Recent advances in marine algae oligosaccharides: structure, analysis, and potential prebiotic activities.

Marine algae contain abundant polysaccharides that support a range of health-promoting activities; however, the high molecular weight, high viscosity, and low solubility of marine algae polysaccharides (MAPs) limit their application in food, agriculture and medicine. Thus, as the degradation products of MAPs, marine algae oligosaccharides (MAOs) have drawn increasing attention. Most MAOs are non-digestible by digestive enzyme in the human gastrointestinal tract, but are fermented by bacteria in the gut and converted into short-chain fatty acids (SCFAs). MAOs can selectively enhance the activities of some populations of beneficial bacteria and stimulate a series of prebiotic effects, such as anti-oxidant, anti-diabetic, anti-tumour. However, the exact structures of MAOs and their prebiotic activities are, to a large extent, unexplored. This review summarizes recent advances in the sources, categories, and structure analysis methods of MAOs, emphasizing their effects on gut microbiota and its metabolite SCFAs as well as the resulting range of probiotic activities.