爱格丽干白葡萄酒发酵过程中典型乙酸酯的生成动力学

Kinetical Feature for Acetate Esters Production during Ecolly Dry White Wine Fermentation

为建立干白葡萄酒中重要乙酸酯的生成动力学模型,以爱格丽葡萄为原料,接种酿酒酵母,按常规工艺酿造干白葡萄酒。发酵过程中监测乙醇和乙酸含量变化,并定时取样进行目标香气物质(异戊醇、苯乙醇、乙酸乙酯、乙酸异戊酯和乙酸苯乙酯)的SPME-GC-MS分析,建立目标香气物质的香气活性值变化曲线,同时从经典化学反应动力学角度构建目标香气物质的生成动力学模型。研究结果表明,乙酸异戊酯在发酵过程中表现出香气活性,乙酸苯乙酯仅在最大检出量时表现香气活性,乙酸乙酯检出量一直低于嗅觉阈值。目标香气物质从开始生成至达到最大生成量的含量变化均符合零级动力学模型(R2>0.95,P<0.001)。模型揭示出,乙酸乙酯的生成与乙醇和乙酸具有同时性,乙酸异戊酯和乙酸苯乙酯的生成分别相对于异戊醇和苯乙醇有延滞效应。结合零级动力学模型特征,为增强葡萄酒的花香和果香特征,可尝试在爱格丽葡萄汁发酵旺盛的香气物质半生成期,调控促进乙酸乙酯和乙酸苯乙酯生成。

Acetic esters are an important contributor to the fruity aroma of wine. The aim of the research was to explore the kinetical feature for the formation of important acetic esters,using Ecolly to ferment dry white wine according to conventional process after being inoculated with active yeast. During the fermentation process, the ethanol and acetic acid contents were monitored and the contents of representative aroma of isoamyl alcohol,phenethyl alcohol,ethyl acetate,isoamyl acetate and phenethyl acetate were analyzed by SPME-GC-MS so as to achieve the feature of odor activity and establish corresponding kinetical models based on the classical principle of chemical reaction kinetics. The results showed that the isoamyl acetate exhibited aroma active through the fermentation process,and phenethyl acetate was only aroma active at the maximum production,while ethyl acetate was lower than the olfactory threshold. The contents of the considered aroma from the beginning to the maximum production were in line with the zero order kinetical feature（R2〉0. 95,P〈 0. 001）,revealing that the production of ethyl acetate was synchronous with the production of acetic acid and ethanol,whilst the production of isoamyl acetate or phenethyl acetate was delayed compared with the production of isoamyl alcohol and phenethyl alcohol. With considering the characteristics of zero order kinetics,the production of acetic acid and phenethyl acetate could be modulated and enhanced at their half-production times so as to improve the floral and fruity odour.