温度波动对冻藏南美白对虾品质的影响

Effects of temperature fluctuation on quality of frozen Penaeus vannamei

为研究不同温度波动对冻藏南美白对虾品质影响规律,对-18℃冷柜设定不同的温度波动(±0.5、±2、±4、±6、±8℃)来冻藏南美白对虾,测量其挥发性盐基氮(total volatile basic nitrogen,TVB-N)、硫代巴比妥酸反应物(thiobarbituric acid reactive substance,TBARS)、L^(*)值、硬度、弹性、咀嚼性等指标在120 d内的变化,并与-40℃冻藏的南美白对虾品质对比。结果表明,南美白对虾TVB-N值、TBARS值和L^(*)值随冻藏时间的延长不断增加,硬度、弹性、咀嚼性等质构指标随冻藏时间的延长显著降低;在(-18±0.5)℃工况下,各物化指标更接近-40℃冻藏南美白对虾的品质,且温度波动幅度越大,各物化指标劣变速度越快,实用贮藏期显著降低;其中,当南美白对虾以全虾状态在(-18±8)℃的冷柜中冻藏至第108天时,TVB-N值超过国家标准规定的初步腐败界限30 mg/100 g,已经不可食用。由此可知在相同冻藏温度的情况下,减小温度波动幅度能有效抑制南美白对虾冻藏过程中的品质劣变,较好地保持其品质。

This study aimed to study the effects of different temperature fluctuations on the quality of frozen Penaeus vannamei.Set different temperature fluctuations(±0.5,±2,±4,±6,±8℃)for the-18℃freezer to freeze Penaeus vannamei.The changes of total volatile basic nitrogen(TVB-N),thiobarbituric acid reactive substance(TBARS),L^(*)value,hardness,elasticity,chewiness,and other indicators of Penaeus vannamei within 120 days were measured.The quality was compared with Penaeus vannamei frozen at-40℃.Results showed that the TVB-N value,TBARS value,and L^(*)value of Penaeus vannamei increased with the prolongation of frozen storage time.The texture indexes such as hardness,elasticity,and chewiness decreased significantly with the prolongation of frozen storage time.Under the working condition of(-18±0.5)℃,each physical and chemical index was closer to the quality of frozen Penaeus vannamei at-40℃.The larger the temperature fluctuation was,the faster the deterioration rate of physical and chemical indexes was,and the practical storage life was significantly reduced.When Penaeus vannamei was frozen and stored in the freezer at(-18±8)℃in the state of the whole prawn until the 108th day,the TVB-N value exceeded the initial corruption limit of 30 mg/100 g specified in the national standard and they were no longer edible.Therefore,under the same frozen storage temperature,reducing the temperature fluctuation can effectively inhibit the quality deterioration of Penaeus vannamei during frozen storage and better maintain its quality.