Quality changes and internal browning developments of summer pineapple fruit during storage at different temperatures

The influences of storage temperature on quality parameters, comprising total soluble solids (TSS), free sugars, vitamin C, titratable acidity (TA) and soluble proteins, and internal browning (IB) of summer pineapple (Ananas comosus L. cv. ‘Comte de Paris’) fruit were investigated. The fruit were subjected to three different temperatures (6, 10 and 25 °C) with relative humidity of 80% for 24 days. In addition, the activities of polyphenol oxidase (PPO), peroxidase (POD) and catalase (CAT) were measured during storage. The results indicated that a decrease in TSS in fruit kept at 25 °C was noted, while TSS remained relatively constant in fruit storage temperature at 10 and 6 °C. A high correlation was observed between the different sugars during storage periods. There was a noticeable decline in sucrose content in pineapple fruit during storage, with a more rapid decrease with higher temperature. The maximum retentions of glucose and fructose concentrations can be achieved with storage of fruit at 6 °C rather than storage at 10 or 25 °C. The effective slowing down of vitamin C and TA rate of decreases was the fruit stored at 6 °C, followed by 10 and 25 °C. There was a decrease in contents of soluble proteins as storage temperature increased throughout the storage period, and significant differences were found between fruit stored at low temperature and room temperature after 12 d in storage. Storage temperature also significantly affected IB development, the incidence of IB was more rapid and with higher intensity in fruit held at 25 °C than 10 °C, and IB intensity was minimal in fruit held at 6 °C. Additionally, PPO activity increased with higher storage temperature during 24 days storage. CAT activity gradually increased at three storage temperatures and in the fruit stored at 25 °C was higher than those at 10 and 6 °C. However, POD activity was not influenced by storage condition. The results suggest that lower temperature can provide a useful means of maintaining quality and resist IB development during storage of pineapple fruit.

► This research studied the effects of different storage temperatures on quality of pineapple fruit during storage.
► The effects of storage temperature on internal browning symptoms in pineapple fruit were observed.
► The relevant quality indices are vitamin C, titratable acidity, total soluble solids, soluble sugars, and soluble proteins.
► Storage temperature influences on the activities of enzymes related to internal browning of pineapple fruit.
► Our work will provide a useful reference for post-harvest pineapple fruit.