Digestibility Of Potato Starch By Microwave-Assisted And Annealing

Resistant starch(RS) is defined as the sort of starch is not absorbed in the small intestine to provide glucose for healthy individuals, it can stimulate the proliferation of microorganism in large intestine to produce the short chain fatty acids such as butyric acid, have the effect to promote beneficial bacteria growth and intestinal peristalsis. Food with higher content of RS reduced postprandial insulin secretion, increases sensitivity to insulin and effectively restrain the rise of blood glucose. This paper mainly researched on improving the potato starch preparation technology to decrease digestibility of starch.On the basis of filtering high RS content potato, microwave and annealing treatment was used for preparation of potato starch to increase content of RS. Finally adding this potato starch with high RS content, a kind of healthy steamed breads with Low sugar and low protein for diabetic nephropathy patients was developed.The results were as follows:RS content and amylose content in Zhangshu3 were highest in varieties test.On the basis of bivariate correlation analysis with amylose content and RS content,there were significantly positive correlation among amylose content and RS content.Zhangshu 3 was taken for further research of preparation technology to decreasing digestibility of starch.The experiments were held with Zhangshu 3, the method of microwave and annealing was used for the preparation of potato starch to increase RS content.On the basis of single factor experiment, by orthogonal experiment optimization, determined the best technological conditions were: ratio of material to water 1:3, microwave effect time 500 s, microwave effect power 500 W, annealing treatment time 18 h, aging time 24 h. Under such conditions the RS content increased to 26.85%.The surface of potato starch with high proportion of RS suffered serious corrosion and sticked together compared with native starch.RS molecules tend to order of crystal structure and the crystallinity were obviously higher compared with native starch. To, Tp, Tc, △H of RS in DSC plot exhibited an obvious increased. Damages the crystalline structure with heat treatment needed more energy. Besides, the rise in gelatinization temperature and the drop in viscosity were observed in resistant starch. Anti-digestive capacity and thermal stability of RS were higher than native starch. Bibulous, emulsification and emulsion stability was much lower than that of native starch.but the capacity of moisture retention better than native starch.According to requirements of diabetes nephropathy patients, Single-factor and orthogonal experiments were carried out to design the optimum formula of steamed breads low in sugar and protein. The results showed that potato resistant starch for 50%, pregelatinized starch for 8%, amylose for 10%, wheat starch for 5%, wheat flour for 25%, instant yeast for 0.5%, improvers for 1% baking powder for 0.5%. With the prescription, the organoleptic investigation of the steamed breads scored 88.8 points were the best with large volume, smooth and white surface and uniform in particle size.Steamed breads under this formula were the food with moderate glycemic index. Protein content could be down to 3%.