Study On The Preparation Of Resistant Starch And Its Effect On Glucoamylase Output Of Aspergillus Niger

Adopting the method of heat and press treatment, the condition was optimizedfor preparation of resistant starch of maize and resistant starch of sweet potato; Itcould find out some theoretic reason for its possible application through comparing itsshape between the granule of resistant starch and the granule of its original;In order to enhance the development of new production and the application of theresistant starch, increase its value and promotion of the income of farmer, theorthogonal experiment was given on the study of effect of resistant starch onproductivity of glucoamylase of Aspergillus niger in fermentation. The results wereshown as follows:1. The optimum conditions of preparation of resistant starch of maize were givenas follow: starch content 35％, the pH value 4.5, the gelatinization temperature 125℃, the time of gelatinization 60min, refrigeration time 120h; The optimum conditionsof preparation of resistant starch of sweet potato were that: the starch content 35％,the pH value 4.5, the gelatinization temperature 115℃, the time of gelatinization70min, refrigeration time 72h. Under the conditions mentioned above, the extractionrate of the resistant starch of maize and resistant starch of sweet potato were 18.26％and 16.42％respectively. The preparation method of resistant starch was simply andthe equipment investment was not to be many. It would be a good prospect ofdevelopment production.2. After being treated by heat and press, the granule appearance shape of starchbecame irregular from original regular; There were obvious difference in its pictureDTA between the resistant starch and the original starch. The result showed that thecrystal form of the resistant starch had changed extensively. Through studying thehygroscopicity and the subsidence rate of the resistant starch, We had known that theresistant starch had many excellent physical properties of application in food industry.3. It can enhance the activity of glucoamylase of Aspergillus niger greatly byusing resistant starch as carbon source of the culture medium during the fermentation.