REVIEW: Variability in Fine Structures of Noncellulosic Cell Wall Polysaccharides from Cereal Grains: Potential Importance in Human Health and Nutrition

Abstract

Noncellulosic polysaccharides from the cell walls of cereal grains are not digested by human small intestinal enzymes and so contribute to total dietary fiber intake. These polysaccharides are becoming recognized increasingly for their potential to lower the risk of serious diet‐related conditions such as type II diabetes, cardiovascular disease, colorectal cancer, and diverticular disease. The effectiveness of noncellulosic cell wall polysaccharides in improving health outcomes is related to the fine structure and associated physicochemical properties. The two most nutritionally relevant wall polysaccharides of cereal grains are the arabinoxylans and the (1‐3,1‐4)‐β‐d‐glucans. These polysaccharides have high molecular mass values but are nevertheless soluble in aqueous media, at least in part, where they adopt highly asymmetrical conformations and consequently form high viscosity solutions. Thus, arabinoxylans and (1‐3,1‐4)‐β‐d‐glucans contribute to the soluble fiber component of human diets. The molecular size, solubility, and viscosity of the polysaccharides vary widely not only between different cereals but also within a single species. The variability in these properties reflects differences in the chemical structure of the polysaccharides, which in turn influences the beneficial effects of arabinoxylans and (1‐3,1‐4)‐β‐d‐glucans in human diets. Here, we summarize information on the variability of fine structures of the arabinoxylans and (1‐3,1‐4)‐β‐d‐glucans in common cereals and relate these to solubility, viscosity, and health benefits. The recent identification of genes involved in the biosynthesis of the (1‐3,1‐4)‐β‐d‐glucans opens the way for the genetic improvement of cereal quality parameters that are important in human health.

Determining the Subcellular Location of Synthesis and Assembly of the Cell Wall Polysaccharide (1,3; 1,4)-β-d-Glucan in Grasses

“…It is vital to plant growth and development, as it determines the functional specialization of cells through regulation of their shape, permeability, and mechanical properties. Walls and their constituent polysaccharides, including mixed-linkage glucan (MLG), also have important roles in the agrifood industry and in human health (Collins et al, 2010).…”

A physical, genetic and functional sequence assembly of the barley genome

“…In more developed societies it has recently been classified as a true functional food. Barley grain is particularly high in soluble dietary fibre, which significantly reduces the risk of serious human diseases including type II diabetes, cardiovascular disease and colorectal cancers that afflict hundreds of millions of people worldwide 5 . The USA Food and Drug Administration permit a human health claim for cellwall polysaccharides from barley grain.…”

Proteomics of Important Food Crops in the Asia Oceania Region: Current Status and Future Perspectives

“…Barley has a long and proud history of human cultivation 140 , and it is reasonable to expect that this will continue due to the sustained level of demand. There is considerable research in progress focusing on analysis of wild varieties of barley, as these are anticipated to contain genetic information that could allow development of barley varieties with, for example, even greater levels of dietary fibre present in the grain (with increased levels of associated health benefits), or enhanced ability to grow productively in ever more marginal areas, and withstand ever more harsh climates 141 .…”