Determination of various properties of yogurt made from cow's milk using starter culture and traditional home made yoghurt

In our study, Physical, chemical, microbiological and sensory properties of yoghurt samples produced by using traditional homemade yoghurt culture and commercial starter culture were investigated on the 1st, 7th and 15th storage period. According to this; According to the analysis results; pH, viscosity, Color L *, a * and b * values were determined statistically different in both yoghurt varieties and storage periods (p<0.05). While it was not determined any statistical differences (p>0.05) among the titratable acidity, dry matter, ash and protein values of yoghurt variaties, changes due to the storage period were found statistically significant (p<0.05), But the differences among the fat values of both yoghurt types, storage periods were not found statistically significant (p>0.05). In terms of microbiological properties, While the total bacteria counts increased in the yoghurt sample prepared with homemade yoghurt, clear decerase was observed in yoghurt sample prepared with commercial starter culture. During the storage period, yeast and mould counts increased in yoghurt samples prepared with home made yoghurt. But it was not determined any yeast and mould in he samples prepared with commercial starter culture. Coliform group bacteria were not detected in both yoghurt varieties. While the number of Lb. bulgaricus increased in both yoghurt types, Str. thermophilus decreased in the storage time According to the sensory analysis results of yogurt samples; the differences in the appearance, consistency, consistency in the mouth, odor and taste scores observed in the varieties and the storage periods were not found statistically significant (p>0.05).The yoghurt sample prepared with homemade yoghurt culture was favored more than the yoghurt prepared with commercial starter culture, in terms of taste and smell.