Viability of probiotic lactic acid bacteria in Malay apple (Syzygium malaccense) during fermentation and storage

Abstract

For lactic acid bacteria (LAB) to be considered probiotic it must colonize and survive the gut environment, also for maximum health benefits it must be ingested in a sufficient amount. Hence, this study was aimed at investigating the probiotic potential of lactic acid bacteria and their viability in Malay apple juice. Five LAB of yoghurt origin were obtained and screened for probiotic potential using acidic pH (1.5) tolerance, bile salt (0.3 %) resistance and non-hemolytic activity as the selection and safety criteria. The compositional and physicochemical characteristics of the apple juice during fermentation were assayed using standard methods. The viable cell counts were determined using standard plate count method. Of the 5 LAB isolates 2 identified as members of Lactobacillus and Lactococcus genera showed good probiotic characteristics with acidic pH and bile salt survival rate of above 80 %, also the 2 LAB isolates were non-hemolytic. After the 72 h fermentation increase in protein content ranged from 0.53 to 1.21 %, titratable acidity increase ranged from 0.35 to 0.53 % and a reduction in pH ranged from 4.54 to 3.58 were obtained, also the viable cell counts were at 4.12±0.38, 2.35±0.15 and 3.18±0.10 CFU/ml in the Lactobacillus, Lactococcus and mixed culture fermented juice respectively. At the end of the 30 days cold (4^oC) storage the viable cell counts were >106 CFU/ml. The Lactobacillus fermented juice had more overall acceptability (7.7) by the panelists. In conclusion the studied LAB isolates were viable probiotics and Malay apple juice a suitable carrier for probiotics.