Research Of Ozone Treatment Effect On Citrus Preservation

Ozone is a safe nonpolluted, strong oxidation and broad-spectrum bactericidal, it can be prepared conveniently and it has low cost. This paper focus on the effects of ozone treatment on quality and physiological and biochemical, the killing effect on citrus peel mold, as well as the degradation of organophosphorus pesticide residues of citrus during storage. The main findings are as follows:1. Ozone treatments of the concentration 57 mg/m3 for 5mins can significantly delay the decrease of TSS, TA, Vc contents and the accumulation of MDA in the late period of storage, significantly inhibit the increase of respiration intensity, weight loss and cell membrane permeability of citrus during storage, increase POD activity, inhibit PPO activity and delay the aging of the fruit. The optimum concentration of ozone treatment on citrus is 57 mg/m3, and the best processing time is 5mins.2. Within a certain range, the higher of the ozone concentration, the better of the antibacterial consequence of citrus is. When the ozone concentration reaches 57 mg/m3, further increase ozone concentration, the inhibitory of effect tested mold has no significant difference; in the same concentrations of ozone, the longer the processing time, the better the inhibitory consequence. When the processing time reaches 5mins, with the extending of the processing time, the inhibitory consequence of mold has no significant increase; the treatment at the concentration of 57 mg/m3 for 5mins has the best antibacterial effect, and can prolong 30 days storage period of citrus compared with the control group.3. The higher the ozone concentration and the longer the processing time, the faster the degradation of dimethoate and chlorpyrifos of citrus peel. However, too long processing time is of no significant effect on increasing the pesticide residues degradation rate; treatment with 18 mg/m3,57 mg/m3 and 90 mg/m3 of ozone on citrus for 5mins can make the dimethoate residues degradation of citrus peel advance about 10,15 and 20 days than the control group respectively, and make the chlorpyrifos residues degradation advance about 15,20 and 25 days than the control group respectively.