基于气相色谱-嗅闻-质谱技术结合化学计量法分析小曲清香型白酒醛异味成分

Analysis of aldehyde off-flavor compounds of Xiaoqu light flavor Baijiu based on GC-O-MS combined with chemometric method

醛异味是小曲清香型白酒常见的感官缺陷,严重影响其风味与品质。为明晰小曲清香型白酒醛异味物质,以更好地控制与提升其风味品质。采用液液萃取和顶空固相微萃取法结合气相色谱-嗅闻-质谱联用技术对小曲清香型白酒进行定性定量分析,进一步结合多元统计方法对醛异味样品和正常样品进行判别分析,明确两者间的显著性差异香气成分。结果表明,在醛异味样品和正常样品中共鉴定出香气强度>2的香气物质61种,基于二者的绝对含量建立的偏最小二乘判别分析模型(orthogonal partial least squares discrimination analysis,OPLS-DA)拟合参数为R_(Y)^(2)=0.984,Q2=0.829,可有效区分醛异味和正常样品,并鉴定出香气活力值(odor activity value,OAV)≥1且变量重要性因子(variable importance in the projection,VIP)≥1的化合物共9种,为乙缩醛、乙醛、正丙醇、乙酸、丁酸、辛酸乙酯、异戊酸、异丁醛、丙酸。上述化合物的含量失调对小曲清香型白酒产生醛异味具有重要影响。

Aldehyde off-flavor is a common sensory defect of Xiaoqu light flavor Baijiu,which seriously affects the flavor and quality of Xiaoqu light flavor Baijiu.To analyze the sources of aldehyde off-flavors in Xiaoqu light flavor Baijiu and to regulate their content from the production process,liquid-liquid extraction and headspace solid phase microextraction were used in combination with gas chromatography-olfactometry-mass spectrometry.The qualitative and quantitative analyses and the discriminative analyses of aldehydic and normal Xiaoqu light flavor Baijiu were carried out,and the significant differences between the two types of spirits were clearly obtained.The aromatic components of the aldehyde off-flavors were identified by combining multivariate statistical analysis.A total of 61 aroma compounds with aroma intensity greater than 2 were identified.The orthogonal partial least squares discrimination analysis model was established based on the content of aldehydic and normal Xiaoqu light flavor Baijiu.The OPLS-DA model(R_(Y)^(2)=0.984,Q2=0.829)based on the content could effectively distinguish between aldehydes and normal Xiaoqu light flavor Baijiu,and nine compounds with OAV≥1 and VIP≥1 were identified,including acetal,acetaldehyde,n-propanol,acetic acid,butyric acid,ethyl caprylate,isovaleric acid,isobutyraldehyde,and propionic acid.The imbalance in the content of these compounds has an important influence on the production of aldehyde off-flavors in Xiaoqu light flavor Baijiu.