Survey of antioxidant capacity and nutritional quality of selected edible and medicinal fruit plants in Hong Kong

Twenty-two samples (including fruits, pulp, peel, or seeds) from 13 edible and medicinal fruit plant species selected in Hong Kong were investigated for their antioxidant capacity, nutritional quality and phenolic profiles. Significant variation existed among the tested samples in all the antioxidant and nutritional parameters. Proanthocyanidins, flavonoids and phenolic acids were identified as major categories of phenolic compounds in these samples. Whole fruits of Hong Kong gordonia exhibited the strongest antioxidant capacity (213.4 mmol trolox/100 g DW) and had the second highest content of carotenoids. Seeds of Annona squamosa possessed the highest contents of total protein, fat and amino acids (17.6, 37.2 and 14.4%, respectively). Most peel and some seeds contained high levels of phenolics, carotenoids and vitamin C, which contributed to their strong antioxidant activity. Some of the fruits, peel or seeds from these Hong Kong plants can be a potential resource of functional components and nutraceuticals.