基于气相色谱-离子迁移谱技术分析不同预处理技术对压榨山茶油风味的影响

Analysis of effect of different pretreatment technology on the flavor of pressed oil-tea camellia seed oil based on gas chromatography-ion mobility spectroscopy

旨在提升山茶油风味品质,采用气相色谱-离子迁移谱(GC-IMS)技术分析微波、烘烤、蒸制3种预处理技术对压榨山茶油中挥发性成分的影响,并结合正交偏最小二乘判别分析(OPLSDA)、相对气味活度值(ROAV)和聚类分析比较不同预处理压榨山茶油挥发性成分的差异。结果表明:不同预处理压榨山茶油中共鉴定出40种挥发性成分,其中醛类18种(40.02%~51.88%)、醇类9种(10.99%~19.85%)、酮类6种(19.37%~27.35%)、酯类3种(4.21%~11.44%)、吡嗪类2种(1.25%~6.50%)、烃类1种(0.19%~0.32%)和酸类1种(0.35%~2.16%),其中微波预处理压榨山茶油的挥发性物质含量最高,其次为烘烤、蒸制的;OPLS-DA建立的模型能够有效地区分不同预处理压榨山茶油,并根据变量投影重要性(VIP)值大于1筛选出了10种特征挥发性成分,分别是2-甲基丁醛D、3-甲基丁醛D、2,3-戊二酮、乙酸甲酯、2-甲基吡嗪、丙酮、3-羟基-2-丁酮、顺-2-庚烯醛、正己醇、1-丁醇,其中前5种为关键风味成分(ROAV大于1);聚类分析表明不同预处理压榨山茶油的10种特征挥发性成分存在差异,分类结果与OPLS-DA分类基本一致。综上,不同预处理技术所得压榨山茶油的风味不同,可通过OPLS-DA和聚类分析进行区分。

In order to improve the flavor quality of oil-tea camellia seed oil,gas chromatography-ion mobility spectrometry(GC-IMS)was used to analyze the effect of microwave,baking and steaming pretreatment on the volatile components in pressed oil-tea camellia seed oil,and orthogonal partial least squares-discriminant analysis(OPLS-DA),relative odor activity value(ROAV)and cluster analysis were used to analyze the difference of volatile components in different pretreated oil-tea camellia seed oil.The results showed that 40 volatile components were identified from the pressed oil-tea camellia seed oil by different pretreatment,including 18 aldehydes(40.02%-51.88%),9 alcohols(10.99%-19.85%),6 ketones(19.37%-27.35%),3 esters(4.21%-11.44%),2 pyrazines(1.25%-6.50%),1 hydrocarbon(0.19%-0.32%)and 1 acid(0.35%-2.16%),and the content of volatile compounds in pressed oil-tea camellia seed oil by microwave pretreatment was the highest,followed by baking and steaming.The model established by OPLS-DA could effectively distinguish the pressed oil-tea camellia seed oil with different pretreatment,and 10 characteristic volatile components were screened according to variable importance in projection(VIP)above 1,they were 2-methyl-butanal D,3-methyl-butanal D,2,3-pentanedione,methyl acetate,2-methylpyrazine,acetone,3-hydroxy-2-butanone,cis 2-heptenal,n-hexyl alcohol,1-butanol,and the first 5 of which were the key flavor ingredients(ROAV>1).Cluster analysis showed that there were differences in 10 characteristic volatile components of oil-tea camellia seed oil with different pretreatment,and the classification results were basically consistent with OPLS-DA classification.In conclusion,the flavor of pressed oil-tea camellia seed with different pretreatment is different,and it can be distinguished by OPLS-DA and cluster analysis.