Abstract: Taking blueberry as a research object， a series of biodegradable composite films based on polyglycolic acid （PGA） and polybutylene terephthalate adipate （PBAT） were prepared by using a twin-screw extruder according the tape casting mechanism. The quality of cling film was characterized in terms of thermal weight loss， gas permeability， and gas composition. The results indicated that a mass ration of PGA to PBAT of 60∶40 could effectively inhibit an increase in the content of polyphenol oxidase （PPO） activity and delay a decrease in ascorbic acid peroxidase （APX）， superoxide dismutase （SOD）， and catalase （CAT） activity. The PGA group delayed the decrease of peroxidase （POD） activity and pH value. Therefore， the biodegradable preservation film composed of PGA and PBAT is more advantageous to the preservation for blueberries， especially for the preservation film containing 60 % PGA and 40 % PBAT. The CO2 volume fraction could be controlled within 2 %~3 %， whereas the O2 volume fraction continued to decrease with a variation of storage time to reach 10 %~12 %. After storage for six days， the enzyme activity was 3.42 U/g for PPO， 5.98 U/g for APX， 8.37 U/g for SOD， 81.12 U/g for POD， and 115.78 U/g for CAT.

Key words: blueberry preservation, biodegradable material, modification of cling film, dynamics