为了探究秋刀鱼冻藏过程品质变化,以蒸煮损失率、TVB-N值、肌原纤维蛋白含量、巯基含量、TBARS值为指标,并结合肌肉组织结构观察,对-20、-30℃和-50℃3个温度条件下秋刀鱼的品质变化进行了研究.结果表明,冻藏温度对秋刀鱼品质有较大影响.总体上,温度越低,秋刀鱼品质劣化程度越低,各项理化指标的值也更接近新鲜鱼肉的水平.秋刀鱼肌肉蒸煮损失率、TVB-N值和TBARS值随冻藏时间的延长不断上升,冻藏180 d时-20℃组TVB-N值极显著高于另两组(P<0.01),而-30℃和-50℃组间差异较小;冷冻贮藏导致肌肉蛋白变性,肌原纤维蛋白含量与活性巯基含量逐渐降低,其中-20℃组下降速率较快;冻藏结束时,3组秋刀鱼TBARS值差异显著(P<0.05),-20℃组TBARS值为1.10 mg/kg已达到脂肪轻微酸败程度;肌肉显微结构表明,冻藏温度越高,会造成肌纤维之间更大的空隙且破坏更多的肌肉纤维束.从品质保持效果和经济效能角度,-30℃适宜作为秋刀鱼的冻藏温度.%Quality changes of frozen Cololabis saira were studied under storage temperatures at-20 ,-30℃and-50 ℃ for 180 days. Quality were measured with cooking loss, total volatile basic (TVB-N), myofibrillar protein content, sulfhydryl content, thiobarbituric acid reactive substances (TBARS)and muscular tissue during frozen storage at regular intervals (each 15 days). The results showed that there were certain influences on the Cololabis saira quality due to different frozen temperature. Low temperature had the least quality loss and the physicochemical characteristics of Cololabis saira closer to fresh muscle. Cooking loss , TVB-N value and TBARS value was decreased with the increased of frozen storage time and TVB-N value was significantly higher than the other two groups (P<0.01) at-20℃,while there were little difference between-30 and-50℃after about 180 days. Frozen storage led to special structure of muscle protein changes , making the protein denaturation, myofibrillar protein content and sulfhydryl content were significantly decreased which -20 ℃group decreased at a faster rate. TBARS value of three temperature were significant difference at the end of the frozen time (P<0.05),while TBARS value was 1.10 mg/kg at-20℃and frozen Cololabis saira developed slight rancidity. Microstructural changes in experimental muscle showed that a higher storage temperature induced visibly larger gap between muscle bers and destroy more muscle ber bundles compared to the other temperature. Therefore, when Cololabis saira was stored at-30℃or below, it could keep the quality and saved economical efficiency better.
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