Sara Forouzandeh; Mohammad Fazel
Abstract
[1]Introduction: Nowadays, various methods have been developed to transfer and improve the absorption of lipophilic compounds in food in the form of coating. Colloidal emulsion-based systems are widely used in commercial systems. Chia seed oil is an oil rich in unsaturated fatty acids, especially omega ...
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[1]Introduction: Nowadays, various methods have been developed to transfer and improve the absorption of lipophilic compounds in food in the form of coating. Colloidal emulsion-based systems are widely used in commercial systems. Chia seed oil is an oil rich in unsaturated fatty acids, especially omega 3 and omega 6, which can be used as the oily phase of nanoemulsions. The aim of this study was to investigate the fatty acid composition of chia seed oil and the effect of oil to water ratio and emulsifier on the properties of nanoemulsions of this oil. Materials and Methods: Clean chia seeds were purchased as a pack from Zistfa Company and all other chemicals were purchased from Marack, Pars Shimi and Dr. Majelli companies. By using the oil set machine, the seeds were treated by cold pressing method and oil extraction efficiency was calculated .Gas chromatography (GC) was used to identify and measure the fatty acid composition of chia seed oil. In this study, nanoemulsions were produced in three levels of oil to water (20%, 35% and 50%) and in three levels of oil emulsifier (5%, 10% and 15%).To produce nanoemulsions, the aforementioned ratios were first calculated and determined .Then, Weigh the tweens 20 and 80 with chia seed oil and water and mix the emulsifiers with the chia seed oil on the stirrer. Then a mixture of 20 and 80 tweens and oil was added dropwise to the weighed distilled water. The mixture was stirred gently by a magnet. After this step, the mixture is placed in the refrigerator to reduce its temperature. After this time, it was placed in an ice bucket and placed in an ultrasonic homogenizer for 9 minutes at a power of 300 watts to form nanoemulsions. Then, the properties of nanoemulsions including particle size and distribution, coating efficiency and antioxidant properties were evaluated. Vasco model DLS (Dynamic light scattering) was used for the particle size. The particle size of nanoemulsions was determined by this device using dynamic light diffraction method. DPPH method was used to measure the antioxidant activity of oils and nanoemulsions and the antioxidant activity was calculated by using the formula. To evaluate the efficiency of coating of nanoemulsions, the amount of surface oil and total oil was measured and the efficiency was calculated by using the formula. The release rate of nanoemulsions was evaluated for 7 weeks. The tests were performed in three replications. Experimental data were analyzed in a completely randomized design with factorial test and Duncan test was used to compare the mean data. Software (Excel, 2010) was used to draw the graphs Results and Discussion: According to the results obtained in this study, it can be said that chia seed oil contains a high percentage of unsaturated fatty acids and has a very high level of antioxidant properties (88.43%), which has antioxidant properties in the structure of nanoemulsions. Oil is better preserved in water. Other results showed that with increasing oil content of nanoemulsions, particle size, antioxidant properties and release increased and the coating efficiency decreased. Also, by increasing the ratio of emulsifier to oil in nanoemulsions, the coating efficiency and antioxidant properties increase and the particle size and release decreases. In the results obtained from these tests, the minimum particle size was 14.08 nm and the highest coating efficiency was 96.40%. The antioxidant activity of the samples was evaluated in the range of 5.61% to 21.43%. Also, the average release of samples at the end of 7 weeks of the study reached nearly 18%. During storage, the treatments were quite stable for five months, which could be due to the low particle size and low release of samples. Considering the mentioned advantages, using nanoemulsions of this oil is a suitable option for enriching beverages.
Food Technology
Khadije Sadat Tabatabae; Mohammad Fazel
Abstract
Introduction: Nowadays, lack of time and busy work schedules have led to increase the demand for ready-to-eat foods. Furthermore, as cardiovascular diseases are on the rise in the world including our country, with nearly 40 percent of deaths being linked to these diseases, there is a growing demand for ...
