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 degrees 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 degrees 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 mu g/g of dry weight to 7.30 and 5.32 mu g/g, respectively. After UV-B irradiation for 2 h, the vitamin D-2 content in common mushrooms reached 12.48 mu g/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 mu g/g to 6.58 and 7.58 mu g/g, respectively. The increase rates in shiitake and straw mushrooms were not as high as in common mushrooms.