Study On The Premium Processing Procedure And Parameters Of Instant Soluble Tea Powder In Industry

The instant tea, the further developed form of tea which is called national drink, is accepted and welcomed by an increasing number of consumers because of its convenience, nutrition, health and good taste. Instant tea is always made of instant tea powder and therefore instant tea powder is the essential raw material of making instant tea. China is the major country of producing tea powder. however, our instant tea industry is hampered by the low yield rate of instant tea powder, the dim armor and low resolution in cold water. So our instant tea industry is confronted with the problem that the yield of instant tea powder is low, which we must resolve.This thesis based on the former work of other researchers studied the extracting process which was the most important process of producing instant tea powder. The experiments evaluated the essential factors of extraction, which were extraction temperature, time and water/tea leaves ratio. The signal factor experiments and quardratic regression orthogonal rotating experiments was executed and the experiment was conducted under the expert condition to get results which are affiliated tightly with the practical conditions. The experiments results were analyzed by the response surface methods and the resulted showed that:The extraction temperature, time, the ratio of water and tea had significant impact on the yield rate of instant tea powder. The premium condition was confirmed as:83℃temperature, extraction 71mins, water/tea leave ratio 20:1. Based on the experiments date, a mathematic model was built to forecast the yield rate:yield rate=26.1+0.67A+0.58B+0.87C-0.012AB+0.063AC+0.013BC-0.71A2-0.46B2-0.74C2, in which the letters A, B, C represent the extraction temperature, extraction time and water/tea leave ratio. Under the premium condition, the model got a yield rate 26.7%, which only a discrepancy with practical yield rate,26.5%. It showed that the mathematic model had high percentage accuracy.Besides the effect of different methods of concentrating on the quality and quantity of instant tea powder was studied and the results showed that the yield rate of the instant tea powder made by the way of scraper concentrating evaporation was higher than that of instant tea powder made by the way of membrane concentrating. However, the results of component analysis indicated that the instant tea powder made by the way of membrane concentrating had better quality than that made by the way of scraper concentrating evaporation. And the sensory evaluation also showed that the instant tea powder made by the way of membrane concentrating had better armor, appearance, and taste. All of the above, the quality of instant tea powder made by the process of membrane concentrating is better than that made by the process of scraper concentrating evaporation as well as the yield rate of instant tea powder made by the process of membrane concentrating is lower than that made by the scraper concentrating evaporation, therefore, which one was chosen depends on the requirement of quality and cost and profit of production.