热处理诱导杨梅汁香气劣变机制及其外源调控

The flavor of bayberry juice could deteriorate during thermal processing, seriously restricting its industry development, to find the solutions to the off-flavor problem has become a main focus in the field of flavor research. Literatures confirmed that glycan have the effect on aroma retention and natural polyphenols can significantly inhibit the off-flavor produced by Maillard reaction. In our previous study, the important volatile compounds contributed to the flavor differentiation were obtained between the fresh bayberry juice and thermal-processed juice. The possible pathways to generate them are that thermal processing leads to the escape of aroma molecules and the occurrence of Maillard reactions. Based on this, the project will study the formation mechanism of the above pathways and exogenous regulation by using healthy and odorless glycan and natural polyphenol. First of all, the target compounds contributed to the changes of free/bound-aroma and the formation of new off-flavor will be revealed at molecular level by using modern sensomic technologies. Solvent-assisted flavor evaporation (SAFE) and dynamic headspace analysis (DHS) combined with odor activity value (OAV) and stable isotope dilution assay (SIDA) are used to investigate the effects of oligosaccharides and polysaccharides on aroma retention and reveal the mechanism of inhibiting the Maillard reactions of thermal-processed juice by natural polyphenols. And finally clarifying the molecular regulation mechanism that inhibiting the aroma deterioration of the thermal-processed bayberry juice. The project will provide an important foundation for the effective regulation of flavor deterioration in thermal-sensitive fruit and the development of fruit and vegetable processing industry.

热处理导致杨梅汁香气劣变，此问题严重制约产业发展，亟待解决。有文献表明，多糖包埋作用和多酚抑制美拉德反应对部分食品香气保持有积极作用。申请人初步鉴定出杨梅汁热处理前后风味差异的贡献组分，分析其可能机理正是通过热加工促进香气分子逸散及美拉德反应产生，项目在此基础上利用健康无味的聚糖及天然多酚，分别对两条机理途径进行研究和调控。首先，采用现代分子感官组学技术，从分子水平精细揭示热加工杨梅汁中游离态和键合态香气变化规律及新异味形成机制；然后，利用溶剂辅助风味提取（SAFE）和动态顶空（DHS）技术，结合香气活性值（OAV）和稳定同位素稀释定量（SIDA）等方法解析低聚糖和多糖物理包埋作用对杨梅特征香气保持效果，并利用液质联用等技术揭示天然多酚对抑制风味劣变作用机理及其构效关系；最终阐明抑制热加工杨梅汁不良风味的分子调控机理。项目将为热敏性果品热加工风味劣变有效调控及果蔬加工产业发展提供重要基础。

杨梅汁热加工过程中风味劣变问题严重制约产业发展，亟待解决。项目申请人利用溶剂辅助风味提取（SAFE）和顶空固相微萃取技术（HS-SPME）技术，结合香气活性值（OAV）、时间强度法（OSME）、香气提取物稀释嗅闻分析（AEDA）等方法探究了杨梅汁热加工过程中感官品质及风味化合物的变化，热处理前后杨梅汁中共检测出100余种挥发性物质，共鉴定出36种FD≥4的重要香气活性化合物，从分子水平揭示了热加工杨梅汁中香气变化规律及新异味形成机制；并通过全二维气相色谱-四极杆飞行时间质谱、气相色谱-质谱联用仪及液质联用等技术揭示了多糖对原汁香气保持及不同种类天然多酚对热加工杨梅汁风味劣变的作用规律，确定最佳抑制效果的多酚结构和浓度，最终阐明了抑制热加工杨梅汁不良风味的分子调控机理。项目将对果蔬热加工风味劣变问题的解决具有借鉴意义。