“氧化鸡脂-谷胱甘肽-葡萄糖”反应体系风味物质鉴定及形成机制

设计"氧化鸡脂-谷胱甘肽-葡萄糖"模型反应,于131℃和pH 6.5条件下反应5 h。采用溶剂辅助蒸发法萃取反应产物中的挥发性风味物质,并采用气相色谱-质谱仪、稀释法嗅闻分析。基于质谱、保留指数、气味特征、标准品,鉴定出89种化合物;其中67种化合物具有气味活性,主要为含硫化合物和醛类化合物。鉴定出由脂肪氧化降解与美拉德反应相互作用形成的带有烷基链的化合物10种,包括2-戊基噻吩、2-庚基噻吩、2-戊基吡啶等,多数具有气味活性。除了2-甲基-3-呋喃硫醇、糠硫醇等产生于美拉德反应的化合物外,带烷基链的2-庚基噻吩、2-甲基吡啶、2-乙基吡啶等也具有较高的稀释因子(Log_3FD≥5),表明在"氧化鸡脂-谷胱甘肽-葡萄糖"体系中,脂肪氧化降解与"谷胱甘肽"美拉德反应相互作用对肉香风味形成具有较大贡献,研究结果对"脂肪控制氧化-热反应"制备肉味香精有指导意义。

Identification and Formation Mechanism of Volatile Flavor Compounds from Oxidized Chicken Fat-Glutathione-Glucose Model Reaction System

An oxidized chicken fat-glutathione-glucose model reaction system was designed and the reaction was allowed to proceed at 131 ℃ under pH 6.5 for 5 h. Volatile flavor compounds in the reaction products were extracted by solvent assisted flavor evaporation (SAFE) extraction, and analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) combined with aroma extract dilution analysis (AEDA). As a result, a total of 89 volatile compounds were identified, 67 of which were revealed to be aroma-active according to their mass spectra, linear retention indices and odor characteristics by co-injection with authentic standards. Among them, 10 alkyl-chain compounds were found, including 2-heptylthiophene, 2-pentylthiophene, and 2-pentylpyridine, which were formed by the interaction of lipid oxidation and degradation with the Maillard reaction. Besides, the compounds solely generated from the Maillard reaction such as 2-methyl-3-furanthiol and 2-furfurylthiol as well as most alkyl-chain compounds such as 2-heptylthiophene, 2-methylpyridine and 2-ethylpyridine had a high dilution factor (Log3FD ≥ 5). Therefore, the interaction of lipid oxidization and degradation with the Maillard reaction of glutathione made a considerable contribution to the development of meaty flavor in the reaction system. These research results can provide a useful guidance for the preparation of meaty flavorings through controlled fat oxidization combined with thermal reaction.