EFFECT OF PROCESSING ON THE MINERAL COMPOSITION AND ANTINUTRIITIONAL FACTORS OF ORANGE FLESHED SWEET POTATO (Ipomoea batatas L. Lam) FLOURS

Studies were conducted on the mineral composition and antinutritional factors of flours produced from two improved orange fleshed sweet potato (OFSP) genotypes (CIP199004.2 and CIP440216), which were processed using two treatments; the unblanched and blanched method. The sweet potato roots were stripped and the striped samples shared into two portions; one portion was unblanched, washed, drained and oven (Gallenkamp, model OV-160) dried while the other portion was blanched in hot water (900C) for 5 minutes, drained and oven dried. The dried samples were milled and later sieved (0.2mm) into flour for mineral and antinutritional analysis. The results showed that the mineral contents of both unblanched and blanched OFSP flour samples differed due to processing and varietal effect with the unblanched flour samples having slightly higher P-carotene content value than the blanched OFSP flour samples. The P-carotene values of CIP 199004.2 flour samples were 3.48 ^g/g (unblanched) and 1.54^g/g (blanched), while CIP 440216 was 5.48^g/g (unblanched) and 4.24^g/g (blanched). The iron content of the unblanched CIP 440216 had a slightly higher value of 0.84mg/g than unblanched CIP 199004.2 (0.63mg/g). The phytate content in unblanched OFSP flour samples seemed relatively higher than the blanched OFSP flour samples and may be as a result of the processing method as it affected the phytate content through leaching process. The result obtained from tannins was generally low. In effect, it seems that utilizing orange fleshed sweet potato in their raw (unblanched) form retains the nutrients more than in their processed form.