Hu Yaqin, Shao Ying, Wu Chunhua, Yuan Chunhong, Ishimura Gakushi, Liu Wenjuan, Chen Shiguo
National Engineering Laboratory of Intelligent Food Technology and Equipment, Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Key Laboratory for Agro-Products Nutritional Evaluation of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Fuli Institute of Food Science, College of Biosystems Engineering and Food Science Zhejiang University, Hangzhou 310058, China.
Department of Food Production and Environmental Management, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan.
Food Chem. 2018 Mar 1;242:330-337. doi: 10.1016/j.foodchem.2017.08.087. Epub 2017 Aug 30.
The present study investigated the mechanism of ε-(γ-glutamyl) lysine cross-links within hairtail (Trichiurus haumela) surimi protein via γ-polyglutamic acid (γ-PGA) and MTGase. The results indicated that the addition of MTGase and γ-PGA markedly improved the gelation properties of hairtail surimi protein, including its maximum breaking force and deformation, water holding capacity and gel strength. The maximum improvements were achieved by adding 0.5units MTGase/g meat paste in combination with 0.06% γ-PGA. SDS-PAGE showed that the band intensity of cross-linked proteins increased, whereas that of myosin heavy chain decreased after treatments. Further scanning electron microscopy (SEM) analysis showed the formation of a denser gel matrix, which was caused by much stronger and more inter- and intra-molecular cross-linking of proteins, via MTGase catalysing ε-(γ-glutamyl) lysine cross-links formed between lysine residues in the gel protein and glutamic residues in the hydrolytic γ-PGA. The results provide reliable guidance for the improvement of hairtail surimi protein gelation properties.
本研究探讨了通过γ-聚谷氨酸（γ-PGA）和转谷氨酰胺酶（MTGase）在带鱼（Trichiurus haumela）鱼糜蛋白中形成ε-（γ-谷氨酰基）赖氨酸交联的机制。结果表明，添加MTGase和γ-PGA显著改善了带鱼鱼糜蛋白的凝胶特性，包括其最大断裂力和变形、持水能力和凝胶强度。通过在每克肉酱中添加0.5单位MTGase并结合0.06%的γ-PGA可实现最大程度的改善。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）显示，处理后交联蛋白的条带强度增加，而肌球蛋白重链的条带强度降低。进一步的扫描电子显微镜（SEM）分析表明，形成了更致密的凝胶基质，这是由于MTGase催化凝胶蛋白中的赖氨酸残基与水解γ-PGA中的谷氨酸残基之间形成ε-（γ-谷氨酰基）赖氨酸交联，导致蛋白质分子间和分子内交联更强、更多。这些结果为改善带鱼鱼糜蛋白凝胶特性提供了可靠的指导。
