Cereal B-Glucans: The Impact of Processing and How It Affects Physiological Responses

Cereal beta-glucans are dietary fibres primarily found in oats and barley, and have several positive effects on health, including lowering the postprandial glucose response and the improvement of blood cholesterol levels. Cereal beta-glucans have a specific combination of beta-(1 -> 4) and beta-(1 -> 3) linkages into linear long-chain polysaccharides of high molecular weight. Due to their particular structure, cereal beta-glucans generate viscosity within the intestinal tract, which is thought to be the main mechanism of action responsible for their positive health effects. However, cereal grains are rarely consumed raw; at least one cooking step is generally required before they can be safely eaten. Cooking and processing methods more generally will modify the physicochemical characteristics of beta-glucans, such as molecular weight, extractability and the resulting viscosity. Therefore, the health impact of beta-glucans will depend not only on the dose administered, but also on the ways they are processed or converted into food products. This review aims at summarizing the different parameters that can affect beta-glucans efficacy to improve glucose and lipid metabolism in humans.