: Increasing diet-linked diseases and following that the consumers ongoing desire for healthier foods makes reduced-fat products of outstanding importance in the food industry. This study aims to reduce the fat content of sauces as a traditional condiment through the incorporation of air bubbles in the oil phase. Response surface methodology (RSM) was used for identifying the effect of aeration process variables on foam properties. However, the main challenge of reduced-fat foods is to ensure their acceptability. Recently fat taste has been introduced as a sixth basic taste. Fatty acids have been considered as the stimulus for this taste. So, linoleic acid as the stimulus for fat perception was added to the formulation to develop a product that tastes almost like full-fat versions but contains less fat. The advantages of aerated foods over conventional products are clear. Nonetheless, the determination of quality and sensory parameters during storage, marketing, and consuming is necessary. For this purpose, produced aerated sauces, along with commercial full- and reduced-fat sauces, were compared by measuring the acidity, pH, oxidative stability, and sensory properties.
Materials and Methods: Required amounts of mono- and diglyceride (MDG) and oil were mixed. Then nonaqueous foams were generated by whipping the MDG-oil mixtures. In the optimization study, the effect of MDG concentrations (2, 6, and 10 wt. %), whipping speed (1100, 3250, and 5400 rpm) and time (5, 15, and 25 min) on foam properties (overrun and drainage) was analyzed using RSM. The foam obtained from the optimum process condition was used to produce an aerated reduced-fat sauce. Sauce preparation was performed according to a usual recipe with the difference that the fat content was replaced by nonaqueous foam. Furthermore, 3.00 mM of linoleic acid as a fat taste stimulus was added to the formulation. First, an aqueous phase containing ingredients was prepared. Then nonaqueous foam was progressively incorporated in the aqueous phase. For the purposes of comparison, aerated sauces (0 and 3.00 mM stimulus), along with commercial sauces (zero, low, and full-fat), were analyzed by measuring the pH, acidity, oxidative stability, and sensory properties.
Results and Discussion: According to the results of the optimization study, the desired foam (overrun ≥ 60 %) achieved by oil containing 10 wt. % MDG at 3400 rpm for 10 min. Overrun increased progressively with MDG concentration but decreased slightly above 10 wt. % due to the difficulty of dispersing air bubbles in such a viscous gel. Considering the effect of whipping speed, and time, it was observed that mixtures reached their maximum volumes within 25 min. With a further increase in the whipping rate, the time required to achieve the maximum amount of foam was decreased. However, at high whipping speed (5400 rpm), foam volume decreased rapidly with time, and almost a lot of foam collapsed. The lowest and highest pH was related to zero and full-fat commercial sauces, respectively. There was no difference (p>0.05) between the pH of the control and the linoleic acid containing aerated, as well as low-fat sauces. Over time, as the pH decreases, the acidity of the aerated sauces increased and making the products with appropriate microbial stability. Due to the significant reduction of fat amount, oxidation of the aerated sauces was much slower than the full-fat one (p<0.05). Appearance, taste, and texture characteristics of aerated sauces provided a sensory profile similar to the full-fat sauce. The aerated sauce containing linoleic acid had higher sensory scores, indicating its general acceptance.
Conclusions: In this study, nonaqueous foam as a new approach for fat replacement in emulsion-based foods such as sauces was practically applied. The optimum aeration process conditions were determined by the help of experimental design. Two types of aerated sauces were prepared based on the linoleic acid concentration, and their physicochemical and sensory characteristics were compared with commercial sauces. The acidity and pH of the sauces were in the standard range, and also their oxidative stability was acceptable during storage time. Generally, the aerated sauce containing linoleic acid had relatively similar sensory profiles to the full-fat sauce. Therefore, it seems that nonaqueous foam could be used successfully to develop reduced-fat alternative foods, which could also be meet the consumers' and marketing requirements.
Materials and Methods:
Required amounts of mono- and diglyceride (MDG) and oil were mixed. Then nonaqueous foams were obtained by whipping the MDG-oil mixtures. In the optimization study, the effect of MDG concentration (2, 6, and 10 wt. %), whipping speed (1100, 3250, and 5400 rpm) and time (5, 15, and 25 min) on foam properties (overrun and drainage) were analyzed using RSM. The foam obtained from the optimum process condition was used to produce an aerated reduced-fat sauce. Sauce preparation was performed according to a usual recipe with the difference that the fat content was replaced by nonaqueous foam. Furthermore, 3.00 mM of linoleic acid as a fat taste stimulus was added to the formulation. First, an aqueous phase containing ingredients was prepared. Then nonaqueous foam was progressively incorporated in the aqueous phase. For purposes of comparison, aerated sauces (0 and 3.00 mM stimulus), along with commercial sauces (zero and full-fat), were analyzed by measuring the pH, acidity, oxidative stability, and sensory properties.
Results and Discussion:
According to the results of the optimization study, the desired foam (overrun ≥ 60 %) achieved by oil containing 10 wt. % MDG at 3200 rpm for 10 min. Overrun increased progressively with MDG concentration but decreased slightly above 10 wt. % due to the difficulty of dispersing air bubbles in such a viscous gel. Considering the effect of whipping speed, and time, it was observed that mixtures reached their maximum volumes within 25 min. With a further increase in the whipping rate, the time required to achieve the maximum amount of foam was decreased. However, at high whipping speed (5400 rpm), foam volume decreased rapidly with time, and almost a lot of foam collapsed. The lowest and highest pH was related to zero and full-fat commercial sauces, respectively. There was no difference between the pH of the control and the linoleic acid containing aerated sauces. Over time, as the pH decreases, the acidity of the aerated sauces increased and making them products with appropriate microbial stability. Due to the significant reduction of fat amount, oxidation of the aerated sauces was much slower than the commercial ones. Appearance, taste, and texture characteristics of aerated sauces provided a sensory profile similar to the full-fat sauce. The aerated sauce containing linoleic acid had higher sensory scores, indicating its general acceptance.
Conclusions: In this study, nonaqueous foam as a new approach for fat replacement in emulsion-based foods such as sauces was practically applied. The optimum aeration process conditions were determined by the help of experimental design. Two types of aerated sauces were prepared based on the linoleic acid concentration, and their physicochemical and sensory characteristics were compared with commercial sauces. The acidity and pH of the sauces were in the standard range, and also their oxidative stability was acceptable during storage time. Generally, the aerated sauce containing linoleic acid had relatively similar sensory profiles to the full-fat sauce. Therefore, it seems that nonaqueous foam could be used successfully to create reduced-fat alternative foods, which could also be meet consumers' and marketing requirements.
Study of the Functional Properties and the Retrogradation Behavior of Native Wheat Starch in the Presence of Cress Seed Gum and Sucrose
Volume 19, Issue 1, March and April 2023, Pages 1-15
https://doi.org/10.22067/ifstrj.2021.69660.1029
Shokohfeh Taziki, Seyed Mohammad Ali Razavi
Abstract Introduction
Wheat starch granules are composed of amylose and amylopectin, which are responsible for the functions of starch such as swelling, gelatinization, pasting, gel formation, and retrogradation. The retrogradation changes the functional properties, it is an undesirable phenomenon in some starch-based foods which reduces the acceptability of food, and shortens the shelf life. Delaying or preventing of starch retrogradation is a major challenge in the food industry. Various ingredients such as carbohydrates imply an important role in improving the functional properties, decreasing amylose leaching and retarding the retrogradation of starch gels. Cress seed gum (CSG), as an emerging galactomannan, has shown the ability to improve the textural and rheological features of food systems based on its unique properties. Addition of CSG to the composite wheat-rice bread increased dough stability and improved the staleness of bread compared to guar gum. Also, the addition of CSG and xanthan gum to gluten-free bread stabilized the texture of bread during storage. Sucrose (SUC) is a common additive in food formulations which is useful as a sweetening agent and textural modification. Sugars have been able to reduce amylose leaching and accelerate or delay starch gel formation. They also delay retrogradation of starch gels during storage. Therefore, the objectives of this study were to determine the impact of different substitution levels of CSG (0, 5, 10 and 15%), SUC (0, 5 and 10%), and their blend on the functional properties (swelling strength and solubility), microstructure features, retrogradation kinetics and synthesis of native wheat starch (NWS) gel (4% w/w).
Materials and Methods
Cress seeds were purchased from a local medicinal market. NWS and SUC were supplied from Sigma Aldrich (Spain) and Merck (Germany) respectively. Starch suspensions (0.6 gr powder/20 ml water) substituted with CSG (0, 5, 10, and 15% w/w) and SUC (0, 5, and 10% w/w) were prepared to estimate the swelling power and solubility index. To produce starch gel, the 4% w/w suspensions of NWS-CSG-SUC were prepared by dissolving the appropriate amount of CSG powder and SUC in deionized water. Then, each suspension was poured into a stainless-steel cylindrical container and was heated to 95 oC and held at 95 oC for 3 min and then cooled to 50 oC while stirring continuously at 160 rpm with a mechanical mixer. Finally, the pastes were kept at ambient temperature (25 oC) for 1 h. To assess gel structure, imaging of the gels was performed by scanning electron microscopy (SEM). The retrogradation kinetics and syneresis of gel samples were determined after storage at 4 oC for 0, 1, 7 and 14 days.
Results and Discussions
The swelling power and solubility index of NWS increased with increasing the replacement level of CSG. CSG promotes adhesive interactions among the gelatinized granules. This can enhance the forces applied to them, facilitating water entering (increasing swelling), amylose solubilization and its exudation. In contrast, SUC compete with starch molecules for water in the system and thus preventing gelatinization and mobility of starch molecules reduced the swelling power. The starch-gum-sugar mixtures had a higher swelling power compared to the starch and starch-sugar samples. The mixed samples had higher solubility values than each of them individually. SEM images showed that the pore size of starch gel decreased and increased from 33.01 to 29.44 µm and to 45.37 µm with increasing the substitution levels of CSG and SUC, respectively. NWS-15% CSG-5% SUC gel had 31.34 µm pore size. After storage for 14 days at 4 oC, the CSG substitution with NWS reduced the rate of retrogradation and syneresis from 0.101 to 0.52 (s-1) and from 50% to 23%, respectively. It could be related to creating a film around the granules by the leaked amylose and the CSG in the continuous phase, so inhibiting further swelling and polymers leaking out and related to high water holding capacity of CSG. The addition of SUC reduced the rate of the process to 0.096 (s-1) but because of its low water holding capacity, the value of syneresis enhanced to 57%. In the mixed gels, more reduction of the retrogradation rate and syneresis was observed which was clearly at high CSG replacement. The retrogradation rate of the NWS-15%CSG-5%SUC was 0.057 (s-1) and its syneresis was 45%. According to the results, it can be concluded that 15% CSG and 5% SUC replacement levels can effectively improve the functional properties and reduce the rate of retrogradation and syneresis of NWS during storage.
