- β-Glucan is a naturally occurring polysaccharide composed of glucose monomers linked together by β-glycosidic bonds.
- Unlike starch and cellulose, which have uniform linkage patterns, β-glucans are structurally diverse: the glucose units can be connected by β-(1→3), β-(1→4), or β-(1→6) linkages, and the specific arrangement varies depending on the source. For example, cereal β-glucans (from oats and barley) are primarily linear polymers with mixed β-(1→3) and β-(1→4) bonds, while fungal and yeast β-glucans often contain β-(1→3) backbones with β-(1→6) branches. This structural diversity underlies the wide range of physicochemical and biological properties attributed to β-glucans.
- In plants, especially cereals like oats and barley, β-glucans are important components of the cell wall. They contribute to cell wall strength, hydration, and flexibility, and also serve as reserve carbohydrates. In fungi, yeast, and some bacteria, β-glucans are essential structural polysaccharides of the cell wall, where they provide rigidity and protection against environmental stress. Because of their abundance and variability, β-glucans represent one of the most widespread and functionally important classes of non-starch polysaccharides in nature.
- From a nutritional and health perspective, β-glucans are recognized as bioactive dietary fibers with numerous benefits. Cereal-derived β-glucans have been extensively studied for their ability to lower blood cholesterol and regulate blood glucose levels. Their viscosity in the digestive tract slows glucose absorption, improving glycemic control, while their capacity to bind bile acids reduces cholesterol absorption, contributing to cardiovascular health. These properties have led to official health claims in regions such as the EU and the US, where oat and barley β-glucans are approved for cholesterol-lowering effects.
- Fungal and yeast β-glucans, on the other hand, are especially known for their immunomodulatory properties. They can bind to specific receptors on immune cells, such as dectin-1 and complement receptor 3, thereby activating innate immune responses. This has made them valuable in supporting immunity, enhancing resistance to infections, and even serving as adjuvants in cancer immunotherapy. Clinical and experimental studies suggest that β-glucans can modulate inflammation, stimulate phagocytosis, and improve host defense mechanisms without being toxic.
- In the food industry, β-glucans are incorporated as functional ingredients in beverages, baked goods, dairy alternatives, and nutritional supplements. Their solubility and viscosity make them useful for thickening, stabilizing, and improving mouthfeel, while also enhancing the fiber content of foods. In biotechnology and pharmaceuticals, β-glucans are explored for their potential in wound healing, drug delivery, and tissue engineering, given their biocompatibility and bioactivity. Cosmetic applications have also emerged, where β-glucans are included in skincare products for their moisturizing and protective effects.
