从抑制/消除油脂氧化产物角度研究大蒜二烯丙基二硫减除油炸体系PhIP的机理

2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) is a kind of heterocyclic aromatic amines (HAAs) which mostly forms in the fried meat products. It has potential hazardness. In the previous studies, the diallyl disulfide (DADs) from garlic was found to be unable to reduce the formation of PhIP in the system without lipid, while could significantly inhibit PhIP in lipid system. Based on the discovery that lipid oxidation was one of PhIP formation pathway, a new thinking involving that DADs could inhibit the formation of PhIP by controlling lipid oxidation is proposed in this study. The quantitation correlation models between the lipid oxidation products (LOPs) in oil with different oxidation degrees and the PhIP concentrations are firstly established to screen out the key LOPs that significantly promoted the PhIP formation. Then, the inhibitory effects of DADs on the key LOPs are evaluated from two aspects including LOPs formation restrain and LOPs elimination: First, the dynamic variation rules for DADs, the high temperature products of DADs and LOPs in oxidized lipid systems are quantitatively analyzed by using the mass spectrometric techniques; Then, the eliminated molecular mechanisms of DADs on key LOPs are investigated by using isotope labeling techniques combined with mass spectra and NMR analysis. The hypotheses are finally verified in fried pork chops. The results of this study may offer a new train of thought to the PhIP inhibitory theories in fried meat products.

2-氨基-1-甲基-6-苯基咪唑并[4,5-b]吡啶（PhIP）是油炸肉制品中形成最多的杂环胺，具有潜在危害性。前期发现大蒜二烯丙基二硫（DADs）在无法显著抑制无油体系中PhIP形成的同时对含油体系中PhIP抑制显著。基于油脂氧化这一PhIP形成途径的发现，项目提出DADs可能通过控制脂肪氧化抑制PhIP形成的新设想。通过构建不同氧化程度油脂中油脂氧化产物（LOPs）量与PhIP形成量的量变关系模型，筛选出对PhIP形成有显著影响的关键LOPs。再从抑制形成和消除两方面，剖析DADs对关键LOPs的抑制作用：采用质谱分析技术，定量分析DADs加入后，氧化油脂体系中DADs、DADs高温产物和LOPs的动态变化规律；再利用同位素标记技术结合质谱、核磁技术探索DADs对关键LOPs消除的分子机制。最终在实际油炸猪排中验证。项目的研究成果，可为油炸肉制品中PhIP的抑制理论提供新思路。

2-氨基-1-甲基-6-苯基咪唑并[4,5-b]吡啶（PhIP）是油炸肉制品中形成最多的杂环胺，具有潜在危害性。前期发现大蒜二烯丙基二硫（DADs）在无法显著抑制无油体系中PhIP形成的同时对含油体系中PhIP抑制显著。基于油脂氧化这一PhIP形成途径的发现，本研究从抑制油脂氧化这一全新角度探索DADs对PhIP的抑制机制。开展了油脂氧化对PhIP形成的影响的研究，通过制备24个不同氧化程度的氧化大豆油，采用GC-MS法在氧化大豆鉴定出71种共有的脂肪氧化产物（LOPs），并进行定量。采用主成分分析法建立氧化大豆油中LOPs含量与其PhIP促进率的量变关系模型，并从中筛选出对 PhIP 形成有显著促进作用的关键LOPs为2-己烯醛和苯甲醛。随后，从抑制形成和消除两个方面，剖析大蒜中DADs对2-己烯醛和苯甲醛的抑制机制，结果发现，DADs能显著抑制2-己烯醛在油炸氧化过程中的形成。同时，可与油脂中形成的苯甲醛发生加合反应，形成新化合物2-苯基-1,3-二噻烷和prop-2-enylsulfanylmethylbenzene。由此可见，DADs在油炸体系中对PhIP的抑制主要是通过抑制关键LOPs的形成和与关键LOPs发生加合（清除LOPs）双途径来完成的。上述抑制机制已在实际油炸猪排体系中得到验证。本研究提出的全新的杂环胺抑制机理，丰富了杂环胺抑制机制的理论体系。同时本研究的理论成果，可有助于开发一种专用于油炸体系的香辛料源PhIP抑制剂，推广和应用后可进一步提高油炸肉制品的健康性，为油炸肉制品安全控制提供新的科学方法和途径。

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