Study On Application Of PVPP In Tea Beverage

PVPP is an inexpensive and excellent absorbent of polyphenols.PVPP can selectively adsorb tea polyphenols in tea beverage,so it can effectively reduce bitter astringency and prevent color browning and the formation of haze initiated by interaction of tea polyphenols,caffeine and protein.As a result,the stability and quality of tea beverage are improved after PVPP treatment.In this present investigation,the high efficiency and specificity of PVPP were investigated in green tea beverage.The influence factors of PVPP application and the effect of filtration process on PVPP residues were analyzed in order to find out the optimal application parameters,to know the safety of PVPP and to provide reference basis for subsequent application test and industrial process.The effects of different treatments on main components,turbidity,color and sensory evaluation of tea beverage were investigated by adding PVPP with different addition time and adsorption time.The results are showed as follows:1?PVPP efficiently adsorbed tea polyphenols,especially EGCG and ECG,without affecting the content of free amino acids and caffeine.The adsorption effect of PVPP pre-swelling treatment was slightly better than non-swelling treatment.About 70%of the adsorption was completed in 2 min and the adsorption equilibrium was reached at 25 min.The temperature and pH had no significant effects on the adsorption of PVPP in the range of 15-95 ? and pH 3.5-6.5,so there is no need to adjust the pH and temperature of the tea beverage during the adsorption.2?In three kinds of tea beverage,PVPP efficiently adsorbed tea polyphenols and slightly adsorbed free amino acids,so the ratio of polyphenol to amino acids reduced and the taste of tea drinks improved.Meanwhile,the brightness and clarity of tea drinks increased.The sensory evaluation of tea beverage showed that the sensory score of green tea beverage and oolong tea beverage increased while the sensory score of black tea beverage did not changed after PVPP treatments.In industrial application,adding PVPP for 10 min during tea extraction is hence recommended due to the application results and simplify process.3?The turbidimeter was able to detect a very tiny amount of PVPP residual(?1 ppm).Through bag filter and high-speed centrifugal,the turbidity of tea drink effectively reduced and meet the general standaed of green tea drink.No particle was detected in the range of particle size of PVPP in tea beverages after high-speed centrifugal,which showed that PVPP could be completely removed through bag filter and high-speed centrifugation and clarity can be significantly improved through membrane filter.