抄録
The influences of α-amylase on the expansion of chou crust were investigated. At first, adding 10.521.0 u. of α-amylase/10g of wheat starch to starch paste resulted in the improvment of expansion of chou crust. However, the addition of 105 u. of α-amylase/10g induced the worse quality compared to the one without α-amylase. Secondly, each 10% wheat starch, solution was reacted with 0,10.5,21.0,105.0 or 210.0 u. of α-amylase/10g, and lyophilized. A powder of partly digested starch was obtained. Egg and shortening were mixed with 50% of each powder solution and corresponding chou pastes were prepared. Then, the effects of reducing starch molecule weight on the expansion of chou crust were examined.
An improvement of the expansion of the chou crust was observed by using powder obtained from the digestion of starch with 10.5 u. of α-amylase/10g. However, the reaction of starch with 105.0 or 210.0 u. of α-amylase/10g induced deterioration of expansion compared to the one without adding α-amylase. Finally, the addition of AgNO3 as an inhibitor of α-amylase to egg depressed the deterioration of expansion in the chou crust of stored chou paste. These results suggest that the reduction of starch molecule by α-amylase in eggs is one of the causes of the deterioration of chou crust derived from chou paste which was preserved under the condition of high temperature for a long period.
