Content and In Vitro Accessibility of Provitamin. A Carotenoids in Some Tanzanian Vegetables and Fruits Effects of Traditional Processing and Preparation, and Influence on Vitamin A Status

Vitamin A deficiency is among the major nutritional problems in Tanzania as in many developing countries. It mainly affects children and pregnant and lactating women. The basic cause of this problem is related to the diet, which contains little preformed vitamin A and plant foods with a low content and bioavailability of provitamin A carotenoids. This thesis reports studies conducted to evaluate the content and bioavailability of provitamin A carotenoids in selected fruits and vegetables from Tanzania and to elucidate the effects of different processing and preparation methods. The vitamin A and provitamin A carotenoid status in pregnant women was assessed in relation to the dietary intake pattern of provitamin A carotenoids and after supplementation with cooking oil. Results showed that leafy vegetables contain high but variable amounts of all-trans-β-carotene (399-914 \ub5g/g dry weight) and minor amounts of α-carotene, 9-cis- and 13-cis-β-carotene. Fruits contain variable amounts of all-trans-β-carotene (191-5502 \ub5g/100g fresh weight) and some fruits have minor amounts of β-cryptoxanthin and lycopene. Open sun dried leafy vegetables had significantly (