Effect of household cooking on the retention of vitamin D₂ and 25-hydroxyvitamin D₂ in pulse UV-irradiated, air-dried button mushrooms (Agaricus bisporus)

Vitamin D deficiency has widespread global prevalence. Fresh mushrooms exposed to ultraviolet (UV) radiation generate vitamin D₂ which remains after drying. It is not clear if vitamin D₂ is retained after rehydration and cooking of dried mushrooms. The aim of this study was to determine the true retention of both vitamin D₂ and 25-hydroxyvitamin D₂ (25(OH)D₂) after cooking UV-irradiated, air-dried, then rehydrated button mushrooms (Agaricus bisporus). Mushrooms were exposed to pulsed UV radiation, then air-dried in a convection oven, followed by rehydration in warm water. Samples were cooked in three different ways: frying (5 min), baking (10 min, 200 °C) and boiling (20 min, 90 °C). Compared to rehydrated, uncooked controls, there was a high retention of D vitamers (≥95%) after cooking. Frying and baking resulted in significantly higher vitamin D₂ retention compared to boiling (p<0.0001). UV-irradiated, dried mushrooms are a valuable source of vitamin D₂ after rehydration and cooking.