三种香型食用牛油的挥发性风味物质分析及鉴定

Analysis and identification of volatile compounds in three types of edible tallow

为了探究3种不同香型(无香、淡香、浓香)食用牛油的挥发性风味物质的差异及其形成机制,利用电子鼻结合顶空固相微萃取-气质联用技术(headspace solid-phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)测定了3种牛油中的挥发性成分及其相对含量,并采用相对气味活度值法(relative odor activity value,ROAV)分析了牛油中的关键风味物质。结果发现,电子鼻能够灵敏地检测出不同香型牛油气味的差异性,而且线性判别方法效果优于主成分分析。HS-SPME-GC-MS检测出风味物质总共62种,其中醛类化合物贡献了绝大部分的香气,主要包括异戊醛、己醛、庚醛、辛醛和壬醛,而(E,E)-2,4-壬二烯醛、戊醛有不同程度増香的作用。除醛类物质外,右旋萜二烯和2-正戊基呋喃也对不同牛油的香气有相应的贡献,(-)-柠檬烯、2-甲基萘是浓香型牛油特征风味的重要来源,酯类化合物对增强牛油风味可能有其特殊作用。不同香型牛油的主要风味物质及相对含量有明显差异,初步推测其风味形成机制在于醛类化合物是造成不同香型牛油香气差异的关键风味物质成分。

To explore the differences of three types of edible tallow flavors(no fragrance,light fragrance,fragrant)in terms of their volatile compounds as well as their formation mechanisms.Volatile compounds and their relative contents in three kinds of tallow were determined by electronic nose(E-nose)and headspace solid-phase microextraction-gas chromatography-mass spctrometry(HS-SPME-GC-MS).Relative odor activity value(ROAV)was used to analyze the key flavor compounds in beef tallow.The results showed that E-nose could distinguish the flavors of different types of tallow sensitively.Moreover,linear discriminant analysis(LDA)showed better results than principle component analysis(PCA).Besides,a total of sixty-two volatile compounds were identified by HS-SPME-GC-MS.Aldehydes were found to contribute to most of the aroma,which mainly contained isovaleraldehyde,hexanal,heptaldehyde,octanal,and 1-nonanal.Both trans,trans-2,4-nonadienal and valeraldehyde acted as flavor enhancers to different levels.Other than aldehydes,both dextroterpenes and 2-n-pentylfuran also contributed to different aroma of the tallow.(-)-limonene and 2-methylnaphthalene were important sources of characteristic flavor of fragrant butter,and ester compounds probably had special effects on enhancing the flavor.In conclusion,main flavor compounds and their relative contents showed significant differences in three types of tallow.The mechanisms of forming different flavors of tallow were preliminarily inferred as aldehydes,which were the main ingredients caused changes in key aromas.