Frozen samples were stored for 0e14 days in order to analyzestarch retrogradation during chill storage at 4 C. Retrogradationproperties were studied by analyzing the melting endotherm ofrecrystallized amylopectin by DSC and results were shown in Figs. 2and 3. There were no significant differences in onset, peak andconclusion temperatures for different rates at the same storagetime except with freezing rate of 0.09 C/min (P> 0.05). The meanmelting onset, peak and conclusion temperatures of frozen cookedrice decreased within 3 days storage (P <0.05), and they were notsignificantly different during the last 11 days of storage (P> 0.05).However, the value of onset, peak and conclusion temperature ofcooked rice frozen with 0.09 C/min were lower than other freezingrates (0.26, 0.33, 0.53 and 1.45 C/min, respectively) within 3 daysof storage, there were not significant differences of all freezing ratesduring the last 11 days of storage. These results indicated that theonset, peak and conclusion temperatures were not significantlyaffected by freezing rates except the rate of 0.09 C/min. However,the onset, peak and conclusion temperatures of cooked rice werehigher than the results of Yu et al. (2009) without freezing. Anexplanation is that the differences may be caused by rice varieties,or by the freezing process which formed ice crystals in frozencooked rice, possibly leading to the damage of the gel structure ofcooked rice grains when thawing at 4 C, thus resulting in theonset, peak and conclusion temperature differences betweenfreezing and cooling cooked rice.
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