Impact of Sodium Nitroprusside and Guar Gum on the Quality Changes of Holy Basil Leaves

HistoryIn this study the effects of sodium nitroprusside (SNP) and guar gum (GG) coatings on the postharvest quality and deterioration of holy basil leaves were evaluated.Fresh leaves were subjected to four treatments: an untreated control, 0.1 mM SNP, 0.3 mM GG, and a combination of 0.1 mM SNP and 0.3 mM GG, they were stored at 8°C and 80 ± 5% relative humidity for 5 days.Visual quality, chlorophyll content, color parameters (L*, a*, b*), weight loss, chilling injury, and electrolyte leakage were assessed.The control leaves showed rapid wilting and browning beginning on the first day of storage and were completely deteriorated by day 5. Leaves treated with 0.1 mM SNP and those subjected to the combined treatment exhibited a slight delay in quality loss.By contrast, leaves coated with 0.3 mM GG maintained better visual quality and green color for up to 3 days and showed only slight wilting at the end of storage.Leaves coated with GG had the lowest browning score (2.67), the highest chlorophyll content (2.37 mg/g FW), and the best color retention, as reflected by higher L* and b* values and lower a* values.Moreover, compared with the other treatments, the GG treatment significantly reduced weight loss (0.80%), electrolyte leakage (6.07%), and the severity of chilling injury.These results indicate that GG coating effectively delayed senescence and reduced the physiological deterioration of holy basil leaves during storage.Overall, the application of 0.3 mM GG was the most effective treatment for maintaining the postharvest quality and extending the shelf life of holy basil leaves, suggesting its potential use as a natural postharvest treatment for leafy herbs.