How to identify the purity of mushroom powders and extracts?

Plant extract adulteration is a common problem in the international market, also a lot of mushroom products are not pure. We recommend the following methods for our customers to identify the purity of mushroom powders and extracts.

The active, beneficial compound in mushrooms is a special class of polysaccharides known as beta-glucans. The alpha-glucans are basic starches with no health-promoting properties. Mushroom fruiting bodies generally have a low content of alpha-glucans (<5%). Therefore, the presence of starchy materials in a mushroom product can elevate a polysaccharide test and give a false positive for the beta-glucans.

The presence of starchy materials can be tested using iodine. The sample solution change colour to dark purple or black when starchy materials are present. Also, a Megazyme kit, designed for the test of beta-glucans in mushrooms and yeast, can be applied for the test of beta-glucans content. Mushroom mycelium and products adulterated with starchy materials always result in high content of alpha-glucans and low content of beta-glucans. The beta-glucans contents of mushroom powders are normally higher than that of mushroom extracts when using the Megazyme kit. This is because mushroom powders contain both water-soluble and insoluble beta-glucans, while mushroom extracts produced using hot water extraction contain only water-soluble beta-glucans, which show higher activity than water-insoluble beta-glucans. Namely, mushroom extracts are water-soluble while mushroom powders and most other sourced beta-glucans are water-insoluble, such as yeast beta-glucans. This would be useful in distinguishing mushroom extracts from yeast beta-glucans and mushroom powders.

The gene sequences of many mushrooms have been decoded. Some laboratories have developed DNA barcodes to identify mushroom varieties. By using ITS, tmH-psbA, we can identify whether the mushroom product is from the true varieties as the supplier claimed, not something else. For example, the reishi product is from the varieties of Ganoderma lucidum, not from Ganoderma subtornatum Murrill.