Galactomannan from Trigonella foenum-graecum L. seed: Prebiotic application and its fermentation by the probiotic Bacillus coagulans strain MTCC 5856

Health benefits of dietary fibers are currently being widely recognized. However, the assessment of dietary fiber as a prebiotic is essential and also important for the development of an improved synbiotic commercial preparation. Thus, the aim of this study was to evaluate the potential of galactomannan extracted from fenugreek seeds as a prebiotic fiber and also its fermentation by the probiotic strain Bacillus coagulans MTCC 5856. Nondigestibility by the gastric acid and pancreatic enzyme hydrolysis of galactomannan were determined using an in vitro model mimicking the in vivo conditions. Further, anaerobic fermentation and utilization of galactomannan by the B. coagulans MTCC 5856 was investigated followed by selective inhibition of Escherichia coli ATCC 25922. The galactomannan from fenugreek seeds was found to be nondigestible to gastric acid and also to pancreatic enzymatic hydrolysis. The galactomannan was fermented and utilized (71.4%) by the B. coagulans MTCC 5856, and also significant amount of short-chain fatty acids production was also observed. Furthermore, B. coagulans MTCC 5856 inhibited the E. coli ATCC 25922 growth when cocultured with galactomannan suggesting competitive fermentation of probiotic bacteria. Galactomannan exhibited prebiotic activity and also showed suitability with probiotic B. coagulans MTCC 5856 in a synbiotic combination. This study provides the first scientific evidence of galactomannan from fenugreek seeds as a prebiotic that may play an important role in modulating gut flora by acting as substrate to beneficial microbes.