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The sun emits ultraviolet radiation in form of ultraviolet-A (UV-A), ultraviolet-B (UV-B), and ultraviolet-C (UV-C) bands. Ultraviolet light has the potential to boost vitamin D 2 production in mushrooms which human bodies cannot synthesize. The ergosterol in mushrooms, a component of fungal cell membranes which serves the same function as cholesterol in animal cells, can be converted into vitamin D 2 by exposure to controlled ultraviolet light. However mushrooms are conventionally grown in the dark, necessitating artificial ultraviolet irradiation. This study investigated the effects of UV-A (365nm) and UV-C (254nm) light exposure time during mushrooms growth, on the concentration of vitamin D 2 in oyster mushrooms (Pleurotus ostreatus species) after harvest. Mushrooms samples exposure times were varied from 10-60 minutes per day at intervals of 10 minutes, and irradiation done for three days. UV spectroscopy was used to determine the amounts of Vitamin D 2. It was found that the absorbance of vitamin D 2 for UV-A light ranged from 0.18-0.49 for the 10-60 minutes of irradiation respectively, while for UV-C light the vitamin D 2 content absorbance was 0.38-0.81 for the 10-60 minutes of irradiation respectively. There was a linear relationship between time of irradiation and absorbance vitamin D 2 content up to 50 minutes for UV-A and 40 minutes for UV-C.

This study investigated the effects of ultraviolet-A (UV-A) and ultraviolet-C (UV-C) light on the mechanical properties in oyster mushrooms during the growth. Experiments were carried out with irradiation of the mushrooms with UV-A (365 nm) and UV-C (254 nm) light during growth. The exposure time ranged from 10 minutes to 60 minutes at intervals of 10 minutes and irradiation was done for three days. The samples for experimental studies were cut into cylindrical shapes of diameter 12.50 mm and thickness 3.00 mm. The storage modulus, loss modulus, and loss factor of the irradiated samples and control samples were determined for both UV bands and there was a significant difference between the storage modulus, loss modulus, and loss factor of the irradiated samples by both UV bands with reference to the control sample, P < 0.05. UV-C light irradiated samples had higher loss modulus and loss factor but low storage modulus as temperature increased from 35 to 100°C with respect to the control sample while UV-A light irradiated samples had lower loss modulus, low loss factor, and higher storage modulus than UV-C irradiated samples.

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