Abstract
Fresh and dried mushrooms naturally generate vitamin D2 when exposed to ultraviolet (UV) radiation. Vitamin D2 and 25-hydroxyvitamin D2 (25(OH)D2) concentrations were compared in dried button mushrooms (Agaricus bisporus) exposed to pulsed UV radiation either before or after air-drying. A further aim was to assess the effect of air-drying on the generation of D vitamers. Fresh button mushrooms were irradiated (Irr) with a total of 200 mJ/cm2 pulsed UV radiation before (Irr/AD) or after (AD/Irr) being air-dried (AD). A third group of fresh button mushrooms was irradiated but not air-dried (Irr). Control mushrooms were fresh and untreated. The D vitamers were quantified in freeze-dried samples using triple quadrupole mass spectrometry. Irr/AD mushrooms had more than double the concentration of vitamin D2 than AD/Irr mushrooms (9.5 µg/g dry weight (dw) vs 4.6 µg/g dw). However, Irr mushrooms contained 6.3 µg/g dw. The concentration of 25(OH)D2 in Irr mushrooms was 0.05 μg/g dw, while 0.14 μg/g dw was detected in Irr/AD mushrooms. There was no detectable 25(OH)D2 in control mushrooms, nor in AD/Irr mushrooms. The sequence of irradiating and drying mushrooms was a key factor in generating vitamin D2.
•Pulsed UV radiation of dried mushrooms generates high amounts of vitamin D2.•Vitamin D2 higher when mushrooms are exposed to UV before drying vs after drying.•UV radiation generated 25-hydroxyvitamin D2 in fresh, but not dried, mushrooms.
