Factors Influencing beta-Glucan Levels and Molecular Weight in Cereal-Based Products

The beneficial role of soluble dietary fiber in human nutrition is well documented and has lead to a growing demand for the incorporation of beta-glucan, particularly from oats and barley, into foods. beta-Glucan with high solubility and high molecular weight distribution results in increased viscosity in the human intestine, which is desirable for increased physiological activity. Molecular weight, level, and solubility of beta-glucan are affected by genotype, environment, agronomic input, and the interactions of these factors and food processing methods. Available literature reveals that the level of beta-glucan in a finished product (e. g. bread, cake, muffins) depends upon several factors in the production chain, whereas food processing operations are major factors affecting molecular weight and solubility of beta-glucans. Therefore, to avail themselves of the natural bioactive compounds, food manufacturers must pay attention not only to ensure sufficient concentration of beta-glucan in the raw material but also to the processing methods and functional properties of beta-glucan, minimizing enzymatic or mechanical breakdown of the beta-glucans in end-product and optimizing processing conditions. This review discusses the different sources of beta-glucan for use in human functional foods and factors affecting the levels and the molecular weight of beta-glucan at various pre- and postharvest operations.