Study On Fresh-keeping Effects Of Chlorine Dioxide On 'Red Fuji' Apple

The fresh-keeping effects of chlorine dioxide (ClO₂) on'Red Fuji'apple were studied.'Red Fuji'apple were sprayed with and dipped into 0,20,50,80 mg/L ClO₂, and stored in chambers at 0±1℃. The clearance rate of colonies, firmness, total soluble solids(TSS), titratable acid(TA), Vc content, the respiration rate, the magnitude of ethylene peak, weight loss, rotten index, cell membrane permeability, the content of malondlaldehyde(MDA), the activity of peroxidase(POD) and phenylalanine ammonialyase(PAL) were studied. The physiological and biochemical mechanism of ClO₂ on'Red Fuji'apple freshness were discussed, which provided theoretical basis for ClO₂ application to fruits storage.The results showed:(1) The treatments increased the clearance rate of colonies of fruit surface. It indicated that the effect and concentrations is proportional;(2) The treatments maintained relatively high fruit firmness, TSS, TA and Vc content. The effect of 50mg/L treatment was best;(3) Be compared with control, the treatments effectively decreased the respiration rate and reduced the magnitude of ethylene peak during the storage. In the scope of this experimental concentrations, the effect of 50mg/L treatment was best;(4) The treatments reduced rotten index during the period of cold storage and shelf life. The treatments only reduced weight loss of fruit during shelf life. It indicated that the effect and concentrations is proportional;(5) The treatment delayed the increase of cell membrane permeability, decreased the content of MDA and enhanced the activity of POD and PAL;(6) The treatment decreased the respiration rate, the magnitude of ethylene peak, weight loss and rotten index of mechanical damaged fruit;(7) The appropriate concentration of ClO₂ on the'Red Fuji'apple was 50 mg/L. Fresh-keeping effects of post-harvest treatment had no significant differences with preharvest treatment.