Conversion of ergosterol in edible mushrooms to vitamin D2 by UV irradiation

Abstract

Analysis of ergosterol content in different tissues of mushrooms showed a significant difference (p < 0.01) in its distribution, and irradiation of each side of the mushrooms for one-hour, was found to be the optimum period of irradiation in this conversion. The optimum moisture and temperature of mushrooms for this conversion was around 80 % (wet weight basis) and a temperature of around 35 oC.Having previously optimized a method for the conversion of ergosterol to vitamin D2 in mushrooms, the study then examined the vitamin D enriched mushrooms (Lentinula edodes) for their bioavailability of the vitamin, using an animal model. A group of 12 rats of the test animals received 1 mg of vitamin D2/day from irradiated mushrooms for a period of four weeks until sacrificed. The remaining 12 rats were fed un-irradiated mushrooms at the same level to act as controls. At the end of a four week period, mean serum 25(OH)D level of the experimental group was 129.42 A? 22.00 nmol/L whereas it was only 6.06 A? 1.09 nmol/L in the control group. Femur BMD of the experimental group of animals was significantly higher (p < 0.01) than the control group. It may be concluded from the results that vitamin D2 from UV-irradiated mushrooms is well absorbed and metabolized in this model animal system. Significant increase in femur bone mineralization (p < 0.01) was shown in the presence of vitamin D2 from irradiated mushrooms compared with the controls.