The process of producing rice starch with increased resistant starch content is achieved by using resistant starch-containing rice as the raw material.

Abstract

The invention relates to a process for producing rice starch with increased resistant starch content from resistant starch-containing rice material, including the following steps: (i) preparation of resistant starch (RS)-containing rice material; (ii) increasing the RS content of RS-containing rice (i) by soaking RS-containing rice (i) in a 0.7% citric acid solution at a ratio of 1:(1 - 5) (mass / volume) at 40°C for 3 hours to obtain base rice; (iii) recovery of the rice starch mixture by milling the base rice (ii), followed by filtration and sedimentation, then treatment with a 0.1% NaOH solution for 24 hours at 4°C and gelatinization of the starch with a 0.2M acetate buffer at pH 5.5 to achieve a concentration of 15% at 80°C - 90°C for 20 minutes, then lowering the temperature and stabilizing at 55°C; (iv) Prepare a base enzyme preparation with an activity of 20U / g as a blended mixture of: the first enzyme preparation based on Bacillus licheniformis strain TP01; the second enzyme preparation based on Streptomyces sp. strain TP03; and the third enzyme preparation based on Bacillus subtilis strain TP06;according to the following mass ratio: first enzyme preparation: second enzyme preparation: third enzyme preparation = (1-2) : 1 : (1-2) calculated by mass of preparation (v) increase the RS content for the first time for rice starch by adding the base enzyme obtained above to the rice starch mixture obtained in step (iii'), and incubate at 55°C for 6 hours, then inactivate the enzyme by increasing the temperature to 85°C for 20 minutes to obtain the first RS-increased rice starch mixture; (vi) increase the RS content for the second time for rice starch by treating the first RS-increased rice starch mixture obtained in step (v) in the following order: (vi1) steam at 115°C for 20 minutes; (vi2) degenerate at 4°C for 4 hours; (vi3) microwave at 590W for 2 minutes to obtain the second RS-increased rice starch mixture; where steps (vi2) and (vi3) are repeated alternately 3 times; and (vii) drying the rice starch mixture with increased RS for the second step (vi) at 45°C for 120 minutes yields rice starch containing 10.5% - 18% resistant starch.;