Food Technology
Zeinab Mohkami; Hasan Ghorbani Ghouzhdi; Fateme Bidarnamani; Yasub Shiri
Abstract
Introduction Yogurt is one of the most widely consumed fermented milk products, which, like any other dairy products, is prone to spoilage and poor quality. On the other hand consumers have become more cautious about their diet and health. Their is an increasing demand for food products with higher ...
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Introduction Yogurt is one of the most widely consumed fermented milk products, which, like any other dairy products, is prone to spoilage and poor quality. On the other hand consumers have become more cautious about their diet and health. Their is an increasing demand for food products with higher nutritional values and health benefits. The continuous improvement of the production process and the quality of yogurt is at the heart of manufacturers’ concerns. Also, finding a safe, cheap and affordable solution that, in addition to controlling blood sugar and preventing the complications of diabetes, relieves the pain of diabetic patients; has always been of interest to researchers. The medicinal plant Bitter gourd (Momordica charantia L.) from the cucurbitaceae family is used in traditional medicine to control blood sugar. Carla fruit is a rich source of phytochemical compounds such as proteins, steroids, alkaloids, mineral compounds, lipids, triterpenoids and polyphenols. Functional yogurt is one of the dairy products that can contain bioactive compounds in order to increase its acceptability and improve its nutritional and medicinal properties. Therefore, this study was carried out with the aim of producing colored yogurt containing Carla fruit powder in order to increase the variety of appearance, marketability of the product and improve the nutritional characteristics of yogurt with emphasis on the consumption of novel product. Materials and Methods In this study, the effects of adding Carla powder to yogurt were investigated with the aim of producing a beneficial food for diabetics. Carla fruit was collected from the medicinal plants collection of the Agriculture Institute, Research Institute of Zabol, Zabol, Iran. Then it was washed with water and cut into thin layers. These parts were completely dried in an electric oven at 40 ºC for 48 hours and pulverized with an electric mill. Carla fruit powder was added to the samples in four levels of 0 (control), 0.2, 0.4 and 0.6%. Physicochemical properties of samples such as pH, acidity, viscosity (using Brookfield spindle viscometer) and water holding capacity were measured. Total phenol content was measured by Folin Ciocalteu reagent method. Antioxidant properties were investigated by scavenging rate of DPPH free radicals. The results were analyzed by SPSS version 21 statistical software at the probability level of 5% (P˂ 0.05). Duncan's multiple range test was performed to determine the statistically significant difference between the means. Results and Discussion The results of this study showed that the highest pH (4.17) was detected in the control and the addition of Carla fruit powder led to a decrease in pH. Storage time also lower the pH in yogurt samples. The highest acidity (1.3%) was measured in the treatment containing 0.6% Carla fruit powder and the lowest (0.59%) was in the control. It means that adding Carla powder to yogurt leads to an increase in acidity. The highest amount of phenolic compounds (475.63 μg equivalent of gallic acid/ml yogurt), was calculated in a sample containing 0.6% of Carla fruit powder. However, extended storage time, decreases the amount of phenolic compounds. By increasing the percentage of Carla fruit powder in yogurt samples, the amount of antioxidant activity increased. So that the highest antioxidant activity (93%) was related to the treatment containing 0.6% Carla powder on the 28th day of the storage. In the present study, the highest percentage of water holding capacity (84%) was observed in samples containing 0.6% Carla powder. The lowest water holding capacity (57.61%) was measured in the control sample at the first day of storage. Conclusion According to the results of this study, adding Carla powder to yogurt at the level of 0.6%, in addition to maintaining appearance properties, can increase its physicochemical properties and produce a novel food. In general, Carla powder can play a significant role in improving the textural properties of yogurt, and by increasing the viscosity and the water holding capacity, can reduce the negative effects of the storage period. Acknowledgement This research was conducted with the financial support by Research Institute of Zabol (Grant code: IR-RIOZ-GR-9027).
Food Technology
Samira Farizad; Hajar Abbasi
Abstract
Introduction
Hydrocolloid is a term refers to all polysaccharides extracted from plants, seeds, and microbial sources that regardless of their biological and nutritional role has various functional properties in food products such as concentration and gel production of aqueous solutions, stabilization ...
