基于全二维气相色谱-飞行时间质谱法对不同品质酱香型白酒的风味组分差异解析

Analysis of flavor component differences of various qualities Maotai-flavor Baijiu based on comprehensive two-dimensional gas chromatography-time of flight mass spectrometry

为了保证白酒质量和提高白酒酿造工艺水平,该研究采用顶空固相微萃取结合全二维气相色谱-飞行时间质谱(headspace solid phase microextraction-comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry,HS-SPME-GC×GC-TOF-MS)技术对不同品质酱香型白酒进行分析。研究发现,酱香型白酒中检出组分1063种~1347种,主要为酯类、酸类、醇类、醛类及酮类等。优质酒A1、A2和杂味酒B1、B2的酯类物质相对含量分别为58.75%、55.47%、42.05%和41.55%;醇类物质相对含量分别为17.14%、16.15%、26.77%和26.92%;酸类物质的相对含量分别为1.47%、2.05%、6.71%和7.69%;优质酒呈现酯高、醇低、酸适中,杂味酒呈现酯低、醇高、酸高等特点;且杂味酒中硫醚类、砜类、硫代酯类、噻吩类等含硫类组分较为突出,而优质酒中则含量很低或未检出。结合主成分分析(principal component analysis,PCA)和正交偏最小二乘判别分析(orthogonal partial least-squares discrimination analysis,OPLS-DA),显示优质酒和杂味酒的风味差异显著,其中变量权重值(variable importance in the projection,VIP)>1的潜在差异风味组分共有85种;筛选出VIP>1且P<0.05的物质绘制热图,结果表明优质酒中丁酸乙酯、己酸乙酯、壬醛、辛醛等含量较高,杂味酒中己酸、乙酸、异丁醇、异戊醇等含量较高。通过感官品评发现,杂质酒中酯香强度较低,高级醇味较强,口感略酸,略有异香,缺乏爽净感等,与杂质酒中组分鉴定的酯低、醇高、酸高以及存在的含硫类物质较多等结果具有一致性。该研究结果表明,HS-SPME-GC×GC-TOF-MS技术可在分子水平对酱香型杂味酒进行探究,为后续酱香型杂味酒的品质提升和工艺控制提供有效的技术支撑。

To ensure liquor quality and improve the brewing process,this study employed headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry(HS-SPME-GC×GC-TOF-MS)to analyze Maotai-flavor Baijiu of various qualities.It was determined that Maotai-flavor Baijiu contains 1063-1347 components,including esters,acids,alcohols,aldehydes,ketones,and sulfur-containing substances.The percentages of esters in high-quality Baijiu A1 and A2,as well as mixed-flavor Baijiu B1 and B2,were 58.75%,55.47%,42.05%,and 41.55%,relative contents of alcohols were 17.14%,16.15%,26.77%,and 26.92%,respectively.The percentages of acids present were 1.47%,2.05%,6.71%,and 7%.69%.High-quality Baijiu exhibited high levels of ester,low alcohol,and moderate acid,while mixed-flavor Baijiu had low ester,high alcohol,and high acid.Sulfur-containing components such as sulfur ethers,sulfones,thioesters,and thiophenes were more prevalent in mixed-flavor Baijiu,whereas they were either negligible or undetectable in high-quality Baijiu.The use of principal component analysis(PCA)and orthogonal partial least squares-discriminant analysis(OPLS-DA)revealed significant variations in flavor between high-quality Baijiu and mixed-flavor Baijiu.A total of 85 potential flavor components were identified,each with a variable importance in the projection(VIP)value>1.Notably,components with VIP>1 and P<0.05 were mapped using a heatmap.The study identified that high-quality Baijiu was characterized by high levels of ethyl butyrate,ethyl caproate,nonanal,and octanal,while mixed-flavor Baijiu had high levels of caproic acid,acetic acid,isobutanol,isoamyl alcohol,etc.The sensory evaluation revealed that the mixed-flavor Baijiu had a lower intensity of ester aroma,a stronger advanced alcohol flavor,a slightly acidic flavor,a slightly unusual aroma,and a lack of crispness,which was consistent with the result of low ester,high alcohol,high acid,and the presence of more sulfur-containing substances.The results of this study indicate that HS-SPME-GC×GC-TOF-MS technology can be used to investigate the Maotai-flavor high-quality Baijiu at the molecular level.This provides effective technical support for the subsequent quality improvement and process control of Maotai mixed-flavor Baijiu.