Effect Of Processing On Crude Fat And Beta-Carotene Content In Three Sweet Potato Varieties

ABSTRACT

Sweet potato (Ipomoea batatas) is one of the crops being considered for the diversification of the staple diet to enhance food security in Zimbabwe in the face of climate change and economic challenges. One of the hurdles preventing adoption of sweet potato as a staple food is its short shelf-life. There has been a call to explore means of preserving sweet potato hence increasing its shelf-life and one method of preservation is processing sweet potato into flour. However, this method has not been embraced because the effect of processing on sweet potato nutrient content is not known. A study was carried out to determine the effect of two methods of post-harvest processing (oven-drying and sun-drying) on fat and beta-carotene content of sweet potato in line with the ZIM ASSET clusters on food security under value addition and beneficiation. Three sweet potato cultivars -Chingovha (crème-fleshed), Germany II (white-fleshed) and Resisto (orangefleshed) were studied. The Soxhlet extraction method was used for fat content determination and the beta carotene content was determined using spectrophotometry. Sun-dried Germany II retained the highest fat content (0.09±.002g/100g) after processing. The fat content was below the threshold required for absorption of beta-carotene by the body (5g/100g). Resisto and Chingovha retained similar fat contents (0.02±.002g/100g – 0.04±.004g/100g). There were significant differences in fat content across the three cultivars and between fresh and processed sweet potato (ANOVA p