Effects of infrared radiation heating temperature and time on starch gelatinization and technological, thermal, and pasting properties of parboiled rice

Abstract

Background and Objectives: The improvement of the physical, chemical, and sensorial parameters of parboiled rice is constantly sought by the industry.Thus, the objective was to evaluate the effects of infrared radiation heating temperature (80°C, 100°C, 120°C, and 140°C) and time (2, 6, 10, and 14 min) on starch gelatinization and technological, thermal, and pasting properties of parboiled rice. Findings:The degree of gelatinization of rice starch subjected to infrared radiation heating ranged from 5.73% to 39.13% and the relative crystallinity from 49.70% to 42.30% in the treatments at 80°C for 6 min and 140°C for 14 min, respectively. The increase in head rice yield is related to an increase in the degree of gelatinization and a reduction in the relative crystallinity of the starch, making the grains more resistant to breakage. There was a tendency to reduce the cooking time at temperatures of 80°C and 140°C, regardless of the heating time. As for hardness, the opposite behavior was observed, with a tendency to increase at temperatures of 80°C and 140°C, regardless of the heating time.Conclusions: Infrared radiation heating can be used to produce parboiled rice. It is recommended to use temperatures between 100°C and 120°C for 6-10 min. Significance and Novelty:The method validated in this study presented to the rice processing industry a new way to produce parboiled rice. The study showed that it is possible to use infrared radiation heating to gelatinize rice starch. The use of infrared radiation in rice processes is widely used in the industry as a source of heating, whether in drying or parboiling, with previous studies showing a reduction of up to 4.6 times in energy consumption compared to conventional sources of heating.