A recent study concluded that ‘‘Vitamin D2 from UVBexposed
mushrooms is bioavailable, safe, and functional in supporting
bone growth and mineralisation in a growing rat model
without evidence of toxicity’’ (Calvo et al., 2013). Recent research
focused on button mushroom (Agaricus bisporus), the commercially
most important species, but intensity, duration and type of light
varied over a broad range, as did the other experimental parameters.
Chemical changes were measured at seemingly arbitrarily
chosen points of time.
The present study followed the formation of vitamin D2 and D4
in oyster mushrooms induced by effective doses of UV-B light over
a period of 1 h. Concurrent formation of non-vitamin sterols as
side-products of the photoreaction and the change of concentrations
of saturated and unsaturated fatty acids were assessed to
determine the side-effects of UV-B light.