银鲳低温冻藏期间品质劣化及水分迁移规律的研究

Study on Quality Deterioration and Moisture Migration of Pampus argenteus During Low Temperature Preservation

为了研究-18、-25和-45℃低温冻藏温度对银鲳品质及水分的影响,以挥发性盐基氮、巯基、质构、内源性蛋白酶活性、水分含量和冰晶大小等为指标,分析银鲳低温冻藏过程中的品质劣化和水分迁移规律变化。结果表明:采用-18、-25、-45℃冻结的银鲳通过最大冰晶生成带的时间分别为225、85和65 min,与-45℃相比,-18℃和-25℃下的银鲳在整个冻藏期内对冻藏时间的敏感性更高,且随着冻藏时间的增加,冰晶呈现出较大且不规则的形状。此外,冻藏至250 d时,3组冻结鱼肉的挥发性盐基氮含量分别为17.77、16.68和15.04 mg·100^(-1)·g^(-1);总巯基含量变化以第75和100天最为显著(P<0.05);银鲳鱼肉的硬度、弹性和咀嚼性在低温冻藏期间逐渐劣化,冻藏温度越低,其劣变速度越缓慢,劣化程度越低;组织蛋白酶B、L和H的活力均随着冻藏时间的延长呈现先降后升的趋势,且组织蛋白酶B的活性要高于组织蛋白酶L和H,在银鲳鱼肉品质劣化中具有更大的作用;低场核磁共振结果显示,结合水在低温冻藏期间变化不大,而不易流动水和自由水易受冻藏温度影响,冻藏前期(0~60 d),不易流动水含量下降,自由水含量上升;冻藏后期(60~120 d),结果刚好相反。低温有助于减缓银鲳鱼肉的水分迁移变化,减缓不易流动水流失和鱼肉品质劣化。综合以上结果,低温能够更好地保持冻藏过程中银鲳的品质,且温度越低,冻结速率越高,形成冰晶越小,品质劣化越缓慢,水分迁移越慢,越有利于鱼肉品质的保持。

In order to study the effects of freezing temperatures of-18,-25,and-45℃onthequality and water content of Pampus argenteus during low-temperature storage,the quality degradation and water migration of P,argenteus during low-temperature storage were analyzed using volatile base nitrogen,sulfhydryl,texture,endogenous protease activity,water content,and ice crystal size as indicators.The results showed that the time for P.argenteus frozen at-18,-25,and-45℃to passthroughthemaximumicecrystal formation zone was 225,85,and 65 min,respectively.Compared with-45℃,P.argenteusfrozenat-18℃and-25℃had a higher sensitivity to freezing time during the entire frozen storage period,and with the increase of freez-ing time,the ice crystals showed a larger and irregular shape.In addition,when frozen for 250 days,the volatile basic nitrogen content of the three groups of frozen fish was 17.77,16.68,and 15.04 mg·100^(-1)·g^(-1),respectivelyi The change of total sulfhydryl content was most significant on the 75th and 100th days(P<0.05);The hardness,springiness,and chewiness of P.argenteus meat gradually deteriorate during low-temperature freezing storage.The lower the freezing temperature,the slower the deterioration rate,and the lower the degree of deteriorationi The activities of cathepsin B,L,and H decreased first and then increased with the prolonga-tion of frozen storage time,and the activities of cathepsin B were higher than those of cathepsin L and H,which played a greater role in the deterioration of P,argenteus meat qualityi The low field nuclear magnetic resonance(NMR)results showed that the bound water had little change during low-temperature frozen storage while the non flowing water and free water were easily affected by freezing storage temperature.During the ear-ly stage of frozen storage(O-60 d),the non flowing water content decreased and the free water content increased;In the late stage of frozen storage(60-120 d),the results were just the opposite.Low temperature can help slow down the water migration and change of P.argenteus meat,slow down the water loss and deterioration of fish meat quality,Based on the above results,low temperature can better maintain the quality of P.argenteus during frozen storage,and the lower the temperature,the higher the freezing rate,the smaller the ice crystals formed,the slower the quality degradation,and the slower the water migration,which is more conducive to the mainte-nance of fish quality.