HEALTH PROMOTING FOODS: ENZYMATIC MODIFIED CEREALS AND THEIR CARBOHYDRATES
Location: National Center for Agricultural Utilization Research
Title: Cereal beta-glucans
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: June 30, 2009
Publication Date: July 15, 2009
Citation: Stevenson, D.G., Inglett, G.E. 2009. Cereal beta-glucans. Book Chapter.
Cereal beta-glucans occur predominantly in oats and barley, but can be found in other cereals. Beta-glucan structure is a mixture of single beta-1,3-linkages and consecutive beta-1,4-linkages, and cellotriosyl and cellotetraosyl units typically make up 90-95% of entire molecule. Lichenase can hydrolyze beta-glucans, enabling determination of molecular structure and novel functionality. The reason grasses synthesize beta-glucans remains unknown, but beta-glucans may play a role in cell-wall support in early plant tissue growth, but new genes that are involved in beta-glucan biosynthesis are discussed. Extraction of beta-glucans by dry milling, solvent extraction, acidic or alkaline conditions, elevated or freezing temperatures, and enzymatic methods are discussed. These extraction procedures have led to many commercial beta-glucan products such as Oatrim, Nutrim-OB, C-trim, OatWell(R), OatVantage(TM), Natureal(R), Viscofiber(R), 'organic natural oat fiber', Glucagel(R) and Cerogen(TM), with the attributes of each product discussed. Beta-glucans provide many health benefits for humans such as blood cholesterol-lowering by binding bile acids, reduced coronary heart disease, diabetes control by lowering glycemic index, lowered blood pressure, cancer prevention and improved gastric emptying and nutrient absorption, in which these health benefits are discussed in further detail. In order for consumers to gain some health benefit, enriched beta-glucan ingredients have been incorporated into many foods, in particular wheat-based baked foods, pastas and noodles, dairy products, meats and salad dressings, with many food applications discussed. To expand the food applications, beta-glucans need to retain structure and biological function during many food processing technologies such as high or low temperatures, acidic or alkaline conditions, high pressure, shear and other mechanical forces, chemical modification, food additives and enzymatic degradation, and research studying resistance of beta-glucans to these processing conditions is discussed. Overall the future is promising for commercialization of cereal beta-glucan products, with increased consumer demand essentially assured due to the degeneration of nutritional standards and increased incidence of nutritionally-related health disorders by the majority of consumers in industrialized nations.