以固相微萃取法分析比較柳橙鮮果皮及果皮精油所含揮發性成分之異同

Using Solid Phase Microextraction Method to Evaluate Volatile Compounds in the Fresh Peel and in the Essential Oils Extracted from the Peel of 'Liucheng' Orange (Citrus sinensis Osbeck)

本研究以固相微萃取法（solid phase microextraction, SPME）結合氣相層析儀（gas chromatography, GC）及氣相層析質譜儀（gas chromatograph-mass spectrometer, GC-MS）分析‘柳橙’（Citrus sinensis Osbeck 'Liucheng'）之新鮮果皮、冷壓法萃取之果皮精油與水蒸氣蒸餾法萃取之果皮精油等三種試樣之揮發性成分差異。冷壓精油之收率為3.91±0.52 g•kg^(-1)；水蒸氣蒸餾精油之收率為17.30±0.98 g•kg^(-1)。冷壓與水蒸氣蒸餾柳橙精油之主要揮發性成分皆為limonene、β-myrcene及β-pinene，而新鮮果皮主要揮發性成分為limonene、β-myrcene及linalool。兩種不同萃取方式所得的精油，主要成分大致相同，但微量成分則有差異。比較三種試樣之香氣，經冷壓或蒸餾加工後之精油組成分hexanal、2-hexenal、decanal、citronellal、neral、geranial、linalool、β-caryophyllene及valencene明顯降低，而perilla aldehyde、α-terpineol、p-Mentha-1,8-dien-9-ol則明顯提高。這些揮發性化合物之增減可能造成其香氣和新鮮果皮不同。 Volatile compounds in fresh peel, cold-pressed essential oil, and steam distilled essential oil of 'Liucheng' oranges (Citrus sinensis Osbeck) were obtained by solid phase microextraction. The components were identified by means of capillary GC and GC-MS. The essential oil yields by cold-pressing and steam distillation methods were 3.91± 0.52 g•kg^(-1) and 17.30 ± 0.98 g•kg^(-1), respectively. The volatile compositions of cold-pressed and steam distilled essential oils were similar, with limonene, β-pinene and β-myrcene being the major constituents. However, the major constituents in the fresh peel were limonene, β-myrcene and linalool. The fresh peel and the essential oils obtained from two extraction methods had similar volatile components, but the extracted essential oils had lower content of hexanal, 2-hexenal, decanal, citronellal, neral, geranial, linalool, β-caryophyllene and valencene, but higher content of perilla aldehyde, α-terpineol and p-Mentha-1,8-dien-9-ol than the fresh peel. The differences might affect the aroma of the products.