Study On Flour Properties And Noodle Qualities By Adding Soybean Powder

Adding proper amount of soybean powder to wheat flour is an effective way to improve nutritive value of wheat flour. Effects of soy powder on dough properties and qualities of noodle were studied in this paper. The main experimental results are as follows:(1)Soy products, including enzyme-active full-fat soy flour, heat-treated full-fat soy flour, enzyme-active defatted soy flour, heat-treated defatted soy flour, were made from the same soybean with different production technology. Four kinds of soy products were blended with medium-gluten wheat flour at different levels to reach similar protein contents (12% and 14.6%) in the flour mixtures. Effects of four different soy power on farinograph properties of dough and storage stability of wheat flour were reseached, and one of soy products was selected to be added to wheat flour based on this. The results showed that dough development time and stability time significantly increased when enzyme-active defatted soybean powder was added to wheat flour, and the other three soybean powder played an negative effects on farinograph properties of dough. For storage stability of soy/wheat flour, peroxide value of mixture containing enzyme-active full-fat soy powder and change rate of acidity value of mixture containing enzyme-active full-fat soy powder were the largest after 20 days storage. So, Enzyme-active defatted soy powder was selected to be added to wheat flour to improve nutritive value of wheat flour.(2) Effects on dough properties and qualities of noodle were studied after adding different amount of defatted soy flour. As adding amount of defatted soy flour increases, the peak viscosity of the mixed powder became smaller, farinograph and extensibility properties of dough showed deterioration trends. Noodle became yellow, water absorption of noodle gradually decreased, cooking loss of noodle increased when defatted soy flour was added to wheat flour. Texture analysis showed that hardness, chewiness and tension force of defatted soy noodle increased, springiness and tension distance decreased. Based on comprehensive consideration of wheat flour nutrition fortification and noodle qualities, the adding amount of defatted soy flour to wheat flour was 9%.(3) Some qualities of noodle with 9% defatted soybean are worse than it without 9% defatted soybean. Therefore enzymes (glucose oxidase, glutamine transaminase, xylanase) and thickener were selected to improve qualities of noodle with 9% defatted soybean flour. The optimized formula was selected by orthogonal design, at GOD 10 mg / kg, TG 0.2%, xylanase 30mg/kg, guar gum 0.2%. TPA test and scanning electron microscopy experiments confirmed the improvement effects of the complex additives.