Fermentation of Gac juice mixture by probiotic lactic acid bacteria

Abstract

Probiotic Gac juice was fermented by lactic acid bacteria in this study. From sensory evaluation, treatment 3 (Gac juice fermented by L. fermentum TISTR 391) was the highest acceptability with the score 6.07 (moderately like). Changes in pH, acidity, total soluble solid and viable cell counts during fermentation under controlled conditions (30°C) at 0, 24, 48 and 72 h fermentation were evaluated. Results were found that changing in pH levels and total soluble solid of probiotic Gac juice were significantly (p ≤ 0.05) decreased at 72 h fermentation. On the other hand, the amount of titratable acidity expressed as lactic acid was significantly (p≤0.05) increased at fermentation for 72 h. The effect of shelf life on viable cells counted in cold storage (4°C) was investigated.  The result was exhibited that the viable cells were reached at 1 week of storage, then sharply declined when the storaged time longer and the lowest was 4 weeks of storage. Finally, the final product was determined the amount of vitamin C, antioxidant activity and cytotoxicity to human colon cancer cell SW620. Interestingly, the amount of vitamin C content exhibited two folds higher than those control. In addition, the free radical scavenging capacity was assayed by DPPH method also shown that IC₅₀ values had significantly (p≤0.05) higher than that those control. However, both fermented Gac juice and control were also tended to be affected to colon cells SW620 when the juice concentration were increased. For the bacterial cell behavior, the scaning electron microscope showed that lactic acid bacteria were grown in an amount the polysaccharide of the juice. These results could be expressed the alternative healthy non-diary probiotic source for vegetarian and milk allergy consumers in the future.