大豆胰蛋白酶抑制剂粗提物对凡纳滨对虾冷藏期间肌肉流变学与热学特性的影响

Effect of crude extracts of trypsin inhibitor from soybean on the rheological and thermal properties of Litopeneaus vannamei muscle during cold storage

为了评价大豆胰蛋白酶抑制剂粗提物对凡纳滨对虾冷藏期间肌肉特性的影响,以注射和未注射大豆胰蛋白酶抑制剂粗提物的凡纳滨对虾分别为实验组和空白组,利用动态流变仪和差示扫描量热仪(differential scanning calorimeter,DSC)分别探究该粗提物对凡纳滨对虾在贮藏(0℃)期间肌肉特性的影响。动态流变仪测定结果表明,两组凡纳滨对虾肌肉蛋白均能形成热凝胶,凝胶开始形成温度为47℃,最终形成凝胶温度为78℃左右,且降温有利于热诱导凝胶的进一步加固;贮藏2、4、6天时,注射组的弹性模量G’值总体上大于空白组,凝胶弹性比空白组好。DSC结果显示,贮藏0、2天时两组凡纳滨对虾主要有3个热吸收峰,对应变性温度大约为48、68、79℃,随贮藏时间延长在53℃左右出现了1个新的热吸收峰;不过,注射组4个热吸收峰的变性温度总体上大于空白组,且2、4天的变性温度差异显著(P<0.05),虾肉蛋白的热稳定性得到了提高。因此大豆胰蛋白酶抑制剂粗提物在凡纳滨对虾贮藏前期(<6天)能提高热凝胶的弹性和蛋白的热稳定性,起到了延缓虾肉软化和蛋白变性的作用。

In order to evaluate the effect of crude extracts of trypsin inhibitor from soybean on the muscle properties of Litopeneaus vannamei during storage （0 ℃ ） , the dynamic rheometer and differential scanning calorimeter were used to investigate the difference between the experimental group injected with crude extracts and the blank. Dynamic rheology research showed that two groups of shrimp could be able to form thermal gel. The formation of the gel began at about 47 ℃ and better network occurred at high temperature （ about 78 ℃）. The gel was further reinforced through cooling. Elastic modulus （ G＇ ） of injecting group was higher than that of the blank on Day 2, 4, 6 during storage. The gel elasticity of injecting group was better. DSC results revealed that on day 0 and day 2 of storage, two groups of shrimp had 3 endothermie peaks and the denaturation temperature were about 48 ℃ , 68 ℃ ,79 ℃, respectively. A new endothermic peak at about 53 ℃appeared with the time extension. However, the denaturation temperature of 4 endothermic peaks of injecting group was higher than that of the blank group as a whole. The crude extracts of trypsin inhibitor had remarkable effect on the denaturation temperature on Day 2 and Day 4 of storage （P 〈 0.05）. Therefore, the crude extracts of trypsin inhibitor from soybean could improve the elasticity of the thermal gel and protein stability during the early stage of the storage （ 〈 6 days） , thus result in delay of softening and degeneration of Litopeneaus vannamei.