| cowpea, kindey bean, sweet pepper, cucumber, celery, chive were selected as trial materials in this experiment. The optimum conditions of vegetable freshness preservations with simple equipment and easy operation (preservative compound, composite chitosan coating, MA MAP, ozone hot calcium) were obtained through different orthogonal tests during simple low-temperature storage, and the solutions were verified by the experiment. Meanwhile, we studied the relationship between the dielectric constant and density quality of six kinds of vegetables during low-temperature storage. We also established on correlation model of the dielectric constant and different vegetables'density quality. The main results were as follows:1.The optimal formula of preservative compound(FB) were 300mg/L D-VC sodium,60 mg/L kojic acid,10 mg/L gibberellins and 10 mg/L salicylic acid. FB has a good fresh-keeping effect on the six kids of vegetables when they were storaged in low temperature, especially for celery and chive. Its effects on preservation, respiratory Inhibition, maintain and nutritional integrity of the body etc was comparable with 1-MCP and its effects on green and weight keeping were excel to 1-MCP.2. The best formulation of composite chitosan coating(FM) was 1% chitosan,0.02% glycerin monostearate,0.4% Span-80,0.5% D-VC,0.5%NaCl and 0.5% EDTA-2Na. FM has the most evident fresh-keeping effect on sweet pepper and cucumber for storage in low temperature. FM could extend the storing period of sweet pepper and cucumber affectively, inhibit the respiratory significantly and dehydration rate. It delayed the quality deterioration caused by degradation of organic matter and kept the postharvest quality effectively. The commodity character of sweet pepper and cucumber in FM group was better than other groups obviously.3. The optimal design of MA MAP was aperture about 1mm and hole density about 30 ports/60cm2. This MA MAP was better on fresh-keeping of celery and chive, extending the low-temperature storing period above 50%. This goods quality of celery and chive in MA MAP group was much better than that in other groups during storing period.4.The best formulation of ozone hot calcium was 2% CaCl2, 150mg/m3 ozone concentration and hot air at 54-57℃for 10-60 minutes. Compared with control and other diets, the specificity of the cowpea and kidney bean with ozone hot calcium is especially suitable for the sterilization and fresh keeping of fruits and vegetables. It could extend the low-temperature storing period of cowpea and kidney bean above 40%, s inhibit the respiratory and dehydration rate significantly,, delay the quality deterioration caused by degradation of organic matter and keep the postharvest quality effectively, which group was better than that in other groups.5. By measuring the parameters of quality and dielectric property of vegetable during storage, correlations between inpedance, capacitance, resistance and fresh indexes were studied. The results showed that the significant correlation between inpedance,capacitance, resistance and water content, TSS, acid content at frequency range (100kHz,400kHz, 800kHz). Finally, the internal qualities of vegetable could be deduced from dielectric property by those equations and the internal qualities could be measured by non-destructively. Chive... |
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