南极磷虾贮藏期间虾壳释放游离态氟的机制

Antarctic krill are widely distributed in Central Antarctic waters, resource reserve is tremendous. Its good nutritional value of protein resource and reserve is considered to be a human important protein library. It has great value of development and utilization. Antarctic krill has a strong ability to enrich fluorine from seawater. There exist multi-forms of fluorine in Antarctic krill. The bioavailability of free fluorine is high and strong harmful，and the content of binding fluorine in krill shells is high. During the storage, the fluorine content of Antarctic krill shells were continuously decreased, and the fluorine content of Antarctic krill meat was continuously increased, which restricted the exploitation and utilization of Antarctic krill resources. In order to reduce the fluorine content of Antarctic krill meat, it is urgent to elucidate the mechanism of releasing free fluorine from Antarctic krill shells. In the study, XRD, FTIR, DSC, SEM, 19F NMR etc. will be used to elucidate the structure of Antarctic krill shell and to reveal its main form of fluorine. The key inducing factors of releasing free fluorine from Antarctic krill of shells will be screened from three aspects of endogenous enzyme, pH and microorganism. The relationship among inducing factors, the structure change of Antarctic krill shells and the free fluorine amount liberated from Antarctic krill shells will be analyzed. The kinetic model of liberating free fluorine from Antarctic krill shells will be established, and the mechanism of releasing free fluorine from Antarctic krill of shells will be revealed. The results of the study will provide theoretical basis for the control of releasing free fluorine from Antarctic krill of shells and the toxicity of the Antarctic krill.

南极磷虾广泛分布于环南极水域，资源蕴藏量巨大，其优良的蛋白资源和营养价值，已被认定为是人类重要的后备蛋白库，具有重大开发利用价值。南极磷虾具有从海水富集氟的超强能力。南极磷虾中氟有多种赋存形态，游离态氟生物利用度高、毒害性大，虾壳中结合态氟含量高。贮藏期间，虾壳氟含量不断下降，虾肉氟含量逐渐升高，限制了南极磷虾资源的开发利用。为了降低虾肉氟含量，虾壳释放游离态氟机制亟待阐明。本项目首先拟采用XRD，FTIR，DSC，SEM，19FNMR等手段对南极磷虾虾壳结构与无机盐组成进行分析，阐明南极磷虾虾壳结构特点，揭示虾壳氟主要赋存形态；从内源酶、pH和微生物三个方面筛选诱发虾壳游离态氟释放的关键因素，分析虾壳游离态氟释放量、诱发关键因素与虾壳结构变化关系。构建虾壳释放游离态氟动力学模型，揭示虾壳释放游离态氟机制。预期研究结果将为控制南极磷虾虾壳游离态氟的释放和降低南极磷虾氟的毒性提供理论依据。

南极磷虾资源蕴藏量巨大，且营养丰富。但氟含量过高严重制约了它的开发与利用。研究南极磷虾氟的赋存形态，尤其是游离态氟的来源及其形成机制，对于了解氟在南极磷虾生命活动中的作用及其降低南极磷虾氟的毒性具有十分重要意义。本研究采用仪器分析与化学分析方法相结合对南极磷虾壳结构进行了表征与无机盐组成及氟赋存形态分析，阐明南极磷虾虾壳的结构特点。通过跟踪、监测南极磷虾贮藏过程中虾壳结构变化与虾壳游离态氟释放量的变化规律，筛选出引起南极鳞虾壳释放游离态氟的主要诱发因素为内源甲壳素酶与类胰蛋白酶。运用硫酸铵分级沉淀、离子交换层析和凝胶层析等方法对南极磷虾甲壳素酶和类胰蛋白酶进行分离、纯化，并对其进行鉴定和酶学性质研究。对甲壳素酶和类胰蛋白酶诱发南极磷虾虾壳释放游离氟的动力学进行研究，跟踪监测虾壳微观结构变化与其释放游离态氟的关系，研究甲壳素酶和类胰蛋白酶引起南极磷虾壳释放游离氟的机制。结果对有效地控制南极磷虾虾壳游离态氟的释放和降低南极磷虾氟的毒性提供了理论依据。