Effects of Sorghum Substitution on the Proximate Composition, Physicochemical Properties, Amino Acid Profile, and Sensory Quality of Millet-Based Kunun-Zaki

Abstract

Kunun-zaki is a traditional non-alcoholic cereal-based fermented beverage commonly consumed in Northern Nigeria. It is traditionally produced from millet through spontaneous fermentation and is valued for its refreshing taste and nutritional attributes. Fermented foods are valued for their beneficial properties and contribution to healthy living. This study evaluated the effect of partial millet substitution with sorghum (0-80%) on the proximate composition, physicochemical characteristics, amino acid profile and sensory attributes of Kunun-zaki. Increasing sorghum substitution reduced ash and carbohydrate contents, whereas moisture, protein and fat contents increased, with the highest values recorded at 80% substitution. Sorghum substitution significantly influenced the physicochemical properties of the kunun-zaki samples, including pH, total soluble solids, total sugar, and total titrable acidity. However, the pH value of Sample C and the total titrable acidity of Sample D did not differ significantly (p > 0.05) from the corresponding values of the control sample. Amino acid concentrations generally increased as sorghum substitution increased. Essential amino acid content increased from 3.02 to 3.82 g/100 g, whereas non-essential amino acid content increased from 4.01 to 5.11 g/100 g. Exceptions occurred in Samples B and C for essential amino acids and in Sample B for non-essential amino acids. Sensory evaluation showed that the formulation containing 60% millet and 40% sorghum received the highest scores for appearance, mouthfeel, taste, aroma, consistency and overall acceptability. However, no significant differences (p > 0.05) were observed between the 60% millet-40% sorghum formulation and the 100% millet sample for mouthfeel, aroma and consistency. These findings demonstrate that sorghum can be utilised as a valuable ingredient in the production of nutritionally enriched Kunun-zaki, thereby promoting product diversification and reducing dependence on millet as the sole cereal substrate.