Chemical structure of β-glucans from the mushrooms of Lactarius spp. for development of polysaccharide-coated liposomes

• The chemical structure of β-glucans from Lactarius sp. were investigated. • Liposomes were coated with either Lactarius sp β-glucans , laminarin or yeast β-glucans. • Lactarius sp. β-glucans were more suitable for coating than laminarin and yeast β-glucans. • The mushrooms β-glucans coated liposomes were stable for at least 3 months. • The length of the side chains influences the coating process and formulation stability. In the present work, the chemical structure of β-glucans from Lactarius scrobiculatus and Lactarius deterrimus were determined and correlated to their ability to coat liposomes. Previous characterized laminarin and yeast β-glucans were included for comparison. After alkali extraction of the mushrooms fruiting bodies and further fractionation by freeze-thawing, the fractions LSA-S and LDA-S were obtained. Chemical characterization demonstrated that these fractions contained two types of β-glucans: a (1 → 3)-linked-β-D-glucan partially branched at O -6 by glucose residues and a (1 → 6)-linked-β-D-glucan presenting some branches at O -3. LSA-S and LDA-S were able to coat cationic liposomes, and the formulations were stable for at least 3 months. Yeast β-glucans were not suitable for this purpose, suggesting that the length of the side chains may influence the coating process and the stability of the obtained product. While short chains may originate stable formulations, probably through steric stabilization, long side chains seem to impair the process. Laminarin was neither suitable for coating, which was attributed to low molar mass (5 kDa). Thus, the chemical structure characterization of β-glucans is an important step in the development of stable β-glucan coated liposomes.