|M.A.J. Wansapala, U.G.Chandrika, A.Bamunuarhchi. K.K.D.S. Ranaweera
Vitamin A is an important micronutrient of animal origin responsible for structure and functioning of the skin, mucous membrane and maintaining of a good vision. According to the recent studies about 36% of pre school children are subjected to vitamin-A deficiency. Since the vitamin-A is a nutrient of animal origin, fish liver oil, dairy, meat products and eggs have been identified as vitamin-A rich food sources.
Majority of people in Sri Lanka are liable to vitamin-A deficiency due to following reasons.
Scientists could find a successful solution for this nutritional problem through carotenoids. Carotenoids are well appreciated as natural colourants responsible for the yellow to red colour of many fruits and have diverse role in biological functions of animals and plants including provitamin A activity, cell communication, immune function enhancement, UV skin protection accessory pigments for light harvesting and protection for against photo oxidative damage.
β-carotene is a potent provitamin A to which 100% activity is assigned. Some fruits and vegetables such as mango, papaya, pumpkin and leafy vegetables have appreciable amounts of β-carotene. Fruits like mango which contain higher amounts of provitamin A carotenoids are available throughout the country in several seasons and are even affordable to individuals at low-income level.
The Beti amba, Gira amba, and Karuthacollamban mango varieties which represent the three main agro-climatic reigons of Sri Lanka (i.e. wet zone, intermediate zone and dry zone) were studied. β-carotene is found as a principle pro-vitamin A carotenoid in all three mango varieties and highest bioavailability of provitamin A carotenoid was reported in Beti amba variety. In order to fulfill the vitamin A requirement of the body, consumption of Beti amba variety is more beneficial than other two varieties (29%). Availability of fruit can be increased by their value added products (i.e. Jam, cordial and osmotically dehydrated products). With respect to the mango based products bioavailability of provitamin A carotenoid is higher in jam (67%) than the osmotically dehydrated mango(64%) and cordial (25%). Sodium metabisulphite which is used as a chemical preservative for cordial is substantially affected to the stability and the bioavailability of provitamin A carotenoids.
The best storage condition that will preserve the maximum amount of provitamin A carotenoid is 28°C. The conditions that are favourable for the formation of the non- provitamin A carotenoid are made by the artificial ripening agent such as Calcium carbide and thereby decrease the content of provitamin A carotenoids.