LAUSR

Abstract The combination of supercritical fluid extraction followed by UV-irradiation resulted in an interesting strategy to obtain ergosterol- and Vitamin D 2 -enriched extracts from Lentinula edodes to design novel functional food. Extractions carried out following a specific experimental design pointed out that extraction yields and ergosterol concentrations were more influenced by pressure than by the extraction temperature although, high temperatures (55–75 °C) might induce transformation of ergosta-7,22-dienol and fungisterol into ergosterol. After extraction, the ergosterol-enriched extracts should be dissolved in methanol or ethanol and irradiated (25 °C, 4 cm) to partially transform ergosterol into vitamin D 2 . Irradiation at 365 nm was less effective than at 254 nm. The fastest transformation was obtained using a UV lamp covering the complete UV spectrum for a maximum of 1 h. However, this lamp also induced vitamin D 4 formation although in lower amounts than vitamin D 2 or lumisterol 2 while with irradiation at 254 nm most of ergosterol was transformed into vitamin D 2 .