Abstract: In this study, the effect of CO2 deastringency treatment on the physicochemical properties of ‘Hiratanenashi’ persimmon fruit was analyzed. The results revealed that after treatment with CO2, soluble solid content and fruit firmness were maintained at a high level despite a slight decrease, soluble tannin content was decreased to an acceptable level for consumption, the contents of malonodialdehyde (MDA) and polyphenols and the activity of polyphenol oxidase (PPO) were significantly reduced (P < 0.05), and total flavonoid and ascorbic acid contents and the activity of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were increased significantly (P < 0.05). This suggests that reactive oxygen species (ROS)-scavenging enzymes and non-enzymatic antioxidants can effectively scavenge the oxidative stress induced by high-CO2/hypoxic atmosphere and maintain redox balance. In addition, 9 957 and 8 984 characteristic ions were identified using metabolomics in the positive and negative ion modes, respectively, with 6 817 and 4 726 of them being annotated, respectively. In the comparison with the untreated control group, a total of 55 and 11 metabolites were found to be up- and down-regulated, respectively, including 6 down-regulated flavonoids metabolites and 14 up-regulated amino acids metabolites. Together, these results study provide valuable information on the effects of CO2-deastringency treatment on persimmon fruit and will contribute to the ongoing popularization of ‘Hiratanenashi’.

Key words: astringent persimmon; CO2 deastringency treatment; physiological quality; metabolites; ‘Hiratanenashi’