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Introduction
Hydrocolloid is a term refers to all polysaccharides extracted from plants, seeds, and microbial sources that regardless of their biological and nutritional role has various functional properties in food products such as concentration and gel production of aqueous solutions, stabilization of foam, emulsions and dispersed systems, prevention of ice and sugar crystals, control of the release of flavor compounds and consequently control and improve food quality. Ultrasound has been widely used in the food industry due to its numerous physical and chemical effects. The effect of ultrasound is due to cavitation, heating, dynamic mobility and shear stresses to the sample. Today, ultrasound is used as a green new technology with unique effects on food storage and processing. One of the newest applications of ultrasound is altering the structure of polymers such as polysaccharides. Changes in the structure of hydrocolloids lead to modification in their functional properties.
Materials and Methods
In this study, effect of ultrasonic waves, time (0-90 min) and processing temperature (25-75 °C) on physicochemical, rheological and functional properties of locust bean gum was investigated. In this regards, different parameters including changes in pH, solubility, minimum gelatinization concentration, viscosity and emulsifying properties (Emulsifying capacity, emulsion stability and particle dimensions) of treated locust bean gum were determined. Response surface methodology in central composite design was used to evaluate the effect of independent variables on qualitative properties of locust bean gum and model their changes. The best treatment condition was determined and the optimum treated samples were evaluated and compared in microstructure using scanning electron microscopy, rheological properties (rotational and oscillatory test) and Fourier transform infra-red.
Results and Discussion
The results showed that with increasing the time of ultrasound treatment, pH, and viscosity of the hydrocolloid decreased and its solubility and minimum gel concentration increased. However, with increasing temperature, pH, minimum gelatinization concentration and hydrocolloid viscosity increased and its solubility decreased. Optimization of treatment conditions was performed by considering the achievement of the best hydrocolloid performance characteristics. Two different temperature and time conditions were proposed for the desirable treatment of the hydrocolloid using ultrasound. In the first case, the selection criteria were to achieve the best solubility and emulsifying properties of the hydrocolloid, and in the second case, the selection criteria were solubility and emulsifying properties improvement while maintaining the gelatinization properties of the hydrocolloid. Based on the desired quality factors, optimization was performed and the results showed that in the first optimal sample (treated at 40 ° C and 48.9 minutes), solubility and emulsifying properties and in the second optimal sample (treated at 66.67 ° C and 15 Min) by maintaining the gelation properties of hydrocolloid, the solubility of the hydrocolloid increased significantly. The performance of treated samples validated developed models. SEM results showed that the ultrasound increased three-dimensional structure of gum. The smaller microscopic structure was observed in untreated sample and the larger one was in treated with ultrasonic waves for 40.9 minutes at 40 ° C. Therefore, ultrasound caused agglomeration of treated freeze dried gum. It is noteworthy that several holes observed in the structure of treated gum with ultrasonic, which can increase solubility of the gum. The flow behavior of the sonicated and control samples showed that the viscosity of all samples decreased with increasing shear rate, which indicates their pseudoplastic behavior. At low shear rates (about 0.01 per second), the viscosity of the control sample was higher than that of the sonicated samples. However, at high shear rates (about 40 per second), viscosity of the three samples were almost the same. Therefore, the control sample was more affective to shear rate compared to the treated samples. The modulus of elasticity (G ') and viscosity (G' ') of the treated specimens were lower compared to the control. Also, the frequency sweep of samples shown that in the frequency range under study, G 'and G'' were frequency dependent and with increasing frequency, the amount of these two parameters increased. This observation indicates the influence of rheological properties of the samples on the frequency changes that are commonly observed in suspensions. At low frequencies, the predominance of viscous behavior over elastic was observed in all three control and ultrasonic samples (G ''> G ') and this feature was higher in the treated samples than the control. The modulus of elasticity and viscosity of the treated sample for 49 minutes was lower than other treated samples for 15 minutes, which shows the effect of ultrasound on the rheological properties of the hydrocolloid.
Conclusion
The results of this study showed that ultrasonic waves provide a good opportunity to change the physical and functional properties of carob seed gum. It is possible to significantly improve the solubility and emulsifying activity of this hydrocolloid using ultrasound. It is necessary to determine the treatment conditions of the sample according to the intended application.
