Research On Extraction Technology And The Material Baking Of The Oolong Tea Concentrate

Though with numerous types of tea beverages on the market,there still exist underdevelopment of process,unevenness and instability of product quality,which not only hinder the development of tea beverage market,but also affect consumers’ expectations for the tea industry.Oolong tea and oolong tea concentrate are basic raw materials of oolong tea beverage.Baking and extraction process are crucial for quality formation which play a decisive role in the quality and physical and chemical factors of oolong tea beverage.Based on box-type baking and reverse osmosis membrane concentration techniques,we analyzed the quality and trends related to physical and chemical properties of tea leaves and tea concentrate in different processes.Combined with market demand and experience in production through qualitative and quantitative analysis,we optimized the technical process of producing oolong tea concentrate to increase the product value of oolong tea,thus enhanced the comprehensive capacity and economic benefits of enterprises and laid a solid technological and theoretical foundation for the development of oolong tea concentrate.By studying changes of flavors and physical and chemical indicators in raw material of oolong tea at different baking temperatures,baking time and thickness of leaves spread out.we draw a conclusion that the water content of tea leaves will be reduced in baking process;the fragrance of tea leaves is remarkable,Roasted aroma is suitable and the taste is mellow and refreshing at temperature of 120℃;water extract and color of tea increase as the temperature and time grow in baking process,while water extract and color of tea go up at first then decrease as the thickness of leaves spread out increases;high temperature and long baking time can both reduce the amounts of caffeine and tannin.According to the research on the raw material of oolong tea in this paper,we find the most suitable baking process whose baking temperature is 120℃,baking time is 1h and thickness of leaves spread out is 1cm,where the water extract of raw tea is 29.29%,the color is 0.934,tannin is 6.23%,caffeine is 2.16%,which are all suitable for further process to tea concentrate from tea.We further studied the process of producing oolong tea concentrate by using the raw material of oolong tea through the most suitable baking process mentioned above.Studies show the changes of flavors and physical and chemical indicators of tea extract in extraction process of different temperatures,time and ratios of tea to water.The research indicates that the flavor of tea slightly reduce compared to directly brewing oolong tea,but tastes more refreshing after deep processing;tea concentration is positively correlated to extraction temperature and time while negatively correlated to the ratio of tea to water;tea color increases along with the extraction temperature and time increase,but is irrelevant to the ratio of tea to water.Tannin and caffeine increase as tea extraction temperature and time grow,but go up at first then decrease as increasing ratio of tea to water.According to the results of research and application of manufacturing practice,we determine that the physical and chemical indicators of concentrate in extraction process at 70℃ for 2h with ratio of tea to water at 1:16 are similar to the counterpart in present process,and the flavors is improved.In this process,Brix is 20.03%the absorbance of concentrate is 1.427,tannin is 4.21%,caffeine is 1.69%,which all reach the customers’requirements.We improve the production efficiency by 16.67%and save 20.5%of energy,which not only guide the quality control and adjustment for oolong tea concentrate,promote the dependence of oolong tea beverage towards green health and energy efficiency.