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Introduction: Nowadays, lack of time and busy work schedules have led to increase the demand for ready-to-eat foods. Furthermore, as cardiovascular diseases are on the rise in the world including our country, with nearly 40 percent of deaths being linked to these diseases, there is a growing demand for low-fat products. The main purpose of the deep frying process is to preserve the aroma and flavor of the ingredients in a crispy crust by immersing the food in hot oil. Frying at high temperatures affects the transfer of mass and heat, which causes some of the water to evaporate and be removed from the product, and the oil is moved into the product, replacing the extracted water. This study aims to use methods that reduce the absorption of oil in the fried product, which can reduce health concerns and increase consumer acceptance of the product. Materials and methods: In this study, a day-old chicken breast fillets were used to prepare the samples. The weight of the samples was between 14.5 and 15 grams, with a diameter of 3.7. Coating solutions include aloe vera gel powder at three levels of 1.5, 3, and 4.5 % (w / v) and whey protein concentrate (WPC) at three levels of 2.5, 5 and 7.5 % (w / v), made with distilled water at 25C. Baguette bread was also used to make breadcrumbs. To coat the chicken breast fillet, the samples were immersed in the coating solution (control samples in distilled water) for 1 minute and then placed in breadcrumbs. After preparation, the samples were fried in an automatic fryer at a controllable temperature of 140 C for 6, 8, and 10 minutes, then the samples were cooled to room temperature for 10 minutes and tested for physicochemical properties. The tests included coating, weight loss, moisture content according to the standard AACC method, adsorption of oil by standard method AOAC, tissue measurement test based on the stiffness of the chicken tissue cutting (catching test), and color analysis of chicken samples using CIE Lab colorimetric system through the determination of color characteristics were performed. Results & discussion: The results showed that the coated samples increased the absorption of the coating glaze due to the increasethe viscosity and thus the absorption of baking powder compared to the non-coated sample. The coating with hydrochloric materials based on barrier properties through strong hydrogen bonds between water molecules forms a gel layer with a high water holding capacity that prevents moisture from escaping. This subsequently reduces weight loss. Moreover, due to the inverse relationship between water and oil content, oil absorption was significantly decreased (p<0.01). Among the studied coatings, the highest moisture retention rate and the lowest oil absorption rate are related to the coated sample with 4.5% aloe vera and 7.5% WPC. As the concentration of aloe vera increased, the hardness of the samples decreased, which may depends on the effect of the meat protein to polysaccharide ratio. As the concentration of WPC increased, the stiffness of the samples increased, increasing the sulfhydryl groups, increasing the disulfide bonds in the meat's myofibrillar protein, and thus increasing the tissue stiffness. Increasing the frying time reduced the moisture and increased the oil absorption, weight loss, and stiffness of the samples. The coating reduces brightness due to the presence of various phenolic pigments, especially light- and heat-sensitive anthraquinones in aloe vera and lactose in WPC, and Maillard's reaction at high processing temperatures, resulting in increased browning index and darkening with increasing product color time. This is correlated with the Maillard reaction. Coating with aloe vera gel and WPC is effective in improving the physicochemical properties of fried chicken.
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 ...
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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.
Atosa Assarzadegan; Mohammad Fazel
Abstract
Introduction: The fruit, with the scientific name of Cydonia oblonga comes from apple family, has a dry and fluffy flesh that, due to high vitamin C, Potassium and fiber has commercial and nutritional value. However, this fruit is as corruptible as other fruits and destructive microbial, chemical and ...
