Impact of heat-moisture treatment on rice starch, applied directly in grain paddy rice or in isolated starch

•Rice grains and isolated starch were submitted to HMT at 13 g/100 g moisture.•HMT reduces extraction yield of rice starch by the alkaline method.•HMT performed in grain or directly in starch affects differently the starch properties.•HMT effects on starches are intensified by treatment time.

Starch is considered an important ingredient in the preparation of safe food. Current study investigates the physicochemical, morphological, thermal and pasting properties of rice starches, subjected to HMT at 13 g/100 g moisture, at different treatment times (10, 30 and 60 min), directly in the grain paddy rice and in the isolated starch. HMT reduced extraction yield of rice starch with increasing HMT time. The HMT starches had lower gelatinisation enthalpy when compared to native starch. HMT in grain reduced extraction yield of starch by the alkaline method with increasing time of exposure to high temperatures, altering the structure of starch-protein. The HMT in grains decreases the setback of the isolated starches, due to amylose-lipid complexation induced by high temperatures applied on modification. The hydrothermal treatment increased the mechanical and thermal stability of rice starches and promoted the strengthening of links, forming a more stable structure.