Effects of Oxygen Partial Pressure and Relative Humidity of Modified Atmosphere Refrigerators on Freshness Preservation of Four Vegetables
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
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.
