GC-O-MS法分析野生刺梨汁游离态和O-糖苷键合态香气活性物质

Analysis of Free and O-Glycosidically Bound Aroma Active Compounds of Wild Rosa roxburghii Juice by GC-O-MS

采用顶空-固相微萃取法提取刺梨汁中游离态挥发性物质和酶法释放刺梨汁中O-糖苷键合态挥发性物质,结合气相色谱-嗅觉探测-质谱技术,对野生种刺梨汁中游离态和O-糖苷键合态香气活性物质进行分析。结果表明,刺梨汁中游离态和O-糖苷键合态香气活性物质分别有23种和17种。构成刺梨汁游离态香气活性物质主要有丁酸乙酯(青草)、正己醇(酒香)、正辛醇(甜香)、异戊酸乙酯(菠萝香)、叶醇(茶香)、苯乙烯(果香)、月桂烯(甜香脂)和芳樟醇(柠檬香)等。而构成刺梨汁O-糖苷键合态香气活性物质有3-羟基己酸乙酯(水果香)、2-庚醇(柠檬香)、3-羟基丁酸乙酯(果香)、叶醇(茶香)、正辛醇(甜香)、苯乙醇(玫瑰香)和2’-羟基-4’,5’-二甲基苯乙酮(花香、甜香)等。叶醇、正辛醇和辛酸为刺梨汁中以游离态和O-糖苷键合态共存的香气活性成分。刺梨中游离态和O-糖苷键合态香气活性物质均以果香/甜香味为主,但O-糖苷键合态香气活性物质的香气总强度较游离态的弱。

The free volatile compounds of wild Rosa roxburghii juice were extracted by head-space solid phase microextraction（HS-SPME） and the O-glycosidically bound volatile compounds were released by enzymatic hydrolysis for analysis by gas chromatography-olfactometry（GC-O） coupled with mass spectrometry（MS）.The results showed that 23 free aroma active compounds and 17 O-glycosidically bound aroma active compounds were identified in R.roxburghii juice.The major free aroma active compounds were ethyl butyrate（grassy aroma）,hexyl alcohol（winy aroma）,capryl alcohol（sweet aroma）,ethyl isovalerate（pineapple aroma）,leaf alcohol（tea aroma）,styrene（fruity aroma）,β-myrcene（sweet balsam aroma）,linalool（lemon aroma）,etc.The major O-glycosidically bound aroma active compounds were ethyl3-hydroxyhexanoate（fruity aroma）,ethyl 3-hydroxybutyrate（fruity or grape aroma）,2-heptanol（lemon aroma）,leaf alcohol（tea aroma）,capryl alcohol（sweet aroma）,phenylethyl alcohol（rose aroma） and 2＇-hydroxy-4＇,5＇-dimethylacetophenone（flower or sweet aroma） etc.Leaf alcohol,capryl alcohol and octanoic acid were the active aroma compounds existing in both free and O-glycosidically-states in wild R.roxburghii juice.Both free volatile compounds and O-glycosidically bound volatile compounds were mainly responsible for fruity/sweet fragrance.But,the overall aroma strength of the latter was relatively weaker than that of the former.