The Quality Improvement of Solid-State Fermentation with Cordyceps militaris by UVB Irradiation

Cordyceps militaris, a medicinal and edible mushroom, was used to ferment buckwheat and embryo rice by solid-state fermentation (SSF). Our aim was to investigate the effect of ultraviolet B (UVB) light irradiation on the content of vitamin D₂ and biologically effective components, and antioxidant properties of buckwheat and embryo rice in SSF with C. militaris. Irradiated samples of buckwheat and embryo rice fermented by C. militaris had significantly increased vitamin D₂ content, from 0-0.3 to 1.18-16.79 μg/g, while the increase in fresh embryo rice fermented by C. militaris was up to 16.79 μg/g. The content of adenosine, cordycepin and polysaccharide in irradiated dry samples fermented by C. militaris was 0.08 to 11.15 mg/g, higher than that of the irradiated fresh samples fermented by C. militaris (0.07-8.40 mg/g). Samples fermented by C. militaris had lower EC₅₀ values and higher content of antioxidants than did unfermented samples. When the solid-state fermented sample was irradiated with UVB light, the content of biologically effective and antioxidant components and antioxidant property of sample decreased. However, it still contained enough of these biologically effective and antioxidant components.