Xylooligosaccharides (XOS) as an Emerging Prebiotic: Microbial Synthesis, Utilization, Structural Characterization, Bioactive Properties, and Applications

Xylooligosaccharides (XOS) have great prebiotic potential and can be incorporated into many food products. XOS seem to exert their nutritional benefits in various animal species, which by definition have an intestinal tract populated by a complex, bacterial intestinal ecosystem. The production of XOS on an industrial scale is carried out from lignocellulosic materials (LCMs) rich in xylan by chemical and enzymatic methods and the latter is preferred in the food industry because of the lack of undesirable side reactions and products. The information available does not provide an exact explanation about the bioactive effects of XOS. Their fermentation results in the acidification of the colonic contents and the formation of short chain fatty acids that serve as fuels in different tissues and may play a role in the regulation of cellular processes. Only data from small trials are currently available to support use of XOS in the treatment of different clinical scenarios. Numerous questions about the molecular mechanisms of action or clinical indications of XOS and other prebiotics remain unanswered. This article presents XOS as an emerging prebiotic with more emphasis on its microbial production, structural characterization, and bioactive properties.