| Abstract: | The organic acids profile in fermented dairy foods is an indicator of the metabolic activity of added bacterial cultures. These acids act as natural preservatives and contribute to the characteristic sensory properties. This study was done to determine the effect of encapsulation on the metabolic activity of probiotic supplements, i.e. bifidobacteria, in plain yogurts. Metabolically active bifidobacteria may increase the concentration of certain organic acids, mainly acetic and propionic acids, which might lead to decreased acceptability of the product. Changes in the profiles of organic acids were determined in plain set and stirred‐type yogurts containing the starter culture and microencapsulated and nonencapsulated probiotic strains of either Bifidobacterium longumB6 or B. longum ATCC15708. Ion‐exchange high‐performance liquid chromatography was used for the separation and quantification of the organic acids. Concentrations of acetic and lactic acid increased during storage, while those of citric and uric acid remained stable. No particular pattern was observed for propionic or butyric acid, while pyruvic acid initially decreased and then increased during storage. |
