Effect of Hot Air-Drying and Pasteurization on Ergothioneine Content in Edible Mushrooms

This study investigates the effects of thermal processing and storage on ergothioneine concentration in three edible mushroom species: Agaricus bisporus (button mushrooms), Pleurotus ostreatus (oyster mushrooms), and Lentinula edodes (shiitake). Oyster mushrooms and shiitake underwent hot air drying, while button mushrooms were subjected to canning. Ergothioneine extracts were quantified using high-performance liquid chromatography. Oyster mushrooms exhibited the highest ergothioneine concentration (2.22 mg/g) and stability when subjected to hot air-drying at 57 °C for 6 hours, in contrast to shiitake (1.02 mg/g). Canning procedures for button mushrooms resulted in reduced ergothioneine concentrations, with the most significant losses occurring during thermal bleaching (33%) and pasteurization (59%). During storage, ergothioneine concentration in canned mushrooms declined by 28%, while it increased in the brine by 72%. In conclusion, the observed variations in ergothioneine concentration among these mushroom species appear to be influenced by their inherent compositions and distinct processing methods. Additionally, our findings highlight that the combination of heat and moisture content is a pivotal factor contributing to the loss of ergothioneine concentration in mushrooms.