Exogenous Putrescine Treatment Maintains Postharvest Quality and Delays Senescence of Guava Fruit

Guava is an important subtropical fruit, valued for its characteristic flavour and high vitamin C content. However, the fruit ripens rapidly after harvest, making it soft, mealy, and prone to spoilage, thus reducing its marketability within a short period. This study aimed to investigate the response of postharvest putrescine (PUT) treatment on quality and senescence of guava. Fruits were treated with PUT (0.5 mM, 1.0 mM, or 1.5 mM) and stored at ambient conditions (27 ± 3 °C). Among the treatments, 1.0 mM PUT was the most effective in minimizing weight loss and decay loss over control, by ~ 20.6% and 28%, respectively. Ripening and senescence were delayed by PUT treatments, as indicated by high chlorophyll retention and minimal lipid peroxidation and carotenoid content. Ascorbic acid, phenolics, flavonoids, antioxidant capacity, and radical scavenging activity were best maintained with the 1.0 mM PUT treatment. However, total soluble solids and acidity content of fruit were less affected by this treatment.