窨茶用栀子花中糖苷酶活性与醇类香气的研究

Fluctuation of Glycosidase Activities and Its Relation to Alcoholic Aroma in Flowers of Gardenia Jasminoides E.

测定了栀子花开放过程中对应8种醇类香气成分的前体物含量及其相应香气催化酶活性的变化,用pNP法测定栀子花开放过程中各部位的5种糖苷酶活性。结果表明:香气前体物含量与香气催化酶活性均从蕾期的低水平骤增至初开时的最高峰,随后酶活性迅速下降而香气前体物含量仍维持较高的水平直至花完全开放。五种糖苷酶活性在开花过程中的变化规律各异,其中β-葡萄糖苷酶活性的变化与香气催化酶活性的变化规律较接近。线性回归分析结果表明,完整花中的β-葡萄糖苷酶活性(r=0.9563*)、花萼中的β-葡萄糖苷酶活性(r=0.9584* )与香气催化酶活性之间的关系达到了显著水平;花瓣中的β-阿拉伯糖苷酶活性(r=0.9992* *)、花萼中的β-半乳糖苷酶活性(r=0.9995* *)与香气催化酶活性之间的关系均达到了极显著水平。从花的组成部位分析,单位鲜重的花萼中的酶活性值明显高于花瓣和完整花。

The amount of precursors of eight different alcoholic aroma substances and the activities of the catalytic enzymes obligated in the aroma production in flowers of Gardenia Jasminoidse E. were examined at different blooming stage. The activities of five different glycosidases were also analyzed using pNP method in different parts of flower. Both the precursor amount and the enzymatic activity increased sharply from their relatively low level at bud stage to the maximum at initially blooming stage. The enzymatic activities decreased quickly afterwards, while the aroma precursor amount still kept at a high level until fully blooming stage. The activities of the five individual glycosidases showed different trends of fluctuation, among which the change of β-glucosidase activities came close to the trends of the catalytic enzymes. Linear regression analysis revealed that ?glucosidase activities in whole flowers (r=0.9563*) and calyx (r=0.9584*) were noticeably correlated to the catalytic enzyme activities, while activities of -arabinosidase in petals (r=0.9992**) and -galactosidase in calyx (r=0.9995**) were extremely correlated to that of the catalytic enzymes. As far as the different parts of a flower were concerned, the enzymatic activities in calyx per unit fresh weight were obviously higher than those in petals and in whole flowers.