受压肌红蛋白色泽对维生素C的响应规律及其机理

As a high commercialized non-thermal food processing technology, high pressure processing (HPP) has a great potential to be applied in the development of good quality meat. Moreover, the ‘whitening effect’ of meat color caused by HPP is a key problem which directly reduces the acceptability of consumers and restricts HPP technology development of meat products. Based on the ability of vitamin C to improve meat color and the previous work, myoglobin, as the research object in this project, will be applied to study the effect and its mechanism of vitamin C on the color of pressurized myoglobin based on analyses of myoglobin structure (protein conformation, heme configuration, sulfhydryl content, etc.), system characteristics (pH value, ion strength, etc.), intermolecular forces (hydrogen bond, disulfide bond, electrostatic force, etc.), and their relationship to the color change of pressurized myoglobin-vitamin C system by using a variety of analysis techniques and data processing methods, including circular dichroism, raman spectroscopy, nuclear magnetic resonance, X-ray diffraction, electron paramagnetic resonance, ANS fluorescent probe, principal component analysis, genetic neural network, etc.. These studies will favor to enrich color-protection theory of meat products treated by HPP, and effectively improve and regulate quality characteristics of that. Meanwhile, this project will provide theoretic foundation for boosting HPP technology industrialization.

超高压处理（HPP）作为一项商业化程度很高的食品非热加工技术，在优质肉类开发中具有巨大的应用潜力。而HPP导致的肉色“白化”是直接降低消费者可接受性、制约肉制品HPP技术发展的一个关键问题。本课题基于维生素C改善肉色的能力和前期的工作基础，选择肌红蛋白为研究对象，应用圆二色谱、拉曼光谱、核磁共振、X射线衍射、电子顺磁共振、ANS荧光探针、主成分分析、遗传神经网络等多种分析检测技术与数据处理方法，从肌红蛋白结构（蛋白分子构象、血红素分子形态、巯基含量等）、体系特性（pH值、离子强度等）、分子间作用力（氢键、二硫键、静电力等）与受压肌红蛋白-维生素C体系色泽的关联性角度，探究受压肌红蛋白色泽对维生素C的响应规律及其机理，以丰富肉品HPP的护色理论，有效改善与调控HPP肉制品品质，为推进肉制品HPP技术产业化提供理论基础。

超高压处理（HPP）作为一项商业化程度很高的食品非热加工技术，在优质肉类开发中具有巨大的应用潜力。而HPP导致肉色劣变及稳定性降低是直接降低消费者可接受性、制约肉制品HPP技术发展的一个关键问题。项目基于前期工作基础与调研资料分析，选用L-抗坏血酸（L-Ascorbic acid, L-AA）、复合氨基酸（Arg/Lys/Cys）、超高压处理（High pressure processing, HPP）等实验因子，从“L-AA改善受压冻融猪肉色泽有效性研究及相关机制分析”、“HPP对冷却肉色泽的影响及机制研究”、“L-AA对受压冷却肉色泽的影响及机制探析”和“Lys/Arg/Cys对乳化香肠色泽的影响与特征分析”四个方面开展肉及肉制品色泽调控与相关机制性研究。研究结果显示：⑴ 添加0.2～0.4% L-AA 可显著提升受压冷鲜及冻融猪肉贮藏a*值稳定性和OxyMb相对含量，降低“白化”现象；⑵ L-AA 可显著提升受压冷却肉MetMb还原酶活性，降低MetMb的贮藏累积，稳定鲜红肉色；⑶ 随着压力水平和保压时间的延长，冷却肉线粒体膜的通透性显著增加，而电子链传递介导的MRA能力却显著降低；当压力水平为300 MPa时，线粒体结构消失，却依然存有活性；⑷ 添加0.2% L-AA可显著增加线粒体膜的通透性、显著降低电子链传递介导的MRA能力，该作用能力不受保压时间和压力水平的影响；⑸ 添加Arg/Lys/Cys能够显著增强熟化亚硝基腌制香肠的特征红度，并促进Mb(Fe2+) 转化为MB(Fe2+)NO，使得血红素铁维持在还原状态。项目研究揭示了肉色变化的关键机制，为新型护色技术的开发提供理论基础，具有十分重要的科技转化前景。