Quantification of fructans, galacto-oligosacharides and other short-chain carbohydrates in processed grains and cereals

TLDR

Whole‑grain grains and cereals contain protective factors, including prebiotic fructans (FOS, inulin) and galactooligosaccharides (GOS), which are poorly absorbed as FODMAPs and may influence gut health. The study aims to provide composition tables of naturally occurring FODMAPs and prebiotics (FOS and GOS) to aid research into their physiological roles in the gut. The authors quantified FODMAPs—including fructose, FOS (nystose, kestose), GOS (raffinose, stachyose), and sugar polyols—using high‑performance liquid chromatography with an evaporative light‑scattering detector, and total fructan via enzymic hydrolysis, across 55 commonly consumed grains, cereals, breads, pulses, and biscuits. Total fructan was the most abundant short‑chain carbohydrate, ranging from 1.12 g per portion in couscous to 0 g in rice, while raffinose and stachyose were most prevalent in pulses.

Abstract

Wholegrain grains and cereals contain a wide range of potentially protective factors that are relevant to gastrointestinal health. The prebiotics best studied are fructans [fructooligosaccharides (FOS), inulin] and galactooligosaccharides (GOS). These and other short-chain carbohydrates can also be poorly absorbed in the small intestine (named fermentable oligo-, di- and monosaccharides and polyols; FODMAPs) and may have important implications for the health of the gut.In the present study, FODMAPs, including fructose in excess of glucose, FOS (nystose, kestose), GOS (raffinose, stachyose) and sugar polyols (sorbitol, mannitol), were quantified using high-performance liquid chromatography with an evaporative light scattering detector. Total fructan was quantified using an enzymic hydrolysis method.Fifty-five commonly consumed grains, breakfast cereals, breads, pulses and biscuits were analysed. Total fructan were the most common short-chain carbohydrate present in cereal grain products and ranged (g per portion as eaten) from 1.12 g in couscous to 0 g in rice; 0.6 g in dark rye bread to 0.07 g in spelt bread; 0.96 g in wheat-free muesli to 0.11 g in oats; and 0.81 g in muesli fruit bar to 0.05 g in potato chips. Raffinose and stachyose were most common in pulses. Composition tables including FODMAPs and prebiotics (FOS and GOS) that are naturally present in food will greatly assist research aimed at understanding their physiological role in the gut.