基于GC-IMS分析不同储存时间金露梅红茶中挥发性有机物

Analysis of Volatile Organic Compounds in Potentilla fruticosa Black Tea with Different Storage Time by GC-IMS

为研究储存时间对金露梅红茶中挥发性有机物(volatile organic compounds,VOCs)的影响,采用气相-离子迁移色谱(gas chromatography-ion mobility spectroscopy,GC-IMS)技术测定2019年、2020年、2021年金露梅红茶中VOCs组成。结果表明,GC-IMS技术从不同时间金露梅红茶样品中鉴定出61个信号峰,通过内置数据库定性出43种VOCs,包括20种醛类、8种酮类、7种醇类、2种酯类、2种烯类、2种吡嗪类和1种呋喃类等。通过主成分分析(prin-cipal component analysis,PCA)2019年样品和2020年、2021年样品差异较大。由指纹图谱分析发现,随着储存时间的延长,2021年样品中VOCs的种类和浓度相对较大,2019年样品中VOCs的种类和浓度最小。通过偏最小二乘法中变量投影重要性值(variable importance for the projection,VIP)判定,分析出金露梅红茶中14种潜在特征性VOCs,结合聚类热图结果发现,金露梅红茶随着储存时间的延长,乙醇、苯甲醛(M)、2-甲基丁醛(D)、二甲基三硫、NF-12等含量逐渐升高,而3-羟基丁酮、己醛、丙酮、反式-2-戊烯醛、壬醛(M)、2-己烯醛(M)、NF-3、NF-4、NF-18等含量逐渐降低。

To explore the effect of storage time on volatile organic compounds(VOCs)in Potentilla fruticosa black tea,the composition of VOCs in P.fruticosa black tea in 2019,2020 and 2021 was determined by gas chromatography-ion mobility spectroscopy(GC-IMS).The results showed that 61 signal peaks were identified from P.fruticosa black tea samples by GC-IMS,and 43 VOCs were determined by built-in database,including 20 aldehydes,8 ketones,7 alcohols,2 esters,2 alkenes,2 pyrazines and 1 furan.According to principal component analysis(PCA),the samples in 2019 were quite different from those in 2020 and 2021.The fingerprint analysis found that the type and the concentration of VOCs in 2021 were relatively large with the extension of storage time,and those of VOCs in 2019 were the lowest.Through the determination of importance of projection(VIP)value in partial least square regression,14 potential characteristic VOCs in P.fruticosa black tea were analyzed.In combination of cluster heat map,it was found that with the extension of storage time,ethanol,benzaldehyde(M),2-methylbutyraldehyde(D),dimethyl trisulfide and NF-12 increased gradually,while acetoin,hexanal,acetone,trans-2-pentenal,nonanal(M),2-hexenal(M),NF-3,NF-4 and NF-18 decreased gradually.