Beta-glucans: bread fortification for attenuated glycaemia

Bread, cereal products and starch-based foods are the main source of available carbohydrates in the human diet, contributing over 50% of the daily dietary energy intake. White bread causes rapid starch digestion and absorption in the small intestine, thus is considered as a high GI food. Given that bread is the main source of available carbohydrates and reducing the GI of the diet is considered beneficial to health, many studies have been conducted so far, aiming to produce low GI breads and bakery products. The strategies for reducing the GI of bread are mainly concentrated on the addition of fibre-rich flours or pure dietary fibre. Beta-glucans, soluble fibre from oats and barley are well known for their efficacy to ameliorate postprandial glucose response, and could be an excellent ingredient for lowering bread’s GI. The purpose of this review is to critically record the clinical studies investigating the efficacy of beta-glucan addition on the attenuation of postprandial glucose response. The review of the literature revealed that beta-glucans from oats and barley are valuable functional ingredients that can be successfully incorporated into bread in order to reduce the GI. The amount of soluble fibre naturally present in barley and oat flour, is not likely to cause significant reduction in postprandial glucose levels, however the use of specific cereal varieties with increased content of beta-glucans, or the addition of pure beta-glucans have been proven effective strategies.