Abstract
Gas-liquid chromatographic (GLC) determination of vitamin D_2 and ergosterol in Shiitake (Lentinus edodes) was investigated and simple routine methods were established. The method for determination of vitamin D_2 includes alkali-saponification, isolation of the unsaponifiable matters, thin-layer chromatography (TLC), trimethylsilylation and GLC. When contents of vitamin D_2 are very small and comparatively large amounts of sterols exist in a sample, however, digitonin-Celite column chromatography should be added before TLC in order to eliminate the influences of sterols. On the other hands, ergosterol is determined by applying directly the trimethylsilyl ethers of the unsaponifiable matters to GLC. When dry Shiitake were irradiated by the ultraviolet lights of 3 E-Viton/cm^2 (30 μW/cm^2), the relationship between yield of vitamin D_2 and irradiation time was proportional and the yield of vitamin D_2 was 29IU/min. The estimated values of ergosterol in commercial dry Shiitake obtained from different production places were distributed in the range of 0.25〜0.74%, while that in a commercial raw sample was 0.05%.
