(1-3)-β-Glucans are widely distributed in nature, especially in algae, fungi and yeast, but also in higher plants. They form the major structural components of cell walls, they act as storage carbohydrates and they sometimes play a protective role by forming at specific sites in response to particular stimuli such as wounding.
Yeast β-glucan substantially enhances the function of the immune system by activating macrophages. Literature indicates that linear 6-branched (1-3)-β-glucan extracted from the mushroom Grifola frondosa (also known as Maitake) can be linked to potent anti-tumour properties.2-4 The use of yeast β-glucan in animal feed, especially broiler, has been demonstrated to be beneficial against some bacterial infections with comparable results to those displayed using antibiotics. Yeast βglucan is therefore a promising replacement for antibiotics use in animal nutrition.5 Some β-glucan forms (e.g. high molecular weight (~ 800 KDa) β-glucan produced by the fungus Botrytis cinerea (grey rot) can however pose technological challenges in winemaking and are linked to clarification and filtration problems.