Effects of edible coatings on postharvest qualities of Huanghua pear fruits during cold storage

To investigate the effects of edible coatings such as shellac coating and SemperfreshTM coating on the quality of Huanghua pear fruits (Pyrus pyrifolia Nakai, cv. Huanghua) during cold storage at 4℃, the changes in respiration rate, weight loss and contents of soluble solids, titratable acidity and ascorbic acid of fruits were recorded periodically for up to 60 days. Nuclear magnetic resonance imaging was used to inspect the internal quality of pear fruits after cold storage. The results showed that two kinds of edible coatings significantly reduced the respiration rate and weight loss of the fruits. After 60 days of storage, the coated fruits showed 74%～80% for weight loss and 68%～81% for respiration rate of control fruits, respectively, and the difference was significant (p＜0.05). Coating treatments still delayed the decreases in contents of soluble solids, titratable acidity and ascorbic acid of Huanghua pear fruits during storage, and maintained a lower signal intensity of nuclear magnetic resonance image of the fruits after cold storage. Compared with SemperfreshTM coating, shellac coating was more effective in maintaining the quality of Huanghua pear fruits, but no significant difference ( p＞0.05) in the signal intensity of nuclear magnetic resonance images was observed.