Nutritional composition and antioxidant properties of the sim fruit (Rhodomyrtus tomentosa)

Abstract

In this study, detailed chemical properties of sim (Rhodomyrtus tomentosa (Ait.) Hassk.) fruit including nutritional composition, phenolic content and antioxidant capacity were determined for the first time. A 150g serving of sim fruit contained high levels of dietary fibre (69.94-87.43% of Recommended Daily Intake (RDI)), α-tocopherol (38.90-51.87% RDI), manganese (>100% RDI), and copper (44.44% RDI) but low levels of protein (2.63% RDI), lipid (1.59-3.5% RDI), and sugars (5.65% RDI). The predominant fatty acid in the sim fruit sample was linoleic acid (75.36% of total fatty acids). Interestingly, total phenolics (49.21±0.35mg gallic acid equivalent (GAE)/g dry weight (DW)) were particularly high and resulted in a high antioxidant capacity (431.17±14.56μmol Trolox equivalent (TE)/g DW). These results, together with our recent discovery of high amount of piceatannol, a stilbene with potent biological activities, highlight the potential of sim, an under-utilised plant species from South-East Asia, as a new source of health-promoting compounds including dietary fibres, essential fatty acids, and phenolic compounds.

Keywords: Antioxidant capacity; Dietary fibre; Nutritional composition; Phenolic compound; Rhodomyrtus tomentosa.