Food Technology
Fariba Hadidi; Ali Ganjloo; Mohammad Hadi Fakoor
Abstract
Introduction
The demand for non-dairy and reduced-calorie products has increased substantially for several reasons. Almond (Prunus dulcis) milk is highly appreciated by lactose-intolerant, hypertensive people and celiac patients whom are not able to consume animal's milk. Thus, the development ...
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Introduction
The demand for non-dairy and reduced-calorie products has increased substantially for several reasons. Almond (Prunus dulcis) milk is highly appreciated by lactose-intolerant, hypertensive people and celiac patients whom are not able to consume animal's milk. Thus, the development of various non-dairy products is essential. Desserts are the most common and popular product containing high amount of fat and sucrose. The consumption of sucrose is restricted for diabetic people due to its high glycemic index. Stevia as a low-calorie sweetener is one of the sucrose substitutes in food products. Sucrose substitutes must mimic the techno-functional properties of sucrose. Generally, commercially available sucrose substitutes do not possess all of the required characteristics. Therefore, using them in blend form with sucrose is suggested. Moreover, sucrose replacement especially in desserts generates a negative effect due to low firmness or higher syneresis. In this regard, hydrocolloids can be used to overcome those drawbacks. Therefore, the current study was carried out to investigate and optimize the non-dairy dessert formulation based on almond milk containing Tragacanth gum and stevia. For this purpose, the effect of Tragacanth gum and stevia as a sucrose replacer on the physicochemical properties such as hardness, viscosity, color coordinates including lightness, redness-greenness (a*), yellowness-blueness (b*), total soluble solids and syneresis was evaluated and optimized using Response Surface Methodology (RSM).
Materials and Methods
All of the materials used for the manufacturing of non-dairy dessert including raw almond, stevia and Tragacanth gum were purchased from a local market of Zanjan, Iran. For the production of non-dairy dessert, the almond milk warmed up to 40 ºC and then stevia as a sucrose substitutes and tragacanth gum powder as a stabilizer were added in the ranges of 25-75% and 0.4-1% w/w, respectively. Later, the temperature of the mixture increased to 72 ºC and kept for 10 min and then, the temperature decreased to 42 ºC to inoculate the starter culture (a mixture of Streptococcus thermophilus and Lactobacillus bulgaricus, 2% w/w). The fermentation process was completed at 37 °C for 24 h. Finally, the temperature of non-dairy dessert based on almond milk was decreased to 4ºC and kept at the same temperature until further analysis. The pH of the desserts was measured using a pH meter model AZ 86502 (AZ, Taiwan). Total soluble of the desserts was determined using a refractometer (ATAGO, Japan). Firmness was determined using a STM-5 texture analyzer (SANTAM Co., Iran) equipped with a 20 Kg load cell and 10 mm probe. Viscosity was measured using a programmable Viscometer (R/S-CPS+, Brookfield, USA) equipped with a cone-plate geometry at shear rate of 100 s−1. Instrumental color measurement was carried out by a handheld colorimeter (TES135-A, Taiwan) considering L*, a* and b* as color coordinates. Syneresis was measured by a centrifugation test. Fifteen semi-trained panelists (7 male and 8 female) were selected to evaluate sensory properties of the control (only contains sucrose) and optimized formulation samples for texture, color, appearance, taste, flavor, total acceptance using a 5-point Hedonic scale (1= dislike extremely and 5=like extremely). The RSM-central composite design was used to build up the experimental design and identify the conditions that yield highest firmness, viscosity, L*, and total soluble solids as well as lowest a*, b* and syneresis.
Results and Discussion
The results obtained revealed that the hardness, viscosity, a* and total soluble solids increased significantly (p<0.05) while the lightness, b* and syneresis decreased significantly (p<0.05) with increasing the Tragacanth gum in the formulation of non-dairy dessert based on almond milk. In addition, increasing the replacement of sucrose with stevia significantly (p<0.05) reduced the hardness, viscosity, total soluble solids, and increasing lightness and syneresis. However, increasing the percentage of sucrose replacement with stevia had no significant effect (p>0.05) on the changes of a* and b*. Optimization of non-dairy dessert formulation based on almond milk was carried out using numerical technique. The optimal formula was 1% Tragacanth gum and 45% replacement of sucrose with stevia. Under these conditions, hardness 0.08 N, viscosity 1.20 Pa.s, lightness 82.77, redness-greenness 0.95, yellowness-blueness 5.60, total soluble solids 8.29 ºBrix and syneresis 11.88% were obtained. The results of sensory evaluation showed that addition of Tragacanth gum and replacing stevia at the optimal levels improved the total acceptance score compared to the control sample.
