Study On Withering Environmental Factors Upon The Quality Formation And Control Technique Of White Tea

Withering is the most important process during white tea process.ZR withering,JW withering and FS Withering are normally used at present.However,the change of parameters of withering environment and the efforts on fresh leaves' physical and biochemical are not completely proved,ZR withering and FS withering have more difficulties in practice,such as needing more time,hard to make tea in rainy days.The problems of unsteady temperature of hot air,quality instability are existed in the method of JW withering. To this end,this paper introduces fine manipulation of Minnan,we use it to make white tea,and study its reasonableness theoretically.We also compare the enviromental,biochemical changes,changes in the color of comparison.(1) The environment temperature and humidity results show that:In early Spring,the average temperature of ZR & FS withering is 18-21℃,have a trend of "high-low-high";the average temperature 29-30℃,has a trend of "high-low",its relative humidity is 75-96%,compare with ZR withering,its temperature increases 10℃,but its relative humidity decreases 12%-36%,so its withering time is shortened. Because of the short time,change of physical is faster than biochemical;pile-fermentation is needed in later period of withering.The parameters of KT withering are in the middle of ZR & JW withering.(2) THI can be used to describe such withering environment "high temperature high humidity,low temperature high humidity,tow temperature low humidity,high temperature low humidity",and the most suitable THI value is between70-80 for white tea.If temperature is low,the connection between temperature and THI is larger.When humidity is low,the connection between humidity and THI is larger.(3) Indoor & outdoor temperature is significant positive,so,heating load of warm withering room should change with outdoor's temperature & humidity,in order to steady the withering temperature.At every test points environmental factors are not significant along X- axis and Y-axis,but Z-axis direction significantly.In the whole process of withering,temperature,relative humidity and THI significantly,the leaf temperature was not significant.(4) The results of dehydration rate in the wilting process show that:during whole wilting process the dehydration rate is fast followed by slow,critical moisture is the turning point.Methods of withering are different,the critical moistures are different.Higher temperature higher critical moisture.ZR withering 28.67%,FS withering 31.63%,KT withering 30.50%,JW withering 36.17%,LKT withering 34.00%,MKT withering 33.39%,HKT withering 33.82%. (5) Image Acquisition of Tea samples Experimental results show that:the external conditions,size about 1.0 MB,a bright indoor flash,the thickness can cover the entire bottom.In the withering and drying process,the R and G value decreases at first and then increases:B value has been decreases,R/G/B ratio has been increasing.(6) On the biochemical composition of tea samples results show that:in spring,tea polyphenols, soluble carbohydrate reduced,and amino acids,flavonoids content increased.In summer,the tea polyphenols reduced,and amino acids,flavonoids,soluble carbohydrate content increased.(7) According to fuzzy comprehensive evaluation method we sort biochemical quality of white tea as: In spring:FS withering＞ZR withering＞KT wilting＞JW withering.In summer:LKT withering＞MKT withering＞HKT withering.(8) According to fuzzy comprehensive evaluation method of Biochemistry and sensory quality white tea we knows:4-01 tea samples before Qingming:KT withering＞JW withering＞ZR withering;It is exactly the same as the tasting results.4-13 tea samples before Guyu:FS withering＞ZR withering＞KT wilting＞JW withering.It is exactly the same as the tasting results.7-26 tea samples in summer:LKT withering＞MKT withering＞HKT withering.It is different from the tasting results.(9) We know that in the simulation of CFD technology on heating Wilt Environmental,the air inlet air TSE smaller,higher temperature,and humidity smaller;the air intake valve TSE larger,lower temperatures, high humidity...