A STUDY ON THE SENESCENCE AND BROWNING IN THE PERICARP OF LITCHI ( LITCHI CHINENSIS SONN ) DURING STORAGE
Chen Wenjun and Horn Qizhong ( Fujian Agricultural College, Fuzhou 350002 )
Litchi Litchi chinensis Sonn cv.Yuan Hong was stored with different kinds of package. The ultrastructure of its pericarp cells and the physiological and biochemical changes of browning and non-browning fruit were studied during storage. Unpacked litchi stored in cartons at room tempsrature for 4 days, the weight loss of the fruit was 24.53% and water loss of its pericarp was 54%. The conductivity of the pericarp tissue increased 5 times. When the PE-film-sealed package fruit was stored at room temperature for 7 days or under low temperature for 27 days and the.n removed to room temperature, the water loss of the fruit w as 21%~22% and that of the pericarp 29.36%, and the conductivity of the pericarp tissue increased 3 times in 24 hours after its unpacking. The fruit became, hrown and stiff. Under the serious water loss of the fruit, the disintegration of its cell ultrastrueture and the cytoplasmic dehydration, contraction and coagulation were observed by an transmission electron microscope. The pulyphcnol oxidase aclivity in the pericarp decreased 80% of more. The content of phenolic substances reduced 50%. On the contrary, litchi fruit, stored in PE-film-scaled package or in cartons with wet cheese-cloth for moisture preservation, Showed less water loss and browning. PE-film-scaled package had particularly good effect on reducing the water loss of litchi pericarp, retarding the disintegration of its cell structure and preventing the phenolic substances from being oxidized. Thus, the senescence and browning of litchi fruit were delayed.