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（OPLS-DA）、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.