姜黄素光动力减缓牡蛎脂质劣化进程的机理研究

Photodynamic sterilization is a new non-thermal sterilization technology, which is a non-toxic photosensitizer at a wavelength of light-activated, resulting in a strong oxidation of reactive oxygen species, inactivation of microorganisms. Our team creatively applied curcumin-mediated photodynamic sterilization technology in oyster processing, which significantly reduced the degree of lipid degradation in oyster. The project is intended to carry out the following studies to elucidate the mechanism of photodynamic sterilization preventing the lipid degradation in oyster. Firstly, the hydrolysis and oxidation of lipid before and after photodynamic sterilization and during oyster chilling will be analyzed. The key step of photodynamic sterilization will be determined. Secondly, the dynamic changes of lipase-related enzymes in the oyster during cold storage will be analyzed. The correlations between enzyme and the process of lipid degradation will be determined with Spearman’s correlation coefficient for ranked data analysis. The key enzymes affecting the lipid degradation process of oysters in photodynamic sterilization group will be identified. Thirdly, the correlation between the compositions of bacteria phase, the abundance of specific bacteria and the process of lipid degradation will be analyzed. Finally, together with the bioinformatics analysis and traditional culture technique of bacteria, the correlation between the specific bacteria and the key enzymes will be identified. Mechanism of curcumin - mediated photodynamic sterilization preventing the lipid degradation in oyster will be elucidated. The results of the project will provide a theoretical basis for the popularization and application of photodynamic sterilization in oyster processing and preservation.

光动力灭菌是光敏剂在一定波长光激活下，产生大量活性氧、灭活微生物的新型非热杀菌技术。课题组创新性地将姜黄素介导的光动力冷杀菌技术（简称姜黄素光动力）用于牡蛎加工中，发现其显著减缓了牡蛎脂质劣化的进程。本项目拟开展以下研究，旨在阐明姜黄素光动力减缓牡蛎脂质劣化进程的机理。1.比较不同处理组、不同冷藏时间牡蛎中脂质水解和氧化情况，确定姜黄素光动力发挥作用的关键环节。2.分析脂质劣化相关酶的动态变化，解析其与脂质劣化的相关性，确定姜黄素光动力影响的关键酶。3.分析肠道微生态，比较分泌脂质劣化相关酶的肠道菌相对丰度变化，解析其与脂质劣化的相关性，确定姜黄素光动力影响的关键菌。4.解析姜黄素光动力对上述关键菌和关键酶的影响，阐明其减缓牡蛎脂质劣化进程的机理。项目的研究成果将为光动力灭菌技术在贝类加工保鲜中推广应用提供理论依据，还将为研究保鲜技术影响贝类品质劣化的作用机理提供新的研究思路。

牡蛎营养丰富，是集药、食、滋补三大功能为一体的海洋食品。因其脂质含量高于其他水产品，极易发生脂质劣化。而光动力灭菌是光敏剂在一定波长光激活下，产生大量活性氧、灭活微生物的新型非热杀菌技术。先前课题组研究发现将姜黄素介导的光动力冷杀菌技术（简称姜黄素光动力）用于牡蛎加工中，可显著减缓牡蛎脂质劣化的进程。因此本项目围绕姜黄素光动力减缓牡蛎脂质劣化进程的机理展开研究。姜黄素介导的光动力延缓脂质劣化的关键环节是姜黄素被光源激发产生活性氧物质的过程。光动力主要通过降低LOX、Lipase、PLA2 等脂质劣化相关酶的活性，从而延缓了脂质的劣化。姜黄素光动力能显著降低牡蛎在冷藏期间的菌落总数，改变菌相组成，降低了腐败菌的相对丰度。光动力处理不仅降低了脂质劣化相关菌-交替假单胞菌属、嗜冷杆菌属和假单胞菌属的相对丰度，而且直接作用于内源性脂肪氧合酶、磷脂酶 A2、磷脂酶 D，降低了酶活性。此外，姜黄素光动力处理还能够延缓牡蛎中的蛋白质劣化进程，其原因与降低丝氨酸蛋白酶和天冬氨酸蛋白酶的活性有关。综上，姜黄素光动力通过影响牡蛎品质劣化的关键菌和关键酶，延缓了牡蛎冷藏期间脂质和蛋白质的劣化进程。本项目的研究成果将为光动力灭菌技术在贝类加工保鲜中推广应用提供理论依据，还将为研究保鲜技术影响贝类品质劣化的作用机理提供新的研究思路。