Factors influencing β-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 β- glucan, particularly from oats and barley, into foods. β-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 β-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 β-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 β-glucans. Therefore, to avail themselves of the natural bioactive compounds, food manufacturers must pay attention not only to ensure sufficient concentration of β-glucan in the raw material but also to the processing methods and functional properties of β-glucan, minimizing enzymatic or mechanical breakdown of the β-glucans in end-product and optimizing processing conditions. This review discusses the different sources of β-glucan for use in human functional foods and factors affecting the levels and the molecular weight of β-glucan at various pre- and postharvest operations.