Preparation Of Retrograded Maize Starch Containing Gliadin

With the development of our living standard,,products with nutrition and health care function have been warmly welcomed by consumers. As the functional food for preventing, alleviating and curing constipation, controlling diabetes, promoting lipid and cholesterol metabolism, improving absorption of mineral and enhancing disease resistance etc, retrograded resistant starch is a kind of dietary fiber with best biological function and special process character. Nowadays, it has been the first choice of dietary fiber because of its delicate in taste, low water holding capacity, white color, light taste and low price. As the product of starch pasting and aging, the retrograded starch is non-toxic harmless, natural purity, high security and wide variety of sources.Retrogradation is a process of resistant starch with crystal structure formed by hydrogen bonds after the amylose and amylopectin is evolved from granules. The retrogradation rate of starch decreased as the result that granules swell instead of breaking, which hinders the dissociation of amylose and amylopectin. Fermentation broths of some microorganisms could destroy those granules and could improve starch to combine with gliadin,those microorganisms were screened. Also their conditions of fermentation and treating starch for high retrogradation rate were investigated initially. The results showed that the fermentation broths of Fuhai02, J:11, Jiuqu1, Qian-1, J:15 and Qu1-3.5 improved retrogradation rate of maize starch more, which improved them from 9% to above 20%. As for Fuhai02, 26%. When Fuhai02 grew on optimum culture of 2.5% glucose and 50 m L gliadin hydrolysate, the fermentation broth made the retrogradation of maize starch reach to 29.1%. The proper conditions for this broth to treat maize starch were 48℃、p H 8.0 、8h,respectively and the retrogradation rate reached to 38.4%. The microorganism Zbx(2)11.7 promoted the combination of gliadin and maize starch and improved the retrogradation rate from 14.3% to 28.5% at normal culture, for optimum condition of 25 m L α-amylase hydrolysate and 50 m L soybean protein hydrolysate, 31.6%. The best conditions for Zbx(2)11.7 fermentation broth to treat maize starch were treating temperature 20℃、p H4、treating time 1h and the retrogradation rate reached to 43.9% on this condition. The mechanism for gliadin to promote retrogradation of maize starch were deduced by comparing the visible, IR, NMR, X-diffraction and DSC spectrum of retrograded maize starch mixed with and without gliadin.