Sara Hoseinpoor; Behnaz Layegh; Asgar Farahnaki; Gholam Reza Mesbahi; Mahsa Majzoobi; Nazanin Darabzadeh
Abstract
Pectin is used as a gelling, texturizing and emulsifying agent in many foods. Sugar beet pulp is a good source of pectin, however due to its low molecular weight and poor gelling characteristic its uses in food industry are limited. In this research, pectin extracted from sugar beet pulp was cross-linked ...
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Pectin is used as a gelling, texturizing and emulsifying agent in many foods. Sugar beet pulp is a good source of pectin, however due to its low molecular weight and poor gelling characteristic its uses in food industry are limited. In this research, pectin extracted from sugar beet pulp was cross-linked by phosphorus oxycholride at pH 11 to improve it functional properties. Rheological tests carried out revealed that modified pectin had a higher viscosity and greater intrinsic viscosity and molecular weight than native pectin confirming the cross-linking of pectin polymers. Ketchup sauces formulated using modified and native pectins were compared with the control sample without pectin. The results showed that the sample containing modified pectin had a higher consistency and a lower syneresis value compared to the native pectin.
Keywords: Pectin, Sugar beet pulp, Cross-linking, Viscosity, Functional properties
Nazanin Darabzadeh; Sahar Sadat Mousavi Nasab; Mahmoud Aminlari; Roghaieh Ramezani
Abstract
In recent years soybean derived foods (such as soymilk) have received considerable attention due to their high nutritional value and functional properties. The purpose of this study was to investigate the changes in protein solubility and electrophoretic behavior of soymilk stored at refrigerator and ...
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In recent years soybean derived foods (such as soymilk) have received considerable attention due to their high nutritional value and functional properties. The purpose of this study was to investigate the changes in protein solubility and electrophoretic behavior of soymilk stored at refrigerator and freezer conditions. A 12% total solid content soymilk was produced and stored at 4 and -18ºC. At different time intervals samples were removed an analyzed for protein solubility and SDS-PAGE. A gradual decrease in solubility of proteins stored at -18ºC with time was observed such that after 3 weeks solubility was dropped from 75% to 45% (30% decrease) and remained at 41% thereafter up to 6 weeks. These changes appeared to follow a first order kinetics with a rate constant (k) of 0.014(day)-1 and half life (t1/2) of 62 days. Similar pattern was seen in the refrigerated sample except that the decrease in solubility occurred slowly and at final stage, solubility decreased by 17%. At this temperature the decrease in protein solubility followed a zero order kinetics with k of 0.625 (day)-1 and t1/2 of 144 days These results indicate that long term refrigeration and freezing of soymilk must be avoided.Keywords: Soymilk, solubility, SDS-PAGE
Marzieh Moosavi-Nasab; Nazanin Darabzadeh
Abstract
Lysine is nutritionally essential for humans and animals. It cannot be synthesized biologically in body. Children and growing animals have a high requirement of lysine, since it is needed for bone formation. Therefore, it must be added to food and feed supplement to improve the protein quality. In addition, ...
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Lysine is nutritionally essential for humans and animals. It cannot be synthesized biologically in body. Children and growing animals have a high requirement of lysine, since it is needed for bone formation. Therefore, it must be added to food and feed supplement to improve the protein quality. In addition, lysine has some pharmaceutical applications in the formulation of diets with balanced amino acid composition. Chemical, enzymatic and biotechnological processes have been used to synthesize lysine. However, biotechnological methods (fermentation) seem to be the most economical and practicable means of producing lysine. In the present study, production of lysine by Brevibacterium linens PTCC 1603 from whey and molasses medium, in the purpose of using agricultural by-products as low-cost sources for production of value-added products, was investigated. Whey medium was prepared by hydrolyzing of lactose with HCl and molasses medium was prepared by addition of some chemicals to it. The production of lysine was examined qualitatively and quantitatively using ascending thin layer chromatography (TLC) and spectrophotometry. Results showed that lysine concentration in both media was increased significantly by the time. The highest concentration of lysine produced from whey and molasses media were 11.8 and 10.5 g.L-1, respectively. Increasing lysine concentration resulted in pH increment in molasses medium, while the pH of whey medium was decreased. After 6 days of fermentation, the amount of lysine in whey medium was significantly higher than in molasses medium.
Keywords: Lysine, Fermentation, Brevibacterium linens, Whey, Molasses
Mahsa Majzoobi; Nazanin Darabzadeh
Abstract
Consumer’s demand for functional foods is increasing, however, production of such food is not an easy task, and sometimes the sensory aspects of food are affected adversely. To ensure the customers of the quality of food, it is necessary to label the product with accurate nutrition information ...
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Consumer’s demand for functional foods is increasing, however, production of such food is not an easy task, and sometimes the sensory aspects of food are affected adversely. To ensure the customers of the quality of food, it is necessary to label the product with accurate nutrition information in order to make people aware of the positive nutrition effects of such foods. The aim of this research was to study the effects of giving nutrition information to the customers on their perception of quality of a wheat germ cake. Therefore, some cakes containing 15% wheat germ were packed in two different packages, one with and the other without nutrition label. These cakes were evaluated by taste panel in terms of color, flavor, taste, texture, general acceptability and possibility of buying. The results showed that despite the similarity of the product, the cake with nutrition information received higher score in many sensory aspects, general acceptability and the possibility of buying than the other one. The results stressed the impacts of giving information and making the culture of the people on the marketing of healthy food products and the costumers' perception of the food quality. Keywords: Food culture, Nutrition information, Consumer perception, Healthy food, Wheat germ cake
