Quality Evaluation of Commercial Yoghurts on Streets of Kano-Nigeria

The study was conducted to evaluate the physiochemical properties of commercial yoghurts offered for sale on the street of Kano metropolis. Different brands of yoghurts were randomly purchased from yoghurt vendors and designated A, B, C and D. The yoghurts were stored in refrigerator (4-10 C) and analysed alternately for 10 days. The Titratable Acidity (TA), moisture content, Total Solids (TS), Total Protein (TP), Total Fats (TF), ash, pH, viscosity and density of the yoghurts were determined. The results showed a significant (p<0.001) difference in TA (lactic acid %) which ranged between 0.58 and 1.31; moisture from 852.7-866.7 g kg-1; TF from 3.7-15.7 g kg-1; pH from 4.27-3.27 and TP from 32.3-36.2 g kg-1. The difference between the lowest and highest viscosity (p<0.01) and density (p<0.001) of the yoghurt brands were 23.84 cp (for brand C), 47.50 cp (for B), 1.05 g dm-3 (for D) and 1.15 g dm-3 (for C), respectively. The TA correlated negatively with moisture (r = -0.634; p<0.01) and TF (r = -0.831; p<0.01) and positively with TS (r = 0.626; p<0.01) and ash (r = 0.602; p<0.01). The period of storage had no significant (p>0.005) effect on total solids, total fat, total protein and ash. However, the moisture content (p<0.05), titratable acidity (p<0.001) and pH (p<0.05) showed significant difference due to days of storage. It was concluded that the total solids, total fat and total protein of yoghurt brands were within the recommended levels while titratable acidity, pH and viscosity were slightly out of normal range during 10 days storage. It is recommended that yoghurt production should be standardized and supervised by the appropriate national food regulatory bodies.