3种贮存方式下老白干原酒挥发性风味成分变化规律研究

Study on Variation Rules of Volatile Flavors in Laobaigan Base Baijiu at Three Storage Methods

贮存老熟过程是提高白酒品质的关键。以老白干白酒的原酒为研究对象,分别采用自然贮存(室温)、恒温贮存(40℃)和变温贮存(每日40℃贮存12 h后自然降温12 h)3种方式贮存156 d,利用顶空固相微萃取结合GC-MS、GC-O研究老熟过程中原酒主要挥发性风味成分的变化,共定性出55种挥发性风味成分。对其中43种含量相对较高且具有白酒风味特征的挥发性风味成分采用标准品外标定量的方式,监测其在156 d贮存期间含量的变化,并计算其气味活性值。结果表明:变温贮存过程中,大部分酯类含量随着时间增长逐渐升高,恒温贮存过程中大部分酯类含量呈现先增后减的趋势。变温贮存156 d时乳酸乙酯、乙酸乙酯、乙酸异戊酯、乙酸己酯、己酸乙酯、己酸异戊酯、异己酸乙酯、壬酸乙酯、十一酸乙酯、肉豆蔻酸乙酯、油酸乙酯、丁二酸二乙酯、壬二酸二乙酯、苯乙酸乙酯的含量高于自然贮存和恒温贮存组。恒温贮存156 d时,仅棕榈酸乙酯的含量比同天数其他2种贮存方式高。19种挥发性风味成分的香气活度值大于1,为白酒整体香气做出重要贡献。研究结果也反映出恒温老熟时间不宜过长,否则会出现酯类含量减少现象,建议恒温贮存的较佳时间是128 d;变温老熟能提高酯类含量,一定程度上缩短老熟时间。研究旨在为白酒原酒生产过程中工艺优化指明方向,也为白酒企业优化酒体设计方案、提升产品质量奠定基础。

Aging process during storage is a key process in improving the quality of Baijiu.Laobaigan base Baijiu as a research project was stored for 156 d with three different methods,natural temperature storage(room temperature),constant temperature storage(40℃)and alternating temperature storage(40℃for 12 h and cooled naturally for 12 h every day).Headspace solid-phase microextraction combined with GC-MS and GC-O were used to study the effects of different aging methods on the changes of volatile flavor components in base Baijiu.A total of 55 volatile flavor components was identified,43 out of these with relatively high contents and Baijiu flavor characteristics were monitored during 156 d storage by external standard quantity,and the changes of odor activity value were calculated then.Results showed that the contents of most esters increased gradually with time at alternative temperature storage,and the contents of most esters increased first and then decreased at constant temperature.The contents of ethyl lactate,ethyl acetate,isoamyl acetate,hexyl acetate,ethyl hexanoate,3-methylbutyl hexanoate,ethyl 4-methyl valerate,ethyl nonanoate,ethyl undecanoate,ethyl tetradecanoate,ethyl oleate,diethyl succinate,diethyl azelate,ethyl phenylacetate at alternative temperature storage were higher than those at natural temperature or constant temperature storages on the 156th day.However,only the content of ethyl palmitate at constant temperature storages was higher than those of the other two groups on the 156th day.Nineteen compounds with odor activity value greater than 1 were potent odorants,they significantly contributed to the overall aroma of Baijiu.The results also showed that the time of constant temperature treatment should not be too long,or the content of esters would regress.The recommended time for constant temperature storage was 128 days.The alternating temperature storage could increase the content of esters and shortened the aging time to a certain extent.These findings pointed out the direction for process optimization in the productive process of base Baijiu,and laid the foundation for the company to optimize the liquor production design and improve product quality.