The Fresh-keeping Effects And Physiological Mechanisms Of Natamycin Coating Compounds Treatment On Red-globe Grape During Storage

In this paper, in order to investigate the physiological mechanisms of natamycin combined with chitosan coating compounds on fresh-keeping of grape,with the "Red-Globe"grape ae material, we used1%chitosan combined with0.20%(T1),0.40%(T2),0.60%(T3) concentration of natamycin respectively coating on red-globe grape, which compared with untreated control (CK1) and the sample coated with1%chitosan (CK2) in cool storage conditions.At the same time, the experiment analyzed the grape physiology and biochemistry indexes including the decay rate, the shattering trait, respiratory intensity, firmness,TSS content, TA content, Vc content, weight loss rate,SOD activity and MDA produce speed, PAL activity, PPO activity, POD activity and total polyphenol content for controling grape post-harvest browning and senescence.The results showed were as followings:1. High concentrations of natamycin coating compounds treatments could sighificantly reduced the decay rate and shattering trait of the grape, in cool storage conditions after150days,the decay rate of the treatmented grape was significantly declined slowly compared to the control, still retaining the quality of the grape..2. The0.40%and0.60%concentration of natamycin combined with chitosan coating compounds treatment could effectively inhibit the respiratory intensity during the storage, maining the good appearance. The firmness,the contents of Vc and TA were also delayed by the coating treatment, but there was no sighificant differneces on the SSC between the coating treatments and controls.3. Compared with the controls, natamycin coating compounds treatments caould inhibit the decline of POD and SOD activities,and significantly suppressed the accumulation of MDA,through enhancing the free radical scavenging ability, inhabited the lipid peroxidation, therefore, the senescence of grape were delated.4. Natamycin coating compounds treatments could inhibit the increase the PPO activity, and retarded the decline of total polyphenol content, thereby preventing the enzyme catalyse response. Meanwhile, this treatment could delay the decline of PAL activities, improving the internal disease-resistance mechanism.5. Natamycin combined with chitosan coating compounds treatments were better than the single use of the chitosan treatment method, Although, the difference of the0.40%and0.60%concentration of composite coating treatments were not sighificant, they were better than0.20%of that.6. Based on the consideration of the economic perspective,0.40%concentration of natamycin combined with the1%chitosan coatings compounds treatment was the best fresh-keeping method for the red-globe grape. In cool storage conditions after120days,the decay rate of the grape treated by the0.40%concentration of natamycin combined with the1%chitosan was only8.52%, still having a certain degree of commodity value.