Chemical composition of Trametes versicolor, Hericium erinaceus, and Pleurotus ostreatus mushroom biomass: deciphering their rich α-glucan composition and nutritional value

This study provides the first comprehensive characterization of the Trametes versicolor (TV), Hericium erinaceus (HE), and Pleurotus ostreatus (PO) biomasses, emphasizing their abundant α-glucan content and the presence of (1→4)-β-glucans. TV exhibited significantly higher levels (dry weight- DW) of soluble protein (1.99 %), ash (1.47 %), free sugars (1.19 %), and free amino acids (AAs; 0.35 %). In contrast, HE had greater fat content (1.82 %) and fiber (6.11 %). Total AAs (5.62–6.16 %) and glucans (76.15–80.45 %) were similar across species. Concerning carbohydrate structures, glucose was the predominant monosaccharide, with (1→4) glycosidic linkages being the most common, suggesting a minor presence of branched glucans. ¹H and ¹³C nuclear magnetic resonance spectra revealed two α-anomeric and one β-anomeric proton, with an α-/β- ratio ranging between 3.22 and 7.26. Polysaccharides exhibited a molecular weight (MW) distribution of over 107 kDa, while soluble proteins had a MW of less than 3 kDa. In TV, a significantly higher content of free AAs was detected, being the main free and total AAs quantified in all species aspartic and glutamic acids. The most prevalent minerals were phosphorous, magnesium, and potassium, while fatty acids were palmitic, oleic, and linoleic. Fourier transform infrared and principal component analysis confirmed species-specific chemical differences. These biomasses differ from mushroom fruiting bodies and mycelium, mainly due to their higher total and α-glucans content and lower levels of insoluble fiber, ash, free sugars, β-glucans, and protein. This study provides new insights into the nutritional properties of MB, their rich α-glucan profile, and their potential applications in the food and health fields.