ABSTRACT

This study investigated the rheological and nutritional properties of flour produced from three cultivars of aerial yarn namely; white cultivars, yellow cultivars and purple cultivars. The aerial yarn (Dioscorea bulbifera) flour was prepared by peeling and slicing the bulbils into 1cm thick and washing them in distilled water. The slices were blanched for 5 minutes and oven dried for 72 hours at 600 C. The samples were analysed for proximate propertics. antinutritional properties and functional properties. The proximate composition results are as follows; moisture (6.99%, 7.07%, 7.12%), Ash (2.58%, 2.62%, 2.67%), Fat (0.88%, 0.91%, 0.98%), Fibre (1.03%, 1.07%, 1.17%), Protein (4.92%, 6.18%, 6.27%), Carbohydrate (81.93%, 82.05%, 82.22%) for yellow, purple and white cultivar respectively. The results showed that blanched white cultivar had the highest moisture content of 7.12% which is significantly higher than the moisture content of yellow and purple(6.99%, 7.07%) cultivar respectively. The yellow cultivar had the highest ash content of 2.67% which were is significantly higher than the ah content of white and purple (2.58%, 2.62%) cultivar respectively. Also the protein content in yellow cultivar was the highest with 6.27% and 4.92% white cultivar as the least. Also the purple cultivar had the highest Carbohydrate (82.22%) which is significantly higher than the Carbohydrate content of white and yellow(81.93%, 82.05%) cultivar respectively. The anti-nutritional factors evaluated were Taniun, Phytate, Oxalate, Alkanoids, Flavonoids. The white cultivar had the highest Tannin, Flavonoid and phytate contents (0.72mg/bOg, 1.63 rng/100g and 0.12 mg/bOg) respectively. Purple cultivar had the highest Alkanoids and Oxalate content (0.96, 0.26) respectively. The yellow cultivar had the least flavonoid, Tannin, Alkanoids and Oxalate content (1.54mg/lOOg, 0.68 mg/bOg, 0.92 mg/bOg and 0.24 mg/bOg) respectively. The functional properties evaluated 'ere Bulk density, Water absorption capacity, Swelling index, Emulsion capacity, Gelation Temperature, wettability and viscosity. Bulk density of the cultivars ranged from 0.60-0.63, Water absorption capacity ranged from 4.22-6.71, Swelling Index 12.5-1.56, Emulsion capacity 52.03-63.93, Gelation Temperalure ranged from 80.03-80.47, Wettability ranged from 1.03-1.29 and Viscosity ranged from 152g-156g. The variation in the functional properties is based on the. cultivars.