Effect of high-pressure treatment on decomposition of potato and wheat starch by α-amylase

Abstract

Gelatinization of starch is essential in order to saccharify starch by amylase. Starch is gelatinized by heat-treatment, which requires a lot of energy. This study investigated the possibility of gelatinization of starch by high-pressure treatment, which was to make a better alternative to heat-treatment with respect to energy conservation. Potato and wheat starches were used in this study. Decomposition of potato starch by amylase accelerated after pressure treatment over 600MPa, while that of wheat starch accelerated over 400MPa. The transition enthalpy decreased at the pressure intensity, where the decomposition of starch accelerated by amylase. Although, the polarized light of small starch grains remained, the polarized light of large grains disappeared after high-pressure treatment. The result shows that the crystal structure of small grains in starch is much stronger than that of large grains. These results clearly show that the decomposition of starch by amylase accelerate after high-pressure treatment because of the crystallinity of starch changed by high-pressure treatment.