Research on the Preparation of Light Speckled Kidney Bean with High Resistance Starch by Autoclaving Processing

In order to improve the content of resistant starch of light speckled kidney bean and reserve the other nutrients, an autoclaved method for preparing light speckled kidney bean with high resistant starch was studied. The essential nutrients, in vitro digestibility and structural characteristics of autoclaving light speckled kidney bean were evaluated. Results showed that, the process conditions of autoclaved method for preparing light speckled kidney bean with high resistant starch were optimized as follows: Autoclaving temperature 124 ℃, solid-liquid ratio 1:1.9 (g:g), retrograded time 73 h, and autoclaving time 24 min. Under the optimized conditions, the content of resistant starch was 35.63%, which was close to the corresponding theoretical value. An analysis on the structural characteristics showed that the original starch grains was changed significantly in morphology and in molecular crystal form, but no new group was generated. After autoclaving, the crude fat, crude protein in the light speckled kidney bean did not obviously changing, but the content of starch and resistant starch increased obviously (P<0.05). The in vitro digestion rate of high resistant starch in the light speckled kidney bean decreased significantly after autoclaving. The method of autoclaving improve the content of resistant starch of light speckled kidney bean would provide a reference for the commercialization and its application in food industry as well.