Effects of Salicylic Acid Incorporated with Lukewarm Water Dips on the Quality and Bioactive Compounds of Rambutan Fruit (Nephelium lappaceum L.)

This study investigated the quality attributes of rambutan cv. Rong-rien treated with salicylic acid (SA) solution and/or lukewarm water (LW). The fruit were dipped in distilled water (control), lukewarm water at 35°C, 1.0 mM sali- cylic acid solution, and 1.0 mM lukewarm salicylic acid solution (SA+LW) at 35 °C for 20 min. The fruit were packed in polyethylene containers and then held at 13±2°C for 9 days. Visual appearance, weight loss, pulp firmness, external browning score, superficial colors, total soluble solids (TSS), total acidity (TA) and bioactive compounds - namely antioxidant capacity, total phenols, total flavonoids and total ascorbic acid contents - were determined. The weight loss of the fruit was small during storage and slightly delayed by salicylic acid or/ and lukewarm water dips. SA and SA+LW dips delayed external browning and effectively inhibited the softening of the fruit. The reduction of lightness (L*) was delayed by salicylic acid and/or lukewarm water dips. All treatments had no effect on superficial colors and taste of the fruit during storage. SA and SA+LW dips clearly enhanced bioactive compounds involving antioxidant capacity, total phenols, total flavonoids and total ascorbic acid content during storage. In conclusion, SA and SA+LW treatments delayed external browning, maintained pulp firmness and enhanced the bioactive compounds of rambutan during storage.