Preharvest Applications Improve the Postharvest Storage and Quality of Tomato Fruits by Enhancing the Nutritional Value and Antioxidant System

Tomato fruit’s quality, firmness, and resistance to hard postharvest handling and storage conditions can be raised via different preharvest applications, including fertilization. This study aimed to study the impact of preharvest field humic acid (HA), fulvic acid (FA), and salicylic acid (SA) treatments on the postharvest quality of tomato fruits. The experiment was arranged in a randomized complete block design in five treatments as follows: 20 mL L−1 HA plus 2 g L−1 FA (T1), 20 mL L−1 HA plus 0.5 g L−1 SA (T2), 40 mL L−1 HA plus 2 g L−1 FA (T3), 40 mL L−1 HA plus 0.5 g L−1 SA (T4), and untreated plants (T5). HA was added as a soil supplementation, while FA and SA were applied as a foliar application. Tomato fruits were collected at the beaker stage and maintained at 12 °C and 95% relative humidity for the postharvest storage period. The results obtained revealed that all physicochemical traits were significantly influenced by all treatments applied when comparing with the control fruit. The firmness of tomato fruits was better retained with the HA plus FA treatments than HA plus SA. T3 treatment improved the carotenoids and total soluble solids by 10.0% and 92.0%, respectively, relative to the control fruits. By the end of the storage period, the highest reducing sugar, ascorbic acid, and pectin content was exhibited by tomatoes subjected to T3 treatment followed by T1 and T4. Preharvest treatment enhanced antioxidant content enzymes of α-amylase, catalase (CAT), and peroxidase (POX) enzymes in tomato fruit during the storage period. Moreover, the T3 treatment recorded the lowest weight loss percentage (5.9%) by the end of storage period. The results revealed that combining preharvest HA and FA treatments effectively maintains the quality and shelf life of tomato fruits.