| The fragrance of jasmine flower is formed and released during its blooming. Jasmine tea shows typical flower note and tea taste. Studies on the physiochemical changes and the effects of temperature and humidity on the aroma releasing during the blooming of jasmine flower have advantages not only to understand the aroma releasing mechanism of jasmine flower,but also to provide theoretic and practical reference on scented-tea production.The organoleptic quality,respiration rate,opening degree,opening rate,as well as fresh weight and dry weight were studied during the opening of jasmine flower. Free-form aromas,bound-form aromas and the activities of enzymes participated in aroma releasing were also investigated. The results showed that bound-form aromas were less than free-form aromas in jasmine flower. Total amount of essential oils and the number of free-form aroma compounds were little in the bud and increased rapidly with the flower opening. The high peak of the essential oils showed at 2:00,while that of respiration rate appeared at 20:00. Advanced studies stated that cytochrome oxidation system participated in the opening and the aroma releasing of jasmine flower by adding respiratory inhibitors. The activities of enzymes displayed different trends during the blooming of jasmine flower. The activity of crude enzyme prepared from the jasmine flower enlarged at 23:00 and lowed at the late stage. 3-Glucosidase activity rose slightly at 20:00. This suggested that P -Glucosidase participated in the aroma releasing. Activity of alcohol dehydrogenase and phenylalanine ammonia-lyase varied during the blooming of jasmine flower. The non-specific esterase isozymes were isolated by different methods. Two enzyme stripes were gained with PAGE (Polyacrylamide gel electrophoresis) method,while eight stripes were obtained with IEF (Isoelectrofocusing) method. From the results,it supposed that the stripe with Rf 0.325 had a negative correlation with the opening and the aroma releasing of jasmine flower,and that the stripe with Rf 0.83 participated in aroma releasing.Effects of temperature and humidity on free-form aroma,respiratory rate,fresh weight,dry weight and the activities of enzymes relating to aroma releasing were also researched. Results showed that temperature made a notice impact upon the blooming and the aroma releasing of jasmine flower by effecting its respiration,enzyme activity and the evaporating rate of water. 35 degree was suitable for the opening and aroma releasing of jasmine flower. Water supplying and high humidity could improve the aroma releasing of jasmine flower by keeping flower fresh. |
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