Evaluation of the Effect of Chitosan/Pectin Multi Layer Edible Coating Containing Microencapsulated Cinnamon or Thyme Essential Oils on Increasing the Postharvest Shelf Life of Cucumber
Volume 20, Issue 1, March and April 2024, Pages 1-18
https://doi.org/10.22067/ifstrj.2022.75208.1146
Shohreh Nikkhah, Fakhri Shahidi, Mohebbat Mohebbi, Farideh Tabatabaei Yazdi
Abstract Introduction
Cucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. Therefore, pretreatments are crucial for prolonging its shelf life. Chitosan is a cationic polysaccharide and can interact electrostatically with anionic, partially demethylated pectin. Besides, chitosan has inhibitory effects on fungal rot and prevents weight loss in fruits. Pectin can form excellent films. Because of increasing demand to reduce synthetic chemicals as antimicrobial agents, substances derived from plants, such as essential oils, can play a significant role in the future. Several essential oils and essential oil components have shown antimicrobial activity against spoilage and pathogenic microorganisms during fruit and vegetable storage. Essential oils of thyme and cinnamon contained phenolic groups have been found to be most consistently effective against microorganisms, however, essential oils are volatile and irritant. Therefore, forming an inclusion complex using b-cyclodextrin can improve solubility, control volatile, and induce off-flavors and unpleasant odor of the essential oils. The objectives of this study were to develop the microencapsulated thymol (thyme) and trans-cinnamaldehyde (cinnamon) essential oils to produce antimicrobial agents and subsequently evaluate the effectiveness of edible coating made of chitosan and pectin containing microencapsulated trans-cinnamaldehyde or thymol essential oils to improve qualitative and quantitative characteristics and shelf life of cucumber.
Materials and Methods
The inclusion complexes of trans-cinnamaldehyde and thymol in beta-cyclodextrin (CD) were prepared separately by freeze-drying. Each essential oil was dispersed in 1000 ml of beta-cyclodextrin aqueous solution (16 mmol/L, 18.15 g) in molecular ratio 1:1 (2.4 gr thymol, 2.11 gr trans-cinnamaldehyde) and mixed in a laboratory stirrer for 24 hour at room temperature , then frozen (-70 ºc) and freeze-dried (<20Pa, 48 h). Lyophilized samples were stored inside a freezer (-20 ºc) until further use. Cucumbers cv. Nagene with uniform size, appearance, ripeness and without mechanical damage or fungal contamination were selected. Then They were then sanitized by immersion in chlorine solution (150 mg/kg) for 1 min and air dried. Edible coatings were prepared as three immersion solutions of chitosan, pectin, and calcium chloride (CaCl2). The fruits were coated with pectin (1%) and chitosan (0-0.5%-1%) containing beta-cyclodextrin microencapsulated trans-Cinnamaldehyde or thymol each (0-0.25%-0.5%). After coating by chitosan, the fruits were immersed in 1% Calcium chloride solution to induce crosslinking reaction. After dipping step, fruits dried for 8 minutes at room temperature to remove the excess solution attached to the surface .Uncoated fruits served as control. Then fruits were preserved in cold storage (temperature: 10ºc; relative humidity: 90-95%) for 15 days. chemical (total soluble solids, titratable acidity) and physical (total color difference, Hardness, and weight loss) Characterization of fruits were measured immediately after harvest and after 5, 10 and15 days. Microbial tests (total count, mold, and yeast) were done at the end of preservation time. Analytical data were subjected to analysis of variance and factorial adopted completely randomized design and a Duncan comparison test was used.
Results and Discussion
The results showed that weight loss, total soluble solids, and the total color difference increased and hardness and titratable acidity decreased gradually in all samples during cold storage (<0.05). Chitosan and essential oils slowed down this rising or decreasing trends. Interactive effects of chitosan, essential oil type, essential oil concentration, and storage time had positive effects on these quality attributes. The fruits coated with the highest concentration of chitosan (1%) and thymol (0.5%) essential oils showed the least weight loss, loss of hardness, and color change throughout 15 days of storage. Besides thymol in comparison with trans-Cinnamaldehyde was more efficient to prevent yeasts and molds on the surface of cucumber. By increasing chitosan and essential oil amounts, the ability of inhibiting microbial growth by coating is enhanced.
Conclusion
The results of chemical, physical and microbial tests, showed that multi-layer coating solution containing chitosan 1% with thymol 0.5% was effective in extending the shelf life of cucumber. The combined usage of microencapsulated thymol essential oil and chitosan-based coating on cucumber could be considered a healthy and effective treatment that reduces microbial spoilage and preserves quality and color characteristics in cucumber and represents an innovative method for commercial application. Therefore, this coating can be used as an alternative to chemical fungicides to prevent fungal rot of cucumber and other fruits, however, it is suggested that more studies should be done in this field.
The Effect of Dual Modification (Fermentation-Extrusion) on the Functional and Qualitative Characteristics of Chickpea-Quinoa Composite Flour and Gluten-Free Muffin Cake Compared to Unprocessed Flour
Volume 22, Issue 2, May and June 2026, Pages 111-127
https://doi.org/10.22067/ifstrj.2026.95085.1469
Zahra Korkinejad Gharaee, Arash Koocheki, Elnaz Milani
Abstract Introduction
Celiac disease is an autoimmune disorder of the small intestine triggered by gluten consumption. The only effective treatment is to follow a strict, lifelong gluten-free diet. However, commercially available gluten-free products often face limitations in terms of quality attributes, such as undesirable texture, poor flavor, and low nutritional value. Consequently, recent research has focused on improving the quality of these products by using alternative flours rich in protein and fiber and employing novel processing methods. Chickpea and quinoa are considered ideal sources for this purpose due to their high nutritional value. However, their use presents challenges, such as off-flavors and poor performance in baking processes. Modification processes like fermentation and extrusion can address these issues by improving the functional, nutritional, and sensory properties of composite flours. This study aimed to investigate the effect of a dual fermentation-extrusion process on the properties of chickpea-quinoa composite flour and the quality of gluten-free muffin cakes produced from it.
Materials and Methods
To prepare the dough, water, sugar, and Saccharomyces cerevisiae were added to the modified flour, and the mix was fermented for 24 hours at 37°C. The dough was then dried and subjected to an extrusion process using a twin-screw extruder. Subsequently, two types of flour (modified and raw) along with three different levels of xanthan gum (0, 0.15, and 0.3%) were used to produce gluten-free muffin cakes based on a standard formulation. The physicochemical properties of the flours, including moisture, protein, fat, fiber, ash, phenolic compounds, and antioxidant activity, were measured according to standard methods. Water absorption and solubility indices (WAI and WSI) were also calculated. To evaluate the produced cakes, parameters such as baking loss, porosity (using image processing), texture hardness (over 7 days of storage), crust color brightness, and sensory attributes (using a five-point hedonic test) were determined. Statistical analyses were performed using a factorial design and Tukey's test at a 95% confidence level.
Results and Discussion
The results of the flour comparison showed that the modified flour, compared to the raw flour, had lower moisture (5.62% vs. 7.13%), higher protein (22.36% vs. 19.84%), higher antioxidant activity (60.47% vs. 54.86%), and higher total polyphenol content (28.73 vs. 23.52 mg GAE/100g). Additionally, the water absorption (WAI) and water solubility (WSI) indices were significantly higher in the processed flour, which contributes to its improved functional properties. In the evaluation of the muffin cakes, samples containing modified flour and 0.15% xanthan gum showed the lowest baking loss, highest porosity, and softest texture. The fermentation and extrusion processes modify the combined flour, by altering the structure of starch and protein, increasing water retention capacity and helped maintain moisture and improving the internal structure of the cake. The rate of texture hardening during the storage period was slower for samples containing modified flour and xanthan gum, indicating a delay in the staling process. Although the crust color of the cakes made from modified flour was darker, these samples received a higher overall acceptability score in the sensory evaluation. The dual processing significantly helped reducing the undesirable beany flavor and improving the aroma and flavor of the end product.
Conclusion
The combined fermentation–extrusion processing of chickpea–quinoa composite flour offers an effective green strategy to improve the nutritional, functional, and sensory quality of gluten-free baked goods. Fermentation enhances protein digestibility, mineral bioavailability, and flavor through bioactive peptide and organic acid formation, while extrusion improves starch gelatinization and protein denaturation, enhancing dough viscoelasticity and reducing off-flavors. The synergistic effect of these processes forms a gluten-like network that increases cake softness and shelf life. The optimal formulation modified chickpea–quinoa flour with 0.15% xanthan gum yielded the highest sensory acceptance, superior texture, and moisture retention, demonstrating the potential of biophysical methods in developing high-quality gluten-free bakery products.
Estimation of the total acceptance of banana fruit using digital image processing and Gaussian process regression model during the storage period
Volume 16, Issue 2, May and June 2020, Pages 171-191
https://doi.org/10.22067/ifstrj.v16i2.79904
Shima Nasiri, Saman Abdanan, Maryam Nadafzadeh
Abstract Introduction: The development of brown spots on banana peel has a notable effect on the texture, color and taste of this fruit. So that the appearance of these spots reduces the quality of the fruit and affect its sale market. In recent years, in order to evaluate the quality and classification of agricultural products, the various systems based on computer vision technology have been widely considered. These systems as the computer image analysis methods have been successful in measuring the visual quality of different products (Riyadi et al., 2007; Roseleena et al., 2011; Rodriguez-pulido et al. 2012). According to research by Probha and Kumar (2015), the extracted color properties from the banana image were more effective than other features in identifying the different stages of the banana ripening. Also, Mendoza and Aguilera (2004) detected the different stages of banana ripening based on the color, texture parameters and the distribution of brown spots on banana peel using image processing technique with a precision of 98%. Nadafzadeh et al. (2018) designed a non-linear mathematical model using the Genetic Programming (GP) to predicting and evaluating the activity of polyphenol oxidase enzymes (PPO) and peroxides (POD) during the browning process of the banana peel; using the extracted parameters from image as inputs of proposed model, the correlation coefficients to predicting of PPO and POD enzymes were obtained 0.98 and 0.97, respectively.
The aim of this study was to investigate the changes of color, dimensions and chemical parameters of several banana fruit groups (different in terms of appearance) as well as their marketability (the total acceptance of fruit) by Gaussian regression model (GPR) during the storage period. Therefore, using the proposed method in this research, the required product can be available according to the consumer demand.
