Biological and Technological Characteristics of Milk-Fermented with Probiotic Lactobacillus acidophilus La-5 and Viable/Inactivated Saccharomyces boulardii 002Y018 Cultures

This study was design to evaluate the effect of using of probiotic Saccharomyces boulardii 002Y018 strain in the viable or inactivated form on the technological and biological properties of milk-fermented with probiotic Lactobacillus acidophilus La-5 culture. The results demonstrated that the addition of S. boulardii 002Y018 strain in the viable form negatively affected the growth of L. acidophilus La-5, but in its inactivated form, it enhanced the viable count of L. acidophilus La-5 compared to that of milk-fermented with L. acidophilus La-5 as a single culture. At the beginning or after 21 days of cold storage, the viable counts of L. acidophilus La-5 or S. boulardii 002Y018 culture in all fermented milk treatments still meet the recommended minimum requirements of 6 Log CFU/mL for probiotic strains. Milk-fermented with S. boulardii 002Y018 culture in its different forms recorded the highest scores of organoleptic attributes. Milk-fermented with co-culture of probiotic strains exhibited the greatest values of proteolysis, ACE-I, and antioxidant abilities on day 1 or after 21 days of storage period. All fermented milk treatments showed a great inhibitory effect on the growth of some pathogenic bacteria and fungi. Fermentation of milk with L. acidophilus La-5 and S. boulardii 002Y018 as a co-culture improved the production of organics acids. Also, the addition of S. boulardii 002Y018 strain promoted the ability to inhibit α-amylase and α-glucosidase that is related to the reduction of diabetes. Ultimately, our findings provide that S. boulardii 002Y018 strain can be successfully applied, in the viable or inactivated form, for the manufacturing of functional fermented milk rich in bioactive components.