It can be concluded that in addition to the reliability of the RSM to select the optimal formulation conditions, Tragacanth gum and stevia can be used to produce a new, reduced-calorie and customer-friendly non-dairy dessert based on almond milk.
Elnaz Shafie; Mohammad Goli
Abstract
Introduction: Milk dessert is a product that contains at least 50% the fresh cow milk or reconstituted milk, which is made with supplementary additives such as flavors, sweeteners, thickeners, and stabilizers, after undergoing heat treatment such as pasteurization or sterilization. Spirulina platensis ...
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Introduction: Milk dessert is a product that contains at least 50% the fresh cow milk or reconstituted milk, which is made with supplementary additives such as flavors, sweeteners, thickeners, and stabilizers, after undergoing heat treatment such as pasteurization or sterilization. Spirulina platensis is a multi-cellular microalgae and a green-blue filament that is a rich source of protein, essential amino acids, essential fatty acids, vitamins, minerals and pigments. Today, as a substitute for sucrose, non-caloric sweeteners are used, which in a small amount make too much sweetness, but they are not absorbed by the body. Of these, stevia with higher sweetness than sucrose (300 to 400 times), less calories and lower glycemia index, is a good herbal sweetener to replace sucrose. Materials and methods: Factor A contains the percentage of algae Spirulina platensis (alternative to milk powder) at 5 levels (0-2 % of the final formula), factor B contains the percentage of stevia replacement with sucrose at 5 levels (0-100), to achieve optimal pudding production formula were selected. Optimization of formula was performed based on the parameters of syneresis, viscosity, hardness and cohesiveness by Response Surface Method (central composite design, α=2 with 6 central points). The results were analyzed using SPSS 20 software and the comparison of the means was done by LSD at 5% level and the charts were drawn by Excel software. Results & Discussion SyneresisGenerally, due to the increase of molecular connections between the chains and the outflow of water from the structure is created. According to the results of Table 3, the independent effect of stevia replacement with sugar, the interaction effect of Spirulina platensis and stevia replacement, and the quadratic effect of each of the independent variables on the Syneresis factor were significant (P <0.05). The rate of syneresis of the samples at higher levels of stevia replacement was reduced by decreasing the percentage of Spirulina platensis replacement, and at lower levels of stevia replacement, with the decrease in the percentage of Spirulina platensis replacement, the amount of syneresis significantly increased. Water holding capacity is linked to the ability of proteins, fats, and dietary fiber to maintain water inside the product structure. Because Spirulina platensis has high levels of protein, dietary fiber and fat, its presence in the formulation of frozen desserts has a significant effect on reducing the product's syneresis. ViscosityAs shown in Table 3, the independent effect of Spirulina platensis replacement and stevia replacement, the interaction effect of Spirulina platensis and stevia replacement, the quadratic effect of Spirulina platensis and stevia replacement on the amount of viscosity was significant (P <0.05 ). The level of viscosity at lower levels of stevia replacement decreased with a decreasing percentage of Spirulina platensis replacement, and at the higher levels of stevia replacement, reducing Spirulina platensis replacement percentage was no significant effect on the viscosity (Fig. 2). In general, the presence of Spirulina platensis in the pudding formulation increased its viscosity, which could be due to the Spirulina platensis protein structure and intercellular interactions. Spirulina with high water absorption reduces water mobility. Also, the presence of fiber and hydroxyl compounds in the structure of this fine algae has a significant effect on the viscosity of the product. Hardness and cohesivenessReplacement of Spirulina platensis and Stevia in pudding formulations did not have a significant effect on the hardness and cohesiveness of texture. While the interaction effect of Spirulina platensis and Stevia replacement on the hardness and cohesiveness of the pudding samples was significant (P<0.001). The quadratic effect of Spirulina platensis and stevia replacement on the amount of hardness and cohesiveness of texture was significant (P <0.05). At lower levels of stevia replacement, by increasing the Spirulina platensis replacement percentage, the hardness of the samples first increased and then decreased, while at higher levels of stevia replacement, with increasing Spirulina platensis replacement percentage, the hardness of the samples first decreased and then increased. Large particles of Spirulina platensis can cause unconnectedness and network connectivity and ultimately create a more sophisticated structure. In fact, Spirulina platensis protein molecules, having a hydrophilic property, compete with other molecules to bind to water molecules, which results in a weaker and more unstable gel structure. On the other hand, tissue hardness is largely dependent on dry matter, the amount and type of protein in the sample. High levels of protein cause cross-linking in the gel network and, ultimately, a rigid and dense structure. But it should be noted that the amount of sample fat plays an important role in the product's texture. Since Spirulina platensis, in addition to protein, also has significant amounts of fat, the intervention of the fatty molecules of this small algae can be effective in forming a weaker gel network and producing soft texture in the product. Finally, optimal formula 1 (2 % Spirulina platensis and 95% Stevia replacement) and optimal formula 2 (0.1% Spirulina platensis and 50% Stevia replacement) were predicted.
