Application of novel microwave-assisted induction heating technology for extending the shelf life of ready-to-eat rice through microbial, physical, and chemical quality preservation

Abstract

Microwave-assisted induction heating (MAIH) is a composite heating system that combines top-down microwave irradiation (1000 W, 2450 MHz) with bottom-up electromagnetic induction (1500 W). Rice samples prepared by both MAIH methods (120 °C for 240 s and 100 °C for 300 s) and traditional steam cooking (100 °C for 30 min) were analyzed for microbial count, color, pH value, and hardness during storage at 35 °C, 25 °C, and 4 °C. The results revealed that MAIH-treated rice demonstrated no detectable microbial growth at any storage temperature, whereas steamed rice exhibited microbial growth with increasing aerobic plate counts at 35 °C, 25 °C, and 4 °C after two, four, and sixteen weeks, respectively. Color analysis revealed a decline in L* and W values, with increased b* values over time for all samples at all storage temperatures. The pH values of the MAIH-treated rice remained stable, while steamed rice demonstrated a pH decrease during later stages of storage at 25 °C and 35 °C. The hardness of MAIH-treated rice slowly increased at 25 °C and 35 °C, whereas the steamed rice experienced a notable decrease. At 4 °C, all samples demonstrated increased hardness, with steamed rice having significantly higher values than MAIH-treated rice. Overall, MAIH treatment effectively delayed color, pH, and hardness alterations in rice in comparison to traditional steam cooking during storage. Industrial relevanceThe MAIH equipment is a novel thermal processing technology and provides the efficient pasteurization, reduced processing time, and improved overall quality of ready-to-eat (RTE) rice. Therefore, the MAIH technology is a viable future alternative for thermal processing method that possesses huge potential in the development of RTE rice products.