Evaluation of prebiotic mannooligosaccharides obtained from spent coffee grounds for nutraceutical application

Abstract

Currently, the study of mannooligosaccharides (MOS) production from Thai spent coffee grounds (SCGs) and the evaluation of their prebiotic potential have not been documented. This research aimed to characterize the MOS derived from SCGs and to determine their prebiotic properties. SCGs were treated with an alkali treatment. Treated-SCGs were digested by mannanase from Bacillus subtilis GA2 (1). The MOS in SCGs were examined by using HPAEC-PAD analyzer. The results revealed that treated-SCGs was composed of mannose, mannobiose, mannotriose, and mannopentaose. The prebiotic properties were determined by the addition of MOS to lactic acid bacteria (LAB) cultures, by the gastrointestinal tolerance, and by in vitro simulation of the gastrointestinal tract. The addition of MOS into L. acidophilus cultivation could promote the enhancing activity (23.96%) and survival rate under gastrointestinal conditions, especially alpha-amylase conditions for 2 h (77.41%). The pathogen growth inhibition test revealed that a culture after L. casei cultivation containing MOS could inhibit S. paratyphi growth (12.55%). The adhesion results demonstrated that the addition of MOS to LAB culture resulted in significant hydrophobicity (p < 0.05). Therefore, the MOS produced from SCGs has potential as a prebiotic applied in nutraceutical.