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 ...
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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.
Zahra Hoseinpour; Hojjat Karazhiyan
Abstract
Introduction: Whipped cream is one of the cream products that is widely used in confectionary products and is bulked by whipping and incorporating air bubbles. Cream is converted to a foam system by aeration process. The continuous phase is liquid serum and the dispersed phase is air bubbles. Profit ...
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Introduction: Whipped cream is one of the cream products that is widely used in confectionary products and is bulked by whipping and incorporating air bubbles. Cream is converted to a foam system by aeration process. The continuous phase is liquid serum and the dispersed phase is air bubbles. Profit formation of a complex foam-emulsion structure of whipped cream to create a desirable texture is dependent on different factors such as whipping conditions, fat content, and presence of stabilizers. A whipped cream with appropriate quality should contain 30-40% milk fat, easily whippable, and produce good foam with high over run. It should also have a long shelf-life and maintain its stability during preservation. Liquorice is one of the oldest pharmaceutical plants, whose active ingredients are used in pharmacy, confectionary, and beverage industries. The most important active ingredient is glycyrrhizic acid which is 50 times sweeter than sucrose. Its root is also an overflowing source of saponin which has different physiochemical properties. Stable foam formation is a property of saponin index. Liquorice saponin can be used in industrial use especially in pharmaceutical, food, and cosmetics industries. The aim of current research is to evaluate physiochemical and rheological properties and textural attributes of whipped cream containing different levels of liquorice powder as an aerating and foaming agent. Matrials and methods: Whipped cream was produced from cream with at least 70% fat content, low fat pasteurized milk with 1.5% fat content, milk protein concentrate with 70% protein content, vanilla, sucrose, and different levels of liquorice powder (2, 4, 6, and 8%). Whipping time, acidity, pH, over run, and syneresis of final products were evaluated. Rheological properties were studied at 40C and at shear rate 0-100 S-1. Textural attributes were evaluated using back extrusion with a cylindrical probe (38 mm diameter) and penetration rate 1 mm/s and penetration depth 30 mm. Results and discussion: Whipping time increased with elevation of liquorice percentage in whipped cream formulation, which is due to presence of stabilizers which can both increase the viscosity of liquid phase and prevent foaming properties of milk proteins from protein-stabilizer interactions. The highest over run belonged to 4% treatment while the lowest magnitude was reported for 8% sample. Over run quantity is dependent on different factors such as mixture ingredients including fat content, solid materials, sweeteners, and presence of stabilizers. Due to presence of saponin in liquorice, it can be concluded that elevation of over run in samples containing liquorice up to 4% is probably because of foaming ability of saponins. From literature review, it has been reported that with the rise in gum concentration (gum in liquorice), over run decreases in the foam system. Generally, with further increase in viscosity of the liquid phase with the growth of gum concentration, air bubbles cannot be introduced to the system through aeration process. Hence, the descending trend in over run of samples containing 6 and 8% liquorice is probably due to higher viscosity of the whipped cream. Acidity content of samples also increased. Acidity increment in whipped cream samples with liquorice rise is probably due to the acidic nature of saponins in liquorice powder. PH was reduced significantly with an increase in liquorice amount in the formulation a growth in