基于化学计量学鉴定不同甜橙精油挥发性成分

Chemometric Identification of Volatile Components in Essential Oils Extracted from Sweet Orange Peels by Different Methods

采用感官定量描述分析、气相色谱-离子迁移谱(gas chromatography-ion mobility spectrometry,GC-IMS)及快速气相电子鼻并结合化学计量学,对采用冷压(cold pressing,CP)、微波辅助水蒸气蒸馏(microwaveassisted hydrodistillation,MAHD)和旋转锥蒸馏塔(spinning cone column,SCC)法提取的甜橙(血橙和脐橙为代表)精油进行挥发性成分差异分析。结果表明:3种方式提取的甜橙精油风味组成存在明显差异,CP提取精油喜爱度最高且具有更强的果香、甜香和花香,MAHD精油具有更强的脂香、青香和木香,而SCC萃取液香气浓度较低;GC-IMS共鉴定出64种挥发性化合物,主要为萜烯类、醇类和醛类,其次是酸类、酯类和其他化合物,指纹图谱结果显示,萜烯类在CP和MAHD精油中含量明显高于SCC萃取液,而醇类和醛类在MAHD精油和SCC萃取液中含量明显高于CP精油;基于相对气味活性值鉴定出β-月桂烯和芳樟醇是甜橙精油风味的主要贡献者;GC-IMS结合偏最小二乘法判别分析和变量投影重要性筛选出13种区分6种精油的标志性差异挥发性化合物;此外,快速气相电子鼻结合主成分分析和判别因子分析也能够成功区分6种甜橙精油挥发物差异。

Quantitative descriptive sensory analysis(QDSA),gas chromatography-ion mobility spectrometry(GC-IMS)and Heracles NEO electronic nose(E-nose)combined with chemometrics were used for differential analysis of volatile compounds in essential oils(EOs)extracted from sweet orange peels(blood and navel)using cold pressing(CP),microwave-assisted hydrodistillation(MAHD)or spinning cone column(SCC).The results indicated that significant variations in flavor composition were found among the three EOs.The CP oil had the highest sensory preference with stronger fruity,sweet,and floral aromas.The MAHD oil had stronger fatty,green,and woody aromas,and the SCC oil had a lower aroma intensity.A total of 64 volatile components were identified by GC-IMS,terpenes,alcohols and aldehydes being the major ones,followed by acids,esters and other compounds.The fingerprint indicated that the contents of terpenes in the CP and MAHD oils were significantly higher than that in the SCC oil,whereas the contents of alcohols and aldehydes in the MAHD and SCC oils were significantly higher than those in the CP oil.Based on relative odor activity value(ROAV),β-myrcene and linalool were identified as the major contributors to the flavor of sweet orange EO.Moreover,using GC-IMS combined with partial least square discriminant analysis(PLS-DA)and variable importance in the projection(VIP),13 differential volatile compounds were identified as aroma markers to distinguish among the 6 oils.Additionally,E-nose combined with principal component analysis(PCA)and discriminant factor analysis(DFA)also successfully distinguished among the 6 EOs according to their volatile compounds.