What is the difference between polysaccharides and beta-glucans?

Polysaccharides are a class of carbohydrates, including starch, maltodextrin, chitin, glycogen and cellulose. Polysaccharides from different substances are in different structures, some consist of alpha-glucans and some consist of beta-glucans. The polysaccharides from mushrooms mainly consist of beta-glucans which are well regarded as active compounds with medicinal functions. The polysaccharides from starch and malt dextrin consist of alpha-glucans which are not active compounds in the healthy application. For mushroom extract products, the measure of beta-glucans is more accurate than that of polysaccharides to represent the quality of the product, as the measurement of polysaccharides can be easily doctored by adding starch, maltodextrin, etc. This is why the measurement of beta-glucans and starch is so important for mushroom products.