MODIFICATION OF CORN STARCH AND FINE FLOUR BY ACID AND GAMMA-IRRADIATION .2. EFFECT OF GAMMA-IRRADIATION AND ACID TREATMENT ON THE CHEMICAL-STRUCTURE OF STARCH AND THE DISTRIBUTION OF PROTEIN-FRACTIONS

The effect of γ‐irradiation and dextrinization on the chain length of the starch molecule was studied. The chain length was decreased from 30.0 to 5.4 G. U. after dextrinization in presence of hydrochlorid acid. The average chain length of the irradiated starch was affected depending on the doses. The results showed that splitting of glucosidic linkage by irradiation occured beside other transformations in the structure of the starch. The formation of little amounts of dialdehyde by irradiation has been proved. Results showed the presence of a fraction containing a monosaccharide and different amino acids. This is partial proof for the presence of a glucoprotein type. In case of irradiation of the fine flour with 700 krad, the percentages of the protein fractions were not affected. In case of acid dextrinized fine flour, there is an increase in the water‐soluble fraction and a decrease in the alkali fraction. Irradiation of fine flour with 700 krad decreased the amylase activity to about half the value. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim