马格努门啤酒花挥发性成分的气相色谱-质谱联用分析

摘要

采用顶空固相微萃取-气相色谱-质谱联用的方法研究马格努门啤酒花中的主要挥发性成分的组成和含量，并与传统的水蒸气蒸馏方法所得到的精油成分进行比较，定性采用质谱谱库检索结合保留指数进行验证。结果表明：两种方法测得的啤酒花中的挥发性成分存在较大的差异。顶空固相微萃取法共鉴定出73种成分，占总峰面积质量分数的99.35%，以葎草烯、石竹烯为主要成分的萜烯类化合物的质量分数达85.35%，其氧化产物仅为0.24%；水蒸气蒸馏法共鉴定出63种化合物，占总峰面积质量分数的98.42%，其中萜烯类化合物的质量分数仅为68.41%，而萜烯类的氧化产物的质量分数达13.27%。而其他含氧化合物醇类、酯类和酮类，两种方法测定结果比较接近，其中，顶空固相微萃取法中的质量分数依次为2.65%、8.14%、1.29%；水蒸气蒸馏法依次为3.42%、10.55%、2.51%。此外，顶空固相微萃取法还检测到3个质量分数占到0.99%的醛类化合物，而水蒸气蒸馏法得到的精油中未检出该类组分。分析结果表明，马格努门啤酒花中的主要挥发性成分为葎草烯、β-香叶烯、β-石竹烯、葎草烯氧化物、石竹烯氧化物、δ-杜松烯、依兰油烯、4-癸烯酸甲酯、古巴烯、丙酮、γ-杜松烯、α-蛇床烯、β-蛇床烯、β-蒎烯、里哪醇、(E)-β-法呢烯、甲酸香叶酯。%Head space-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the composition and contents of major volatile compounds in Magnum hops. The identification and validation of volatile compounds were performed using mass spectral library searching based on Kovats retention index (KI). Greatly different results were obtained for the volatile composition of Magnum hops using HS-SPME and the conventional steam distillation (SD) method. A total of 73 volatile compounds were detected in Magnum hops by HS-SPME, together accounting for 99.35%of the total pear area, and terpenes, mainly humulene andβ-caryophyllen, together accounted for 85.35%of the total amount of volatile compounds compared with only 0.24%for their oxidized products. A total of 63 identified volatile compounds were extracted by the conventional SD method, together accounting for 98.42%of the total peak area, and terpenes accounted for only 68.41%of the total amount of volatile compounds while the content of oxidized terpenes was as high as 13.27%. For other oxygen-containing compounds such as alcohols, esters and ketones, similar results were obtained using both extraction methods, showing relative contents of 2.65%, 8.14%and 1.29%in the HS-SPME sample and 3.42%, 10.55%and 2.51%in the SD sample. Moreover, three aldehydes, together accounting for 0.99%of the total amount of volatile compounds, were detected in the HS-SPME sample rather than the SD sample. The above results suggest that the major volatile compounds in Magnum hops are humulene,β-mycrene,β-caryophyllene, humulene oxide, caryophyllene oxide, δ-cadinene, muurolene, 4-decenoic acid, methyl ester, copaene, 2-propanone,γ-cadinene,α-selinene,β-selinene,β-pinene, linalool, (E)-β-farnesene and geranyl formate.