Comparative prebiotic activity of mixtures of cereal grain polysaccharides

Abstract

The main components of the non-starch polysaccharide (NSP) fraction of wheat flour are arabinoxylan (AX) and β-glucan. These are also present in other cereal grains, but their proportions vary with AX being the major component in wheat and rye and β-glucan in barley and oats. Therefore, it was hypothesised that these NSPs could act synergistically when fermented in vitro at the ratios present in the major foods consumed, resulting in increased prebiotic activity. AX and β-glucan were therefore tested in in vitro fermentation studies to assess their prebiotic activity when used individually and/or in different ratios. Short-chain fatty-acids (SCFAs) produced from in vitro fermentation were measured using HPLC and bacterial populations were measured using flow cytometry with fluorescence in situ hybridisation (Flow-FISH). Fermentation of AX alone resulted in a significant bifidogenic activity and increased concentrations of SCFAs, mainly acetate, after 8–24 h of fermentation, however β-glucan alone did not show prebiotic activity. The greatest prebiotic activity, based on concentration of total SCFAs and increases in total bacteria as well as beneficial Bifidobacterium and Clostridium coccoides/Eubacterium groups, was observed when AX and β-glucan were combined at a 3:1 ratio, which corresponds to their ratios in wheat flour which is major source of cereal fibre in the diet. This indicates that the population of bacteria in the human GI tract may be modulated by the composition of the fibre in the diet, to maximise the prebiotic potential.

Foods as First Defense Against COVID-19

“…Whole grains are also valuable source of bioactive molecules and dietary fibers, which increase the interest to use them in the development of high-value food products with enormous healthy outcomes [47]. Recently, whole grains become more important in dietary guidelines due to the discovery of their effective role in prebiotic activities for gut microbiota, important for immunity and well-being of the host [48,49]. Moreover, ample quantity of whole grain consumption is beneficial in lowering risk of multi-morbidities [50].…”

Prebiotic Potential of Cereal Components

“…DF in cereals are predominantly molecules found in the walls of cells in the cereal kernels, with the exception of arabinogalactan-peptides (AGP) and fructans [19][20][21]. Indeed, the main DF found in wheat flour stem from these endosperm cell walls, and 2 to 3% of the dry wheat flour weight is DF.…”

Reference values for intake of six types of soluble and insoluble fibre in healthy UK inhabitants based on the UK Biobank data

“…Eubacterium and Coprococcus genera share a similar behaviour and are often characteristic for people who consume diverse types of plant fibres (102,105) , alongside some members of the Prevotella genus (105,105) . Also observed in Mediterranean-style diets is a lesser abundance of microbes in the Proteobacteria phylum, particularly of Enterobacteria (106,107) .…”