Materials and Methods: In this study, one hundred banana samples were prepared from a market on the first day of the experiments. Samples were different in terms of shape and size, and were classified into 5 different groups. Group A had small size and curvature; B group compared to Group A had more curvature; the curvature of the samples in the group C was high, and in terms of size were medium. While the size of the bananas in group D was large, they had a small curvature. Also, the features of the group E were similar to the group D, but the curvature was greater in this group (group E). All of the samples were kept at the ambient temperature (25° C) away from the direct light for 7 days. During the days of experiments (days 0, 2, 4 and 6), five samples were examined from each group: after taking images of samples under the constant light conditions, and performing of manual measurements, they were subjected to destructive tests (laboratory tests) and sensory tests. After the images acquisition of samples, the preprocessing operations such as image enhancement, noise removal by the area opening, and the implementation of the image segmentation process using the method of Otsu adaptive thresholding were conducted (Gonzalez et al., 2004). Finally, 11 color parameters (R, G, B, L, a, b, h, s, v, C, H) and 4 dimensional characteristics (diameter, curvature radius, long and small length) were extracted from each image. In the laboratory method, the TSS value was measured by a digital refractometer, and amount of pH and acidity were also measured by a fruit juice analysis titrator. Eventually, in order to investigate the changes of measured parameters, statistical analysis was performed in a randomized complete block design by SAS 9.3 software at a significance level of 5% using Duncan's multiple comparison test.
Results and discussion: Gradually along with the appearance of dark spots on the banana peel, many of the qualitative parameters such as the color, dimensions and chemical features were changed during the storage period. According to results of the Duncan's multiple range test, the values of color coordinates R, G, B, L, b, h, v, C, and H gradually reduced, and the values of these parameters were significant in all the experiments days (p<0.05). The parameter S also had a decreasing trend during the storage period, and the changes of this parameter was significant in the first days of the experiments compared to the ending days; during this period, the color parameter a increased significantly. Due to the changes of the banana fruit texture, the amount of the curvature radius, the small and large lengths, total soluble solids, pH and total titration acidity gradually decreased. Based on the results of the statistical analysis, there were no significant differences between dimensional parameters measured by non-destructive method and manual measurement (p>0.05). It is worth noting that in this study, the spent time to conduct the manual measurements of the dimensional parameters of a banana sample was 510 seconds, while all of these measurements were performed using a digital image processing method at 1.015 seconds. Therefore, it can be said that when the number of samples is high, using of the proposed method is also very cost-effective in terms of time, and it has high accuracy during the measurement. In the sensory evaluation, the results show that the best and most acceptable group of bananas were groups C, D and E, which had long size and low curvature; these groups of bananas had delicious texture, desirable flavor and low levels of brown spots on their peel. In the following, the non-destructive parameters were used to the development of Gaussian regression model (GPR), and finally, it was shown that the quality of banana fruit as well as its marketability (the total acceptance of fruit) are predictable during the storage period by GPR with a correlation coefficient of 0.91, MAPE (20.47), RMSE (0.43), SRE (0.71) and RAV (0.20).
The appearance quality of the banana fruit is very effective in its acceptability for customer. In this research, the image processing technique as a non-destructive method was used to extract a set of color (R, G, B, L, a, b, h, s, v, C and H) and morphological properties (diameter, curvature radius, long length and small length) from banana image in order to evaluate its quality during storage. According to the results of Duncan's statistical analysis at the probability level of 5% and Pearson correlation results, the most suitable parameters were chosen to apply in Gaussian regression model. The results showed that the image processing technique is capable to evaluating the changes of color and dimensional parameters of banana fruit, and also the proposed model have a satisfactory performance (R2=0.91) in predicting the overall acceptance parameter of the banana.
Investigation of Characteristics of Alginate Film Containing Probiotic Lactobacillus plantarum for Sliced Sausages Coating
Volume 20, Issue 2, May and June 2024, Pages 183-198
https://doi.org/10.22067/ifstrj.2022.75042.1143
Dina Shahrampour, Morteza Khomeiri, Seyed Mohammad Ali Razavi, Mahboobeh Kashiri
Abstract Introduction
Increasing public awareness of the impact of diet on health has increased the demand for healthy food products, especially probiotics. Probiotics are living and non-pathogenic microorganisms with beneficial effects on the host when consumed on a regular basis and sufficient amounts (106 cfu/gr or ml). A significant number of probiotics become inactive during various food processes (thermal, mechanical and osmotic stress), storage condition (exposure to oxygen, UV light and low or high temperature) or during interaction with food ingredients. In addition, the breakdown and passage of food through the digestive system can also affect the survival and ability of probiotics to form colony in the intestine. Therefore, it is a challenge for food manufacturers to maintain and deliver live probiotic cells in sufficient quantities via food product. On the other hand, the variety of probiotic food products in the market, especially in Iran, is low and is mainly limited to dairy products, fermented drinks and pickles. Bioactive edible films and coatings are defined as biopolymer-based structures that carry bioactive components such as vitamins, enzymes, peptides, etc, and slowly release them on the food surface during storage. Biopolymers such as polysaccharides, proteins, and lipids are used in the preparation of edible films and coatings. Trapping probiotic bacteria in the structure of edible films and coatings is a new approach that has been proposed to increase the survival of these microorganisms and to develop new probiotic products in the food industry.
Materials and Methods
In this study, an alginate-based probiotic bioactive film containing L. plantarum was fabricated after centrifuging of overnight culture of probiotic bacterium from MRS medium and adding the bacterial cells into film forming solution. The effect of bacterial addition on physical, mechanical and prevention properties of alginate film was evaluated. In addition, the effect of two temperatures 4 °C and 25 °C on the survival of embedded probiotic bacterium in the film structure during one month of storage was also investigated by microbial count assay on MRS agar medium. Then, the model food was covered with probiotic film and the survival of probiotic bacterium during storage at 4 °C was determined.
Results and Discussion
The results showed that the population of probiotic bacterium declined about 4.61% after drying of alginate film solution. Addition of probiotic bacterium to the alginate film increased the thickness, turbidity, and tensile strength of the film, while had no significant effect on solubility, water activity, Elongation (%) and microstructure of alginate film. In addition, the probiotic film containing bacteria had less Lightness (L*), and moisture content than the control film. Also, the incorporation of L. plantarum in alginate film could decrease the water vapor permeability (WVP) from 0.755 to 4.51 (×10-10 g m-1s-1pa-1). The total color difference (ΔE) of alginate film containing probiotic bacteria compared to control film without probiotic bacteria was 1.1. The SEM images were confirmed the proper and uniform distribution of probiotic L. plantarum cells on the surface of alginate film. The survival percentage of L. plantarum in alginate film after one month of storage at 4 °C and 25 °C was 96.84 and 47.29%, respectively. Also, the population of embedded bacteria in the film structure on the food model (sausage) surface after three weeks storage in refrigerator was in desired level of probiotic products (> 106 cfu / gr).
Conclusion
The viability of probiotic bacteria after the application of alginate film containing L. plantarum on the surface of food model (sausage) during cold storage remained at the optimal recommended level for three weeks. Therefore, alginate film is recommended as a suitable carrier for probiotic microorganisms to produce new functional products.
Evaluation of Ethyl Oleate, Sodium Chloride and Blanching Pretreatments on Vacuum Drying of Sweet Pepper (Capsicum annum)
Volume 19, Issue 2, May and June 2023, Pages 195-216
https://doi.org/10.22067/ifstrj.2021.70205.1040
Narmela Asefi, Nasibeh Alirezaloo, Pouya Barman Veisi, Haleh Soraiyay Zafar
Abstract Introduction
Sweet Pepper (Capsicum annum) has a very important place among the vegetables produced in the world. Therefore, it is necessary to apply practical solutions to increase their sustainability to develop and improve production. The growing consumer rejection of chemical additives and the demand for more natural products have increased attention to some methods, including the drying method. One of the physical changes that occur during the drying of food is its reduction in volume. Vacuum drying is a method in which water and other solvents that have been absorbed into the volume or surface of the material are removed. Combining vacuum with heating can be an effective way to dry; because in this case, a high level of dryness can be achieved without the need for a large increase in temperature. A thermal process that is applied to vegetables and fruits as a pre-process step for freezing, drying and canning to inactivating enzymes, modifying texture, preserving flavor and nutrients, and extracting Interstitial air.
Materials and Methods
This study aimed to investigate the impact of various factors ethyloleate (concentrations 0,2,4%), sodium chloride(concentrations 0,2,4%) and blanching on the drying kinetics, physical properties, chemical composition and nutrients of green bell pepper, dried under vacuum at 60°C and pressure of 10 kpa using the response surface methodology. At the end of the drying time, 10 g of the treated samples were weighted to investigate the drying kinetics and the rest of the samples were kept for analysis. To achieve the drying kinetics, the samples were taken out of the oven (Behdad Company, model 3494, made in Iran) at 30 minute intervals and weighed by a digital scale, and dried down to moisture content of 12% ., and then for relevant analyzes on dried samples, the samples were stored in plastic packages until the day of experiments. Investigation of independent and interaction effects of immersion in different concentrations of sodium chloride and ethyloleate solution on the kinetics and drying time separately in blanching and non-blanching samples on the parameters of color, chlorophyll content, phenolic substances and vitamin C remaining in dried Sweet peppers were evaluated using minitab16 software and response level method (RSM).
Results and Discussion
The results showed that the drying process occur in the range of falling rate and also effect blanching in boiling water for 3 minutes and immersed in an alkaline solution of ethyloleate and sodium chloride with concentrations of 2 and 4% for 1 minute, significantly increase the drying rate. In blanching and treated samples with 4% ethyloleate and sodium chloride, the drying time was about 3.5 hours, while the control sample was dried under the same conditions for 7.5 hours. Pretreatment of samples, showed the chlorophyll content, phenolic compounds and vitamin C were higher than the control sample. Due to the effectiveness of ethyloleate in the protection of ascorbic acid, phenolic compounds and residual chlorophyll, the highest amount of ascorbic acid with a value of 39.77 was related to the samples treated in ethyloleate solution with a concentration of 4% and 4% NaCl and the minimum value of 17.98 was related to the control treatment. The highest amount of residual chlorophyll was 23.6 in the pretreated samples with a concentration of 4% ethyloleate and 4% NaCl and the lowest amount was related to the control sample with a concentration of 12.9%. The color of the dried samples showed that the lowest amount of color changes was related to the non-blanching sample with 4% ethyloleate and 4% NaCl with a value of 4.94. While the blanching and ethyloleate solution had no positive effect on the color of pepper and dried samples were dark. Comparison of blanching with non-blanching shows that blanching samples cause darkening of the primary color of the samples.The best sample in terms of quality and speed of drying, was belonged to the samples which blanched, treated with 4% solution of ethyloleate and sodium chloride.
Conclusion
In order to achieve the best quality in vacuum drying of pepper samples, pretreatments of blanching and using a concentration of 4% solution of ethyloleate and sodium chloride showed the most desirable quality. The best quality of dried samples were obtained when subjected to constant temperature and pressure during drying conditions. The benefits obtained using the pretreatment of ethyloleate and sodium chloride as an appropriate method of drying include increasing the absorption of water, keeping the chlorophyll, phenolic compounds and vitamin C content with time-saving in drying.
