摘要
采用SDE法分析了黄棪原料叶和杀青叶的香精油及其香气组分和在茎叶中的分布,拟探明做青对乌龙茶游离态香气和结合态醇系香气前体分布与含量的影响及乌龙茶主要香气形成途径。结果表明,黄棪原料叶中游离态香精油含量以茎中最高,达20.95mg/kg,叶最低;键合态醇系香气的数量分布与游离态香气正好相反。杀青叶中游离态香精油含量差异不大,以梢中最高,达48.22mg/kg,叶最少。通过做青,茎叶游离态香精油大量增加,使二者之间的差距缩小。做青使茎、叶键合态醇系香气总量减少了13.2%～27.4%。从橙花叔醇、香叶醇键合态含量变化结果推断:萜烯类香气的产生可能主要是由异戊烯焦磷酸(IPP)通过多级酶促反应转化而来,而糖苷酶水解释放途径仅为次要途径。
SDE was used to analyze the essential oils content of fresh and fixation materials of Huangdan cultivar, and aroma composition and its alcoholic precursors distribution compared between Huangdan raw material and fixation materials, in order to find out the effects of fixation procedure on free aroma compositions and its alcoholic precursors distribution and content, so as to find the major pathway to transform aroma compositions of oolong tea. The results showed that the contents of free essential oil of raw material in stems are the highest （20.95 mg/kg）, and that in leaves was the lowest （8.15 mg/kg）. But the content and distribution of bound alcoholic essential oil were reverse with those of free essential oil. The content of free essential oil of fixation material in shoots is the highest （48.22 mg/kg）, and that in leaves the lowest （43.75 mg/kg）. After fixation procedure, the content of free essential oil in stems and leaves increases significantly, while the difference between stems and leaves is reduced. Besidse, total content of bound essential oils is reduced about 13.2% - 27.4% in stems and leaves. The changes of bound nerolidol and geraniolinvolved are that terpene aroma is majorly transformed from isopentenylpyrophosphate （IPP） via multilevel enzymecatalyzed reactions, while the approach of hydrolysis release of glycosidase is only the subordinate pathway.
出处
《食品科学》
CAS
CSCD
北大核心
2008年第4期102-105,共4页
Food Science
基金
广东省农业科学院院长基金项目(2001-基金-12)
农业部茶叶化学工程重点开放实验室开放课题(20020605001)
关键词
黄棪
原料叶
杀青叶
游离态香气
结合态香气
分布
Huangdan
raw material
fixation leaves
free state aroma
bound state aroma
distribution
