Production and evaluation of a functional fruit beverage consisting of mango juice and probiotic bacteria

This study examined the probiotic potential of Lactobacillus casei UK 318, isolated from Iranian yogurt, and its application in mango juice. L. casei UK 318 was stable to acidic pH (at pH 2.5: 9.25–6.23 log CFU/mL), gastric and intestinal juice (6.66 ± 0.38), and bile salt (the survival of the isolate decreased progressively as the bile level rose from 0.1 to 0.7%). The strain also showed 38.46% hydrophobicity, 30.28% auto-aggregation, 22.19% co-aggregation, 9.10% adhesion to Caco-2 cells, 20.11–40.19% anti-adhesion against pathogenic strain of Escherichia coli , 42.17% antioxidant activity, 39.30% cholesterol removal, and high antimicrobial effect on pathogenic bacteria. The strain exhibited no DNase or hemolytic activity, and it was highly susceptible to nitrofurantoin and ciprofloxacin. Therefore, concentration levels of 0, 1, and 2% of the probiotic strain were used in a mango juice model. Probiotic survival, sensory acceptance, and physicochemical stability (pH, titratable acidity, and color) of the juice were evaluated after 21 days of storage at 4 and 25 °C. Storage at 4 °C did not negatively alter the pH or acidity of the probiotic-loaded mango juice. At the ends of storage time, the juice containing 2% L. casei UK 318 at 4 °C had the lowest color change and the highest viable cell count (~ 8.01 log CFU/mL). Moreover, mango juices with 2% L. casei UK 318, when stored at 4 °C, had the highest sensory acceptance. Mango juice has shown to be suitable for the production of probiotic beverages based on the findings of this study.