Effects of post-harvest UV-B irradiation on phenolic content and antioxidant activity of Rhodomyrtus tomentosa fruit

Abstract

In this study, Rhodomyrtus tomentosa (Ait.) Hassk. (sim) fruits were treated with UV-B radiation for 0, 1, 3 and 6 hours with an average fluency rate of 0.67 mW/cm² at a distance of 30 cm. Fruits were, then, stored at 8 °C to 10 °C for 21 days. During storage, the fruits were analysed for hardness, total soluble solids, and total dry matter every 7 days. The total phenolics, total anthocyanins and antioxidant capacity of the skin+pulp and the seed parts were determined. The results showed that the storage time and UV-B irradiation time significantly affected the antioxidant phenolic content of both skin+pulp and seed parts. The total polyphenols and antioxidant capacity increased immediately after UV-B treatment and decreased during storage. UV-B irradiation slowed down the decrease of antioxidant phenolic compounds in the fruit during storage. This indicated that UV-B irradiation could be a potential way to enhance phenolic antioxidants in fruits rich in phenolics.

Keywords:
Rhodomyrtus tomentosa; UV-B treatment; Phenolic; Antioxidant; Anthocyanin; Fruit storage

HIGHLIGHTS

• The total polyphenols and antioxidant capacity increased immediately after UV-B treatment of sim fruit.

• UV-B irradiation slowed down the decrease of antioxidant phenolic compounds in the fruit during storage.

• The increase in phenolic compounds right after UV-B irradiation indicated that the stimulation of phenolic biosynthesis in sim fruit took place mainly during irradiation.