Development of a Simple HPLC Method for the Analysis of Ergosterol and UV-Enriched Vitamin D₂ in Mushroom Powders

In this study, a straightforward and cost-effective HPLC-UV method was developed for the rapid determination of vitamin D2 and ergosterol in mushrooms. These bioactive components are known to play a significant role in the nutritional value of mushrooms, particularly in the production of mushroom-based food supplements. The method, designed for routine analysis, involves a simple sample preparation process combining saponification and solid–liquid extraction, followed by HPLC-UV detection. High recovery rates (97–99%) were achieved by the method, with limits of detection (LOD) and quantitation (LOQ) of 0.1 mg/kg dry weight and 0.5 mg/kg dry weight, respectively. The enrichment of vitamin D₂ content in mushroom powders through UV irradiation was also investigated. In Agaricus bisporus, vitamin D₂ levels increased from an initial 1.92 mg/kg to 4.66 mg/kg following heat treatment at 100 °C, and reached a maximum of 28.13 mg/kg when heat treatment was combined with UV irradiation. In contrast, Lentinula edodes exhibited an initial vitamin D₂ content of 7–8.5 mg/kg, with the highest levels achieved through UV treatment alone, which also preserved ergosterol content. These findings highlight species-specific differences in vitamin D₂ conversion and present an effective approach for enhancing the nutritional profile of mushroom-based products, while providing a reliable analytical tool for quality control.