Postmortem biochemistry of marine animals - digestive enzymes and transglutaminases

渔业是加拿大农业食品部门的重要组成部分，每年产生数百万美元的收入。然而，近年来鱼类资源一直在减少。这一事实，再加上海鲜收获的季节性和原料的高度易腐烂，因此有必要制定更有效的程序来减少变质，以确保产品可供人类食用。导致鱼类品质迅速丧失的两个主要因素是微生物活性和内源酶的自溶作用。到目前为止，已经很好地研究了微生物对鱼的变质，而对自溶对变质现象的贡献的研究较少。这项拟议的研究将调查基于高压与其他屏障(如天然抗氧化剂和低温储存)相结合的新方法，作为保存优质海鲜质量的工具。海鲜加工还会产生大量的废物，目前这些废物还没有被用于高价值用途。然而，这些废物中有丰富的有用的生物化学物质，如酶，这些化学物质可以以纯形式回收，用于几种商业用途。据估计，全球酶的市场规模为每年13亿美元，年增长率为12%-15%。人们越来越需要发现新的酶来源来满足市场需求，而水产品加工废弃物是一种未得到充分利用的资源材料，具有满足这一需求的潜力。在拟议的研究中，将回收两组鱼类酶(鱼类脂肪酶和转谷氨酰胺酶)，并在酯交换反应中进行研究，以在人类食物中加入有用的生物分子(例如，omega 3多不饱和脂肪酸)以促进健康；以及将鱼类加工废弃物中的油转化为生物柴油作为替代燃料，以减少对化石燃料的依赖。鱼转谷氨酰胺酶也将被用来修饰生物分子，使其更耐降解，从而促进食品和非食品用新型生物材料的开发。与使用化学品在食品中实现类似的修饰相比，这种转谷氨酰胺酶的使用将更容易被消费者接受。

The fish industry is an important component of Canada's agri-food sector, and generates millions of dollars in revenue each year. However, fish stocks have been declining in recent years. This fact coupled with the seasonal nature of the seafood harvest and the high perishability of the raw material make it necessary to develop more effective procedures to reduce spoilage to ensure availability of the products for human consumption. The two main factors responsible for the rapid loss of fish quality are microbial activity and autolysis by endogenous enzymes. Thus far, fish spoilage by microorganisms has been well studied, while the contribution of autolysis to the spoilage phenomenon is less well studied. The proposed study will investigate novel approaches based on high pressure in combination with other barriers such as natural antioxidants and low temperature storage, as tools for preserving premium seafood quality. Seafood processing also generates high volumes of discards that are currently not put to high value uses. However, the discards are rich is useful biochemicals such as enzymes that may be recovered in pure forms for several commercial applications. The global market for enzymes is estimated at 1.3 billon dollars (US) per year, with a growth rate of 12-15% per year. There is a growing need to discover new sources of enzymes to meet the market demands, and fish processing discards represent an underutilized resource material with potential to fill this need. In the proposed studies, two groups of fish enzymes (fish lipases and transglutaminases) will be recovered and investigated in transesterification reactions to incorporate useful biomolecules (e.g., omega 3 polyunsaturated fatty acids) in human foods for health benefits; and for transforming oils from fish processing discards into biodiesel as alternative fuel to reduce the dependence on fossil fuel. Fish transglutaminases will also be prepared and used to modify biomolecules to make them more resistant to degradation, and thereby facilitate the development of novel biomaterials for food and non-food uses. Such use of transglutaminases will be more acceptable to consumers compared with the use of chemicals to achieve simalar modifications in food products.