Effects Of Vibration Stress On Physiological Changes And Quality In Tea Leaves

Mechanical vibration stress can promote tea leaf containing material to transform into each other,and can achieve continuous operation of mechanization.The research on vibration stress on the tea leaf physiological changes has practical significance in the mechanization of vibration in the application of the tea production.In 28℃,relative humidity of 76 percent of the conditions,this test with different intensity of the vibration stress takes vibration treatment on the leaves of Fuxuan9 tea and Qingxin Oolong tea,through the methods combined chemical testing and sensory integration review,and explores the effect of vibration stress on physical and chemical changes and quality in tea,results are summarized as follows:1.Vibration stress speeds up the moisture loss rate in tea leaf,and the greater vibration strength, moisture losses sooner.After vibration treatment,the two varieties of moisture content in tea leaf compared with the check were reduced respectively by 0.95%to 4.71%and 1.07%to 2.10%,and the vibration stress test results show that,in the entire withering process,the moisture content in all tea leaves show a downward trend,and the moisture content in the tea leaf with vibration treatment is always lower than that of check.2.Vibration stress on tea leaf increases significantly the respiratory intensity,the size of ZD₃＞ZD₄＞ZD₂＞ZD₁.Compared with the check,the two varieties of tea leaf respiratory intensity increase respectively by 96.43%to 29.51%and 34.41%to 90.60%;the sustained effect of vibration stress shows that,in the entire withering process,the respiratory intensity of dealing with tea leaf shows a "low-high-low" trend,a declining trend in check,and vibration treatment has always been higher than that of check.3.The vibration stress causes increased the cell infiltration rate of tea leaf,and the greater the intensity of vibration,the greater the cell infiltration rate.Vibration treatment,the cell infiltration rate of two varieties of tea leaf were increased respectively of 45.99%to 73.86%and 47.24%to 74.71%,the sustained effect of vibration stress shows,the entire withering process,the cell infiltration rate of all the tea leaves had always been an upward trend,and vibration treatment has always been higher than that of check..4.The vibration stress caused the increase of malondialdehyde(MDA)in tea leaf,and the greater the intensity of vibration,the content of malondialdehyde(MDA)was more.After vibration treatment,the two varieties of tea leaf MDA compared with the check increase respectively by 6.43%to 28.75%and 24.30%to 42.17%;the sustained effect of vibration stress shows that in the entire withering process,the content of malondialdehyde(MDA)in tea leaf had always been an upward trend,and with more than vibration check.5.Polyphenol oxidase(PPO)activity,peroxidase(POD)activity,pectinase(PG)activity results showed that:in the entire process,PPO activity of vibration processing tea leaf showed a "high-low-high-low" trend,natural withering tea leaf showed a "low-high-low" trend,POD activity of vibration processing tea leaf showed a "low-high-low-high" trend,natural withering tea leaf showed a "high-low-high" trend,and POD activity of vibration treatment tea leaf has always been lower than that of check with check treatment;in the entire process,PG activity of all the tea leaves showed "high-low-high-low" trend,but overall activity is smaller,and the vibration treatment has always been higher than that of natural withering.6.The major biochemical component analysis showed that,in the entire withering process,tea polyphenol content gradual declined;amino acid content decreased in the process of vibration, increased in the withering process,and was higher than that of check;in the entire withering process, tea polysaccharide content decreased,tea leaf with vibration treatment in the early a few hours during the withering process declined faster than that of check,then slowed down,in the entire withering process,the water extraction gradually decreased,in the prophase of the withering process tea leaf with vibration treatment fell faster,slower declined in the latter part.7.The organoleptic evaluation showed that:in the early stage of withering process,all the drying samples of tea showed the quality characteristics of liquor color with yellowish green,aroma with clean and high,and the taste with fresh and brisk,scores were close to each other,it showed that in the prophase of the withering process,the qualities of natural and vibration tea were little difference,and in the anaphase of the withering process,compared to the drying samples of tea in natural withering,the liquor color of vibration treatment showed the change from yellowish green to pale yellow,a pleasant potpourri,mellow and thick taste,the score was significantly higher than that of drying samples of natural withering tea.