Sodium nitroprusside (SNP) spray to maintain fruit quality and alleviate postharvest chilling injury of peach fruit

•Sodium nitroprusside (SNP) treatment affected postharvest peach chilling injury.•SNP affected ethylene production and fruit antioxidant constituents during storage.•100 μmol L−1 SNP decreased antioxidant activity and accelerated fruit peroxidation.

Peaches, cultivar 'G.H. Hill', from trees that were sprayed with 0, 25, 50 and 100 μmol L−1 sodium nitroprusside (SNP) 14 days before harvest were stored at 4 °C for 4 weeks. Chilling injury (CI), ethylene production, weight loss, firmness, malondialdehyde, hydrogen peroxide and vitamin C concentrations, antioxidant capacity (AC), and superoxide dismutase, peroxidase and polyphenol oxidase activities in the fruit were measured during storage. SNP treatments reduced ethylene production and maintained firmness, AC and vitamin C of the fruit. Treatment with 25 and 50 μmol L−1 SNP reduced CI but 100 μmol L−1 SNP increased it. SNP at 100 μmol L−1 promoted the accumulation of reactive oxygen species, decreased the activity of antioxidant enzymes and accelerated peroxidation in fruit during storage. These results indicated that preharvest SNP (25 and 50 μmol L−1) treatment increased chilling tolerance of peach fruit through suppressing ethylene production, maintaining firmness, AC and vitamin C and enhancing anti-oxidative enzyme activity.