Effect of pulsed controlled atmosphere with CO2 on the quality of watercored apple during storage.

• 1% and 3% CO 2 pulsed controlled atmosphere can delay the loss of fruit water-core • There is the best effect of 1% CO 2 on maintaining the overall visual and sensory quality of fruit • The endurance of watercored apples to 5% CO 2 is less than 45 days • The internal browning of fruit is related to unstable membrane system and dense cell arrangement Watercored 'Fuji' apple with special water core and unique flavor is a characteristic fruit. However, the problems of water core disappearance and browning in the apples are outstanding during postharvest storage. In this study, pulsed controlled atmosphere (pCA) with CO 2 was used to protect the water-core and resist browning of apples. Effects of different concentrations of CO 2 on the quality of apple fruits was investigated, and CO 2 injury characteristic to apple fruits were studied as well. Results showed that pCA with CO 2 could effectively maintain the sensory and texture qualities of watercored apples. Treated with pulsed controlled CO 2 , the degree of membrane lipid peroxidation of the apples was effectively reduced and the membrane system was well maintained. Meanwhile, the activity of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) of the apples were inhibited and the browning was reduced. On the whole, pCA with 1% CO 2 presented the most significant effects on the quality preservation of watercored apples while higher CO 2 showed negative effects on the quality of the samples. Under the condition of pCA with 5% CO 2 , the endurance of watercored apples was less than 45 days and the internal browning was serious. In conclusion, 2%～3% O 2 and pCA with 1% CO 2 was the best and most effective in the long-term preservation of watercored apples, and it is beneficial to guide for the preservation of apple fruits. [ABSTRACT FROM AUTHOR]