Controlled atmosphere storage with high CO2 concentration extends storage life of fresh pomegranate fruit by regulating antioxidant capacity and respiration metabolism.

BACKGROUND

Pomegranate is susceptible to low temperature. Controlled atmosphere (CA) with high CO2 concentration can prolong storage life by affecting fruit quality. Our study probed into the effect of CA storage on the pomegranate fruit quality as well as antioxidant attributes at 5 ℃ for 30 d, plus at 18 ℃ for 9 d in simulate marketing conditions. The atmosphere compositions of 7% O2 + 4% CO2 (CA1) and 2% O2 + 5% CO2 (CA2) were chosen, the regular air as control (CK).

RESULTS

In arils, the highest contents of total phenols, total flavonoids, and anthocyanins were all found after CA2 treatment, significantly higher 0.04 g kg-1 FW, 0.19 g kg-1 FW, and 0.70 g L-1 FW than those in CA1, respectively. Also, the highest enzyme activity of superoxide dismutase (SOD), glutathione reductase (GR), and ascorbate peroxidase (APX) in husks were presented in CA2, 36.30%, 36.05%, and 4.36%, higher than in CA1, respectively. Thus, CA2 treatment maintained better husk appearance due to significantly reducing chilling injury, malondialdehyde content, electrolyte leakage, and two enzymes activity, including peroxidase (POD) and/or polyphenol oxidase (PPO), meanwhile improving phenylalanine ammonia-lyase (PAL) enzyme activity. Also, CA2 effectively maintained the postharvest quality and reduced nutrition loss for fresh pomegranate fruit by reducing respiration rate, maintaining suitable energy charge, increasing ROS scavenging ability.

CONCLUSIONS

Totally, 2% O2 + 5% CO2 (relative higher CO2 concentration) could prolong the storage life of pomegranate fruit during cold storage by regulating antioxidant capacity and respiration metabolism, both higher nutrition value and better appearance.