Coupled ethanol–trehalose processing accelerates thawing of rapid‐frozen cooked rice through water‐state modulation

Abstract BACKGROUND Freezing preserves cooked rice, but ice formation and water redistribution can cause structural and textural deterioration. The individual and combined effects of ethanol soaking and trehalose‐assisted cooking on freeze–thaw behaviour, water state, texture, and microstructure were investigated. Rice was soaked in water or an aqueous ethanol solution containing 700 mL L −1 ethanol, cooked in water or a trehalose solution (30 g L −1 ), frozen at −20 or −55 °C, stored at −18 °C for 7 days, and passively thawed at 27 °C. RESULTS The ethanol‐soaked/trehalose‐cooked sample frozen at −55 °C (ET55) exhibited the highest freezing rate (1.37 °C min −1 ) and shortest thawing time (34.3 min). Differential scanning calorimetry showed lower apparent melting enthalpy and freezable‐water content in the combined‐treatment samples; values for ET55 were 56.8 J g −1 and 170.3 g kg −1 , respectively. Time‐domain nuclear magnetic resonance showed shorter T 2b and T 2c relaxation times in ET samples than in the corresponding water‐soaked/water‐cooked controls, indicating restricted mobility of weakly bound and free water without a reduction in relative free‐water signal amplitude. Scanning electron microscopy of samples frozen at −20 °C showed that the combined treatment produced a compact freeze‐dried matrix with smaller pores. ET55 hardness was numerically close to that of its freshly cooked counterpart. CONCLUSION Coupling ethanol–trehalose processing with rapid freezing at −55 °C yielded the shortest passive thawing time. This was associated with lower freezable‐water content, lower apparent melting enthalpy, and restricted water mobility. This combined approach may therefore improve thawing efficiency and freeze–thaw stability in frozen cooked rice. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.