冻结和冻藏对中华绒螯蟹蟹肉品质的影响

Effects of freeze and frozen storage on changes of quality of Eriocheir sinensis

为了研究冻结和冻藏对中华绒螯蟹蟹肉品质的影响,本研究对冻结和冻藏中华绒螯蟹的蛋白质特性、游离氨基酸、核苷酸关联成分、Ca2+-ATPase活性以及解冻汁液流失率进行了全面的评价。中华绒螯蟹较耐冻结但不耐冻藏,冻藏2周后蟹肉弹性程度开始下降。中华绒螯蟹在冻藏过程中,蟹肉中游离氨基酸、呈味核苷酸、Ca2+-ATPase活性以及解冻汁液流失率都发生明显变化。冻藏12周后相对于新鲜蟹,游离氨基酸、呈味核苷酸、Ca2+-ATPase活性以及解冻汁液流失率分别下降了25.3%、100%、41.6%和增加了9.2%。普通冻藏(-20℃)条件下,中华绒螯蟹蟹肉发生快速蛋白质分解和ATP降解,表现为游离氨基酸成分与ATP关联物成分都发生很大变化,蛋白质变性显著、汁液流失现象严重等。推测中华绒螯蟹蟹肉不耐冻藏可能与其自身的自溶酶和ATP酶类有关。

The effect of freeze and frozen storage on Eriocheir sinensis was studied by evaluation of the characteristics of protein, the contents of free amino acids and flavor nucleotides, the activity of Ca^2＋ -ATPase and the thawing loss rate. The results showed that E. sinensis had freeze resistance but no frozen storage resistance and the elasticity decreased after 2 weeks＇ frozen storage. The contents of free amino acids and flavor nucleotides,the activity of Ca^2＋ -ATPase and the thawing loss rate changed significantly during frozen storage. After frozen storage of 12 weeks,the contents of free amino acids and flavor nucleotides,the activity of Ca^2＋ -ATPase decreased by 25.3 % , 100% , and 41.6% respectively, compared with those of fresh crabs. While the thawing loss rate increased by 9.2%. The high activities of autolytic enzyme and ATP correlative catabolic enzyme accelerated the decomposition of protein and ATP correlatives at common freezing （-20 ℃ ）. The protein of E. sinensis was easy to be denatured, which resulted in serious protein denaturation and thaw loss of crab meat. The reason that E. sinensis had no frozen storage resistance might have connection with its autolytic enzyme and ATP correlative catabolic enzyme.