Optimization of foam production in foam mat drying of celery juice and evaluation of its powder properties
Volume 17, Issue 2, May and June 2021, Pages 217-231
https://doi.org/10.22067/ifstrj.2020.39265
Mahsa Kamali Sarvestani, Mohebbat Mohebbi, Masoud Taghizadeh
Abstract Introduction: Celery is one of the most consumed and highly nutritious vegetables with high dietary fiber, phytochemicals, vitamins, and minerals, which offers great benefits for utilization as a functional food ingredient. Fruit and vegetable juice powders have many benefits and economic advantages over their liquid precursors such as reduced volume/weight, reduced packaging, easier handling/ transportation, and much longer shelf-life. Also, powders can be reconstituted to produce juice and used for preparation of products such as snacks, chutney, soups, baby foods, etc. In foam-mat drying, food liquids and pastes are first whipped into stable foam by the addition of different foaming agents or stabilizing agents and then dried in the form of thin layer. This foam structure dries rapidly due to the increase of the surface area of the material by incorporating air/gas and forms a porous structure which gives high quality and instant properties of the dried product. The dried product is scraped off from the drying surface in the form of flakes, which is then converted to a fine powder. Response surface methodology (RSM) is a combination of mathematical and statistical techniques used to investigate the interaction effects of independent variables on responses. There is considerable information on foam-mat dried food powders, but there is no scientific literature related to foam-mat drying of celery juice. The present research was thus focused on optimizing the foaming conditions (WPC as a foaming agent, Xanthan gum (XG) concentration as the stabilizer and whipping time (WT)) to minimize foam density (FD) and drainage volume (DV) using RSM. The effects of drying temperatures on some physicochemical properties of powder were also investigated.
Materials and methods: Celery was purchased from the local market.XG and WPC powders were purchased from Sigma Chemical Company (St. Louis, MO) and Milei Company Germany, respectively. Celery juice was extracted by using a juicer machine (Robert Bosch Stand mixer MMB 2000 /05 FD 8611 Type CNSM03EV, 600W, Slovenia). Based on preliminary tests, XG solutions were prepared by dissolving the appropriate amount of the defined gum powder in distilled water and stirring with a magnetic stirrer to achieve a uniform solution. This solution was refrigerated at 4°C overnight to complete hydration. RSM was used to estimate the main effects of the process variables on FD and DV in celery juice foam. The experiment was established based on a face-centred central composite design (FCCD). According to the experimental design, to prepare 100 g of samples, the appropriate amount of celery juice, WPC, and XG solution were poured to a 250 mL beaker. Then the mixture was placed into a water bath for 5 minutes at 55 °C temperature. The mixture was then taken out of water bath and was whipped by a mixer (Gosonic, model No. GHM- 818, 250W, China) with the maximum speed of 5400 rpm at ambient temperature during the given time. The density of foamed celery juice was determined in terms of mass over volume and expressed in g/cm3. To assess foam stability, the drainage test was performed for 1h. Furthermore, the effects of drying temperatures on some physicochemical properties of powders were investigated.
Results and discussions: The quadratic model was selected as a suitable statistical model for both FD and DV. ANOVA showed that this model is significant for both responses. Moreover, lack-of-fit was not significant for response surface models at a 95% confidence level, indicating that this model is adequately accurate for predicting responses. Based on the constrain criteria, the optimized foaming parameters were: XG concentration of 0.42% (w/w), WPC concentration of 6% (w/w), and WT of 9.30 min. The amount of FD and FDV for foam at these optimum conditions were 0.4 g/cm3 and 0 ml, respectively. The results showed the moisture content and water activity of the celery powders decreased with the increase in drying temperature. By increasing drying temperature from 40 to 70 °C, bulk density also decreased. Increase in drying temperature results in decrease in moisture content and bulk density. Tapped density generally behaves similar to bulk density because by shaking powder, the space between the particles is filled and occupied volume by the powder is reduced. By increasing in temperature, particle density decreased. Overall, with increasing drying temperature, the porosity of powder increased. Increasing temperature and reducing moisture content, the possibility of approaching and join together of particles is increased and the space between the particles becomes less. The numerical value of the car index parameter in this study was 15.3% to 24.67%. The highest value of flowability related to the sample was dried at 70°c. With decreasing in drying temperature, the moisture content of powders increased and due to forming liquid bridges between particles making them less flowable. The numerical value of the Hausner parameter in this study was 1.15 to 1.32. Except for powder produced at 70 °C, the powder was placed in the intermediate cohesiveness powder class. By increasing drying temperature, the cohesiveness of powder decreased significantly.
Evaluation of oxidative stability of frying olive oil during thermal and frying processes
Volume 15, Issue 2, May and June 2019, Pages 235-243
https://doi.org/10.22067/ifstrj.v15i2.74403
Fatemeh Habibi Nodeh, Reza Farhoosh, Ali Sharif
Abstract Introduction: Frying is one of the oldest and popular preparation techniques broadly used at home and food industry. High temperatures plus the presence of air as well as the water from the food being fried cause many destructive reactions. Therefore, thermal stability and performance of oil during frying is considered as one of the important criteria in the selection of frying oil. In this regard, balanced chemical composition, presents it as a valuable option for frying purposes. Studies show lipid autoxidation considered as the most important deteriorative reaction in the olive oil. This reaction leads to the formation of a series of primary and secondary oxidation products. Hydroperoxides are the primary oxidation products of lipid oxidation. Carbonyl value (CV) does measure secondary decomposition products are more stable than peroxides and the CV seems to be a good index of oxidative changes in lipids. Therefore, the determination of carbonyl compounds in frying oils is very important for evaluating the quality of frying fats and oils. Several studies have been carried out on the oxidative stability of edible oil during frying. Rancimat test has also been considered among the accelerated methods of lipid oxidation measurement due to ease of use and reproducibility. However, although estimate of oxidative stability of edible oil according to accelerated methods, is used widely but there is always worries about accordance the results of such tests with the results found under real frying conditions and Presence of food. Therefore, necessity of simultaneous study oxidative stability is essential in order to justify and extension of result together during heating and frying. Materials and methods: Six refined olive oil samples of different brands in 1 lit glass bottles were purchased from local shops and were stored at 4 ºC for further analysis. Fatty acid methyl ester (FAME) standards, and all chemicals and solvents used in this study were of analytical reagent grade and supplied by Merck and Sigma Chemical Companies. The ratio between monounsaturated and polyunsaturated fatty acids (M/P) was determined by gas–liquid chromatography. The spectrophotometric method was used to determine the PV. The AV was determined according to the AOCS. The TT content was determined according to the colorimetric method. The TP content was determined spectrophotometrically using Folin–Ciocalteau’s reagent. The CV of the oils was measured using 2-propanol and 2,4-decadienal as solvent and standard, respectively. A Metrohm Rancimat model 743 (Herisau, Switzerland) was used to measure the OSI and IPCV of olive oil samples. Frying process was performed in bench- top deep- fryer at 180ºC. ANOVA and regression analyses were performed according to the MATLAB and Excel software. Significant differences between means were determined by Duncan’s multiple range tests. Results and discussion: There was good correlation between the OSI and induction period (IPcv) at the temperature range studied with a high determination coefficient (R2>0.99) in the Rancimat test. Generally, the results of the present study showed that the Rancimat method at 110 ºC correlated well with stability under frying condition and this correlation decreased as temperature increased in the Rancimat test. These observations can be explained by the fact that steps or pathway of chemical reactions that take place at low and high temperatures are different. Thus, choosing the right levels of operational parameters in the Rancimat method can produce the least possible difference between frying and the OSI test.
Evaluation of the effect of non-thermal plasma on the physicochemical, technological and functional properties of wheat flour
Volume 18, Issue 2, May and June 2022, Pages 330-342
https://doi.org/10.22067/ifstrj.v19i1.88117
Seyed Amir Tavakoli Lahijani, Fakhri Shahidi, Mahmoud Habibian, Arash Koocheki
Abstract [1]Introduction: Bread has a major role in the diet of people in Iran. One of the important factors affecting the quality of bread is the quality of wheat flour protein called gluten. Gluten is the principal structure forming elements of most baked products, contributing to the elasticity, cohesiveness and viscosity characteristics of the dough. Thus, gluten substantially control the quality of wheat flour based products. Due to the importance of the role of gluten and the requirement for improving the flour quality, providing a simple, economical, and efficient method to improve the technical quality of wheat and bread is also an important and controversial challenge. Oxidizing agents are generally added to the wheat flour to accelerate the natural maturing and the flour becomes paler and yields dough with improved baking properties. However, increasing concern about their adverse effects has highlighted the need for the development of alternative oxidants. Atmospheric cold plasma (ACP) is an emerging advanced oxidation process which has recently drawn considerable interest from food scientists. Therefore, the objective of this study was to investigate the effect of non-thermal plasma treatments on the properties of wheat flour.
Materials and Methods: For this purpose, medium wheat flour was prepared from local silages and treated with ACP at 25V for 0, 2, 4, 6, 8 and 10 min. Chemical composition of flour samples (moisture content, protein and ash) were determined using standard methods (AACC, 2002). Color properties, damaged starch water soluble index, wet gluten, gluten index, zeleny and falling number values, water and oil absorption capacities, swelling power and solubility of wheat flour samples were also measured.
Results and Discussion: The results obtained from the measurement of properties for the treated and untreated flour showed that the water and oil absorptions, swelling power, and solubility, wet gluten, gluten index, Zeleny number and whiteness increased significantly with increasing time, while the pH, moisture content, b * and a * indices, were decreased by plasma treatment. In addition, the results showed that ACP conditions have a significant effect on functional properties that can be created floursand products with various characteristics. The results showed that plasma treatment affected the gluten index and wet gluten and techno functional properties of wheat flour. Overall, this study demonstrated that non-thermal plasma is a quick, efficient way to improve the technological properties of wheat flour, as an alternative to chemical oxidants
Acrylamide in Espresso Coffee: Occurrence and Risk Assessment Study in Adolescents and Adults
Articles in Press, Corrected Proof, Available Online from 24 August 2026
https://doi.org/10.22067/ifstrj.2026.98206.1560
Shima Taghavi, Marzieh Moeenfard, Reza Farhoosh
Abstract Introduction
Coffee is one of the most widely consumed beverages worldwide, with an estimated annual intake of about 500 billion cups. Roasting is a key step in coffee processing that develops the desirable color, flavor, and aroma, but it also promotes the formation of acrylamide through the Maillard reaction. Acrylamide is classified as a probable human carcinogen and has attracted increasing attention due to its occurrence in a variety of heat-treated foods. Given the growing popularity of coffee among the Iranian population, determining acrylamide levels in espresso and assessing the associated health risks are of public health importance. Therefore, this study aimed to determine acrylamide levels in commercially available espresso coffees and assess the related cancer and non-cancer risks in adolescents and adults.
