EFFECT OF DRYING TEMPERATURE AND PACKAGING MATERIAL ON THE QUALITY PARAMETER OF ORANGE-FLESHED SWEET POTATOES

Abstract

Orange fleshed sweet potatoes (OFSP) contain significant quantities of β-carotene, a precursor for vitamin A. The crop is being promoted to tackle vitamin A deficiency, a serious public health problem affecting children and pregnant/lactating women in sub-Saharan Africa. This research aims to evaluate the effect of drying temperature and packaging material on the quality parameter of OFSP flour. This study evaluated the effect of drying temperature on the quality parameter of OFSP flour, this was done using two drying methods, sun drying, and oven drying (90°C, 45°C, and 65°C), and was further studied by evaluating the effect of five packaging material (Transparent low-density polyethylene (LDT), dark low-density polyethylene (LDD), dark high-density polyethylene (HDD), transparent high-density polyethylene (HDT) and Laminated brown paper(HDDL)) on the retention and degradation kinetics of carotene during storage. The moisture, ash, protein, fat, fibre, and carbohydrate were in the range of 7.91 to 10.92%, 1.67 to 3.67%, 3.36 to 4.39%, 0.75 to1.25%, 0.30 to 0.69%, 81.15 to 84.12% respectively. The sugar, carotene, TTA, and pH were in the range of 2.88 to 7.89 mg/100g, 2.92 to 9.18µg/100g, 0.67 to 1.05 %, and 4.89 to 5.96 respectively. The color difference and yellowness index were in the range of 59.47 to 71.92, and 49.80 to 67.81 respectively. The OFSP dried at 65 oC had the highest yellowness index of 67.81, implying carotene retention at 65 oC was higher, the yellowness index was directly proportional to the carotene content in the samples. The OFSP that was dried at 65℃ produced the flour with the highest carotene retention (9.18µg/100g) and was used for storage. At the beginning of storage, all packaging material had (100%) carotene, after a month of storage, HDDL packaging material retained the highest carotene (95.06 %) followed by HDD (82.36 %), LDD (72.49 %), HDT (58.96 %), and LDT (51.28%) respectively, this shows the impact of light in carotene retention OFSP flour has shown potential to combat vitamin A deficiency (VAD). Hence, OFSP flour should be advocated as a tool for achieving not only food security but nutritional security.