Applying of sodium nitroprusside (SNP) on postharvest Nam Dok Mai No.4 mango fruits delay ripening and maintain quality

The aim of this study was to evaluate the concentrations of sodium nitroprusside (SNP), a nitric oxide donor, on postharvest ripening and quality of mango fruit cv. Nam Dok Mai No.4. The fruits were dipped in 1 or 2 mM of SNP solution for 30 min while control fruits were dipped in tap water for 30 min. After treatment, all fruits were stored for 18 days at 13°C and RH 90%. Both SNP doses showed significantly reduced ethylene production and respiration rate, maintained the fruit firmness, decreased the changes in total soluble solids and titratable acidity, and reduced fruit weight loss. The treatments of SNP also delayed color development in fruit peel and pulp. SNP-treated fruits showed higher L* and hue angle values and lower a* and b* values in comparison with control fruits. No significant differences were found between 1 and 2 mM SNP treatments. SNP applying on dose of 1mM to postharvest ‘Nam Dok Mai No.4’ mango fruits and then stored at 13°C changed ethylene production and respiration rates, maintained firmness pulp, decreased weight loss and slowed the changes in fruit peel and pulp color, total soluble solids (TSS)  and titratable acidity (TA).   Key words: Mangifera indica L., sodium nitroprusside, biochemical changes, fruit quality.