Study On Preliminary Processing Technologies Of Tea(Camellia Sinensis) Flower Beverage

Tea (Camellia sinensis) flower is rich in tea polysaccharide, tea polyphenol, tea saponin, SOD and so on. These biological active substances have many healthy functions, such as bringing down the blood sugar, bacteriostasis and antioxidant. In addition, the pesticide residues in tea flower are very low. Compared with tea leaves, tea flower is more healthy and safe. The beverage made with tea flower has both tea flower fragrance and flavor and tea functions, and could enrich our beverage market. Using tea flower as material in this paper, and choosing leaching amount of quality components, such as tea polyphenol, amino acid, caffeine and water extract of tea flower and sensory evaluation as evaluation index, the key technology of tea flower extraction, the optimal formula and storage stability of tea flower beverage were studied. The main results were as following:(1) The best option of extracting tea flower of tea flower was microwave-assisted extraction. The single factor experiments and orthogonal optimization experiment showed that the best option of ultrasonic extraction was:ultrasonic frequency was 80kHz, the solid-liquid ratio was 1:60, the temperature was 70? and the extraction time was 15min. And the best option of microwave-assisted extraction was:microwave power was 480W, the microwave pretreatment time was 3min. the solid-liquid ratio was 1:70. the temperature was 70?, and the extraction time was 10min. Ultrasonic extraction and microwave-assisted extraction compared with the conventional water-bath extraction showed that extractive contents of former two extraction methods were significantly higher than that of conventional water-bath extraction. The result illustrated that tea flower was dealt with ultrasonic and microwave, would benefit the extractive content of quality components in tea flower and sensory quality. In addition, microwave-assisted extraction of tea polyphenol and water extract were 78.87±1.03mg/g and 448.28±1.52mg/g, both were significantly higher than that of ultrasonic extraction. The above results showed that microwave-assisted extraction was the optimal extraction technology of tea flower, and the relevant parameter was:microwave power was 480W, the microwave pretreatment time was 3min, the solid-liquid ratio was 1:70, the temperature was 70? and the extraction time was 10min.(2) According to the results of single factor experiments, and using the design of Box- Benhnken for beverage formula. With multiple regression fitting of experimental data showed that the quadratic multinomial regression equation between the score (Y) of sensory evaluation and added content of tea flower extract (A), sucralose (B), vitamin C (C), as follows: Y=82.56667+4.0875A+1.1125B-0.65C+1.625AB-0.3AC+5.15BC-3.42083A~2-1.5208B~2-9.19583C~2Through the regression equation calculated that the optimal formula of beverage was:tea flower extract was 241ml/L, sucralose content was 40mg/L, vitamin C content was 223mg/L. In this condition, the sensory evaluation score was highest at 84.(3) Using the optimal extraction technology and formula to make tea flower beverage, the beverage had many good qualities, such as soft, sweel, no peculiar smell flavor and delicious, and had also tea flower fragrance and aroma coordination. The color was pale yellow, bright and transparent, and the beverage was not hierarchical; pH at 6.25, and light transmittance content was more than 96.5%, tea polyphenol content was more than 140mg/100ml, amino acids content was more than 2.08 mg/100ml, caffeine content was more than 34.5mg/100ml, which were higher than the requirements of liquid beverage national standard(GB/T 21733-2008).(4) The stability was studied during the storage of tea flower beverage. The results showed that beverage had different degrees of change, when stored in different conditions such as refrigerated 5?, room temperature 25? and high temperature 37?. With the extension of storage time, tea flower beverage by the original light yellow color gradually transformed into deep yellow, aroma thin, and appeared a little precipitation. Moreover, the quality component of tea flower such as tea polyphenol, amino acids, caffeine, light transmittance and pH value in tea flower beverage all had some extent decrease. When stored under the refrigeration of 5?, the change of beverage evaluation index was minimal, which compared with other stored conditions. In order to keep the quality of the original tea flower beverage, it should be stored in low temperature.