Disappearance of tachysterol in white button mushrooms
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Abstract
Vitamin D has proven to be an important factor in health through a plethora of studies. Tachysterol is a photoproduct of previtamin D with sun or ultraviolet radiation exposure. While vitamin D is well known for its importance in bone health, the biologic function of tachysterol is unknown. Many vertebrates and fungi can produce vitamin D from a precursor after UV irradiation or sun exposure, including white button mushrooms. This project aims to determine if tachysterol might have a biologic function in white button mushrooms by determining if the disappearance of tachysterol2 was due to some active process in live mushrooms.
To provide evidence that tachysterol serves a function, tachysterol2 disappearance in white button mushrooms was monitored after 24 hours. The aim was to create conditions in a white button mushroom, including freezing and microwaving them to determine their effects on tachysterol2 disappearance at 24 hours. The idea was that freezing or microwaving the mushroom would disrupt any metabolic process in the mushroom, providing a clue as to the mechanism of tachysterol2 disappearance. The hypothesis was that freezing and microwaving the white button mushroom would cause a reduction in tachysterol2 disappearance. To evaluate this, 1) white button mushrooms were irradiated with ultraviolet radiation (UVB, 290nm-320nm), 2) an irradiated white button mushroom was frozen, and 3) an irradiated white button mushroom was microwaved. These white button mushrooms were biopsied in triplicate, extracted, and run on high-performance liquid chromatography in order to determine the concentrations of tachysterol2 in the mushrooms. A white button mushroom without UVB irradiation was biopsied in triplicate and extracted to confirm that the store-bought mushrooms did not contain tachysterol2. A tachysterol2 standard was incubated in organic solvent to determine if tachysterol2 was stable.
The results showed statistically significant decrease in tachysterol2 for the irradiated mushroom, the frozen irradiated mushroom, the microwaved mushroom 24 hours after irradiation, compared to the standard tachysterol2 in organic solvent. The decrease in tachysterol2 in the microwaved mushroom was 65% in 24 hours, which was not significantly less than in the irradiated mushroom and the frozen irradiated mushroom (p= 0.10 and 0.22, respectively). The decrease in tachysterol2 for the frozen mushroom was 93%, which was not significantly less than the irradiated mushroom (p = 0.21). These findings suggest that microwaving a mushroom at 5mW and 60 seconds and freezing a mushroom does not significantly interfere with metabolic processes that may involve tachysterol2, although microwaving a mushroom trended towards less of a decrease in the tachysterol concentration.
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Thesis (M.A.)--Boston University