Superheated steam pretreatment of rice flours: Gelatinization behavior and functional properties during thermal treatment

Abstract

The effect of superheated steam pretreatment on the gelatinization behavior and functional properties of waxy and non-waxy rice flour were studied. The superheated steam-treated waxy rice flours and non-waxy rice flours showed significantly lower onset of gelatinization temperatures (58.8 and 56.1 degrees C, respectively) than that of their respective control. Water binding capacity, swelling power, solubility and particle size of rice flours were evaluated from 20 to 90 degrees C. Before the gelatinization temperature (<60 degrees C), the water binding capacity and swelling power were about 1.7 times higher for the superheated steam treated waxy rice flour and 1.4 times higher for the superheated steam treated non-waxy rice flour than those of their control. The superheated steam treated non-waxy rice flour had a significantly higher particle diameter (82 mu m) than the other flours. The granules of superheated steam-treated flours were swollen more than the native flours granules due to partial gelatinization. Superheated steam may be a promising physical method for modification of specific properties of rice in terms of gelatinization behavior, granular structure and functional characteristics of rice flours.