The Co-fermentation Of Dairy Products Using Lactobacilli And Saccharomyces Boulardii

The overall objective of this study is to formulate a broad planning setting out a framework for the probable synergies of lactobacilli and Saccharomyces boulardii.Initially,to investigate the metabolism activity of microorganisms used whether S.boulardii or lactobacilli,such microorganisms were allowed to grow for 12 h of co-fermentation to consume the most common nutrients present in the formulations of milk fortified with vegetal juices.To achieve the theoretical synergistic effects between S.boulardii and lactobacilli,we addressed the main aims of this study through isolation of S.boulardii,investigation the metabolic efficiency during fermentation of vegetal-based milk or in a combination with lactobacilli strain during fermentation of milk fortified with kiwi juice.First,isolation and identification of Saccharomyces boulardii from a product"High Active Dry Yeast"were presented in this study.The morphological identification approached the isolated yeast to S.boulardii that was revealed by the circular shapes,elliptical morphology,and whitish cream color.Subjecting the S.boulardii was recognized through the 26S rDNA D1/D2 region that was recommended as specific useful tools for identification of S.boulardii molecularly.The resulted sequence length of 26S rDNA gene was present by 585 bp and assigned the isolate to S.boulardii.Second,metabolism of Saccharomyces boulardii during fermentation of skimmed milk fortified with orange,kiwi,jujube,blueberry,or Wheat Grain juices individually?4%v/v?was studied.Yeast growth and metabolism affected by either the negligible contents of glucose or unavailability if the fermented milk was free of juices.S.boulardii channeled the sugars for the production of lactic?0.61–1.35 g/100g?and acetic acids?0.16–0.29 mg/g?rather than ethanol?3.53–8.08 mg/100g?when the milk was fortified with fruits juices.However,the accumulation of ethanol in the formulations where the milk was fortified with jujube or kiwi juices was one of the causes of growth inhibition reduced to 6.57×10⁴ and4.63×10⁷ colony forming units per mL(CFU mL^-1),respectively.On contrary,channeling sugars by S.boulardii for its metabolism during fermentation of skimmed milk fortified with Wheat Grain juice was not enough to make any significant effect on ethanol yield?0.27mg/100g?,and even pH developments??5.33?.Third,the synergy interactions between Saccharomyces boulardii and preselected strains of lactobacilli during fermentation of milk fortified with kiwi juice?4%v/v?were also studied.The S.boulardii channeled the sugars for the ethanol production rather than acids(?4.83_{pH value})if it was allowed to culture alone.The increased production of ethanol was great as much as 51.86?mg/100g?in the case where Lb.plantarum RS?35-11?,Lb.casei LCS,and Lb.fermentum F9 were inoculated with S.boulardii together.The ethanol yield introduced an antagonistic effect on lactobacilli to a level which had a significant impact on cells growths.Kiwi juice enhanced also the lactic?1.35 g/100g?and acetic?0.29 mg/g?acids production by S.boulardii when it was allowed to culture alone.Moreover,inoculation of lactobacilli with S.boulardii together addressed their synergistic relationship.And so,the acids concentrations when S.boulardii was inoculated with Lb.casei 20975 was great as much as 2.36?g/100g?for lactic and 0.71?mg/g?for acetic.The distinct production of tryptophan and glutamic acid were observed when the formulations were inoculated with lactobacilli and S.boulardii together.And so,the increased production was greater as much as?5.40 mg/L?tryptophan?and?12.09 mg/L?glutamic acid?when Lb.casei 20975 had a chance to grow in the milk with and without added kiwi juice where the S.boulardii was present.It is clear from this study that fortification of milk with kiwi juice could induce the metabolic activity of lactobacilli much more than S.boulardii,regarding the growth rates and produced metabolites during fermentation.