Antioxidant activity of tropical fruits as related to their polyphenol, vitamin C and carotenoid contents: a review

National audienceToday's consumers are more and more concerned with foods containing components that are providing health benefit, such as polyphenols, vitamins and carotenoids. The contribution of these components to health benefit in plant-derived food has often been related to their antioxidant properties. Most studies on these components in fruits have been carried out in temperate countries. Less is known about them in fruits from tropical areas, whereas the international trading of tropical fruits is developing. This paper summarizes knowledge on polyphenols, vitamin C and carotenoids in tropical fruits in relation to their measured antioxidant activity. Data on the composition of these fruits in vitamins have been recently published. Less information is available on their total phenolic content and their phenolic composition. A statistical analysis including data on various tropical fruits has shown that the correlation coefficient between antioxidant activity and total phenolic content was 0.96. The corresponding coefficient for ascorbic acid amounted 0.23 to 0.35, depending on the method used to measure the antioxidant activity. It is noticeable that in acerola (Malpighia emarginata) and guava (Psidium guajava), which exhibit the highest antioxidant activity, this activity is highly linked to both total phenolic and ascorbic acid contents. Antioxidant activity was shown to be negatively correlated to carotenoid content in guava. However, it is generally not clear which compounds are responsible for the antioxidant properties of tropical fruits, as they have rarely been simultaneously analyzed for their composition in all these components and their antioxidant activity. Moreover, total phenolic, ascorbic acid and carotenoid contents may be highly influenced by cultivars, as suggested in mango and guava pulp. The effects of the development and maturation stages and of postharvest storage conditions on these components and on antioxidant activity in tropical fruits still need to be investigated