acidity. Saponins present in the extract can produce acidic properties to some extent. The highest extent of syneresis in different samples was reported for 6% while the lowest amount was for 2%. Syneresis in confectionary cream shows emulsion rupture and has a close relationship with product viscosity. So it can be expected that higher viscosity in whipped cream results in less syneresis in the final product. According to the results of the current research, syneresis value in 2% was lower compared to control sample, which is probably due to the increase in viscosity of the whipped cream. With elevation of liquorice, syneresis increased compared to the control sample. As indicated, liquorice root has gum and gums increase the viscosity of the final product, thereby reducing syneresis by absorbing water and incorporating it in the gelly network. Power law model was selected for predicting rheological properties of samples. The results suggested that flow index behavior was less than 1 in all samples indicating non-Newtonian, pesudoplastic behavior. Apparent viscosity versus shear rate showed shear thinning behavior, which indicated that the apparent viscosity diminished with increase in the shear rate. Gums have shear thinning behavior, so regarding the presence of gum in liquorice and augmented liquorice percentage, more deviation from Newtonian state was observed. Textural analysis indicated that hardness, adhesiveness, and adhesive force had an ascending trend with increase in liquorice percentage except for 4% sample. Totally, it can be concluded that a desirable product with higher over run and profit texture can be obtained using liquorice powder as a natural, native, local plant product in whipped cream formulation with pharmaceutical properties which can be potentially useful for the health of consumers.
Maryam Nejadmansouri; Seyed Mohammad Hashem Hosseini; Mehrdad Niakosari; Gholam Hossein Yousefi; Mohammad Taghi Golmakani
Abstract
Adequate consumption of ω-3 essential fatty acids (EFAs) has a positive impact on human health. EFAs-enriched functional foods may be used for this purpose. Nanoemulsion is a promising delivery system for incorporating EFAs into a variety of foods and beverages. In this work, fish oil nanoemulsions ...
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Adequate consumption of ω-3 essential fatty acids (EFAs) has a positive impact on human health. EFAs-enriched functional foods may be used for this purpose. Nanoemulsion is a promising delivery system for incorporating EFAs into a variety of foods and beverages. In this work, fish oil nanoemulsions developed by sonication method were subjected to various analyses as a function of hydrophilic lipophilic balance (HLB) and surfactant to oil ratio (SOR). Analyses were performed upon production and during 1-month storage at two temperatures (4 and 25 ˚C) in the presence (100 ppm) or absence of α-tocopherol. Increasing in HLB and SOR decreased the particle size and surface tension; while, increased the refractive index and viscosity. During storage, the particle size of α-tocopherol-loaded nanoemulsions decreased; whereas, that of α-tocopherol-free nanoemulsions increased in a temperature-dependent manner. Irrespective of the storage temperature, surface tension values of antioxidant-loaded nanoemulsions remained constant. However, their viscosity values increased. Antioxidant incorporation fairly increased the nanoemulsions stability likely due to partitioning at the interface. TEM micrographs confirmed the results obtained by static light scattering. The results of this study may help the rational design of functional foods using nanoemulsion-based delivery systems.
Asefeh Latifi; Mohsen Esmaiili
Abstract
Introduction: More than half of the world's people consume rice. Rice consumers, especially in Asia know that cooking properties of rice change with its storage. This phenomenon is called aging. The increase in hardness, decrease in adhesiveness during cooking and decrease in solid loss, are the major ...
