Abstract
Owing to ergosterol content, after UV irradiation yeast become a well-known source of ergocalciferol (vitamin D2). Additionally, pharmaceutical yeast-based supplements may represent a suitable option for treating hypovitaminosis, especially in patients adhering to a vegan diet. Using the high-performance liquid chromatography-ultraviolet (HPLC-UV) methodology our study sought to analyse three commercially available yeast-based vitamin D2 supplements while comparing the effect of UV-C irradiation (254 nm) on yeast biomass derived from the brewing process and pure ergosterol. The two compounds were precisely separated under the described conditions in an efficient and quick manner with a retention time (Rt) of 4.152 ± 0.018 minutes for vitamin D2 and 5.097 ± 0.013 minutes for ergosterol. However, when approaching the quantitative analysis, based on our findings, it appears that the pharmaceutical supplements deviate from the declared amount of substance indicated on the label. 15 minutes of UV-C irradiation generates vitamin D2 in yeast biomass with a conversion rate of 1.78%. Also, high content of ergosterol, beside vitamin D2 formation after irradiation, may trigger the appearance of secondary products such as tachysterol.