| 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 one kinds of dietary fiber. In recent years research we have proved that RS can not be digested in the small intestine, and not supply glucose, but it can be fermented in the large intestine by intestinal microorganisms florae. In this period RS produced some short chain fatty acid, such as butyric acid etc. The butyric acid can stimulated the growth rate of the availability florae, and inhibited the growth of cancer cell. Because of small molecular weight and low water retention property, RS is a suitable material of dietary fiber and processed food. All kinds of physiological functions about RS are studied both here and abroad,, Lots of crystal are produced in the process of preparing the resistant starch. Why the resistant starch can resist the enzymolysis is ascribe to the compact structure of crystal. Because corn starch and potato starch have high amylose content, in this study , we use corn starch and potato starch as materials, the optimal parameters for preparation of resistant starch was investigated, choose the better material for resistant starch, and develop high additive produce, and analyse physical and chemical quality to adequate learn the character of resistant starch for food, the results indicated:For these factors in resistant starch preparation, the subsequence of importance was starch concentration> cooking temperature>pH> retrogradation time>drying temperature > retrogradation temperature. With the starch concentration 14%,pH6.0,heated at 130℃ for 60 minutes, then retrograded at4℃ for 24 hours, and drying at 80℃ ,the original starch yield of 18.81 % (corn ) 15.22 %(potato)RSoCompared with corn RS and potato RS ,we can learn that corn RS have high produce rate than potato RS ,so corn RS are suitable material .Multiple press-heat reaction can greatly increase the produce,but considering the economic factor twice press-heat reaction is most suitable. Because the effect of multiple press-heat is not obviously high than twice press-heat reaction. The twice press-heat reaction yield 21.23% (corn), 18.91 % (potato).Combined the press-heat method and enzyme method ,we greatly increased the yield of RS. poloenzyme get a great deal of effect that is because high amylose content can increase the yield of RS. The yield of RS in this method is 28.06%(corn)> 24.63% (potato )oWhen we research the lipidic we found lipidic have greatly effect to the yield of RS o low lipide starch can produce32.23% RS ,none lipide is 29.85%(all is corn starch) o we can learn that low lipide starch are more effect than none lipide starch ,and they are both higher than original starch ,at the same time,we can more easy to acquire the low lipide ? It is more useful to produce <,Through the electron microscope and viscosity analysis , We can learn that the structure of RS is tightness , the grain is the high density ,the viscosity is stability, the gelatin is easy to formation, and the rheology characteristic is very fine, so RS can be used as food thickener o The brightness of RS is a little lower than original starch, but the whole sense is still the white dustc The content of crozzle and SO2 are not changed ,which proved that RS change the original starch is from the structure not the component ,so RS can be used in all kinds of mianshioThrough the physical and chemical analysis ,we can learn that the wet content of RS is 4.51 % (corn) , 5.15 % (potato) ,which is more lower than the content of original starch which is 12.10% (corn) 15.25% (potato )? Its clearly that RS is low water retention property , RS is low water retention property and untranslucidus and high viscosity,all of these feature proved that RS fit to produce dense beverage ?...
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