Effect of Addition of Coffee Extract on Physicochemical and Sensory Properties of Yoghurt

Abstract

Yoghurt is among high value dairy products that are cultured using live organisms and termed as a probiotic carrier. Yoghurt was flavoured using coffee extract to allow diversification of dairy cultured products. In this research, the potential effect of coffee extract on the physicochemical and sensory properties of coffee flavored yoghurt was studied. A complete randomized design was used where four treatments were assigned to twelve experimental units. The treatments were prepared by addition of coffee extract to the yoghurt in the ratio of 0.0% (control), 0.1%, 0.2%, and 0.3%. The treatments were made in three replicates. The samples were analyzed for physicochemical properties and sensory evaluation. Physicochemical properties analyzed included pH, titratable acidity, viscosity and syneresis. Sensory evaluation was conducted by eighteen untrained panelists who were consumers of yoghurt. All were drawn from both students and the staff in the Institute of Food Bioresources Technology, using a nine-point hedonic scale. Data was analyzed by use of ANOVA, means separated by fisher’s LSD at p<0.05 level of significance. From the findings, pH gave readings between 4.45±0.0 and 3.92±0.0. Results for titratable acidity was between 0.78±0.0 and 0.93±0.0. Viscosity ranged from 3241.7±62.9 to 2041.7±14.4, while results for Syneresis were between 8.93±0.5 and 25.33±0.6. Significant differences were recorded in all physicochemical properties evaluated in this research, while sensory scores ranged from 6.5 to 8.5 and significance difference was recorded in all sensory parameters used except in texture and aroma. Physicochemical properties of yoghurt were found to influence the quality and overall acceptability of yoghurt by the consumers.