Impact of Magnetic Field-Assisted Freezing on the Physicochemical Properties and Starch Structure of Cooked Rice: Effects of Magnetic Types, Intensities, and Cryostasis Time

Abstract

A magnetic field-assisted freezing system was developed to mitigate the degradation of taste quality in frozen cooked rice (FCR). The physicochemical properties and starch structure were analyzed under varying magnetic field types, intensities, and cryostasis time. The analysis of freezing characteristics indicated that treatments with 10 mT SMF and 6 mT AMF yielded optimal results, significantly reducing the duration of the maximum ice crystal generation zone by approximately 18 minutes (P < 0.05). Compared to no magnetic field (NMF) treatment, a 16-day frozen storage experiment showed significant improvements in the texture characteristics and sensory quality of cooked rice treated with magnetic fields. Additionally, the texture characteristics of rice treated with AMF after 16 days of frozen storage closely resembled those of freshly cooked rice, with a delayed decline in moisture content after reheating compared to SMF treatment. Throughout the storage period, the crystallinity for the AMF treatment exceeded that of the SMF treatment by 2.99%. Furthermore, compared to SMF treatment, water molecules in FCR treated with AMF are more tightly bound. These findings indicate that while SMF can reduce the degradation of FCR quality, AMF is more effective at preserving texture, taste, and structure density.

Keywords: Keywords: Magnetic field, Frozen cooked rice, Physicochemical properties, Starch structure, Storage stability