Effect Of Chlorine Dioxide On The Storage Physiology And Quality Of 5 Kinds Of Fruits And Vegetables Like Broccolis

At present, chlorine dioxide (ClO₂) is internationally acknowledged as the newest high efficient, broad-spectrum and safe fresh-keeper and bactericide. It has no poisonous and side effect, doesn't cause malformation and cancer, doesn't bring about harmful influence on environment. ClO₂ passed the examination of American food medicine bureau(FDA) ,the American environmental protection bureau(EPA) and American Department of Agriculture(USDA) in 1980s. It is a kind of fresh-keeper, bactericide and disinfector, which is allowed to add in food.Now the research of The ClO₂ in the fresh-keeping realm mostly localized at the liquid ClO₂. The vacancy of research on the relation of gas ClO₂ and the fruit fresh-keeping still exist. Using strawberries, grapes, straw mushrooms, bananas and broccolis as materials, different treatments of gas ClO₂ were applied in the experiment. Through room storage, bananas and broccolis' cold storage, treating mode with ClO₂ fit for fruit and vegetables' freshness is explored. At the same time, applied value of ClO₂ in cold storage is affirmed, and the proper treating concentration of ClO₂ in broccolis' cold storage is chosen. The main contents and results of the experiment are as follows:(1) In room storage experiment, one-off treatment with high concentration of ClO₂, continuous treatment with low concentration of ClO₂ and intermittent treatment with ClO₂, were used in strawberries, grapes, straw mushrooms, bananas and broccolis. The respiration rate, ethylene productive velocity and rotten rate were determined. Taking all factors in account, treating materials 25min each 24 hours with 0.3μL/L ClO₂ could repair the blemish, that the effect of ClO₂ can't maintain long time in one-off treatment with high concentration of ClO₂, and avoided the side effect of ClO₂ in the posterior storage in continuous treatment with low concentration of ClO₂. This intermittent treatment is more economic and it is the best treatment compared with the other two kinds of treatment. Through storage experiment of different concentration, the conclusion is made that the storage effect is closely related to the concentration of ClO₂.The relatively low concentration suits the application of the fruit and vegetables' fresh keeping.(2)In bananas' cold storage experiment, Bananas were treated with 0.2μL/L ClO₂ 30 minutes each 3.5 days, and the physiological indexes were periodically determined. The result indicated that, the treatment postponed the bananas' climacteric, and significantly lowered respiration rate. ClO₂ inhibited the endogenesis ethylene's production, lowered the MDA content, and decreased the bananas' peel membrane penetration. ClO₂ braught total hydroxybenzene's content down, raised the activity of PPO in the bananas' peel, but inhibited banana of browning. In all, ClO₂'s treatment postponed bananas' speed of decrepitude, and kept the stored quality.(3) In broccolis' cold storage experiment, Broccolis were treated with 0.1,0.2,0.3μL/LClO₂ 25 minutes each 48 hours, and the physiological indexes were periodically determined. The result indicated that, ClO₂ treatment made no influence on the respiration rate of the broccoli, increased ethylene productive velocity, kept its chlorophyll content, restrained the etiolation of ball-flower, reduced the loss of Vitamin C, and inhibited the ascension of the MDA content. ClO₂ raised the activity of PPO, postponed the fastigium of POD, and inhibited the POD activity. On the sensory index, ClO₂ inhibited the rotten rate and rotten index of the broccolis. In addition, ClO₂ significantly made the broccolis' pathogeny number down. Synthetically considering, treating broccolis with 0.2μL/LClO₂ 25 minutes each 48 hours is the best way in broccolis' storage.