The effect of activated soy flour on the physicochemical, textural and sensory proreties of pan bread

The main problems of bread that increased by reducing flour extraction efficiency are the loss of sensory properties especially color, texture features and accelerating staling rate mainly due to the low fiber content by reduction or elimination bran of flour. The use of alternative fiber sources such as soybean flours that lipoxygenase enzyme is active, which is one of the best ways to naturally enrich, improve quality, and reducing staling. Soy flour, derived from ground soybeans, boosts protein, brings moisture to baked goods, and provides the basis for some soymilks and textured vegetable protein. Adding soy flour to baking products increases the yield of dough, improves the quality of the product and improves the properties of texture, taste and enhancement of the quantity and quality of the protein and acts as an emulsion. So the effect of replacing soybean flour on three levels of 4 %, 8 % and 12 % with wheat flour on qualitative and sensory properties, staling and color of bread on a completely randomized design were investigated. Specific volumes were measured by rapeseed two hours after baking. The crust color analysis was carried out by determining three indices L *, a * and b * in the time interval 2 hours after cooking according to San method, and as well as The brian color analysis was carried out by determining three indices L *, a * and b * in the time interval 2 hours after cooking according to San method. In order to assess crumb porosity of between 2 hours after cooking method Haralyk was used. The bread tissue was evaluated 2 and 48 hours after baking using a tissue weighing machine 1 (CNS Farnell model, ertfordshire UK) based on Pour Farzad method. For sensory evaluation, a 5-point hedonistic scoring method was used, in which characteristics such as shell color, appearance of the skin, texture (ductility or unusual softness, stiffness of the bread, crispness and fragility), aroma, taste, flavor and odor and overall appearance and in The total acceptance is based on the total score of the parameters of the color of the brain, the color of the skin and the appearance of the skin and the appearance of the public within 2 hours after the bread is baked. Also, for sensory evaluation, the sensory evaluation for staling was used according to AACC 11-38 at 24 and 48 hours after baking. The results clearly showed that increasing the percentage of active soybean meal increases the L * bread component, delaying the bread staling, the highest amount L * crust of the sample with 12 % of soy flour was equal to 72 and the lowest in the control sample was 61. With an increase in the percentage of soy flour, has been reduced the component a * bread brains and a * bread crust and as well as with an increase in the percentage of soy flour, increased the component b * bread brains and b * bread crust, as well as with increasing the amount of soy flour, the porosity of the control sample was significantly decreased. As the increased percentage of soybean, decreased the specific volume of bread, adding more than 4 % soy flour had a negative effect on the bread volume. The addition of 4 % of soybean flour has no significant effect on stiffness, but adding more than 4 % in both times cause increase this parameter. The least stiffness was observed in the control treatment at 2 and 48 hours after baking, which was not significant with 4 % active soybean flour. The highest rigidity was observed in the treatment containing 12 % active soybean flour. The increase in the percentage of soybean flour has slowed the staling process at 24 and 48 hours after cooking. Adding soy flour increases the absorption of dough water and, as a result of preserve more moisture, its mechanical properties improve. The results showed the color of bread improved by increasing the amount of soybean flour and retards the staling but increasing more than 4 % soy flour in bread formulation reduced tissue, flavor, odor and overall appearance. Use of soybean flour as a substitute for wheat flour in pan bread improves the quantitative and qualitative characteristics of the final product and therefore, reduces waste.