Effects of Copper Sulfate and Low Temperature Storage on Physical-chemical Characteristics and Internal Browning of Tainung No.17 Pineapple Fruits

• Main Authors: An-Chi Chien, 簡安祺
• Other Authors: Ching-Cheng Chen
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/73857392717204257883

碩士 === 國立中興大學 === 園藝學系所 === 105 === Pineapple fruits stored at low temperature are easy to develop chilling symptoms, leading to internal browning and fruits quality decreasing. Because there are no external symptoms on affected fruits, it may cause losses of business reputation and profits. The main objective of this study was to investigate whether an increase of copper level in ‘TN17’ pineapples pulp will cause an increase in internal browning incidence, and to analyze the occurrence of internal browning of ‘TN17’ pineapple fruits which were stored at different low temperatures to provide information about the key factor to internal browning development. After spraying copper sulfate on‘TN17’ pineapple fruits in the field, copper concentrations in the shell were significantly higher than in the pulp. After stored at 8℃ for 1 week and followed at room temperature for 2 days, copper level of flesh slighity increased with internal browning symptom occurrence. Both copper level and internal browning index increased in ‘TN17’ pineapple fruits which were dipped in copper sulfate solution and stored at 8℃ for 1 week followed at room temperature for 2 day. Low temperature storage can delay ‘TN17’ pineapple skin color development. No internal browning appeared in fruits stored at low temperature for 1 week, however, it occurred in fruits stored at low temperature for 1 week followed by 4 days at room temperature. Internal browning index was significantly increased in fruits stored at 4℃, followed by fruits stored at 12℃ and only slightly increased in fruits stored at 8℃. More severe internal browning was found in fruits stored at low temperature for 2 week, followed at room temperature for 4 days. Fruits stored at 12 ℃ for 2 weeks followed by 4 days at room temperature had the highest internal browning index, compared with 4℃ and 8℃ treatments. Calcium ions moved from inner pulp to outer pulp during storage may affect the tolerance of the ‘TN17’ pineapple inner pulp cells to low temperature stress. The copper level was significantly higher in pineapple fruits with more severe internal browning. In this study, ‘TN17’ pineapples stored at 4℃ for 2 weeks followed by 4 days at room temperature had slightly internal browning, but fruit section was seriously turned brown after treated with PPO substrate. The longer low temperature storage period, the higher PPO activity was found after 4 days at room temperature. The total protein content of fruits decreased during low temperature storage, and then increased after stored at room temperature. The bromelain activity increased after stored at low temperature, then decreased after moved to room temperature with internal browning occurrence. The relationship between bromelain activity and internal browning is worthy of further study. Taken together, for ‘TN17’ pineapples, it is not that the lower storage temperature, the more internal browning occurrence. In this study, the results showed that 8℃ storage had lower internal browning incidence than 4℃ and 12℃ storage. In combination with waxing or hot water dipping before storage, pineapples may have better storage quality.