IMPROVEMENT OF IN VITRO BIOACCESSIBILITY OF PROVITAMIN A CAROTENOIDS BY FERMENTATION OF TROPICAL LEAFY VEGETABLES

Abstract

The purpose of this study was to assess in vitro bioaccessibility of provitamin A carotenoids in fermented leafy vegetables. These fermented leafy vegetables are often used to prepare dishes in some parts of tropical Africa. Carotenoids were extracted from fermented leafy vegetables and analyzed by using High Performance Liquid Chromatography (HPLC). In order to simulate the human digestion tract, the in vitro bioaccessibility method known as simple, inexpensive and reproductible tool was performed. All leafy vegetables contained considerable amount of provitamin A carotenoids (26.61 ± 1.98 – 305.85 ± 14.38 μg/g dw) with the concentration varying from one source to another. Fermentation of leafy vegetables resulted in losses (24.5 – 78.22%) of provitamin A carotenoid contents. The in vitro bioaccessibility of provitamin A carotenoids of non fermented leafy vegetables ranged from 3.58 to 5.21% while that of fermented leafy vegetables was siginificantly different (P ˂ 0.05) and ranged from 11.51 to 15.32%. The results also showed that fermented leafy vegetables may contribute between 9.48 and 111.31% of the vitamin A daily requirement (RDA) estimated to 550 μg for individuals in developing countries. This study highlighted that fermentation appears as a suitable non thermal processing to improve the bioaccessibility of provitamin A carotenoids of leafy vegetables. Thus, an increased consumption of fermented leafy vegetables could help combat vitamin A deficiency (VAD) which remains a major public health problem in developing countries.