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.