Study On The Processing Technology And Digestion Kinetics Of High Resistant Starch Purple Sweet Potato Biscuits

The purple sweet potato(Ipomoea batatasLam.,PSP),a tuberous root crop belonging to the family of Convolvulaceae,is rich in starch,dietary fiber,anthocyanins and many kinds micronutrients.It has various healthy functions including hypoglycemic effect,promoting gastrointestinal motility.Based on the nutritional characteristics of PSP,this study investigated and optimized the processing technology of PSP biscuit to increase the resistant starch content.A crispy PSP biscuit with high resistant starch content and low glycemic index was developed,and its production standard was set up.The main contents of the article were as follows:1.The optimization of the recipe of PSP crispy biscuit.According the results of single factor experiments,using the additive amount of PSP starch,butter,baking soda as independent variable,and frangibility,chewiness and sensory score as dependent variable,a L9(34)orthogonal experiment was carried out to determine its optimum production recipe was as follows:12.49%PSP starch(considering the amount of low-gluten flour as 100),25%butter,0.42%baking soda,25.01%sugar,7.5%milk powder,30%egg mixture and 12.5%water.2.The effects of microwave processing time,microwave processing intensity,baking temperature and baking time on the resist starch content in the PSP biscuits.The results of single factor experiment showed that microwave processing time,microwave processing intensity and baking time have significant influence on the resist starch content in the PSP biscuits(P<0.05).Based on the results of the three factors and three levels response surface experiment,the optimum processing technology was determined as follows:microwave processing time of 19 s,microwave processing intensity of 700 W and baking time of 19.5 min.to determine its optimum process technology.Under these conditions,the resistant starch content in PSP biscuit reached to 18.06±0.32%.3.Using the method of complex enzymatic hydrolysis in vitro,the digestibility of biscuit was determined by the pepsase and a-amylase,and the effects of the amount of PSP starch on the digestibility of biscuit was investigated.Through analyzing curve of starch hydrolysis and utilizing first level dynamics simulation equation to predict glycemic index of PSP biscuits.The results indicated that the glycemic index of PSP biscuit was 63.29,which is belonging to a moderate glycemic index food.High resistant starch PSP biscuit could lower glycemic index and exhibit a functional characteristic as slow digestible starch.4.According to GB 7100-2015<national food safety standards of biscuit>,physical,chemical and microbial indicators of biscuit were detected and proved to meet the national standards.In the last part,the quality standards of PSP crispy biscuit was set up,and HACCP system was established and carried out to insure the quality and safety during the industrial processing.