Estimation of Gelatinization, Retragradation and Destruction of Mochi (glutinous rice cakes) for Arare by Degree of Dispersion

Abstract

Estimation of gelatinization, retrogradtion and destruction of mochi (glutinous ricecakes) for Arare was studied by using uncooked glutinous milled rice; steamed glutinous rice; fresh mochi; and cooled retrogradated mochi. (1) Use of a 0.04% sodium lauryl sulfate solution for dispersion medium permitted the determination of the degree of dispersion to correspond to the degree of gelatinization evaluated by the β-amylase-pullulanase method. (2) It was found that degree of dispersion of retrograded starch increased with an increase of the dispersion temperature from 30°C to 52.5°C, and that of gelatinized and swelled starch decreased with a decrease in concentration of 1.0% to 0.1% (3) The degree of gelatinizasion of mochi could be estimated by the degree of dispersion at 1.0% concentration at 30°C. The degree of gelatinization of mochi at α stage could be estimated by the degree of dispersion at 1.0% concentration at 52.5°C. The degree of retrogradation of mochi in strongly bonding micelles could be estimated by the differrence of the degree of dispersion at 1.0% concentration at 52.5°C and that at 1.0% concentration at 45°C. The degree of destruction of mochi could be estimated by the degree of dispersion of a O.1% filtrate of its supernatant at 52.5°C.