Anti-Inflammatory and Antioxidant Properties of Pulsed Light Irradiated Lentinula edodes.

Intense pulsed light irradiation is used in food decontamination and in production of mushrooms with high level of ergocalciferol. Lentinula edodes (Berk.) Pegler, shiitake, was freeze-dried and milled into powder and irradiated with 20, 40 and 60 pulses of pulsed light at a distance of 6 cm and the irradiation energy were 26.2, 52.4 and 78.5 kJ/m2, respectively. The contents of ergocalciferol and total phenols increased dose-dependently whereas ergothioneine contents were not affected. The most effective conversion of ergosterol to ergocalciferol was 20-pulse treatment. Further, irradiated and nonirradiated shiitake showed a moderate inhibition in decreasing nitric oxide and interleukin-6 productions but no effect on tumor necrosis factor-alpha production. In addition, pulse light treatment could improve antioxidant activities. Overall, using pulsed light irradiation could produce irradiated shiitake as an excellent vitamin D2 supplement with similar ergothioneine and higher total phenols contents as well as similar anti-inflammatory and better antioxidant activities. Practical Applications Using intense pulsed light irradiation, ergosterol could be efficiently transformed into ergocalciferol in freeze-dried shiitake powder at proper distance and treatment time. The content of ergocalciferol in freeze-dried shiitake powder could be increased from 5.91 to 37.17 μg/g after irradiating for 20 pulses (near 7 s), which is sufficient for the daily requirement of 15 μg for human body upon consumption of 0.4 g powder. In addition, the content of total phenol would be increased from 6.91 to 7.42 mg/g after 60 pulses of pulsed light irradiation, and the content of ergothioneine was similar during the different pulse treatments. Therefore, the irradiated shiitake powder could be a beneficial supplement which contains abundant vitamin D and exhibits good antioxidant activities. [ABSTRACT FROM AUTHOR]