Materials and Methods
In this study, a total of 35 espresso coffee samples were collected from the market. Of these, 26 samples were obtained from coffee shops (ES-C), and 9 were prepared at home from commercial coffee powders using a household espresso machine (ES-H), following common local preparation practices. Acrylamide concentrations in all samples were determined using HPLC-DAD with a mobile phase composed of water/acetonitrile (97:3, v/v) at a flow rate of 0.7 mL/min and a detection wavelength of 202 nm. The average daily intake (ADI) of acrylamide (μg/kg body weight/day) was estimated for adolescents and adults based on the measured acrylamide concentrations and the available consumption data. Health risk assessment was performed by calculating the margin of exposure (MOE) for carcinogenic effects, estimating the incremental lifetime cancer risk (ILCR), and evaluating the non-carcinogenic risk using the target hazard quotient (THQ). The obtained MOE values were compared with the reference value of 10,000. In addition, carcinogenic and non-carcinogenic risks were evaluated against internationally accepted benchmarks, including those established by the United States Environmental Protection Agency (USEPA).
Results and Discussion
Acrylamide was detected in all analyzed espresso samples. The concentration of acrylamide in ES-C ranged from 2.15 to 9.16 μg/100 mL and was consistently higher than that observed in ES-H, which ranged from 0.93 to 4.00 μg/100 mL. Despite the presence of acrylamide in all samples, the estimated dietary exposure via espresso consumption was relatively low. The EDI of acrylamide from espresso was calculated to be 0.004 μg/kg bw/day for adolescents and 0.007 μg/kg bw/day for adults. For all samples and both age groups, the MOE values were greater than 10,000, indicating a low level of concern and a low priority for risk management regarding carcinogenic effects. The incremental lifetime cancer risk attributed to acrylamide exposure from espresso consumption was estimated at 0.244 × 10-5 for adolescents and 0.221 × 10-5 for adults. Since both values were below the 10⁻⁵ benchmark proposed by the United States Environmental Protection Agency (USEPA), the associated carcinogenic risk was considered to be low. Non‑carcinogenic risk indices were 0.0019 for adolescents and 0.0026 for adults, clearly below the threshold of 1, suggesting that non‑cancer effects are unlikely at the observed exposure levels. For all evaluated parameters, acrylamide exposure and the associated health risks were higher in adults than in adolescents. This difference can be attributed to higher consumption rates and greater body weight-adjusted intake among adults.
Conclusion
This study shows that acrylamide was present in all espresso coffee samples collected from the market, with coffee shop espresso generally containing higher levels than household espresso coffees. Nevertheless, acrylamide exposure through espresso consumption alone does not appear to pose a serious health risk to the studied adolescent and adult populations. The high MOE values, low estimated cancer risks, and non‑carcinogenic indices well below 1 collectively support a low level of concern. However, espresso is considered only one contributor to total dietary acrylamide intake, as acrylamide can also be formed in other thermally processed foods. Therefore, evaluation of combined exposure from various dietary sources and further investigation of cumulative health risks are recommended to provide a more comprehensive risk assessment.
Investigating the sensory properties and antimicrobial effect of frankincense and shallots essential oil on Listeria monocytogenes bacteria in white brined cheese
Volume 16, Issue 4, September and October 2020, Pages 343-356
https://doi.org/10.22067/ifstrj.v16i4.80935
Farnaz Sadeghi, Leila Nateghi
Abstract Introduction: There have been great efforts to find safe and potent natural antioxidants from various plant sources. Due to the side effects of chemical preservatives and as a support of the idea for consumption of green natural food, demand for studies on the antimicrobial properties of natural preservatives and essential oils on the important food borne pathogens in vitro and in food products has been increased. Medicinal plants are complex natural mixtures which contain compounds at quite different concentrations, and their antioxidant activities are due to many substances including some vitamins, flavonoids, terpenoids, carotenoids, phytoestrogens, minerals, etc. Essential oils existed in some herbs or their antioxidant components as preservative agents in food makes them to be proposed as potential substitutes of synthetic antioxidants in food stuff. Antioxidants are also widely used as additives in fats and oils and in food processing to prevent or delay spoilage of foods regarding to the harmful effects of synthetic preservatives on consumers’ health, there is an increasing attention, both in food industry and authorities, to medicinal and aromatic plants as natural preservatives in food products. White brined cheese is a kind of hard cheese which is produced from raw milk of cow, lamb and the main characteristics of the taste are pickling and salinity. White cheese, salt water, including products that may be at the time of manufacture or during storage by microorganisms such as Listeria. The objective of the present study was to investigate physicochemical properties, anti-microbial and sensory properties of frankincense essential oil and shallot oil in white brined cheese.
Material and methods: The whole treatments in this research were included: T0 (control), T1 (0.5% (w/w%) Frankincense and 0% shallots essential oil), T2 (0.6% (w/w%) Frankincense and 0% shallots essential oil), T3 (0.7% (w/w%) Frankincense and 0% shallots essential oil), T4 (0% Frankincense and 0.05% (w/w%) shallots essential oil), T5 (0% Frankincense and 0.1% (w/w%) shallots essential oil), T6 (0% Frankincense and 0.2% (w/w%) shallots essential oil), T7 (0.6% Frankincense and 0.1% (w/w%) shallots essential oil). In order to produce a white brine cheese, in the first step, the raw milk was pasteurized at 72 ºC for 15 seconds and cooled at 35ºC, then 5 liters of milk were poured into each of the sterile specialty dishes. Then, Listeria monocytogenes (103 cfu / ml) were then inoculated into milk samples. In the next step frankincense essential oil concentrations (0.5%, 0.1%, 0.6%) and shallot oil concentrations (0.05%, 0.1%, 0.2%) and mixture (0.1%+ 0.6%) were added. Then 0.02% (w/v) calcium chloride was added and after 0.5 % (w/w) of starter culture containing lycoplastic bacteria Lactobacillus bulgaricus and Streptococcus thermophiles were added into the milk samples and mixed. Finally, after the milk pH reached about 6.5, 0.001% (w/v) of microbial rennet was also added (Sanjiu Mito Japan Co.) After dissolving it, sterile water was added into the milk at 35 °C and 8 minutes for milk coagulation resting time was given. After coagulation (60 min), the cheese samples were cut into 1-2 cm slices and wrapped in a cloth to be kept in room temperature for 6 hours under 12 kg weight plates for dewatering. Coagulants were impregnated in 20% (w/v) salt water for 6-8 hours after cheese samples were cut while transferring to 8% salt water at 12-14 ° C for 15 days. Therefore, samples after the initial arrival time to arrive at the final arrival were kept at 4 ° C for 60 days (ISIRI NO. 5772, 2001). The essential oils chemical composition were determined by gas chromatography equipped with mass spectroscopy (GC/MS). GC-MS analysis of the essential oil was performed using Agilent-Technologies 6890N. Physicochemical, microbial and sensory properties of samples immediately on days 1, 30, 60 were measured but protein and fat on day 1after produced were measured. Total protein was determined by macro kjeldahl method with national standard No. 1811 (Anonymous, 1383). Fat was determined by Gerber's method with national standard No. 8587. pH was determined by a MA-Mettler pH-meter and titratable acidity (percentage of lactic acid) was determined by 0.1 normal and phenolphthalein as identifiers using national standard No. 2852 (Anonymous, 1385). Level of moisture was determined by national standard No. 1753 (Anonymous, 1381). Salt percentage was determined by Moher method with national standard No. 1809 (Anonymous, 1356). To measure the number of Listeria monocytogenes, the microorganisms were measured in Palcam Agar Surface cultivation method at 30ºC for 72 hours (Khosravi and Malekan, 2004). Sensory analysis was performed by 10 trained panelists using a five point hedonic method with scales of one (very good), two (good), three (average), four (bad), and five (very bad) for taste, smell, texture, and overall acceptability with national standard No. 3442 (Anonymous, 1387). In order to design the treatments, a completely randomized design with factorial arrangement was used. For data comparison, Duncan's test was used at 95% confidence level. Minitab 16 software was used to analyze the statistical data.
Results and discussion: The results showed that the antimicrobial essential oils of the highest possible antimicrobial against Listeria monocytogenes was shallots average number of bacterial treatments 0.2% essential oil shallots (T5) and 0.7% Frankincense essential oil (T3) at the end of the maintenance period cheese was 0.147 ×102 cfu/ml and 0.000 cfu/ml, respectively, when compared with other treatments maximum reduction showed (p≤0.05). Sensory evaluation results showed that the control cheeses had the highest sensory acceptability. Given that treatment with 0.2 shallot oil had the highest germicidal effect and organoleptic properties statistically significant difference between treatment and control samples were not mentioned. Therefore, the use of essential oils 0.2% in the formulation of white cheese shallot salt water in order to prevent the growth of Listeria monocytogenes is recommended and the treatment was selected as the best treatment.
Comparison of the Effect of Sodium Nitrite and Nanocapsules Carrying Astaxanthin from Haematococcus pluvialis with Maltodextrin-sodium Caseinate Combined Coating in Controlling Oxidative and Microbial Spoilage of Common Sausage
Volume 20, Issue 4, September and October 2024, Pages 351-367
https://doi.org/10.22067/ifstrj.2023.78749.1202
Soheyl Reyhani Poul, Sakineh Yeganeh, Reza Safari
Abstract Introduction
One of the synthetic and harmful preservatives used in sausage formulation is sodium nitrite. This compound helps to increase the shelf life and marketability of meat products by preventing the growth of anaerobic bacteria, especially clostridium, exerting an antioxidant effect, stabilizing the red color of meat and improving the taste. Despite these benefits, sodium nitrite is very dangerous for health and it can cause malignant diseases. For this reason, it is necessary to replace this substance using a natural preservative. Pigments extracted from aquatics such as astaxanthin due to having antioxidant activity, antimicrobial properties and pink color may be a good substitute for sodium nitrite. However, these pigments must be nanoencapsulated at first due to their sensitivity to food processing conditions, including high temperatures. The aim of the current research at the first was to extract astaxanthin from Haematococcus pluvialis microalgae using the acid-acetone method and pigment nanoencapsulation using maltodextrin-sodium caseinate combined coating. Then, sodium nitrite in the sausage formulation was replaced by the carrier nanocapsules with different proportions and oxidative and microbial spoilage tests, color and sensory evaluations were performed for different treatments.
Materials and Methods
At first, astaxanthin pigment was extracted from Haematococcus pluvialis using the acid-acetone technique. Then, the extracted pigment was nanoencapsulated using maltodextrin-sodium caseinate combined coating and the resulting (carrier) nanocapsules in the form of treatments A (120 mg/kg sodium nitrite), B (120 mg/kg nanocapsules carrying astaxanthin), C (90 mg/kg sodium nitrite+30 mg/kg nanocapsules carrying astaxanthin), D (60 mg/kg sodium nitrite+60 mg/kg nanocapsules carrying astaxanthin) and E (30 mg/kg sodium nitrite+90 mg/kg nanocapsules carrying astaxanthin) were replaced sodium nitrite in the sausage formulation. These treatments were evaluated in terms of oxidative and microbial spoilage, color indices and sensory properties during 28 days of storage at refrigerator along with the control (without sodium nitrite and carrier nanocapsules). This research was conducted in a completely randomized design. Data were analyzed by one-way analysis of variance and the difference between the means was evaluated by Duncan's test at 95% confidence level.