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Introduction: The fruit, with the scientific name of Cydonia oblonga comes from apple family, has a dry and fluffy flesh that, due to high vitamin C, Potassium and fiber has commercial and nutritional value. However, this fruit is as corruptible as other fruits and destructive microbial, chemical and mechanical factors that reduce its effective longevity. Enzymatic browning is a major problem for reducing the shelf life of freshly chopped fruits and vegetables. This reaction often occurs due to the activity of polyphenol oxidase (PPO) and peroxidase (POD) enzymes. Blanching is used to deactivate the relevant enzymes. Blanching is done before such processes as drying, canning, and freezing and somewhat determines the quality of the product. Sulfites are multi-functional compounds that inhibit enzymatic and non-enzymatic browning. Dehydration is one of the oldest techniques for keeping food products. Osmotic dehydration process has been emphasized in recent years due to the negative effects of conventional drying procedures, this process is done to partially remove the water from the plant tissue by immersion in a salt or salt solution. Chitosan is non-toxic, biodegradable substance that can be used as an edible coating to maintain the quality and increase the life after the fruits and vegetables harvest. This protective performance improves by adding antimicrobial, antioxidant. The lemongrass extract was added to the chitosan coating as antimicrobial. The purpose of this study is to investigate the effect of chitosan coating containing lemongrass extract on the shelf life of dehydrated quince fruit slices.
Materials and methods: Metabisulfite was used in order to prevent the browning reactions of slices prepared from blanching, water vapor and chemical solution of sodium. Then, quince slices are dehydrated with osmotic solutions of sorbitol, sucrose by immersion with chitosan containing (0, 0/5, 1 and 2 % lemongrass extract) coated and kept in sterile plates at refrigeration temperature (4±1˚C) for 4 weeks. The experiment was carried out in factorial method based on a completely randomized design with three iterations. Variables include the type of osmotic solution (sucrose, sorbitol) and coating treatments (chitosan coating containing 0, 0/5, 1 and 2% lemongrass extract). The studied characteristics included weight loss (%), acidity, pH, ascorbic acid concentration, total phenol, inhibitory activity of free radical (RSA), color properties (components L*, a*, b*, BI) of tissue that was investigated in the first, second, third and fourth week.
Results & discussion: Fruits coated with chitosan containing 2% lemongrass extract had less weight loss changes than other treatments. This can be due to the role of the extract in preventing decay, its antimicrobial properties and the formation of the semipermeable membrane by coating, which prevents weight loss. Edible coatings containing extract, by changing the internal atmosphere and reducing the respiration rate of the fruit, help to maintain better organic acids .Lemongrasses extract causes the delay in the consumption of organic acids in metabolic reactions, including respiration, due to its antioxidant properties. It seems increasing the pH of the fruit is the result of biochemical changes in the fruit during storage time, such as the decomposition of organic acids into sugars and participating the respiratory cycle in which the coating of chitosan containing extract can reduce the breakdown of organic acids by reducing respiration rate. The decrease in the drop of Vitamin C and phenolic compounds of the coated sample is due to oxygen permeation reduction and the creation of adapted atmosphere by coating. The high level of antioxidant activity of lemongrass extract is because of high phenolic compounds of which the highest amount was observed in treatment coated with chitosan containing 2% lemongrass extract. By increasing the concentration of the extract, its phenolic compounds increases which preserve more vitamin C and phenolic compounds and consequently antioxidant properties. Free radical inhibition activity was preserved due to better preservation of phenolic compounds, ascorbic acid and increasing the antioxidant capacity of fruit by chitosan coating containing lemongrass extract. The product brightness decreases during storage. Before the hot-water blanching coating process, sodium metabisulfite and osmotic dehydration have inactivated browning enzymes. Therefore, in quince coated with chitosan, the amount of color changes was not tangible due to the less respiration and as a result, less enzymatic activity of fruit. Coating containing lemongrass extract has created due to the color of coating extract with the green-tinted color. The increase in the extract concentration reduces the redness and increases the greenness of fruit, which is because of the extract color and as the effect increases, the concentration increases. By decreasing the brightness, increasing the greenness and yellowness during storage time and the browning increased. In quince coated with chitosan, the amount of softening wasn’t tangible due to less respiration and as a result, less enzymatic activity of fruit. As the concentration of lemongrass increases the stiffness of the tissue is reduced due to the effect of lemongrass on the fruit tissue cells that cause structural changes. Based on the results, the edible coating containing 2% lemongrass extract is suggested as the best formulation.
Peyvand Gholipour; Mohammad Fazel
Abstract
Introduction: Ficus carica, commonly known as fig, is among the oldest types of fruit known to mankind. Drying is defined as a thermal process under controlled conditions in order to reduce the moisture in different types of food via evaporation. Edible films and coatings are used to enhance food quality ...
