Probiotic potential of noni juice fermented with lactic acid bacteria and bifidobacteria

The present study assesses the feasibility of noni as a raw substrate for the production of probiotic noni juice by lactic acid bacteria (Lactobacillus casei and Lactobacillus plantarum) and bifidobacteria (Bifidobacterium longum). Changes in pH, acidity, sugar content, cell survival and antioxidant properties during fermentation were monitored. All tested strains grew well on noni juice, reaching nearly 10(9) colony-forming units/ml after 48 h fermentation. L. casei produced less lactic acid than B. longum and L. plantarum. After 4 weeks of cold storage at 4 degrees C, B. longum and L. plantarum survived under low-pH conditions in fermented noni juice. In contrast, L. casei exhibited no cell viability after 3 weeks. Moreover, noni juice fermented with B. longum had a high antioxidant capacity that did not differ significantly (P<0.05) from that of lactic acid bacteria. Finally, we found that B. longum and L. plantarum are optimal probiotics for fermentation with noni juice.