Variation in physico-chemical parameters of probiotic yogurt during refrigeration storage

The obtained products (clasic and probiotic yogurt) were analyzed under the following aspects: organoleptic characteristics: clot appearance, aroma and taste and physicochemical characteristics: acidity, pH, fat, dry matter, ash. At the end of the analyzed period classic yogurt had an acidity of 166°T, with 9°T more than in the first day so the rate of acidity increase was 0.31°T/day during refrigeration and probiotic yogurt had an acidity of 177°T, with 12°T more than in the first day so the rate of acidity increase was 0.41°T/day during refrigeration storage. Acidity of probiotic yogurt evolved faster than that of classic yogurt, due to addition of lactic bacteria specific cultures which hydrolysis lactose to lactic acid. Both products, classic and probiotic yogurt had a preservation period of 21 days in witch organoleptic characteristics were classified as normal issues.