A review on nutritional composition, antioxidant activity and bioactive compounds content of traditional fruits from Madeira Island

Madeira Island is a Portuguese region with excellent climate conditions for the production of some exotic and tropical fruits, such as, surinam cherry (Eugenia uniflora) and tree tomato (Solanum betaceum). The production of such fruits has increased in the last years due to their attractive sensorial properties and because they are claimed to be a good source of vitamins and other bioactive compounds, like polyphenols or carotenoids. Because of this new and emerging market, there is a growing demand and need for new studies regarding the consumption and health benefits of such fruits. Food composition databases (FCDB) provide detailed information on nutritionally important components in foods. However, in some FCDB there is a significant lack of information on the nutritional composition of traditional fruits. Analytical methods are critical elements for the correct and accurate determination of bioactive compounds. This review focuses on the traditional fruits from Madeira Island and it was found that most of the reported studies in the literature, only determine antioxidant activity (most of the time using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging capacity method and/or Folin-Ciocalteu assay), and/or proximate composition of these fruits. Therefore, bioactive compounds are not frequently identified and quantified in traditional fruits. Although fruits cultivated in temperate parts of the world have already been and continue to be studied for their nutritional and health-promoting value, traditional fruits from Madeira Island remain an expansive and potentially novel source of natural products that up to now have not been characterized.Tânia Gonçalves Albuquerque is grateful for research grant (BRJ/DAN-2012) funded by National Institute of Health Dr. Ricardo Jorge, I.P. This work was funded by National Institute of Health Dr. Ricardo Jorge (INSA), I.P. under project “Compostos bioactivos e os seus benefícios para a saúde” (2012DAN730)