Abstract
Early stage (within 24 h storage) retrogradation of cooked rice stored at 4°C or 15°C were evaluated by instrumental methods, that is, differential scanning calorimetry (DSC), whiteness, hardness and adhesiveness of rice grain under 25% or 80% deformation, and sensory test. The rate of retrogradation of cooked rice measured by instrumental methods increased after 6 h storage at 4°C, although the rate was low and the increase in retrogradation was slow in the case of storage at 15°C. The retrogradation score for cooked rice stored at 4°C by sensory evaluation increased earlier than that by instrumental measurements. Coefficients of correlation between instrumental measurements and sensory evaluation indicated that storage temperature influenced physical properties of cooked rice, and as a result, the index for evaluating cooked rice stored at 15°C was different from that for stored at 4°C. Concretely, whiteness, DSC and hardness under 25% deformation were closely related to sensory evaluation in the oral cavity for cooked rice stored at 4°C, while adhesiveness under 25% and 80% deformation correlated to sensory evaluation in the oral cavity for cooked rice stored at 15°C.
