Study On Improvement Of Resistant Starch From Buckwheat Powders By Physical And Enzyme Methods

Resistant starch (RS) is defined as the sum of starch and products of starch degradation not absorbed in the small intestine of healthy individuals. Now, it is a kind of the dietary fiber. Recently, researches have proved that RS can not be digested in the small intestine, and not supply glucose. However, RS can be fermented in the large intestine by intestinal microorganisms florae, which produced some short chain fatty acid, such as butyric acid etc. The butyric acid can stimulate the growth rate of the availability florae, and inhibit the growth of cancer cell. All kinds of physiological function about RS are studied both here and aboard. Lots of crystal are produced in the process of preparingthe resistant starch .Why the resistant starch can resist the enzymolysis is ascribe to the compact structure of crystal. Because of some molecular weight and low water retention property, RS is a suitable material of dietary fiber and processed food.This paper researches the technology of the processing of the RS3 using the buckwheat powders, because it hasn't more protein, fat, vitamin,and microelement than rice, corn and other food stuffs, but also has the particular chlorophyll and rutin. A series of experiments to improve the content of RS3 have been done, through autoclaving, enzyme-autoclaving, and autoclaving-enzyme-autoclaving methods. The better process conditions are confirmed and several qualities of RS are determined. At last, it is analyzed that some characters of RS which will be ready for high product of RS.First, for these factors in resistant starch preparation, the subsequence of importance was powders concentration> pH > cooking time > cooking temperature.With the powders concentration 15%, pH7.0, heated at 120℃for 15 minutes, then retrograded at 4℃for 24 hours, and drying at 80℃,the original starch yield of 20.3% RS.Second, based on the best process condition of the autoclaving method, thermo stable a-amylase and pullulanase are used on the starch. The content of RS is increased further. The parameters of the enzyme-autoclaving method are that the added quantity of the thermo stable a -amylase is 80U/g starch, the reaction temperature is 95℃and time is 30min. Finally, the added quantity of the pullulanase of 150U/g starch is added, reacting under the pH4.7, 55℃for 6h. The content of RS can reach about 30.45% under this conditions.Combining with the autoclave and enzyme methods, choosing the best option, multipling autoclaved reaction can greatly increase the qualty, but considering the economic factor, autoclave 1 time reaction is most suitable. Because the effect of multiple autoclave reaction isn't obviously higher than autoclave reaction 1 time. The autoclave reaction 1 time yield 31.8%.When we research the lipidic we found lipidic have greatly effect to the yield of RS. None lipide powders can produce 34.9%, low lipide can produce 32.4% RS, We needn't make none lipide RS, if we stand in the industrical cost and techonology.