木质素结构对熏烤肉制品中多环芳烃形成的影响及机制研究

On account of the formation of undesired toxins such as polycyclic aromatic hydrocarbons (PAHs) during the smoked and grilled process, it is crucial to figure out the formation mechanism of PAHs and controlling their contents from the source for the health concerns. During smoked or grillied process, the formation of PAHs was mainly caused by incomplete combustion of wood; in other words, the thermal pyrolysis of lignin in lignocellulose. Up to date, it was not clear that the influence and mechanism of different types of wood on the formation of PAHs in smoked and grilled meat products. In this project, we will study the influence of lignin’s structure on the formation of PAHs in smoked and grilled meat products, the pyrolysis of typical lignin β-O-4 dimer was studied for investigating the pyrolysis of lignin from different wood; the possible precursors or intermediates during pyrolysis reaction of β-O-4 models through Density Functional Theory (DFT) simulation will be explored; the change of precursors and PAHs will be analyzed through establishing the chemical model for the formation of PAHs; and it was expected to find out the effect of the structure of lignin on the formation of PAHs and the detailed mechanism by comparing chemical model study with experimental results. It is of significance of science and banausic prospects that the research establishing the chemical model by predicting the reasonable precursors or intermediates through DFT simulation, combining with experimental results to disclose the influence mechanism of different types of wood on formation of PAHs during the smoking and grilling, and offering theory basis for studying the formation mechanism of PAHs during heat-processing of meat products.

熏烤肉制品中易产生多环芳烃（PAHs）类有害物，研究PAHs的形成机制，从根源上控制其生成对人类健康至关重要。熏烤中木材的不完全燃烧，本质上为木材中木质素的热裂解，是PAHs形成的主因之一。目前，木材类型对熏烤中PAHs形成的影响及机制尚不清楚。本项目拟考察木质素结构对熏烤肉制品中PAHs形成的影响，以典型的木质素β-O-4二聚体裂解作为木质素裂解反应模型，通过密度泛函理论（DFT）等计算方法，从分子角度探讨不同来源木质素的热裂解过程，推测可能前体物；通过前体物研究构建PAHs形成的化学模型体系，考察模型体系中前体物与PAHs的变化规律；将实验结果与模型体系研究对比分析，提出木质素结构对熏烤肉制品中PAHs形成的影响机制。通过理论模拟、化学模型构建、模型体系与实验研究结合，揭示木材类型对熏烤肉制品中PAHs形成的影响本质，为PAHs的形成机制提供理论借鉴；具有重要的科学意义和应用前景。

肉制品热加工，特别是熏烤过程中，易产生多环芳烃（PAHs）类有害物质。PAHs是一类广泛存在于环境、食品内的污染物，具有强致癌性、致突变性、致畸性。研究加工肉制品中PAHs类有害物的形成及机制，科学有效控制其生成，对降低其对人类健康的潜在危害，提高食品安全性至关重要。熏烤肉制品中，木材的不完全燃烧是产生PAHs的主要原因之一，考察熏材中木质素结构对PAHs生成的影响，有助于揭示熏材类型对PAHs形成的影响本质。本项目考察了熏烤肉制品生产实际中常用五种木材的木质素的结构特性以及相应的热解特性；借助模型化合物，研究了不同木质素模型的热裂解行为，探索分析了其相应的热裂解规律及断裂路径；借助热裂解气相色谱-质谱连用分析了不同种类木材木质素的热裂解行为，初步分析了木质素热裂解过程中与PAHs生成相关的可能的前体中间物；构建了化学模拟体系，考察了不同温度条件下前体物添加对模型体系中PAHs生成的影响；初步探讨了木质素结构对PAHs形成的影响机制。本项目研究结果可为研究熏烤肉制品中PAHs形成机制提供理论借鉴，为后续肉制品的安全加工提供指导建议，降低加工肉制品的食品安全隐患。