Results and Discussion
According to the results, the lowest levels of thiobarbituric acid and peroxide value during the storage period were related to treatments B, E and D (p>0.05). Treatments A and C had no significant difference in terms of thiobarbituric acid and peroxide value until day 14 (p>0.05), but with increasing storage time, this difference became significant and treatment A showed higher values (p<0.05). The results of this section showed that the power of astaxanthin in controlling oxidative spoilage is significantly greater than sodium nitrite, and if the purpose is only to control this type of spoilage, there is no need to replace or use sodium nitrite. The results also showed that in terms of controlling microbial spoilage, sodium nitrite has more power than nanocapsules carrying astaxanthin. So that, the lowest amount of total volatile basic nitrogen (TVB-N) and the most standardized pH were related to treatments A, C and D (p>0.05) during the storage period (p<0.05). Treatments B and E (p>0.05) were ranked next (p<0.05) in terms of the two mentioned indicators. The results of this section showed that if sodium nitrite reduced from 120 mg/kg to 60 mg/kg and replaced by nanocapsules carrying astaxanthin in the sausage formulation, the resulting product has the same antimicrobial power as the product containing 120 mg/kg sodium nitrite. Evaluation of the color and sensory properties of treatments showed that A, C and D treatments are at a higher level than B, E (treatments) and control in terms of color indices and general acceptance (p<0.05). The comparison of the color indices and sensory properties of the treatments on days 0 and 28 of storage at refrigerator showed that the color and sensory indices remained constant in the formulated treatments, unlike the control.
Conclusion
Nanocapsules carrying astaxanthin with maltodextrin-sodium caseinate combined coating as a natural product with many properties in health, control and prevention of various diseases, have a high efficiency to replace the sodium nitrite in sausage formulation. So that, if 30 to 60 mg/kg of the permissible limit of 120 mg/kg of sodium nitrite in the sausage formulation is replaced by nanocapsules carrying astaxanthin, the resulting product will be similar to the product containing 120 mg/kg of sodium nitrite in terms of shelf life, resistance to oxidative and microbial spoilage, color indices and sensory properties.
The effect of wheat germ powder on physicochemical, microbial and sensory properties of kefir beverage
Volume 15, Issue 4, September and October 2019, Pages 395-406
https://doi.org/10.22067/ifstrj.v15i4.76680
Soheila Ahmadian Mask, Farideh Tabatabaei Yazdi, Seyed Ali Mortazavi, Arash Koocheki
Abstract Introduction: Kefir is a traditional beverage produced by fermented milk with kefir grains, which is becoming increasingly popular throughout the world due to its health benefits and disease prevention properties beyond its basic nutritional value. The grains contain a mixture of complex microflora such as lactic acid bacteria, yeast and sometimes acetic acid bacteria which are lodged by a polysaccharide matrix calls “kefiran”. Kefir is a self-carbonated beverage that owes its distinctive flavor to a mixture of lactic acid, ethanol, carbon dioxide and other flavor products such as acetaldehyde and acetone. Kefir has been recommended for the treatment of several clinical conditions such as gastrointestinal problems, hypertension, allergies, and ischemic heart disease. Kefir grain fermentations from various substrates have been evaluated and a wide variety of bioactive compounds have been observed, such as organic acids, CO2, H2O2, ethanol, bioactive peptides, exopolysaccharides (kefiran), and bacteriocins. These compounds may act independently or together to produce the various health benefits attributed to kefir consumption. Nowadays, its popularity has been expanded worldwide and it is considered as a healthy product with high nutritional value in Europe, Asia, and South and North America. Wheat germ, corresponding to 2–3% of the total weight of wheat kernel, is almost systematically removed during milling since it adversely affects the keeping and processing quality of the flour. Wheat germ (WG) is widely recognized as a nutritious raw material for incorporation into food product formulations or as an independent food product. Wheat germ, containing about 8% - 14% oil (average 10%), is mainly used in food, medical and cosmetic industries as a source of oil. Unfortunately, the whole quantity of the germ produced in Iran is currently utilized in the production of animal fodder. According to chemical analyses, wheat germ contains magnesium, zinc, calcium, selenium, sodium, potassium, phosphorus, chromium, antioxidants including beta-carotene (for vitamin A), vitamin E, vitamin C, vitamin B12, vitamin B6, thiamin, riboflavin, niacin, folic acid, iron, amino acids, and enzymes, and has a high dietary and medicinal value. The purpose of this study was to investigate the effects of various concentrations of wheat germ powder on physicochemical, microbial and sensory properties of kefir beverage.
Materials and methods: A commercial freeze-dried Kefir starter culture (ABT_2) was purchased from Chr. Hansen (Denmark) also Saccharomyces cerevisiae was supplied from Saf-Levure (France). Cow milk were obtained from the Department of Food Engineering, Ferdowsi University of Iran. Wheat germ was supplied from Isar Qaynat Co. All chemicals were from Merck Co.
Steam stabilized wheat germ powder at 1, 2 and 3% levels with DVS starter and Saccharomyces cerevisiae at 25 ° C were transferred to full fat cow’s milk and the fermentation was ended at pH 4.6. Microbial, physicochemical and sensory tests were performed at 24, 48 and 72 hours after inoculation. The pH and acidity of kefir were determined according to National Iranian Standard Number 2852. The viscosity was also determined using a Brookfield viscometer (spindle 3, USA) at the temperature of 5°C and a shear rate of 80.0 1/s. Spectroscopic measurement of alcohol was performed according to Sayyad et al. (2015). Lactobacilli counts were performed on MRS medium at an incubation temperature of 37°C for 3 days. Yeasts counts were carried out on YGC at an incubation temperature of 25°C for 5 days. Total counts were performed on PCA at an incubation temperature of 30°C for 2 days. All statistical calculations were completed using the Minitab Version 16. Analysis of variance (ANOVA) was carried out using the general linear model (glm) procedure and Tukey test was used to determine the differences among means.
Results and discussion: Wheat germ is a by-product derived from the wheat milling industry and is a rich source of vitamins, proteins, dietary fiber and minerals. Due to its antioxidant, sterol and essential amino acids contents, it has a lot of health effects and is known as a nutritious raw material for its composition in food formulations. Therefore, in this study it was used to produce kefir beverage to produce a high-nutritional product. Based on the obtained results, increasing the percentage of wheat germ powder concentration on the physicochemical, microbial and sensory properties of kefir beverage has a significant effect. The sample containing 3% wheat germ powder showed the highest acidity, ethanol, yeast and total microbial count, during the storage period, acidity, ethanol and yeasts increased in all samples, while pH, Lactobacilli, total microbial count and apparent viscosity had decreasing trend and samples of kefir containing wheat germ powder showed non-Newtonian flow behavior according to the power law model. On the other hand, the apparent viscosity of the samples significantly decreased with increasing wheat germ concentration. According to the sensory evaluation results, kefir produced with one percent wheat germ received the highest overall score within 72 hours after inoculation.
Evaluation of Oxidation Development of Soybean Oil Enriched with Essential Oil from Aerial Parts of Ferulago angulata Boiss during Accelerated Storage
Volume 19, Issue 4, September and October 2023, Pages 399-414
https://doi.org/10.22067/ifstrj.2021.69813.1033
َAlireza Hemmati, Ali Ganjloo, Kambiz Varmira, Mandana Bimakr
Abstract Introduction
It is believed that edible oils and fats with high levels of unsaturated fatty acids are susceptible to oxidation. Soybean oil as one of the four important edible oils has high content of polyunsaturated fatty acids and so prone to oxidation. Generally, lipid oxidation leads to deterioration of nutritional quality and organoleptic properties of edible oils and fats as well as accelerate the development or progression of cancer, mutagenesis, carcinogenesis, aging and cardiovascular diseases through the formation of free radicals. Therefore, edible oils and fats fortification with antioxidant compounds in order to protect them against oxidation is essential. In recent years, numerous studies were carried out on exploration of natural and safe antioxidant compounds due to the consumers concerns about potential health risk of synthetic antioxidants, such as butylatedhydroxyanisole (BHA), butylatedhydroxytolene (BHT), tert-butylhydroquinone (TBHQ) and propylgallate (PG). In this regard, TBHQ as the most powerful synthetic antioxidant is prohibited as food additive in Japan, Canada and Europe. Ferulago angulata Boiss which called chavir or chavil belongs to the family of Apiacea consisting of 35–40 species that 8 species grow in Iran. It was reported that Ferulago species are used in folk medicine for their tonic, digestive, sedative, aphrodisiac properties from ancient times. Therefore, in the current study, the oxidation development of soybean oil enriched with F. angulata essential oil (EO) during accelerated storage was investigated.
Materials and Methods
EO from freeze dried aerial parts of F. angulata was extracted through hydrodistillation using Clevenger type apparatus. Gas chromatography-mass spectrometry (GC-MS) was used to identify main components of the EO. Total phenolic and flavonoid content of the EO were assessed using Folin–Ciocalteu and aluminium chloride colorimetry methods, respectively. Antioxidant activity of EO was measured through 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) and reducing power (RP) tests. Then, the EO of F. angulata at three concentrations, i.e. 200 ppm (SO-200), 400 ppm (SO-400), and SO-Mixture (100 ppm TBHQ + 100 ppm EO) were added to soybean oil. The synthetic antioxidant of TBHQ at the concentration of 200 ppm was added as control. The effect of EO from freeze dried aerial parts of F. angulata on oxidative stability of soybean oil stored under accelerated conditions at 65 ºC for 24 days was evaluated through acidity, peroxide (PV), p-anisidine (p-An) and TOTOX values.
Results and Discussion
Extraction yield, total phenolic and flavonoid contents of EO of F. angulata were 2.5% v/w, 188 mg GAE/g and 70.90 mg QE/g respectively. Furthermore, DPPH free radical scavenging activity and RP were 55.45-13.21% and 3.61-2.72 in the concentration range of 1.6-4.6 mg/ml of EO, respectively. Based on GC-MS analysis, the EO contains 41 natural compounds, representing 96.97% of the total EO. F. angulata EO could effectively reduce the acidity, PV and p-An values. For control sample, the maximum values of acidity, PV peroxide, p-An and TOTOX were 1.52 mg KOH/g, 10.60 meq O2/kg, 12.48 and 33.68 respectively after 24 days under accelerated conditions. While these values were 0.085 mg KOH/g, 4.5 meq O2/kg, 9.16 and 18.16 respectively for the soybean oil containing the lowest concentration of EO of F. angulata.
Conclusion
The results confirmed the instability of soybean oil during storage as well as the ability of EO from F. angulata for soybean oil protection against oxidation. As a result, EO from aerial parts of F. angulata could be suggested as a natural and effective antioxidant to be used instead of TBHQ as a synthetic antioxidant for soybean oil stabilization.
