Effects of Oxalic Acid Dipping and Wax Coating on Pericarp Browning and Storage Life of Fresh Vietnamese Longan Fruit cv. Long

This research was designed to study the impacts of oxalic acid (OA) and bees - carnauba mixed wax (MW) on pericarp browning and storage life of fresh Vietnamese longan fruit cv. Long. The experiments were carried out by soaking fruits in 5 and 7.5% OA for 5 min. After drying, soaked fruits were coated in 6% MW for 30 seconds, and stored at 5±1?C for 30 days. Untreated fruits were used as control. Pericarp browning; pericarp color; pericarp pH; weight loss; fruit decay; total aerobic bacteria; and total soluble solids (TSS) content were monitored during the storage period. The results showed that 7.5% OA soaking in combination with 6% MW coating could postpone pericarp browning for 25 days in storage which was indicated by the lowest browning index, and high lightness (L* value) and yellowness (b* value) of fruit pericarp. Moreover, this treatment maintained low pericarp pH, low total aerobic bacteria, low fruit decay, and low weight loss; and the TSS content of the longan fruit revealed no difference over time. The results indicate that the using of 7.5% OA and 6% MW can be considered for commercial application in extending storage life and maintaining fruit quality of ‘Long’ longan fruit.