Effects of potassium sulfate on swelling, gelatinizing and pasting properties of three rice starches from different sources

This study evaluates the effects of potassium sulfate (K2SO4) on the swelling, gelatinization, and pasting properties of indica rice starch (IRS), japonica rice starch (JRS), and waxy rice starch (WRS). As a result, the gelatinization temperatures (T-p), swelling capacities, and pasting viscosities of rice starches in water followed the order of WRS > JRS > IRS, showing positive correlations to amylopectin content and molecular weight. At K2SO4 concentration of 0.05-0.6 M, T-p increased by 10-13 degrees C due to a more compact structure of starch granules resulting from increased interactions of starch chains with K+. However, the swelling capacity decreased with increasing K2SO4 concentration and followed the order of WRS < JRS < IRS, which decreased sharply from 27.3 to 2.5 g/g for WRS. K2SO4 dramatically reduced the pasting viscosity of starch pastes due to the decreased swelling capacity. This study provides the scientific basis for rice starch processing with K2SO4.

Automated summary

The study evaluated the effects of potassium sulfate (K2SO4) on the properties of different rice starches, showing that increasing K2SO4 concentration led to higher gelatinization temperatures and lower swelling capacities, resulting in decreased pasting viscosities. Waxy rice starch (WRS) exhibited the most significant changes in response to K2SO4.