Daiwa Kasei KK

Digestion of boiled rice by various amylases was tested in vitro at pH 6.0 and 4.7, and at 37°.The results showed that the digestion was best related to the starch liquefying activity of the amylases among the 3 expressions of the amylase activity, i.e., saccharifying, dextrinizing, and liquefying.Aspergillus oryzae amylase had a weak dextrining activity with amylopectin itself, and was weaker with starch, because it had more affinity to amylose than to amylopectin.A. oryzae amylase was adsorbed markedly on boiled rice at pH 4.7 and 37°, and it remained active as a saccharifying amylase.Salivary amylase had a weak dextrinizing activity with amylopectin itself, but it had a strong starch liquefying activity because of its marked affinity to amylopectin in starch.Bacillus subtilis amylase had a strong starch liquefying activity as well as dextrinizing activity with amylopectin and was characterized by its high reaction rate in the early stage of amylopectin decomposition