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Introduction: Ficus carica, commonly known as fig, is among the oldest types of fruit known to mankind. Drying is defined as a thermal process under controlled conditions in order to reduce the moisture in different types of food via evaporation. Edible films and coatings are used to enhance food quality by precluding oxidation and color changes in inappropriate conditions. Carboxymethyl cellulose (CMC) is thus widely used to improve food shelf life.
Materials and methods: All experiments were carried out on fresh edible green variety figs planted in the county of Neyriz Estahban. The figs were then immersed in the following solutions:
Distilled water as a control variable without coating; carboxy methyl cellulose (CMC) solution 1% containing 0.25 gr/L glycerol; and CMC solution 1% containing 0.25 gr/L glycerol and 2% ascorbic acid. Preliminary tests including average diameter, pH, total flavonoids content, and antioxidant activity were performed on the figs. The fruits were dried using a device designed by the authors. At 60 ̊C, 70 ̊C, and 80 ̊C, the airflow in the device was 0.5 m/s, 1.0 m/s, and 1.5 m/s, respectively. After drying the samples, secondary experiments were performed which, in addition to the previous tests, included texture analysis, water reabsorption, volume measurement, shrinkage, and color analysis. A total of 27 treatments were applied in 3 rounds. A full factorial design was employed for statistical analyses while average values were compared via Duncan’s test at 5% significance. Calculations were performed using SPSS 16.0.
Results & Discussion: Using CMC coating, shrinkage increased compared to the control sample. As airflow accelerates from 0.5 m/s to 1.5 m/s, higher levels of shrinkage are observed. This could be attributed to the drier surface of the fruit caused by faster airflow. Shrinkage increases with the speed of airflow going from 0.5 m/s to 1.5 m/s. This is because at higher speeds, the sample is dried in a shorter period of time and sustains less damage.
Water reabsorption was found to decrease with higher temperature and airflow. Weak reabsorption results from the breakdown of the internal structure of the fruits.
CMC-ascorbic acid, CMC, and the control sample had the highest to lowest levels of firmness, respectively. The acid was found to preserve the internal cellular structure and preserve its breakdown. Moreover, firmness increases with the drying temperature.
According to the results, the samples coated with CMC and CMC-ascorbic acid had lower pH compared to the control sample. Airflow speed and temperature are inversely and directly related to pH, respectively.
In the CMC-ascorbic acid treatment, antioxidant capacity increased compared to the other two treatments. This may be associated with ascorbic acid’s higher ability to act as a carrier of anti-browning agents. Also, higher levels of antioxidant behavior were observed with higher temperature as it causes faster drying. Moreover, the coating acts to preserve the antioxidant and eliminates the impact of temperature.
The highest amount of flavonoids was observed in the CMC-ascorbic acid treatment followed by the control sample and the CMC treatment. This is because the ascorbic acid serves to maintain the flavonoids in the samples. The flavonoid content increases with the airflow speed since the sample is dried in a shorter duration and the flavonoids are preserved. However, higher temperature reduces the flavonoid content since heat damages the pigment.
The application of the CMC coating (alone or in combination with ascorbic acid) increased luminance compared to the control sample due to the preventative effect of the edible coating on the oxidation of the pigments in the fig samples. With faster airflows, surface moisture begins to vary which causes the coating to become lighter with higher L*. An increase in the temperature leads to lower L* as the heat causes the carotenoids and chlorophyll to break down and form brown pigments in the samples.
Using the CMC-ascorbic acid coating increases a* in figs. Furthermore, as the temperature goes up from 60 ̊C, a* also increases.
The coated samples demonstrate higher levels of b* compared to the control sample. In fact, the coating preserves the pigments and thus maintains the yellow color of the figs. The value of b* is directly related to the speed of the airflow because it decreases drying time. As a result, the product undergoes less heat. Finally, higher temperature leads to higher b* in the dried figs.
