Application of Pulsed Ohmic Heating for Rapid Cooking of Indica Rice: Quality Enhancement and Mechanistic Insights

Rice cooking is a time-consuming process, and conventional heating methods often suffer from low heating efficiency and non-uniform heat transfer, which may compromise cooking quality. Although pulsed ohmic heating (OH) has shown potential for accelerating food heating, its effects on the quality formation and structural evolution of cooked rice remain insufficiently understood. Therefore, this study applied OH technology to improve the cooking efficiency and quality of indica rice. Through single-factor and response surface methods, the optimal OH parameters were determined: 18 min treatment time, 9.4 μs pulse width, 0.52 kV/cm electric field strength, and 265 Hz frequency. Under these conditions, the cooking time was significantly reduced by 28% compared to traditional rice cookers, achieving a comprehensive quality score of 88.42 points. Optimized OH treatment improved water absorption and volume expansion ratio, reduced hardness, and enhanced the overall flavor characteristics, accompanied by changes in the microstructure and starch organization. Multi-scale structural analyses indicated that OH treatment was associated with accelerated starch gelatinization, reduced starch crystallinity, enhanced moisture migration, and possible alterations in starch-protein interactions, which were consistent with the observed improvements in rice texture. Importantly, at the 18 min maturation point, the estimated glycemic index of OH-treated rice showed no significant difference compared with traditionally cooked rice (83.69 vs. 82.88, p > 0.05), ensuring nutritional quality. These findings suggest that OH is a promising technology for improving rice cooking efficiency and quality while maintaining nutritional properties.