AsA-GSH循环调控气调果蔬呼吸代谢途径异味机制

Off-flavor is a serious problem of fruits and vegetables under controlled atmospheres, which mainly occurs in respiratory metabolism pathway and closely relates to the sensitive high CO2 characteristics of fruits and vegetables. Ascorbate-glutathione (AsA-GSH) cycle not only has the role in eliminating active oxygen and stabilizing cell microstructure, but also produces NAD+ which can promote glycolysis and competitively inhibit anaerobic respiration. In this project, broccoli (Brassica oleracea L. var. italica，CO2 tolerance) and cauliflower (Brassica oleracea L. var. botrytis，CO2 sensitive) are used as materials, and high O2/CO2 controlled atmospheres is used as treatment. For elucidating the regulation mechanism of AsA-GSH cycle to high CO2 endurance, two principle lines, including AsA-GSH cycle→alleviate active oxygen stress→stabilize cell microstructure→enhance the process of tricarboxylic acid cycle and oxidative phosphorylation→increase ATP→ eliminate anaerobic respiration, and AsA-GSH cycle→provide NAD+→increase glycolysis and competitively inhibit anaerobic respiration, are followed. Ascorbic acid and glutathione spraying treatment is used in testing and verifying the theory proposed in this project. Thereafter, through the treatment of high O2/CO2 controlled atmospheres by fixing CO2 and successively increase O2 proportion, combining AsA-GSH cycle, elucidate the reduction mechanism of respiratory off-flavor. Results of this project have important theoretical and practice meaning, in illuminating the high CO2 endurance metabolism mechanism and regulation mechanism of off-flavor reduction of fruits and vegetables storage.

异味是果蔬气调贮藏期间容易出现的严重问题，主要发生在呼吸代谢途径，且与果蔬不耐高CO2特性密切相关。抗坏血酸-谷胱甘肽（AsA-GSH）循环不仅对消除活性氧、稳定细胞结构起重要作用，且产生的NAD+，有助于糖酵解进程和竞争性抑制无氧呼吸。本项目以青花菜（CO2耐受型）和花椰菜（CO2敏感型）为试材，高O2/CO2气调为处理手段，从AsA-GSH循环→减轻活性氧胁迫→稳定细胞结构→促进三羧酸循环和氧化磷酸化→提高ATP→避免无氧呼吸及AsA-GSH循环→提供NAD+→促进糖酵解、竞争性抑制无氧呼吸，两方面揭示AsA-GSH循环对果蔬耐高CO2调控机制，并通过外源喷施AsA+GSH进行验证。进而，通过固定CO2逐步提高O2的高O2/CO2气调处理，结合AsA-GSH循环，揭示高O2/CO2气调对呼吸异味减免机理。本研究对于揭示果蔬耐高CO2代谢模式和异味物质调控模式，具有重要的理论和实践意义。

异味是果蔬气调贮藏期间容易出现的严重问题，主要发生在呼吸代谢途径，且与果蔬不耐高CO2特性密切相关。本项目在规范西兰花采收规格的基础上，研究了O2/CO2气调对西兰花保鲜效果的影响，通过设置不同CO2体积分数探讨了高CO2产生异味途径，通过浸施谷胱甘肽阐释了AsA-GSH循环对呼吸代谢异味的调控机制，发现谷胱甘肽浸施刺激了AsA-GSH循环，提高了NAD+水平，促进了抗氧化能力和呼吸代谢相关酶活性，致使能荷处于较高水平，从而抑制了乙醛、乙醇等异味物质的产生。在此基础上，研发了适于物流保鲜的O2/CO2主动自发气调技术，并探索了西兰花、羊肚菌、蒜薹、平菇、香菇等的需要充入的初始O2/CO2比例；同时，进行了O2/CO2主动自发气调对霉菌的抑制机理，发现O2/CO2主动自发气调显著抑制了桃吉尔霉、枝孢菌活性和孢子萌发，为果蔬的物流保鲜及病害控制提供了技术参考。.本项目研究发表研究论文11篇，网络首发论文1篇，其中SCI一区2篇，SCI二区2篇，EI收录5篇，卓越期刊论文4篇；申请国家发明专利4项；培养毕业研究生6名，在读2名。