Effect of oxalic acid on antibrowning of banana (Musa spp., AAA group, cv. ‘Brazil’) fruit during storage

• Oxalic acid was applied on postharvest banana fruit.
• It affected the changes in fruit color and browning.
• Oxalic acid increased the activity of anti-browning-related enzymes POD and PPO.
• The application of oxalic acid could keep total phenol content higher and increase reducing power.

The effect of anti-browning by application of oxalic acid on banana (Musa spp., AAA group, cv.‘Brazil’) fruit during storage was investigated. Banana fruit were dipped into solutions of 0 (control), 8 and 20 mM oxalic acid for 10 min and then stored at room temperature (23 ± 2 °C, 75–90% relative humidity). The results showed that oxalic acid at 8 and 20 mM obviously delayed the decrease in fruit color, and maximal chlorophyll fluorescence (Fv/Fm) of banana fruit. Furthermore, fruit treated with oxalic acid exhibited higher activity of anti-browning-related enzymes (peroxidase, POD; polyphenol oxidase PPO), which correlated with the reduction in brown coloring of fruit skin as compared to untreated fruit. In addition, the total phenol content decreased slowly and the reducing power of peel was maintained at a higher level after oxalic acid treatment. Overall, oxalic acid could improve the anti-browning activity to ensure a smooth surface and long-term storage of bananas at room temperature.