Study on Aroma Components of Tea (Camellia Sinensis) Flowers
|School||Zhejiang Technology and Business University|
|Course||Of Food Science|
|Keywords||tea (Camellia sinensis) flower main aroma components blooming stages cultivars drying treatments|
Tea (Camellia sinensis) flower, with a fresh sweet floral aroma, has long florescence and large yield. Promising utilization of tea flower for some business such as to be used for beverage and cosmetic products, makes it necessary to do a systematic and complete research on tea flower.The extract method of tea flower was studied, the optimization condition was : 10 g dried flower added into 500 mL water with 0.5 Ml defoamer in round bottom flask for boiling 60 min. SDE was used to collect the aroma components of tea flower. The components of tea flower were analyzed and identified with GC and GC-MS. The main aroma components of fresh tea flower of Jiukang c.var in different blooming stages, the aroma characteristics of those flowers from eight cultivars, concentration of aroma components of tea flower dried by different methods were studied. The results were as following: 1 The main aroma components of bursting tea flower were aliphatic alcohols, aromatic alcohols, terpenols, and aromatic ketons, accounting for 84.1—95.6% of the essential oil. These could be classified into two types according to the concentration to the flavor types. One includes the components with weedy or grassy aroma, including 2-pentanol, 2-heptanol, (Z)-3-hexen-1-ol, 3-pentanol, 1-penten-3-ol, 2-hexanol, etc. The other includes the components with sweet floral aroma, including acetophenone, linalool, alpha-methyl-benzenemethanol, phenylethyl alcohol, methyl salicylate, etc. acetophenone and alpha-methyl-benzenemethanol were characteristic flavor compounds.2 The volatile profiles in the essential oils from tea flower of cultivar Jiukang in different blooming stages were similar. The essential oil of the early blooming and full blooming stages was similar and both were far higher than that of flower bud. In the aroma compounds of flower bud, the relative proportion of aliphatic alcohols, such as 2-pentanol, 2-hepeanol, was high. With the flowering process going on, aromatic alcohols, ketons, and aldehydes compounds released continuously. But the content of acetophenone and alpha-methyl- benzenemethanol, accounting for 50% of essential oil, sharply increased during the blooming stage.3 The main volatile profiles in the essential oils from tea flower from eight cultivars were similar. Therefore, the main flavor type was not changed while the aroma characteristics were different because of different aroma profiles. The order of the concentration of reducing essential oil was Zhenong 21 > Yixing > Meizhan > Zhenong 139 > Xinyang > Zhenong117 > Ruian > Dahongpao. The essential oil concentration of Zhenong21 and Yixing were much higher than the others. Acetophenone of the other seven cultivars except for Ruian is highest in concentration.4 The volatile profiles in the essential oils from tea flower dried by frozen, freeze-drying, oven-drying, and shadow-drying were different. Compared with the frozen flower, there were similar aroma components and similar main compound in the essential oil of flower by drying treatment. The order of the concentration of s reducing essential oil was frozen > freeze-drying > shadow-drying > oven-drying. The concentration of most aroma components decreased, especially for acetophenone. Essential oil concentration of Zhenong21 and Yixing were much higher than the others. Acetophenone of the other severn cultivars except for Ruian is the highest in concentration. Compounds with lower boiling point decreased significantly, while some aromatic alcohols, aldehydes, and terpenols increased in different degrees, and phenylethyl alcohol increased significantly.5 The aroma profiles were significantly changed and the concentration of essential oil and most aroma components decreased after tea flower was stored for 20 d and 80 d. The concentration of compounds with lower boiling point decreased significantly, while compounds with higher boiling point, such as acetophenone and linalool oxides, decreased slowly and linalool, beta-ionone, phenylethyl alcohol, and benzyl alcohol increased. The relative proportion of the main aroma components increased significantly. Therefore, the aroma type of the tea flower was not changed with the storage time.