Evaluation of the effect of cheese powder and ultrasonic wave on physicochemical and sensory properties of gluten-free oil cake
Volume 17, Issue 4, September and October 2021, Pages 423-435
https://doi.org/10.22067/ifstrj.v17i4.86707
Bahareh Sahraiyan, Fatemeh Pourhaji, Behrooz Alizadeh Behbahani
Abstract Introduction: Celiac disease leads to the malabsorption of nutrients and damage to intestinal mucosa. High nutritional value is one of the advantages of dairy powders, associated with their high calcium, protein and essential amino acid contents. Research has shown that such powders boost the gluten quasi-network by forming interfacial films. They are also able to increase the moisture, improve the organoleptic properties, and retard the staling of gluten-free bakery products. In addition, it has been reported that ultrasonic waves can accelerate the oxidation and increase the aeration, volume, porosity and moisture content of bakery products. They can also reduce the hardness and improve the color of such products, thus resulting in the enhancement of their quality and marketability. Consequently, the aim of this study was to improve the appearance, flavor and texture of the gluten-free cake based on rice, germinated quinoa and potato flour using cheese powder at 0, 3, 6 and 9% and ultrasound intensity of 0, 30 and 70% for 5 min.
Material and methods: In this study, cheese powder at 0, 3, 6 and 9% and ultrasound intensity of 0, 30 and 70% for 5 min were used to improve the quality of gluten-free cupcake. Control cake formulation had 70 g rice flour, 15 g germinated quinoa flour, 15 g potato flour, 52 g sugar, 50 g water, 36 g egg, 36 g oil, 12 g invert syrup, 2 g baking powder, 0.2 g vanilla, 1.5 g guar gum and 0.5 g xanthan gum. Moisture, specific volume, firmness, crust and crumb color, sensory properties, porosity and scanning electron microscopy (SEM) (with 100× magnification) were evaluated. To study the effect of processing parameters on color components of gluten-free cupcake, the RGB color space images were converted to L*a*b space. For determination of gluten-free cupcake porosity using image analysis, the color images were first gray scaled and then thresholded using isodata algorithm. The porosity was measured from the ratio of white to the total numbers of pixels. Results were reported as the average of three replications. In order to assess significant differences among samples, a complete randomized design of triplicate analyses of samples was performed using the Mini-Tab17. Turkey’s new multiple range tests were used to study the statistical differences of the means with 95% confidence.
Result and discussion: Results revealed that moisture content increased as the cheese powder and ultrasound intensity were elevated. Cheese powder caused the moisture content to increase by boosting the gluten quasi-network and ultrasonic waves brought about this phenomenon by dissociating the polymeric chains of starch molecules and forming hydrogen bonds between water molecules and free hydroxyl groups. The sample containing 6% cheese powder sonicated at 30% intensity had higher specific volume (4/4 Cm3/g) and porosity (31.2%) as well as lower hardness (3.4 and 4.4 N after 2 hours and one week respectively) compared with other samples. Cheese powder, by boosting the gluten quasi-network and improving the dough elastic properties, and ultrasound, through enlarging the air bubbles present in the dough, caused an increase in the porosity, specific volume and softness. The results also indicated that the rise in the cheese powder content up to 6% led to an increase in the L* value (from 44.9 to 53.5) and up to 9% in the a* value (from 2.6 to 8.4) of the gluten-free cupcake crust. On the other hand, the results demonstrated that as the ultrasonic intensity was increased, the L* value of the gluten-free cupcake crumb also increased (from 60.3 to 77.9), while its b* value was reduced (from 17.3 to 7.9). This could be due to the aeration and oxidation acceleration which resulted in the increased whiteness and decreased yellowness of the cake crumb. Finally, the findings of sensory evaluation showed the preference of the samples containing 3 and 6% cheese powder sonicated at 30% intensity (4.2 and 4.4 score). The SEM and binary images of the preferred samples also confirmed the integrity of the internal structure and the gluten quasi-network of these samples, compared with the control.
Effect of Pumpkin Powder and Malt on Physicochemical, Textural and Sensory Properties of Sponge Cake
Volume 14, Issue 4, September and October 2018, Pages 451-460
https://doi.org/10.22067/ifstrj.v1396i0.60891
Safura Jalali, Hossein Jalali, Seyyed Hossein Hosseini Ghaboos
Abstract Introduction: Cakes by appropriate organoleptic characteristics are considered the most commonly used flour products all over the world. According to the role of dietary fiber on health and its ability to prevent some types of cancer and diabetes, fans of high-fiber foods is increasing. Pumpkin is a good source of carotene, water-soluble vitamins and amino acids. Pumpkin can be converted to powder with longer shelf-life. Pumpkin flour is used because of its highly-desirable flavor, sweetness and deep yellow orange –red color. In this study, kinetic modeling of pumpkin drying in an infrared-hot air dryer was investigated. Malting is a result of biochemical processes that includes steeping, germination and kilning of cereal in controlled environment in which hydrolytic enzymes are synthesized and cell wall, protein and starch of endosperm are largely digested. The aim of this study was to determine the physico-chemical, textural and sensory properties of sponge cake supplemented with four different levels (0, 10, 20 and 30 %) of pumpkin and malt powder Materials and methods: Fresh pumpkins (Cucurbita moschata) were obtained from local market. Slices of pumpkin with 5 mm thickness were prepared with the aid of a steel cutter and were immediately placed into the dryer. The pumpkin slices were dried in a hot air dryer (65°C). The effect of pumpkin and malt powder replacement with wheat flour on physicochemical and sensory properties of sponge cake including pH, fat, protein, moisture, ash, fiber, β-carotene, mineral, carbohydrate, texture and color were evaluated. The ingredients used in the sponge cakes formulation were cake wheat flour, sucrose, sunflower oil, fresh eggs, whey, baking powder, vanilla, water and nonfat milk powder. In this study pumpkin and malt powders at four levels of 0, 10, 20 and 30 % as wheat flour replacer were used. For each cake, 40 g of cake batter was poured into a cake pan and baked at 180-200°C for 20-25 min in an oven. Cakes were then allowed to cool for 40 min, and removed from the pans. The cooled cakes were packed in polypropylene bags at room temperature before performing physico-chemical and sensory evaluation s. Moisture content of the samples was determined in an oven at 105°C for 4 h (AOAC, method no. 934.06). For measuring β – Carotene content 1 gram of cake was dried and then crushed in 10-15 ml of acetone with the help of pestle and mortar and few crystals of anhydrous sodium sulphate were added. The supernatant was decanted into a beaker. The process was repeated twice and combined supernatant was transferred to a separating funnel, then 10-15 ml of petroleum ether was added and mixed thoroughly. Two layers separated out on standing. The lower layer was discarded and upper layer was collected in 100 ml volumetric flask. The volume was made to 100 ml with petroleum ether and optical density was recorded at 452 nm using petroleum ether as blank. The crumb color determinations of cake samples from the midsection of the cakes was measured with HP Scanner (Hp Scanjet G3110). L* (lightness/darkness that ranges from 0 to 100), a*(redness/greenness ranges from -120 to 120) and b* (yellowness/blueness ranges from -120 to 120) were measured. In this study, the image analyses of sponge cakes were performed using Image J software version 1.42e, USA. The texture analysis of sponge cake samples (2.5 × 2.5 × 2.5 cm) from the midsection of the cakes was performed using a texture analyzer (TA-XT Plus, Stable Micro Systems Ltd., Surrey, UK) and a test speed of 1.0 mm s−1. The crust of cake samples was removed in cake texture determination. The textural properties were determined using Texture Expert 1.05 software (Stable Microsystems). Each measurement was conducted in triplicate, except for the sensory evaluation (n=16). The experimental data were subjected to analysis of variance (ANOVA) for a completely random design using SPSS 19 and Excel 2010. Duncan’s multiple range tests were used to determine the difference among means at the level of 0.05. Results & Discussion: The results showed no significant differences between treatment on fat, protein and pH. With increasing of pumpkin and malt powder in sponge cake formulation, significant difference was observed between the fiber contents of cakes. Fiber contentof all treatments was in the range of 0.28-1.13. Redness (a*) and yellowness (b*) indexes of cakes were increased but lightness (L*) index was decreased. Significant difference (P
Effect of lipid edible coatings on physicochemical and microbial properties of raisin
Volume 11, Issue 5, November and December 2015, Pages 496-507
https://doi.org/10.22067/ifstrj.v0i0.38002
Azam Ayoubi, Nasser Sedaghat, Mahdi Kashani-Nejad, Mohebbat Mohebbi, Mehdi Nasiri mahalati
Abstract Introduction: Raisin is a principal traditional export product of Iran and has a special position in the foreign trade of the country.During storage, the product turns sticky and hard due to exudates syrup and moisture loss. To solve this problem, the application of edible coating would be an appropriatesolution. Edible coating may enhance the boundary layer resistance resulting to the enhanced shelf life of the product. Edible coatings are thin layers of edible materials applied to the product surface in addition to or as a replacement for natural protective waxy coatings and provide a barrier to oxygen, water and solute movement. They are also applied in foods to minimize the migration of components within the food systems or between the foods and their surrounding environment. They are used directly on the food surface by spraying, dipping or brushing to create a modified atmosphere. There are different kinds of films which are used such as polysaccharide, protein, lipid and composites. Lipid based coatings are primarily used for their hydrophobic properties which make them good barriers to water loss. In addition to preventing water loss, lipid coatings have been used to improve appearance by generating a shiny coverin fruits and vegetables, and to decrease respiration, thereby extending shelf life. The moisture barrier properties of hydrophilic coatings can sometimes be improved by addition of lipid materials The purpose of this research was to study the effect of lipid based edible coating (glycerylmonoestearate and carnauba wax) on physicochemical and microbial properties of raisin.
Material and methods: Raisin samples (cvAskari)were dried usingsoda oil method and treated with coating materials based on lipid with essential oil of thyme (thymus vulgaris).Glycerylmonoestearate, carnauba wax and tween 80 were purchased from Sciencelab, Sigma-Aldrich and Merck Co. respectively.
