肉制品中晚期糖基化终末产物的生成机制及调控途径研究

Meat emulsion products, such as sausage, meatball and roast sausage, are mainly made from frozen raw meat (pork, chicken and duck meat) due to cost pressures. Advanced glycation end products (AGEs) are a series of harmful compounds and easily formed during the processing of meat products, such as broiling, frying and sterilization. Thus, their security is being questioned by consumers. At present, there have been some reports describing generation kinetics of AGEs based on Maillard reaction in the sample model system. Less is known about the effects of lipid oxidation, protein oxidation, food components, phase transitions or ingredients on the formation of AGEs. The inhibition theory and technology are lacking in meat products. Therefore, the objective of this study was to investigate the effects of different degree of oxidation of lipid and protein on AGEs formation. The role and dynamic characteristics of different AGEs formation pathway were elucidated during processing of meat products. The effects of typical food system (such as emulsification system and multi-dispersion system) and processing conditions on the generation of AGEs were also investigated so as to seek the inhibition pathway of AGEs formation in this work. Finally, we seek to the control technology for AGEs generation by controlling the raw meat materials, screening the blocking agent and controlling the reaction kinetics of AGEs. This research will provide strategies to reduce the formation of AGEs in meat products, which is of great practical significance for improving food safety and public health.

香肠丸子烤肠等肉糜制品在制造时，基于成本考虑会采用冷冻猪肉鸡鸭等易发生氧化原料，并有着烤制、油炸和杀菌等高温操作，导致肉制品中晚期糖基化终产物（AGEs）等已被证实的有害物含量较高，产品安全性存在疑虑。迄今为止针对AGEs的研究主要集中在基于美拉德反应的简单模拟体系中进行，而对实际体系中由于脂肪氧化、蛋白质氧化及复杂组分和相态变化等影响AGEs生成的研究很少，缺乏调控理论及技术。本项目重点研究肉制品中脂肪氧化和蛋白氧化对AGEs生成的影响，阐明各种AGEs的生成途径在肉制品加工过程中所起的效应及动力学特征；研究乳化体系/多分散体系等典型肉制品体系和加工条件对AGEs生成的影响，寻求调控途径；以香肠为研究对象，通过控制原料、筛选阻断剂及控制反应动力学等手段寻求实际肉品体系中控制AGEs生成的技术。该研究将为控制肉制品中AGEs的生成提供新思路，对提高食品安全性，保护公众健康具有重要现实意义。

晚期糖基化终末产物(AGEs)是食品生产加工过程中通过美拉德反应生成的一系列复杂化合物的总称。它可通过饮食进入人体血液循环，诱发多种慢性疾病的发生。因此，关于食品中AGEs的生成机制、影响因素以及控制途径的研究逐渐得到关注。本项目以肌原纤维蛋白 (MFP)、原料肉以及肉制品为主要研究对象，首先研究了冷冻储藏时间对原料肉肌内脂肪、肌原纤维蛋白氧化以及理化特性的影响。结果表明：随冻藏时间延长，肌内脂肪的氧化程度逐渐升高，肌原纤维蛋白中羰基含量显著上升(P < 0.05)，总巯基、自由氨基、内源性色氨酸荧光、表面疏水性含量总体呈下降趋势(P < 0.05)；肉色趋近于由亮变暗，略偏黄色，失水率和蒸煮损失都显著增大(P < 0.05)。MFP溶解度、凝胶保水性、白度及强度均显著下降(P < 0.05)。其次，采用LC-MS/MS法结合主成分分析考察了脂肪氧化、蛋白羰基、总巯基、自由氨基、表面疏水性、内源性色氨酸荧光强度等微观结构变动对肉制品中AGEs生成途径的影响，结果显示：随原料肉冻藏时间延长，原料肉中脂肪和蛋白质将会发生一定程度的氧化，导致蛋白内部的氨基酸残基（如赖氨酸和精氨酸等）发生一定程度的暴露，这些结构上的微观变动将会进一步促进AGEs的生成，导致其含量升高。这也可能是蛋白质氧化程度与AGEs含量之间具有显著相关性的原因之一。随后，在含有氧化亚油酸的模拟体系中探讨不同氧化程度和水解程度的MFP对AGEs生成途径的影响，结果表明：氧化亚油酸可以诱导MFP发生一定程度的氧化，轻度氧化的MFP有助于AGEs的生成，而重度氧化的MFP可以阻碍AGEs的产生；经水解处理的MFP，由于氨基酸残基含量的升高，导致AGEs的含量较高。最后以模拟体系为研究对象，采用荧光光谱法结合主成分分析调查了不同浓度的姜黄素（0-160 μg/mL）和胡椒碱（0-160 μg/mL）对AGEs生成的影响。结果显示：姜黄素和胡椒碱的添加可以显著抑制MFP的氧化，进而导致AGEs含量的降低。当姜黄素和胡椒碱的添加量为160 μg/mL时，AGEs的抑制率分别高达100%和93%。本项目研究对于提高加工肉制品的安全性提供理论基础，为降低肉制品中AGEs含量提供方案。