Survivability of probiotic strains, Lactobacillus fermentum CECT 5716 and Lactobacillus acidophilus DSM 20079 in grape juice and physico-chemical properties of the juice during refrigerated storage

In this study, non-fermented probiotic grape juices were produced with the inoculation of two different strains of lactic acid bacteria (Lactobacillus fermentum CECT 5716 and Lactobacillus acidophilus DSM 20079) separately. The viability of probiotic microorganisms, as well as the grape juices' physicochemical properties were evaluated throughout 21 days of storage at 4 degrees C. In grape juice, both strains had similar survival rates, and viable cell counts remained above the recommended therapeutic minimum (10(7) CFU mL(-1)) throughout the monitored storage time. Both of the probiotic samples showed a drop in pH, total phenolic content and viscosity during storage, as well as an increase in acidity. The values of lightness, redness, and yellowness in grape juice containing L. acidophilus DSM 20079 were reduced over cold storage period; otherwise, color characteristics for the control and sample with added L. fermentum CECT 5716 were maintained. This study showed that grape juice is an effective vehicle for delivering the Lactobacillus strains studied, with their probiotic activity remaining for 21 days at 4 degrees C, making it a probiotic beverage alternative for non-dairy product users. Furthermore, L. fermentum CECT 5716 can be more suitable due to its maintenance of color properties in grape juice over the storage.