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Introduction: More than half of the world's people consume rice. Rice consumers, especially in Asia know that cooking properties of rice change with its storage. This phenomenon is called aging. The increase in hardness, decrease in adhesiveness during cooking and decrease in solid loss, are the major changes in rice which caused by aging. However, while some consumers prefer new rice like Japanese (Zhou, 2002) Iranian and many other consumers prefer aged rice. The change in physicochemical properties of aged rice is caused by the alteration and interaction in lipid, protein and starch (Juliano, 1985; Sodhi, et al. 2003; Teo et al. 2000). The conventional aging of rice takes 3-6 months (Jaisut et al. 2009; Soponronnarit et al. 2008).Yet this method needs more space for storage leading to high operating costs. It is necessary to examine other methods that can reduce the aging time and maintain the rice properties similar to those obtained by the conventional aging process. The process for accelerated aging could be developed either by dry or wet heat (Rayaguru et al. 2011; Rosniyana et al. 2004). The dry heat method was successfully tested with heating of rice in high temperatures in a closed container (Battacharya, 2013). One of the basic problems that occur during dry heating is that any moisture loss leads to cracking. Although the concept is simple in theory, it is complicated in practice. Another drying process for accelerated aging of rice employs a fluidized bed dryer. However, this may decrease head rice yield (Soponronnarit et al. 2008; Wiset et al. 2005), not to mention the fact that these dryers are rare and expensive in rice producing countries. Hence, wet heat is more practical and economical in the mentioned countries. The environmental optimum conditions for accelerated aging of Basmati paddy, at temperature 30–50 °C, relative humidity 50–90% and aging period 3–14 days, has been studied and reported to be 43 °C, 71.0% relative humidity (RH) and 11 days (Rayaguru et al., 2011). Parboiling has been implemented as a method of improving the quality of rice. Nonetheless, it is a lengthy process involving soaking, steaming and drying, which results in the complete gelatinization of starch (Gujral, and Kumar, 2003). According to the importance of accelerated aging, the aim of this study was to evaluate quality attributes and physicochemical properties improvement of Tarom variety of paddy.
Materials and methods: In this study, Tarom variety of paddy (a local variety, with high-quality and large area cultivation in Mazandaran province) was chosen. For accelerated aging, two methods were done: Steaming (or steam curing) and controlling the environmental conditions. In steaming method, the paddy was divided into two portions. The first which had an initial moisture content of 24% (wet base) and the second was the paddy which had been rested at the ambient temperature allowing its moisture content to reach 17%. To accelerate aging of the paddy in two moisture levels i.e. 24 and 17%, the samples were treated by steaming (or steam curing) for 5, 10 and 20 min, and then both of samples were dried with fixed bed dryer at 40 ◦C until the grain moisture content reached 11%. Afterwards, the paddy samples were dehusked and polished with satake miller apparatus. Milled whole rice kernels were separated from broken rice for evaluation of physicochemical properties. In controlling the environmental conditions, the samples were dried with fixed bed dryer at 40 ◦C until the moisture content reached 12%, and then stored at 43 °C and RH=74% for 11 days. Similarly, to produce white rice, the paddy samples were dehusked and polished as mentioned above. The control sample which had an initial moisture content of 24% (wet base) was only dried at 40 ◦C to moisture contend wet basis 11%. Several parameters including head rice yield (the percentage of the mass of white rice that remained as head rice after milling), hardness of raw kernel (the maximum force for breakage of raw white rice), color (b value), chalkiness (weight of the kernel that had chalkiness over one half of the kernel surface in 5 gram of white rice), aroma (using hedonic test), pasting properties (including the peak viscosity, final viscosity, breakdown viscosity and setback viscosity), texture profile analysis (TPA) and thermal properties of rice (the onset temperature, peak temperature, conclusion temperature and enthalpy of gelatinization) were determined. The resultant data were subjected to the analysis of variance using SPSS (ver. 19) software. Duncan’s test was used to establish the differences between mean values at 95% confidence interval.
Results and discussions: The quality attributes of the produced white rice were compared with that of the control samples. By doing the steam curing treatment, solid loss of the rice decreased, adhesiveness decreased, gelatinization temperature increased and viscosity changed. All of the mentioned changes were similar to the alterations that occur in naturally aged rice. By controlling the environmental conditions, the solid loss decreased and the elongation increased. According to sensory and apparent characteristics including aroma and chalkiness, treatment by controlling the environmental conditions could be recommended. Steaming treatment for the three levels of time led to complete loss of aroma.
Narges Samanian; Seyed Mohammad Ali Razavi
Abstract
Sensory evaluation of food materials is an important factor to choose and even produce new formulations. Being time consuming, results in being difficult to interpret and the necessity to educate specialists make these methods kind of impractical. In this study, we have made an effort to introduce physical ...
