Study On Process Of White Tea Beverage

Using white tea from Zhenghe, Fujian Province as raw material to study the application of Ultrasound in white tea beverage product. Quadratic Orthogonal Rotation Combination Design was applied to the study. Research contents include, the affection of ultrasound extract factors to the quality of tea beverage; The mathematical model establishment of white tea extraction processing; The correlation between color difference and sensory evaluation; The correlation between tea drink chemical compound and sensory evaluation; The processing of ultrafiltration in white tea drink.45kHz was chosen to be the ultrasound extraction frequency after the comparison with other different frequency include 20kHz and 100kHz. The mathematical model of extraction was got through regression analyses. The chemical contents assumed quadratic connection with extraction temperature. The chemical contents assumed logarithmic correlation with extraction time. The chemical contents assumed exponential correlation with ratio of tea to water. Base on these results, the levels of factors are as follows, extraction temperature between 30 to 60℃, extraction time between 15 to 40 min, ration of tea to water between 1:20 to 1:60.Through the Quadratic Orthogonal Rotation Combination Design, the equations were as follows, （Solid contents Y₁, Tea polyphenol Y₂, Amino acid Y₃, Soluble carbohydrate Y₆, Extract temperature X₁, Extract time X₂ , Ratio of tea to water X₃）Through stepwise regression analysis, the model of correlation between color difference result （Lightness X₁、a-value X₂、b-value X₃、ChromaX₄、Hue of color X₅、Color Saturation X₆）and sensory evaluation was founded as follows. p =0.0001). The model of correlation between chemistry compounds and sensory evaluation was also founded.Using flat membrane ultrafiltration to study clarification processing of tea. Research contents include correlation between membrane pore and membrane flux; Correlation between membrane pressure and membrane flux; The effect of membrane ultrafiltration to color difference and sensory changes of the white tea drink. The results showed that the lightness and clarity were improved. So the membrane pore can affect sensory grately. The membrane with small pore will intercept some chemical contents, and it may lead to the decrease of sensory evaluation. The optimized results were as follows, membrane pore was 6～10units, membrane pressure was 1～2 kg/cm².Several critical factors in white tea drink production were studied. The model of sensory evaluation and optimized conditions were provided to give reference material for industry production.