Abstract

The effect of processing methods on the physiochemical, mineral, vitamin C and carotenoid content of orange fleshed sweet potatoes were investigated. The processing methods used were boiling, steaming, roasting, frying and microwaving. The result of the proximate composition showed that the roasted orange fleshed sweet potatoes (OFSP) had the highest ash content ranging from 0.32-0.99%, crude protein 0.96-3.12%, crude fiber 0.50-3.40% and carbohydrate content 13.98-40.10% with a decrease in the moisture content from 83.10% - 49.25%. Fat content of the fried OFSP ranging from 0.96-6.01% was higher than the other samples. Steaming method enhanced the vitamin C content of the OFSP when compared to other processing method, while carotenoid losses were higher after frying 2.59mg/g, than after microwaving 3-91%, roasting 4.73mg/g, boiling 4.60mg/g and steaming 2.68mg/g. Mineral analysis showed that the boiled orange flesh sweet potatoes (OFSP) had zinc, copper and magnesium content higher than the other heat treated samples with 6.21mg/g, 4,164mg/100g and 479.88mg/100g respectively. Sensory analysis results showed that there were no significant (p<0.05) differences in the sensory scores of the orange-fleshed sweet potatoes. The study therefore showed that roasting and frying made available more protein, fat, ash and carbohydrate content, while boiling made available more minerals.

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