2.1. Materials and chemicals
Fresh mushroom (F. velutipes) trimmings were obtained from
Cosmic Farm Co. Ltd. (Niigata, Japan). The ME was prepared using
a food processing line at Yamaki Foods Co. Ltd. (Ehime, Japan). L-
(+)-Ergothioneine (L-ESH) was purchased from Bachem AG (Hauptstrasse,
Bubendorf, Switzerland). Methanol and high-performance
liquid chromatography (HPLC)-grade distilled water were
purchased from Kokusan Chemical Co. Ltd. (Tokyo, Japan). All other
chemicals were of analytical grade and purchased from Sigma–Aldrich
(St. Louis, MO) and Wako Pure Chemical Industries Ltd. (Osaka,
Japan), unless otherwise indicated.