Indian Journal of Ecology

Button ( Agaricus bisporus ) and oyster ( Pleurotus florida ) mushrooms irradiated with ultraviolet (UV) radiations (UV-A, UV-B and UV-C) at a distance of 30, 45 and 60cm and with sun rays for 10, 20 and 30min followed by freeze drying resulted in an enormous increase in vitamin D₂ content. The irradiation dose of treating mushrooms for 30 min with UV-A, UV-B and UV-C was 17.9, 21.5 and 15.7 kJ/m², respectively. Irradiation of mushrooms with UV-B rays at a distance of 60 cm for 30 min resulted in the maximum spike in vitamin D₂ content with 228 and 141 folds increase in button mushrooms and oyster mushrooms, respectively. Freeze dried UV-B treated mushroom powder were significantly high in in-vitro protein digestibility and total phenols. The supplementation of UV treated button and oyster mushroom powder in traditional food recipe led to a significant increase in vitamin D₂ content, protein, ash, fibre and minerals like iron, copper, phosphorus, potassium, zinc and selenium, total phenol and in-vitro protein digestibility as compared to the control (without mushroom powder). There was retention in vitamin D₂ in the mushroom powder after incorporation in the food product. This vitamin-D₂ enriched mushroom powder can be extensively used as a food based approach to combat the problem of vitamin-D deficiency and to boost immunity. Mushroom powder and its supplemented food product stored in air tight glass containers for 5 months had negligible microbial growth.