Effects of orange-fleshed sweet potato supplementation on the phytochemical composition, physicochemical, and sensory properties of sorghum-based kunu-zaki

The phytochemical, physicochemical, and sensory properties of the blended kunun-zaki were determined. The fermented sorghum paste was substituted for orange-fleshed sweet potato puree at 0, 5, 10, 15, 20, 25 and 50% to produce orange-fleshed sweet potato-sorghum blended kunun-zaki. The phytochemical composition: carotenoids, flavonoids, and vitamin A content of the blended kunun-zaki increased from 0 to 28.14 mg/100g, 0 to 191.50 mg/100g and 0.44 to 7.74 mg/100g respectively, while the tannin content decreased from 4.97 to 1.51 mg/100g, with an increase in added orange-fleshed sweet potato puree. The effects were significant (p = 0.05). The physicochemical properties: pH, total soluble solids, total solid and specific gravity increased from 3.97 to 4.10, 4.95 to 8.25°Brix, 1.55 to 2.80 g/100g and 5.65 to 13.70 g/100g respectively, while the acidity decreased from 39.21 to 12.00 g/100g, with increase in the added orange-fleshed sweet potato puree (0-50%). The average mean scores for sensory quality; flavour, colour and taste increased from 6.70 to 7.06, 6.70 to 7.41 and 6.43 to7.40 respectively, whereas odour, mouth feel and appearance decreased with increasing inclusion level of oranged-fleshed sweet potato puree from 7.90 to 6.93, 7.40 to 6.40 and 7.26 to 6.72 respectively. Overall results show that the beverage formulated were generally acceptable of which the sample containing 20% orange-fleshed sweet puree was most preferred. The addition of oranged-fleshed sweet potato puree improved the phytochemical content and the sensory quality [taste, flavour and colour] of the sorghum-based kunun-zaki.