Effect of Azuki Bean Protein on Gelatinization of Azuki Bean Starch

Abstract

Gelatinization of azuki bean starch in the presence of azuki bean protein or some other proteins has been studied by measuring viscosity with the Brabender amylograph, to understand the gelatinization of starch in azuki Ann granules, which were prepared from azuki bean. The temperature of initial viscosity increment rised with increasing the amount of azuki bean protein added, the viscosity at 95°C decreased regardless of the amount of the protein added, and the viscosity after 10min at 95°C decreased slightly by adding 10% protein calculated on dry-starch basis, whereas it increased by adding 50% protein. The addition of 20% casein, gelatin, polypeptone or ovalbumin resulted in temperature rise of initial viscosity increment of azuki bean starch paste. Viscosities at 95°C and after 10min at 95°C decreased by adding casein, gelatin or polypeptone, while the viscosity increased by adding ovalbumin. The effects of azuki bean protein on gelatinization of potato, sweet potato, corn, and wheat starch were also examined. These results suggest that the swelling of azulci bean starch is suppressed at a wide range of temperature by adding relatively small amounts of azuki bean protein, and at low temperature ranges by adding large amounts of the protein, but it is promoted at high temperature ranges by adding large amounts of the protein.