Ultraviolet Irradiation Increased Vitamin D₂ Content in Edible Mushrooms

Fresh common ( Agaricus bisporus ) and high-temperature mushrooms ( A. bitorquis ) were irradiated with ultraviolet-C (UV-C) for 0, 0.5, 1, and 2 h at 12 °C. Fresh common, shiitake ( Lentinula edodes ), and straw mushrooms ( Volvariella volvacea ) were irradiated with UV-B for 0, 0.5, 1, and 2 h at 12 °C. After UV-C irradiation for 2 h, vitamin D 2 contents in common and high-temperature mushrooms increased from 2.20 and 4.01 μg/g of dry weight to 7.30 and 5.32 μg/g, respectively. After UV-B irradiation for 2 h, the vitamin D 2 content in common mushrooms reached 12.48 μg/g. UV-B irradiation resulted in higher vitamin D 2 conversion for common mushrooms. After UV-B irradiation for 2 h, vitamin D 2 contents in shiitake and straw mushrooms increased from 2.16 and 3.86 μg/g to 6.58 and 7.58 μg/g, respectively. The increase rates in shiitake and straw mushrooms were not as high as in common mushrooms.