Impact of the natural resource of UVB on the content of vitamin D(2) in oyster mushroom (Pleurotus ostreatus) under subtropical settings

Vitamin D deficiency is a pandemic problem. Non-animal source of vitamin D is obtained from edible mushrooms. Oyster mushroom (Pleurotus ostreatus) was sliced into the size of 1 cm(3), 4 cm(3) and 9 cm(3), and treated with the sun as a natural resource of UVB under subtropical settings in Ethiopia. The content of vitamin D was measured by using high-performance liquid chromatography (HPLC). After sun treatment, there was a significant increment in the content of vitamin D(2) from nil to 67.4 ± 28.0 µg/g dry weight (DW). Based on the results of the overall pairwise comparisons, 1 cm(3) size of slice group had the highest content of vitamin D(2). Duration of sun exposure, sizes of mushroom slices and moisture content were identified as determining factors for vitamin D(2) synthesis. Exposing slices of oyster mushroom to the sunlight for <30 min provides the amount that satisfies the current recommended dietary allowance (RDA) of vitamin D without any visible change in color and texture. Thus, sun treatment of oyster mushroom is an effective and economically cheap strategy in the fight against vitamin D deficiency.