Sepideh Etezazian; Mohammad Fazel; Hajar Abbasi
Abstract
Introduction: Sponge cake is one of the most demanded and consuming grain products, but due to its gluten content, it is not usable for patients with celiac disease. In recent years, gluten-free products have gained a great attraction. However, producing gluten-free products has several difficulties ...
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Introduction: Sponge cake is one of the most demanded and consuming grain products, but due to its gluten content, it is not usable for patients with celiac disease. In recent years, gluten-free products have gained a great attraction. However, producing gluten-free products has several difficulties such as lack of gluten viscoelastic network protein constituents, lower technological quality and advent of some quality problems in production including low volume and weak texture. Some compounds such as certain enzymes and gums with the aim of improving the texture, mouth feeling and general acceptance, as well as imitating viscoelastic properties of gluten could be employed in the formulation of gluten-free products to make them acceptable for the celiac patients. For this purpose, guar gum is used widely as a thickener and stabilizer for producing gluten-free products. Also, addition of enzymes to grains produce could help in increasing the holding water capacity, improving softness and dough flexibility, enhancing texture and final product’s volume. Furthermore, notwithstanding widely researches on the cake, comparing to other production, this production has low nutrition values yet. So, enriched cakes with dietary fiber and natural antioxidants, is one of the goals of the industry. The researches has shown that dried, powdered and extracted pomegranate peel has rich fiber, bioactive materials and high antioxidative characteristics. Therefore, the main purpose of the present research is to study the effect of replacing the pomegranate peel (0-12 %), Guar gum (0-1.5 %) and Hemicellulase enzyme (0-90 ppm), respectively on the physiochemical properties.
Material &Methods: Moisture content measurement of moisture by oven, density by using rapeseed seeds displacement method, hardness (STM 200 device), color index of crumb and crust by using CIE Lab colorimetric system that measure L* (brightness), a* (redness) and b* (yellowish), antioxidant activity with spectrophotometery method in 517 nm wavelength, and sensory properties of gluten-free sponge cake based on wheat starch. In association with sensory test,30 panelists was used for checking desirability of mouth texture, appearance texture, smell and taste, color, after-taste and general acceptance with six point hedonic test that they rated samples from most agreeability to most un agreeability. For this aim, the statistical plan of response surface method (RSM) of central composite design (CCD) with three variables and four central points were used and the texture test was applied four times and the other tests were applied three times. For this purpose the Design-Expert 7.0.0 software was utilized for determining of optimum point (a point in which the minimum density and hardness that this parameters considered as a blank in the cake limits), Duncan examination was used for comparing the average of data and analyze of data was implemented with SPSS 16 software.
Results & Discussion: The results have shown that increasing the percentage of pomegranate peel in the formulation, density and bright and yellowish cakes were decreased and moisture, a* index, DPPH and hardness were increased. From the other hand, increasing the amount of replacing the gum caused to increase density, moisture and hardness. Adding the enzyme had effect in decreasing the light of crust and increasing density and color index in the crust of the cake. Totally was determined pomegranate peel had more effect on the antioxidant activity, density, hardness and colorful properties. Guar gum had fewer effect on this parameters and played most important roll on moisture of cakes. About enzyme can say it didn’t have significant effect on properties of cakes. Then, the optimum points has been defined via the software that the amounts of pomegranate peel and the guar gum were estimated at 9.1 and 0.56 %respectively, and the amount for hemicellulase enzyme calculated as 0 ppm. After that, the properties of the optimum cake were compared with blank cake and in addition to previous tests, sensory test was also performed. Moreover moisture and hardness of optimum cake was investigated in during of 14 days storage (days of 1, 7 and 14).The results have shown the physical, chemical and texture properties of optimum cake were largely similar to the blank samples and the main difference was in taste sensory properties of pomegranate peel that will corrected with the use of flavor agents. Over time, also, moisture was decreased and hardness was increased primarily and decreased later in both of blank and optimum sample. Therefore, gluten-free cake based on wheat starch with 9.1 percent pomegranate peel and 0.56 percent guar gum can be used, that only doesn’t have adverse effect on its properties, but also is acceptable for celiac patient.