Raisinswerecoated with the following coating solutions:
-Aqueous solution of tween 80 (0.5% w/w)
-Aqueous solution of glycerylmonoestearate (0.5% w/w), tween 80 (0.5% w/w)
-Aqueous solution of glycerylmonoestearate (0.5% w/w), tween 80 (0.5% w/w), 150 ppm essential oil of thyme
-Aqueous solution of carnauba wax (0.5% w/w), tween 80 (0.5% w/w)
-Aqueous solution of carnauba wax (0.5% w/w), tween 80 (0.5% w/w), 150 ppm essential oil of thyme
Control sample was treated with aqueous solution of tween 80 (0.5% w/w).Distilled water was used for preparing all of coating solutions. Coating solutions were stirred and heated to 75oC (melting point of coating materials) for 30 min on a hotplate with a magnetic stirred to obtain uniform solutions. Dipping technique was used for coating of raisins. The coated raisins were placed on a basket to drip off residual coating solution and were dried in 25oC. The raisin smples were packaged in a 3 laminatedlayer bags (PE/PA/PE) with thickness of 80µ by Henkelman packaging machine and were stored at20, 35 and 50oC for 12 weeks. During the storage period, moisture content, water activity, hardness, color parameters (L*(lightness), a*(redness) and b*(yellowness)), percent of pestilence and microbial properties (total count, mold and yeast) were evaluated. Hardness of raisins was determined in apuncture test using a QTS texture analyzer (CNS Farnelll, Essex, UK) equipped with a needle probe (stainless steel cylinder of 2 mm of diameter with a conical needle bit) and a test speed of 60 mm. min−1 during the test. Hardness was defined as maximum force to puncture raisin from the top to a 2mm depth (Rolleet al. 2011).For colormeasurement, raisins were placed in to a black wooden box (interior size of 0.5 (width) × 0.5 (length) × 0.8 (height) m3 and were illuminated using 3 fluorescent tube lights (10W, 6500K; 40cm in length). A digital camera (Canoon EOS 1000D, Powershot, Taiwan) was located vertically at a distance of 20cm from the raisin surface. The images were preprocessed by Adobe Photoshop software, version 5.5. The Color properties were analyzed using ImageJ software, version 1.44o. The experiments were factorial with a completely randomized design. The coating material, temperature and storage time were the independent variables. Analysis of variance (ANOVA) was conducted for data using MSTAT-C software, version 1.42 (Michigan State University). Differences among the mean values were also determined using Duncan’s Multiple Range test. A significant level was defined as a probability of 0.05. The experiments were carried out on 4, 8 and 12 weeks after storage with three replications.
Results and discussion: Results showed that coating, temperature and storage time would have considerable effect on the physicochemical and microbial properties of raisin. Coating caused decreasein moisture loss, hardness, lightness and redness. Increasing temperature and storage time increasedmoisture loss and hardness. Minimum hardness values were measured for 20 oC and 4 weeks storage and maximum hardness values were related to 50 oC and 12 weeks storage. Also it seems that increasing temperature and storage time influences thehardness by increasing moisture loss. Increasing temperature and storage time significantly decreased L* (p≤0.01). Increased enzymatic browning in raisins with increasing temperature was accompanied by an increase in a* value, and a decrease in b* value and caused to presenting dull colors. Total count, mold and yeast of coated samples decreased during storage period. Carnauba wax was more effective than glycerylmonoestearate on stability of raisin. Essential oil of thyme also caused improving color and microbial properties. Least values of redness (-2), total count (2.06 log cfu/g) and mold and yeast (1.32 log cfu/g) were related to carnauba wax coating with essential oil of thyme.
Influence of k-Carrageenan on Whey Protein Isolate Cold-Set Emulsion Filled Gel: A Rheological and Mechanical Study
Volume 20, Issue 5, November and December 2024, Pages 499-515
https://doi.org/10.22067/ifstrj.2023.81976.1251
Mohammad Reza Salahi, Seyed Mohammad Ali Razavi, Mohebbat Mohebbi
Abstract Introduction
Emulsion-filled gel is a sort of gel system that traps oil droplets as a filler and contains a wide range of semi-solid to solid food products. It can also be utilized as a dual system to distribute and control the release of both lipophilic and hydrophilic bioactive and micronutrient substances. The main polymers involved in gel formation in food products are proteins and polysaccharides. Using molecular interactions between biopolymers, a wide range of rheological and physicochemical properties of gels can be methodically created. As a result, the interaction between proteins and polysaccharides has received a lot of attention in order to generate novel products. Because of their functional qualities and high nutritional value, whey proteins are frequently used in the food industry. As a result, mixed gels based on whey protein have gained a lot of attention. k-Carrageenan is commonly utilized in the food industry as a gelling and firming agent. Because k-Carrageenan, like whey protein isolate, can form a gel independently, its interaction with whey protein isolate in emulsion gel systems appears appealing. Therefore, in this study, the effect of k-Carrageenan gum (0.0, 0.1, 0.3, 0.5, and 0.7%) on the textural (uniaxial compression test), rheological (steady shear, strain sweep, and frequency sweep tests), and water holding capacity of cold-set emulsion-filled gel based on whey protein isolate was investigated.
Materials and Methods
Whey protein isolate (WPI) (98.9% protein, dry basis) was given as a gift by Agropur Ingredients Co. (Le Sueur, Minnesota, USA). -Carrageenan and CaCl2 ( : 147.01 gr/mol) were purchased from Sigma Aldrich Co. (USA) and Merck Co. (Darmstadt, Germany), respectively. Sunflower oil was supplied from local supermarket. Stock dispersions of WPI and -Carrageenan were prepared by dissolving sufficient amounts of their powders in deionized water. To prepare uniform oil in water emulsion, sunflower oil was added to the WPI dispersion and the obtained mixture homogenized first using a laboratory rotor-stator homogenizer (15000 rpm, 3 min), then by an ultrasonic homogenizer (20 kHz, 5 min). The prepared emulsion and -Carrageenan dispersions were poured into Schott bottles and heated in a water bath (90 °C, 40 min). WPI emulsion and AG dispersion were mixed in a cylindrical container on a stirring plate at a speed of 600 rpm for 6-8 min to obtain a homogeneous mixture. After decreasing the temperature to 60 °C for the ion-induced gelation, the mixtures were charged with CaCl2 (10 mM). The prepared samples were incubated in a refrigerator overnight to stabilize the 3D network. The final mixed EFG samples contained 5.5% WPI, 20% oil, and 0, 0.1, 0.3, 0.5, and 0.7% (w/w) of k-carrageenan. The tests performed on emulsion-filled gel samples were: 1) steady shear (0.01-10 s-1), 2) strain sweep (strain: 0.1-1000%, frequency: 1 Hz), 3) frequency sweep (frequency: 0.1-100 Hz, strain: 0.5%), 4) uniaxial compression (target strain: 80%, deformation speed:1 mm/s), and 5) water holding capacity (by utilizing a microcentrifuge, 600×g for 10 min).
Results and Discussion
According to the results of steady shear test, all samples had a shear thinning behavior, and based on the power-law model, this behavior was intensified in the presence of k-Carrageenan; and with increasing the gum concentration from 0 to 0.7%, the consistency coefficient increased from 339.9 to 545.7 Pa.s. In the strain sweep test, with the increase in the gum concentration, the values of the elastic and viscous modulus in the linear region and the modulus at the crossover point increased, and tan dLVE decreased from 0.17 to 0.13, which indicated an increase in the strength of the emulsion gel network structure. Based on the frequency sweep test, with the increase in k-Carrageenan concentration, the parameters and , network strength and network expansion increased from 5311.8 Pa, 939.9 Pa, 1.5380 Pa.s1/z and 10.05 in the control sample to 25080 Pa, 3574.9 Pa, 16097.7 Pa.s1/z and 16.41 in the sample containing 0.7% k-Carrageenan, respectively. Moreover, the frequency dependency of elastic modulus decreased from 0.095 in the control sample to 0.050 in the 0.7% k-Carrageenan contained sample. According to the large deformation test, in general, in the composite emulsion-filled gels, the values of apparent modulus of elasticity and fracture stress were higher and fracture strain and fracture energy were lower than in the control sample. Also, the results showed that different k-Carrageenan concentrations had no significant effect on the water holding capacity.
Conclusion
The obtained results showed that k-Carrageenan had considerable influence on the rheo-mechanical features of cold-set emulsion-filled gels based on whey protein which can add to the knowledge base for the production of new functional foods.
Evaluation of physicochemical characterization of hawthorn (Crataegus pinnatifida) during various storage conditions and modeling of changes using kinetic models
Volume 16, Issue 5, November and December 2020, Pages 507-523
https://doi.org/10.22067/ifstrj.v16i5.79355
Mohsen Zandi, Ali Ganjloo, Mandana Bimakr
Abstract Introduction: Hawthorn (Crataegus pinnatifida), belonging to the Rosaceae family, consists of small trees and shrubs. The color of the ripe fruit varied from yellow, through green to red and on to dark purple. Most of the species ripen their fruit in early to mid-autumn. Beneficial effects of hawthorn fruit extracts have been confirmed by various studies. Pharmacological data showed that hawthorn fruit and its preparations enhance myocardial contraction and conductivity, protect against ischemia. They have a sedative action, a protective effect against arrhythmia and increase of coronary vessel flow. They have also positive effects on the cardiovascular system. Hawthorn is one of the most widely consumed horticultural products, either in fresh or processed form. It is also an important component of many processed food products because of its excellent flavor, attractive color and high content of many macro- and micro-nutrients. Uncertain storage conditions lead to considerable quality loss in hawthorn fruits, which affect their consumer acceptability. Properties such as color, firmness and moisture provide valuable information for the monitoring of quality changes in postharvest fruits because of their reliability and rapid and easy measurement. These changes are consequences of many biochemical and physiological processes that occur during fruit ripening, such as respiration and transpiration. In addition, these changes depend on the external conditions to which the fruit is exposed. To estimate changes in fruit quality as a function of storage conditions, the evolution of certain quality-indicative properties such as color, firmness or weight can be used to provide related information on the quality grade of the product stored. Kinetic models can be used as tools to describe quantitative physicochemical changes in foods during processing. Kinetic models can be linear or non-linear forms of rate law equations. The rate process of food constituents is usually defined by zero, first or second order kinetics.
Method and material: In this study, changes in physicochemical characteristics associated with fruit quality were investigated during various hawthorn fruit storage conditions include: cold (1ºC and RH=90%), refrigerator (10 ºC and RH=85%) and room conditions (25 ºC and RH=60%). Color quality parameters (L*, a*, b*, C*, h* and ΔE), geometrical parameters, weight loss, firmness, total soluble solid (TSS), pH, titratable acidity (TA) and ripening index (RPI) were the measured factors. Different mathematical models were successfully proposed and adjusted to represent the change in physicochemical properties as a function of storage temperature. Among various kinetics model, five models (Zero-order, First-order, Second-order, Fractional conversion and Weibull models) were fitted to experimental data and model parameters in equations were determined by multiple regression analysis.
Result and discussion: Storage of hawthorn fruits at different temperature affected their color (L*, a*, b*, C*, h* and ΔE), geometrical, physical (weight loss, firmness) and chemical properties (TSS, pH, TA and RPI). Storage at all conditions had significant impact on the physicochemical parameters analyzed (except some geometrical characteristics). Significant alterations in hawthorn color, firmness and weight loss were observed. The firmness, titratable acidity, pH, ripening index, color characteristics (except a* and C*) decreased while weight loss, total soluble solid, a* and C* increased significantly (p<0.05). Hawthorn stored at low temperatures revealed a delay on quality reduction reactions in terms of color, firmness and weight loss. The results indicated that the First-order and Weibull kinetic models provided the best prediction of the changes in physicochemical parameters. The storage temperature effect was successfully described by the Arrhenius law. Understanding the mechanisms in which these conditions affect the quality changes processes is of great importance because it allows their appropriate modification to maintain quality and maximize storage time. The outcomes of this study provide additional and useful information for hawthorn fruits under various storage conditions.
