广陈皮精油的特异性分析

Specificity Analysis of Essential Oil from Pericarpium Citri Reticulatae ‘Chachiensis’

摘要:

本研究采用水蒸气蒸馏法，提取广陈皮和来自广西、浙江、四川地区陈皮的精油，同等质量广陈皮的精油含量高于其他地区陈皮（p<0.05）。采用气相色谱-质谱（GC-MS）从精油中共鉴定出111种组分，其中48种组分是第一次在广陈皮中被分析鉴定到。利用主成分分析（PCA）和热图（heatmap）对广陈皮与其他地区陈皮精油组分及含量进行统计学分析，发现存在明显差异：不仅表现在相对含量较高的D-柠檬烯、γ-松油烯、2-（甲氨基）苯甲酸甲酯，还表现在一些相对含量较少的α-合金欢烯、松油醇和石竹烯等成分上。偏最小乘法判别分析（PLS-DA）陈化一年和两年的广陈皮精油组分和含量，首次揭示对广陈皮与其他地区陈皮的差异来源贡献较大的化合物还有香芹酮（0.03%~0.23%）、（E,E,E）-2,6,10-三甲基-2,6,9,11-十二烷四烯-1-醛（0.03%~0.80%）、紫苏醛（0.04%~0.34%）、4-甲基-1-甲基乙基-双环-己2烯（0.51%~0.84%）和6,6-二甲基-2-亚甲基-双环庚烷（1.42%~2.28%）；其中香芹酮、（E,E,E）-2,6,10-三甲基-2,6,9,11-十二烷四烯-1-醛和紫苏醛仅在广陈皮中检测到，而4-甲基-1-甲基乙基-双环-己2烯和6,6-二甲基-2-亚甲基-双环庚烷在广陈皮中的含量显著高于其它地区陈皮。另外，陈化一到五年的优质广陈皮精油PLS-DA分析结果显示，陈化一年的广陈皮与陈化两到五年的广陈皮精油差异较大，提示陈化的最初两年是广陈皮陈化特定风味物质形成的关键点，是研究陈化机理的重要时期。

Abstract:

In this study, the essential oil of Pericarpium Citri Reticulatae (PCR) from Guangdong (Pericarpium Citri Reticulatae ‘Chachiensis’, PCR-C) and from Si Chuan (C), Zhe Jiang (Z) and Guang Xi (G), were extracted by steam distillation. The content of essential oil extracted from PCR-C was much higher than those of the other PCRs (p<0.05). A total of 111 components were identified in essential oils through GC-MS analysis, of which 48 components were identified for the first time from PCR-C. The compositions of essential oil were statistically analyzed using Principal Component Analysis (PCA) and heatmap, and significant differences were found not only in the components with relatively high contents such as D-limonene, γ-terpinene and 2-(methylamino)-methyl ester, but also in the minor components with relatively low contents such as α-farnesene, terpinol and caryophyllene. Partial least squares discriminant analysis (PLS-DA) of essential oil in PCR aged for one and two years revealed for the first time that the major contributors to the difference between PCR-C and PCR also included (-)-carvone (0.03%~0.23%), (E, E, E)-2,6,10-trimethyl-2,6,9,11-dodecanetetraen-1-al (0.03%~0.80%), 4-(1-methylethenyl)-1-cyclohexene-1-carboxaldehyde, (0.04%~0.34%), 4-methyl-1-(1-methylethyl)-bicyclo-hexanene (0.51%~0.84%) and 6,6-dimethyl-2-methylene-bicyclic heptane (1.42%~2.28%). Among which, carvone, (E, E, E)-2,6,10-trimethyl- 2,6,9,11-dodecanetetraen-1-al and perillaldehyde were only detected in the PCR-C, while the contents of 4-methyl-1-methylethyl- bicyclo-hexanene and 6,6-dimethyl-2-methylene-bicyclic heptane were significantly higher in PCR-C than that in PCRs. In addition, the PLS-DA analysis of the high-quality PCR-C aged for 1-5 years revealed a large difference in the essential oils between the PCR-C aged for 1 year and PCR-C aged for 2-5 years. These results suggested that the first two years of aging were the key period for the formation of specific flavor substances of PCR-C, and for studying the mechanism underlying PCR-C aging.