冻融循环对冷冻罗非鱼片品质的影响

Effects of freeze-thaw cycles on the quality of frozen tilapia(Oreochromis niloticus)fillets

以冷冻罗非鱼片为研究对象,通过感官评价不同冻融次数感官品质,并测定冻融循环过程中罗非鱼片的质构特性、色泽、pH值以及解冻损失、蒸煮损失、持水力等理化指标的变化,探究冻融循环对冷冻罗非鱼片品质的影响。研究结果表明,随着冻融次数的增加,冷冻罗非鱼片肌肉的各理化指标均与感官品质出现相同的劣变趋势,但1、2次冻融样品与新鲜样品的品质没有显著性差异;3、4次冻融样品与新鲜样品相比,持水性和色泽均呈现显著性劣化从而导致品质劣变显著,但感官可接受;5~7次冻融样品与新鲜样品相比,感官评价较低,各理化指标劣变严重。随冻融次数的增加,罗非鱼片品质呈现下降的趋势,与新鲜样品相比,可分为无显著变化(1、2次冻融)、劣变显著(3、4次冻融)、劣变严重(≥5次冻融),该结论可为制订冷冻罗非鱼片在贮藏、运输和销售期间的品质控制规程提供参考意义。

The sensory quality of different freeze-thaw cycles of frozen tilapia fillets was evaluated by sensory.Meanwhile,the texture characteristics,color,pH value,thawing loss,cooking loss and water holding capacity of tilapia fillets as indicators were measured during freeze-thaw cycles for the study the effect of freeze-thaw cycles on the quality of frozen tilapia fillets.The results showed that the physicochemical indicators exhibited the same deterioration trend as the sensory quality with the increase of the number of freeze-thaw cycles,but there was no significant difference in the quality of the samples by 1st or 2nd times freeze-thaw and the fresh one.Compared with fresh samples,3rd and 4th times freeze-thaw samples showed significant deterioration of water holding capacity and color which leading to significant quality deterioration even though the sensory was acceptable.Besides,compared with fresh samples,lower sensory evaluation was showed at 5-7th times freeze-thaw cycle samples,and all physicochemical index deteriorated seriously.The quality of tilapia fillets decreased as the number of freeze-thaw cycles increases.So three deterioration degree can be classified,which were no significant changes(1 and 2 freeze-thaw cycles),significant deterioration(3 and 4 freeze-thaw cycles)and serious deterioration(≥5 freeze-thaw cycles).This conclusion could provide a reference for formulating quality control of frozen tilapia fillets during storage,transportation and sale.