模糊数学结合响应面法优化葛根酒发酵工艺参数及其香气成分分析

为消除主观因素对感官评价的影响,以宜宾葛根为原料,采用模糊数学结合响应面法对葛根酒发酵工艺进行优化。在单因素实验的基础上,选取发酵初始pH、发酵温度、酵母添加量为影响因素,以通过模糊综合评价得到的品质等级值为响应值,运用Box-Behnken中心组合试验设计建立数学模型,进行响应面分析,并采用顶空固相微萃取结合气相色谱-质谱联用技术(HS-SPME/GC-MS)对葛根酒的香气成分进行检测。结果表明:葛根酒最优发酵条件为发酵初始pH5.5、发酵温度30 ℃、酵母接种量0.5%。在此条件下,感官评价等级值为3.68;葛根酒中共检测出30种香气成分,醇类物质含量为8.414 mg/L,以异戊醇、苯乙醇、异丁醇和异丙醇为主;酯类物质含量为2.229 mg/L,其中乙酸乙酯、乙酸苯乙酯、乙酸异戊酯、辛酸乙酯、己酸乙酯含量较高;此外还检测出酸类、醛类、酮类物质,如乙酸、己酸、辛酸、乙缩醛、3-羟基-2-丁酮等,这些香气物质相互融合协调,构成了葛根酒独特的风味。

Optimization of Fermentation Process of Gegen Wine by Fuzzy Mathematics Combined with Response Surface Methodology and Analysis of Its Aroma Components

In order to liminate the influence of subjective factors on sensory evaluation, with Yibin gegen as raw material, fuzzy mathematics combined with response surface methodology was used to optimize the fermentation conditions of gegen wine. Based on single facter experiment, initial pH, fermentation temperature and inoculum size of yeast were chosen as the major factors for further optimization by mathematical modeling using Box-Behnken design and response surface analysis. The quality level values obtained by fuzzy comprehensive evaluation were selected as response variables. Headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS) was used for the analysis of volatile compounds in gegen wine. The results showed that, the optimum fermentation conditions of gegen wine were initial pH5.5, fermentation temperature (30℃), inoculum size of yeast (0.5%). Under these optimal conditions, the quality level value was 3.68. Thirty aroma-active components were identified from gegen wine, alcohol content was 8.414 mg/L, mainly including isoamyl alcohol, phenylethyl alcohol, isobutanol, isopropanol. The content of esters was 2.229 mg/L, among which ethyl acetate, phenylethyl acetate, isopentyl acetate, ethyl octanoate, and ethyl hexanoate contained more. In addition, acids, aldehydes, ketones, such as acetic acid, caproic acid, octanoic acid, acetal, 3-hydroxy-2-butanone, etc., had also been detected. These aroma substances were coordinated with each other and constituted the unique flavor of gegen wine.