Effect of processing methods on the chemical composition and bio‐accessibility of beta‐carotene in orange‐fleshed sweet potato

Abstract

This study investigated the effect of baking, frying, and extrusion on the chemical composition and in vitro bio-accessibility of beta-carotene in orange-fleshed sweet potato (flour and paste). The vitamin B1, B2, B6, and B9 contents in the samples fell within the range of 32.85–35.22 µg/100 g, 84.35–151.85 µg/100 g, 46.75–54.35 µg/100 g, and 7.65–21.55 µg/100 g, respectively. The fried paste had the highest beta-carotene content (1,093.64 µg/100 g) when compared to the fresh root (116.12 µg/100 g) and would contribute approximately 22.8%, 11.4%, and 10.72% of the Recommended Daily Allowance for Vitamin A (µg RAE/100 g) of children, pregnant women, and lactating mothers, respectively. Frying of OFSP in the paste/puree form showed the highest bio-accessible beta-carotene (342.48 µg/g) compared to the fresh root (57.72 µg/g) and other samples (263.22–330.83 µg/g). Extrusion gave the highest protein content while baking yielded better mineral retention levels. Processing methods, as well as the form in which OFSP was processed did have a significant effect on the nutrient composition of the final product. Frying is nonetheless encouraged for dietary plans targeted at alleviating Vitamin A deficiency. Practical applications Orange Fleshed Sweet Potato (OFSP) has gained considerable popularity as an intervention crop for Vitamin A Deficiency (VAD) and hunger driven states. This work has shown the possibility of utilizing OFSP paste and flour using simple processing methods that can be employed by commercial food industries and even at household levels. OFSP flour or paste could be incorporated in pastries, bakery goods, extruded snacks, and local food recipes. Frying of OFSP paste was identified as the best processing method to yield the highest beta carotene content and higher bio-accessibility. This would help in addressing the problem of malnutrition and Vitamin A deficiency (VAD) in affecting developing countries. Also, the knowledge from this work is important in planning diets targeted at addressing VAD and also informing nutritionists, consumers, and producers on the effect of processing on the nutrient composition of OFSP.