不同氧分压和相对湿度气调冰箱对4种蔬菜保鲜效果的影响

为探究新型气调冰箱对蔬菜的保鲜效果，以普通冰箱作为对照，选取菠菜、生菜、黄瓜和蒜薹4种蔬菜分别置于气调冰箱和普通冰箱中冷藏，分析蔬菜在贮藏期间理化品质、酶活性的变化以及霉菌、酵母菌的繁殖情况。试验证明，气调冰箱叶菜失重率仅为8%～12%，黄瓜和蒜薹失重率低于5%，随着氧分压的降低，失重率降低。蔬菜在氧分压为15%、相对湿度为86%的A3气调冰箱贮藏12 d后，生菜可溶性固形物含量提高了14.41%，黄瓜可溶性固形物含量仅下降了21.28%。叶菜总酚含量增加，菠菜总酚提高了46.48%，生菜总酚提高了56.19%。A3冰箱内蔬菜细胞膜渗透率变化较小，生菜仅为18.65%。气调冰箱对蔬菜过氧化物酶（Peroxidase,POD）和多酚氧化酶（Polyphenol Oxidase,PPO）活性抑制作用增强，A3冰箱内蔬菜POD酶活性呈现先上升后下降趋势，显著低于其他贮藏条件。上述结果表明，供试三种气调冰箱中氧分压为15%，相对湿度为86%的A3气调冰箱对菠菜、生菜、黄瓜和蒜薹的保鲜效果最佳。研究结果为气调技术在冰箱保鲜中的应用提供理论指导。

Effects of Oxygen Partial Pressure and Relative Humidity of Modified Atmosphere Refrigerators on Freshness Preservation of Four Vegetables

To study the effects of new modified atmosphere refrigerators on the freshness preservation of vegetables, four vegetables namely spinach, lettuce, cucumber, and garlic shoots, were selected and placed in a modified atmosphere refrigerator and an ordinary refrigerator, respectively. The changes in their physicochemical quality and enzyme activity as well as the reproduction of mold and yeast during storage were analyzed. The experiment showed that the weight loss rates of leafy vegetables in the modified atmosphere refrigerator were only 8%~12%, and the weight loss rates of cucumber and garlic shoots were <5%. Furthermore, the weight loss rate declined as the oxygen partial pressure decreased. The soluble solid contents of leafy vegetables increase by 14.4% and that of cucumber decreased by only 21.28% after 12 d of storage in an A3 modified atmosphere refrigerator with an oxygen partial pressure of 15% and a relative humidity of 86%. The total phenolic contents of leafy vegetables increased by 46.48% for spinach and 56.19% for lettuce. The cell membrane permeability of vegetables stored in the A3 refrigerator changed by only 18.65% for lettuce. The inhibition effects on peroxidase (POD) and polyphenol oxidase (PPO) activities were enhanced by the modified atmosphere refrigerator. Meanwhile, the POD activities of vegetables in the A3 refrigerator showed an increasing and then decreasing trend, and they were significantly lower than those of vegetables under other storage conditions. The above results suggest that, among the three modified atmosphere refrigerators tested, the A3 refrigerator with 15% oxygen partial pressure and 86% relative humidity gives the best preservation effects on spinach, lettuce, cucumber, and garlic shoots. The results provide theoretical guidance for the application of modified atmosphere technology in food preservation by refrigerator.