The Effect of Postharvest Polyamine Application on the Physicochemical Traits, Bioactive Compounds, and Antioxidant Activity of Sweet Lime Fruit

The present study aimed to investigate the effect of postharvest polyamine application on the physicochemical characteristics, bioactive compounds, and antioxidant activity of sweet lime fruit. The fruits were dipped in putrescine (2 and 4 mM), spermidine (1 and 2 mM), spermine (1 and 2 mM), or distilled water (control) for 10 min. Evaluations were conducted after 2 and 4 months of storage at 10 °C and 85% relative humidity. In general, treatments had no effect on the total acid and pH of the fruit juice. Using polyamines led to lower rates of weight loss or decreases in juice total soluble solids, and treated fruits had a better taste index when compared to the control. The content of ascorbic acid in fruit juice increased with storage time, but total phenol content and antioxidant activity decreased. When compared to the control, polyamine-treated fruits had higher levels of ascorbic acid, total phenol, and antioxidant activity in the juice. The treatment with both concentrations of spermine had the greatest efficacy in maintaining the juice taste index and ascorbic acid content than the other treatments. Fruits treated with spermine and spermidine had the same taste index. Moreover, spermine-treated fruits had the same amount of ascorbic acid as fruits treated with 2 mM spermidine and putrescine. Finally, dipping in 1 mM spermine was found to be the most effective treatment for reducing weight loss and preserving juice total phenol content and antioxidant activity, and is recommended as the best treatment for preserving sweet lime fruit quality.