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Sensory evaluation of food materials is an important factor to choose and even produce new formulations. Being time consuming, results in being difficult to interpret and the necessity to educate specialists make these methods kind of impractical. In this study, we have made an effort to introduce physical properties as a substitute for sensory evaluations in a semi solid food such as chocolate pudding. Higher reliability, reproducibility and higher pace are among some of the advantages of instrumental measurements. Thus, if sensory evaluation can be predicted based on physical properties solely, besides increasing the inspection pace, they would be available to be used online. The obtained results can also be used in designing new products for special consumers such as the dysphasia patients. The results showed that parameters such as shear viscosity, plastic viscosity, yield stress, extensional viscosity, apparent modulus and adhesive force can be used to design and produce new materials; they make sense beside each other though. In this way, the products which have been designed for the patients with swallowing difficulties should have suitable texture in mouth and also good swallow ease.
Asal Gachpazian; Sodeif Azadmard Damirchi; Javad Hesari; Seyed Hadi Peighambardoust; Mahbub Nemati; Sadegh Alijani; Effat Ahmadi
Abstract
Milk and dairy products are in diet almost every day. Milk fat contains 70% of saturated fatty acids which can cause an increase in total and low-density lipoprotein cholesterol, and the risk of cardiovascular diseases. Therefor, modification of fat composition at dairy products such as yoghurt seems ...
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Milk and dairy products are in diet almost every day. Milk fat contains 70% of saturated fatty acids which can cause an increase in total and low-density lipoprotein cholesterol, and the risk of cardiovascular diseases. Therefor, modification of fat composition at dairy products such as yoghurt seems necessary. Walnut has high amount of essential fatty acids, anti oxidants and other beneficial components. In this study, ground walnut is added to yoghurt at level of 0 (control sample), 3, 6 and 9% and their texture properties (synersis and viscosity), sensory, fatty acids profile and dry matter were analysed every week for 4 weeks during storage. Results showed that fortification of yoghurt samples with ground walnut and storage had significant effects ( ) on synersis, viscosity, fatty acids profile and dry matter. Control sample had the highest synersis and the lowest viscosity and dry matter among samples. By adding ground walnut to yoghurt samples, the amount of saturated fatty acids decreased and the amount of unsaturated fatty acids increased. Major fatty acids of yoghurt incorporating ground walnut were linoleic acid, oleic acid, linolenic acid, palmitic acid and stearic acid, respectively. The highest final score in sensory evaluation in 1, 14 and 28 days of storage time were for yoghurt samples with 9% of gorund walnut, yoghurt with 6 and 3% of ground walnut and yoghurt with 3% of gorund walnut, respectively. Results of this study showed that adding ground walnut modifies yoghurt fat composition, forify it with essential fatty acids and also has good effect on its texure properties.
Hoda Khalesi; Mohammad Alizadeh khaled abad; Mahmoud Rezazadehbari
Abstract
Zedo gum is a polysaccharide that exudates from Amygdalus scoparia Spach tree. In this study the apparent viscosity under the influence of the gum concentration (0.5%, 0.75%, 1%, 2%, 3%, 4% and 5% w/v), temperature (20, 45, and 70 ˚C), pH (2, 5 and 8) and salt concentration (0-0.5 M) has been investigated. ...
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Zedo gum is a polysaccharide that exudates from Amygdalus scoparia Spach tree. In this study the apparent viscosity under the influence of the gum concentration (0.5%, 0.75%, 1%, 2%, 3%, 4% and 5% w/v), temperature (20, 45, and 70 ˚C), pH (2, 5 and 8) and salt concentration (0-0.5 M) has been investigated. Zedo gum is composed of soluble and insoluble components that respectively have the properties of solubility and swelling in water. The apparent viscosity changed due to temperature and pH. The highest viscosity was obtained at pH of 7.2 and 24 ˚C. Viscosity was changed by addition of certain strong electrolytes. The emulsion capacity and stability of oil in water emulsion increased by increasing gum concentration. Thermal behavior of Zedo gum with different moisture content was studied by differential scanning calorimetry (DSC). Thermal profiles showed an endothermic event. Considering the results obtained, Zedo gum is a potential natural and domestic additive for industry as a thickening agent, emulsifier and stabilizer.
Food Engineering
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 ...
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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).
