The Base Research Of Tchnology On The Caffeine Reduced Pressure Sublimation Removing From Green Tea

Decaffeination tea, with high added value, is quite a potential and promising product. The technology of the caffeine removal from Green tea by decompression and sublimation can effectively raise the tea profound process level. In addition, this technology can solve the limitation and deal with problems which lie in the traditional research on this subject. On the basis of the caffeine existence form and the removing characteristic of tea, and proper application of theories and principles in several subjects, including the Tea-biochemistry, Tea producing, and Natural products chemistry, this paper, referring to the existing related research results, ultimately proposes the method of heat treatment in low temperature, as well as decompression and sublimation.This paper first inspected in caffeine removing condition in different cases. Analysis has been done about requirements on the caffeine removing from dry tea in the reduced pressure condition. The result indicated that caffeine's removal, decompression and sublimation in green tea are closely related with temperature, pressure, moisture, the contour and types. Caffeine' removal rate is also affected by decompression, sublimation and pressure. The temperature being 70℃, under the -0.02～-0.08MPa condition, decompression and sublimation for about 14h, caffeine removing rate can achieve 17% in the blue green tea, moisture content of which is 20% steams. Moreover, in this condition tea's color, fragrance, and taste do not change. As well, caffeine's decompression, sublimation, and removal of the green line-shaped steam tea (moisture content 20%) have a good result. Moisture content in tea can promote caffeine's decompression and sublimation. Employing the decompression and sublimation technology, requirements on the technique condition and the equipment is comparatively less. Compared with traditional methods, this method has the obvious superiority in reducing caffeine in green teaTo improve the traditional technology on lowering caffeine' content in green tea, this paper further studied how caffeine of the tea sample was influenced by the processed condition and the procedure of tea working under the pretreated condition. The experiment showed that after rubbed, the damage of cells in steam green tea is more serious than fry green tea, and caffeine's removal in steam green teas is efficient. Moreover, tea after washed by impregnant has a better result in removing caffeine than washed by hot water. The experiment indicated that caffeine's removing rate order from large to small in steam blue green tea is: Edible resolver dip processing> water dip processing > the edible resolver infiltration > compares. It can be seen that Edible resolver dip processing has the biggest caffeine's removing rate is 41.80%. Compared with the biggest caffeine's removing rate in fries the blue green tea, we can conclude that the order of biggest caffeine's removing rate is duplicate to rub edible resolver dip processing > duplicate to rub hot water dip processing > to kill the leafiness hot water dip > to kill the leafiness duplicate to rub the resolver dip > to compare .From it, we can see the biggest is duplicate rubs resolver dip processing coffeine removing .It's rate is 41.23794%: It is clear that the pretreatment can increase the coffeine's sublimation and removal rate effectively, the removing effect of duplicate rubs the leaf surpasses that of killing the leafiness, and the caffeine's removal rate of duplicate rubs the leaf surpasses that of hot water processing.This paper studied the effect of caffeine's decompression, sublimation and removal in the pretreatment tea sample after the ultrasonic wave or the microwave processing systematically. The result indicated that after physical method processing, caffeine's sublimation removal in pretreatment sample has a great deal to do with the ultrasonic wave, the microwave process time, and lotion types. When the tea sample is under the ultrasonic wave condition, the tea type biggest caffeine's removal rate size order is: Ultrasonic wave 20min edible resolver dip processing > ultrasonic wave 40min edible resolver dip processing > ultrasonic wave 60min edible resolver dip processing > the ultrasonic wave 60min water dip processing ultrasonic wave > ultrasonic wave 40min water dip processing > ultrasonic wave 20min edible resolver dip processing > edible resolver dip processing > water dip processing > compares (CK).The edible resolver dip processes 20min under the condition, the reduced pressure sublimation processes about 14h, may cause resolver dip processing caffeine's removal rate achieve 69.47%after rubbing in the tea sample,and maintain the green dark brown, the fragrance, the taste. Under the microwave condition, tea type's biggest coffeine removing rate size sorting is: Microwave 3min edible resolver dip processing > microwave 2min edible resolver dip processing > microwave 1min edible resolver dip processing > microwave 3min edible resolver infiltration processing > microwave 2min edible resolver infiltration processing > microwave 1min edible resolver infiltration processing > microwave 3min water dip processing > microwave 2min water dip processing > microwave 1min water dip processing (A) > compares. processing 3min through the edible resolver dip the tea type about 14h after the reduced pressure sublimation, may enable the caffeine removal rate of tea sample to achieve 42.15%.It indicated that the microwave and the ultrasonic wave pretreatment can increase the caffeine's sublimation removing rate effectively. Moreover after analyzing tea main quality ingredients and the appraisal effects we can see that caffeine's removal rate of the ultrasonic wave processing is higher than that of microwave processing. After obtaining microwave processing, other content ingredient destruction are few, while the removing effect is good.This paper's findings have provided a foundation for the technology of caffeine's removal from Green tea by decompression and sublimation, and put forward technical way for practice. This research is of great theoretical significance to enrich the technology for tea profound process .It is also valuable for the study on caffeine's removal from Green tea by decompression and sublimation...