Effect of UV-B exposure on the concentration of vitamin D-2 in sliced shiitake mushroom (Lentinus edodes) and white button mushroom (Agaricus bisporus)

Abstract

The aim of this study was to investigate the effect of UV-B on vitamin D-2 concentration in shiitake mushrooms and in white button mushrooms. After the exposure to UV-B, at a dose of 25 kJ/m(2) the concentration of vitamin D2 was increased to 36.7 +/- 1.4, 68.6 +/- 4.9, and 106.4 +/- 14.7 mu g/g (dry weight) for pileus, middle, and gill parts of shiitake mushroom, respectively. The gill side of whole shiitake mushrooms exposed to 0, 25, 50, and 75 kJ/m(2) increased to 2.8 +/- 0.2, 13.8 +/- 1.9, 40.7 +/- 4.4, and 61.9 +/- 10.6 mu g/g (dry weight) at 25 degrees C, respectively. Irradiating slices of white button mushroom was a more efficient way of increasing the vitamin D-2 content than irradiating the gill or pileus of whole mushrooms, due to the larger exposure area. As the irradiation doses increased, the vitamin D-2 concentration also increased for both types of mushrooms. In conclusion, exposure to ultraviolet light offers an effective way of increasing the concentration of vitamin D-2 in mushrooms.