Carbohydrate and bioactive compounds composition of starchy tropical fruits and tubers, in relation to pre and postharvest conditions: A review

In some tropical countries, people are suffering from both undernourishment and noncommunicable disorders, such as overweight/obesity. Starchy tropical fruits and tubers are of particular interest for their carbohydrate content and for the micronutrients they provide. The present study summarizes the content in carbohydrate, phenolics, carotenoids, and vitamin C, as well as the antioxidant activity of a wide range of tropical fruits and tubers. The energy content of fruits and tubers studied is in the range of 1,200 to 1,800 kJ/100 g of dry weight. They are thus important staple foods and, due to their diversity and seasonality, they can provide energy all year long by alternating the resources in the human diet. Starchy fruit and tuber crops have antiobesity properties as they are bulky, rich in moisture, and contain less than 2% of fat. Noncolored fruit and tubers provide total phenolics at about 20 to 140 mEq/100 g fresh weight. They thus have a high antioxidant capacity, as related to their total phenolic content but also to the presence of carotenoids, such as lutein, mostly in Dioscorea bulbifera and cocoyam. Yellow and orange-fleshed varieties contain more total phenolics and also more provitamin A carotenoids than noncolored fleshed ones. The contents in total phenolic and carotenoid greatly vary with the species and variety. The influence of pre and postharvest conditions on micronutrient content is discussed. Further studies on new processing methods are needed to maximize polyphenols and carotenoids retention in the foods and increase the bioaccessibility of these compounds. PRACTICAL APPLICATION: This paper provides information on the nutritional quality of starchy tropical fruits and tubers. Nutritional quality is studied from the point of view of providing energy and bioactive compounds. The paper aims to promote the use of local resources in tropical areas, which could ultimately limit the adverse effects of food globalization on noncommunicable disorders. It could also lead to tropical countries being less dependent on food imports.