A new complex carbohydrate in barley has been discovered by researchers at the University of Adelaide's School of Agriculture, Food and Wine in Australia. The cereal polysaccharide is the first of its kind to be discovered in 30 years and possibly holds potential in food, medicine and cosmetics applications.
“From a food ingredient perspective, this polysaccharide has the potential to occur in structures that form insoluble fibers, viscous gels or soluble aqueous solutions,” Senior Research Scientist, Dr. Alan Little tells.
The newly discovered polysaccharide is a mix of glucose, commonly found in cellulose, and xylose, which is found in dietary fiber. Based on the relative proportions of each sugar, the hybrid polysaccharide has the potential to behave as a structural component of the wall providing strength or conversely to add viscosity.
“The question still remains whether this could be utilized as a dietary fiber, however, its fermentability throughout digestion is unknown at this stage,” he notes.
According to Little, common dietary fibers include mixed-linkage glucan (glucose-based polysaccharide), well known for making porridge sticky and xylan (xylose-based polysaccharide), which is a main fiber component of psyllium products, for example.
“This new polysaccharide is composed of both glucose and xylose and may provide an alternative to the above sources or could lead to novel properties that can be exploited further,” he tells.
Published in the American Chemistry Society journal ACS Central Science, the study discovered that the complex carbohydrate can be found in the roots of barley. It suggests that the compound may play a role in plant growth or resistance to external stresses such as salinity or disease.
“Knowledge of this new polysaccharide will open up further research to determine its role in the plant,” says Little.
According to the researchers, plant cell walls contain components that are of major interest for various industries such as renewable sources for energy production or composite materials for food products.
Existing polysaccharides have a wide range of uses. They improve the quality of dietary fiber in porridge and are also used extensively in biomedical and cosmetic applications. More research is warranted to understand how exactly the new polysaccharide could be adopted.
“The properties of the new polysaccharide could be manipulated to suit the desired function, increasing the range of potential uses,” says Dr. Little. “The genes involved in the biosynthesis of the new polysaccharide were also discovered as part of this work.”
The same genes can be found in all major cereal crops, not just barley, Little explains. The researchers hope to use this knowledge to find ways to increase these polysaccharides in crops. This would provide the possibility to generate plant material with a range of different physical properties for industrial applications.
By further observing the natural variation of the polysaccharide in different cereal crops the researchers are seeking to identify links to potentially important agricultural traits.
The next step would be to investigate the amount and tissue distribution of this polysaccharide in other cereals such as wheat, rice, maize and sorghum.
“Extracting the polysaccharide from each source will allow us to characterize the inherent properties that each structure inherently holds. From here we will be able to identify potential applications and ways to value add to the crops produced by the farmers,” Little concludes.
