不同冻藏状态下南美白对虾品质与微观结构的变化

Quality and Microstructure Changes of Penaeus vannamei under Freezing States

本文研究了不同冻藏状态,即玻璃态(T冻藏温度<Tg′特征玻璃化转变温度):-80℃,部分冻结浓缩态(Tg′<T<Tm′特征冻结终点温度):-60℃和-40℃,橡胶态(T>Tm′):-18℃条件下冻藏6个月,对南美白对虾品质与微观结构的影响。结果表明-80℃(玻璃态)冻藏下南美白对虾的色差(􁇞E值)、汁液流失率、挥发性盐基氮(TVB-N)含量、以及pH值最小,分别为5.33、4.80%、15.35 mg N/100 g以及7.22;硬度,弹性和咀嚼性、SPP含量和感官评分最高,分别为652.86%,65.76%和184.90、80.04 mg/g和7.40,显著优于部分冻结浓缩态以及橡胶态下冻藏的南美白对虾(p<0.05),并且-80℃冻藏下南美白对虾组织中的冰晶比其他条件尺寸较小、分布更均匀。而-60℃和-40℃仅在pH值无显著差异(p>0.05),-18℃下南美白对虾品质最差。随着冻藏时间延长,即使在玻璃态下虾的品质也仍在变化,但与其他状态相比,玻璃态下南美白对虾的品质下降最缓慢。本文表明,玻璃态冻藏能有效抑制南美白对虾冻藏过程中的品质劣变,较好地保持冷冻虾的品质。

To investigate the effects of three freezing state:glass state(T<Tg′,-80℃),partially frozen concentrated state(Tg′<T<Tm′,-60℃and-40℃),rubber state(T>Tm′,-18℃),on the quality and microstructure of Penaeus vannamei meat,the microstructure,color,drip loss,total volatile base-Nitrogen(TVB-N),pH,texture,salt soluble proteins(SSP)and sensory score were detected during six months storage.The results showed that samples frozen at glassy state had the lowest values of color(5.33),drip loss(4.80%),total volatile base-Nitrogen(TVB-N)(15.35 mg N/100 g),pH(7.22);the highest values of hardness(652.86%),springiness(65.76%)and chewiness(184.90),salt soluble proteins(SSP)(80.04 mg/g)and sensory score(7.4).In addition,the microstructure of Penaeus vannamei meat at-80℃was better than partial-freeze-concentrated and rubbery states.There was no significant difference in texture,drip loss and pH value(p>0.05),but color,SSP and sensory scores were found to have significant difference(p>0.05)between frozen at-40℃and-60℃.Furthermore,the samples frozen at-60℃was significantly better than those frozen at-40℃(p<0.05),and the samples frozen at-18℃(rubber state)had the worst quality.It indicated that glassy state storage can effectively inhibit the deterioration of the quality of Penaeus vannamei and improve the quality of Penaeus vannamei.