Vitamin D-enriched extracts obtained from shiitake mushrooms (Lentinula edodes) by supercritical fluid extraction and UV-irradiation

From the paper

Abstract

The combination of supercritical fluid extraction followed by UV-irradiation resulted in an interesting strategy to obtain ergosterol- and Vitamin D2-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, 4cm) to partially transform ergosterol into vitamin D2. Irradiation at 365nm was less effective than at 254nm. The fastest transformation was obtained using a UV lamp covering the complete UV spectrum for a maximum of 1h. However, this lamp also induced vitamin D4 formation although in lower amounts than vitamin D2 or lumisterol2 while with irradiation at 254nm most of ergosterol was transformed into vitamin D2.