Attempts for Determining the Degree of Gelatinization in Starchy Materials

Abstract

AbstractDuring the thermal treatment of food and feed materials the most important change taking place is the partial or total gelatinization of starch which is a major constituent of food or feed. The degree of gelatinization depends upon the source material and its moisture content as well as the duration, temperature and pressure at which the material is processed. In this context, it is of general interest to know the degree of starch gelatinization and to develop a simple, relatively specific and economical method to determine the same. There are numerous methods in the literature, and the most popular method is based on its increased susceptibility to enzyme attack, since food materials are heterogeneous mixtures. Attempts have been made to estimate the degree of gelatinization by selective digestion of gelatinized starch using glucoamylase and then by estimation of released glucose colorimetically. By doing this a standard curve is obtained using pure maize starch as well as maize meal, and the degree of gelatinization of an unknown material can be directly read from this graph. The method can be extended to find out the degree of starch gelatinization in pretreated flours, extruded products, baked goods and baby food as well as in cattle feed.