Storage temperature and UV-irradiation influence on the ergosterol content in edible mushrooms

•The free ergosterol content of mushrooms ranged from 0.3 to 6.8mg/g.•Two ergosteryl esters were found in all mushrooms.•UV light radiation produced ergosterol peroxides.•Storage at −20°C decreased the ergosterol oxidation. Ergosterol (5,7,22-ergostatrien-3β-ol) and ergosteryl derivatives from different genera of edible mushrooms were separated and quantified by an isocratic reversed-phase high performance liquid chromatography (HPLC) method. The technique allowed a rapid separation of free ergosterol and two ergosteryl derivatives occurring in mushrooms. The ergosterol content varied considerably depending on the fungus. Thus, the species Agaricus bisporus and Hygrophorus marzuolus presented high quantities of ergosterol (6.4–6.8mg/g, dry matter) followed by Pleurotus ostreatus, Calocybe gambosa, Lentinus edodes, and Boletus edulis (3.3–4.0mg/g). In contrast, other species, such as Cantharellus cibarius, Lactarius deliciosus and Craterellus cornucopioides, contained significantly lower ergosterol amounts (0.2–0.4mg/g). Two ergosteryl derivatives were found in mushrooms and also the content depended on the fungus. The stability of ergosterol, in terms of the formation of ergosterol peroxide, was evaluated under different storage temperatures and UV radiation. The lower the temperature (−20°C) and the radiation time (10min), the lower ergosterol oxidation was observed.