Ultraviolet irradiation: The generator of Vitamin D2 in edible mushrooms

Abstract

Fresh Shiitake mushrooms (Lentinula edodes), Oyster mushrooms (Pleurotus ostreatus), Button mushrooms (Agaricus bisporus), and Abalone mushrooms (Pleurotus cystidus) were irradiated with Ultraviolet-A (UV-A; wavelength 315-400 nm), Ultraviolet-B (UV-B; wavelength 290-315 nm), and Ultraviolet-C (UV-C; wavelength 190-290 nm). Irradiation of each side of the mushrooms for 1 h, was found to be the optimum period of irradiation in this conversion. The conversions of ergosterol to vitamin D2 under UV-A, UV-B, and UV-C were shown to be significantly different (p < 0.01). The highest vitamin D2 content (184 ± 5.71 μg/g DM) was observed in Oyster mushrooms irradiated with UV-B at 35°C and around 80% moisture. On the other hand, under the same conditions of irradiation, the lowest vitamin D 2 content (22.9 ± 2.68 μg/g DM) was observed in Button mushrooms. © 2005 Elsevier Ltd. All rights reserved.