Optimum Preparation Conditions And Application Of Highland Barley Slowly Digestible Starch

Starch is the main energy material in human body.According to the digestibility in vitro and availability of starch, it can be divided into rapidly digestible starch(RDS),slowly digestible starch(SDS) and resistant starch(RS).SDS is that can be digested in the small intestine but the rate of digestion is slow(20-120 min), it release energy slowly but continuously, keep postprandial blood sugar stably, reduce postprandial insulin secretion, and improve the body’s sensitivity to insulin.Highland barley has high level of protein,fiber and vitamins, low content of fat and sugar.Highland barley has very high value of nutrition, so this paper selected barley starch as raw materia to prepare slowly digestible starch, raise the content of the highland barley slowly digestible starch.1.The optimization of preparation conditions of highland barley slowly digestible starchThis experiment used highland barley starch as material, respectively produced slowly digestible starch(SDS) by Pullulanase,α-amylase,β-amylase,β-amylase and transglucosidase, α-amylase and transglucosidase these five kinds of methods, and optimized the conditions of SDS preparation. Optimum solutions of SDS were the method of Pullulanase and the method of β-amylase and transglucosidase by the orthogonal test,the content of SDS respectively were 34.81%, 32.53%. The treatment conditions of pullulanase method: the amount of pullulanase was 200 U, the enzymolysis time was 10 h, the refrigerated resuscitation time was 1d, and the concentration of starch was 15%. The treatment conditions of β-amylase and transglucosidase method:the amount of β-amylase was 0.032%,the amount of transglucosidase was 0.192%, the enzymolysis time was 8 h, the retrogradation time was 5d, the concentration of starch was 15%.2. Determination of the relative molecular weight distribution of highland barley starch by using High performance size exclusion chromatographyThis experiment measured the relative molecular weight distribution of highland barley starch and these five kinds of highland barley starches after dealing withPullulanase,α-amylase,β-amylase,β-amylase and transglucosidase, α-amylase and transglucosidase by using HPSEC. Maps showed that highland barley starches after treatment of Pullulanase,β-amylase and transglucosidase,α-amylase and transglucosidase compared with the original barley starch, the ratio of amylopectin were reduced, the proportion of low molecular weight molecules increased, the ratio of amylopectin to amylose decreased, the distribution of molecular weight changed significantly, and the content of slow digestion starch of three kinds of highland barley starches were increased. Maps showed that highland barley starches after treatment ofβ-amylase and α-amylase,molecular weight were lowered but the amylopectin still accounted for a significant share, and the content of slow digestion starch had no significant change.3. The application of highland barley slow digestion starch in soda biscuitsBy in vitro digestion experiment, the SDS content of highland barley slow digestive biscuit is 26.42%, its SDS content was higher than biscuits made of daily grains such as corn, wheat, and part of cookies in the market. Through the analysis of hydrolysis curves of seven kinds of cookies, glucose concentration of highland barley SDS biscuits elevated relatively slowly within 30 min~120 min, the growth of glucose concentration in 0min~30 min also lower than the other six kinds of biscuits. This suggests that the nature of slow digestion of highland barley SDS biscuits was more significant than daily grain biscuits and some biscuits in market. There was little difference in morphology and sticky degree,but major difference in color, degree of degeneration and texture roughness between highland barley SDS biscuit and other six biscuits through the sensory evaluation. The colour and lustre of highland barley SDS biscuits is deep, and the taste was more rough.