Fresh common (Agaricus bisporus) and high-temperature mushrooms (A. bitorqu
is) 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 1
2 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 i
rradiation 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, resp
ectively. The increase rates in shiitake and straw mushrooms were not as hi
gh as in common mushrooms.