Cryoprotective effect of collagen hydrolysates from squid skin on frozen shrimp and characterizations of its antifreeze peptides
Shaoqian Cao, Jinxiu Cai, Xiuzi Wang, Kenan Zhou, Liang Liu, Luyao He, Xiangyang Qi, Hua Yang
Abstract
The cryoprotective effect of collagen hydrolysates from squid skin (CH-SS) on shrimp muscle was investigated during the freeze-thaw cycles, and the antifreeze peptides (AFPs) in CH-SS were separated and identified. The results showed that CH-SS generated by acid protease had the highest antifreeze activity. It was further found that CH-SS showed an inhibitory effect on the denaturation and structural changes of myofibrillar protein during the freeze-thaw cycles, and partially retained the ability to bind water. SEM analysis indicated that CH-SS could effectively reduce the mechanical injury caused by ice crystals to shrimp muscle. The fraction with the highest antifreeze activity from CH-SS was obtained by Sephadex G-25 chromatography, and its main amino acid sequence was identified as DVRGAEGSAGL by the UPLC-MS analysis. This study provides a theoretical basis for the intensive processing of squid skin and the development of new antifreeze agents.