A rapid HPLC post-column reaction analysis for the quantification of ergothioneine in edible mushrooms and in animals fed a diet supplemented with extracts from the processing waste of cultivated mushrooms

For establishing an efficient and sensitive method for the quantitative determination of 2-thiol-l-histidine-betaine (ergothioneine, ERG) in edible mushrooms and the blood and muscles of animals, a technique using reversed-phase separation and post-column reaction between 2′-dipyridyl disulphide and ERG was developed. A corresponding derivative 2-thiopyridone, detected at 343 nm, was used for estimating ERG concentration. The flow rate, temperature, pH, and composition of the solution were optimised. A low limit of quantification (1.41 ppm) and a simpler sample preparation made this technique more rapid compared to other methods using liquid chromatography–mass spectrometry. The coefficient of variation (CV) values for the reproducibility and recovery of ERG were within the acceptable values of 6% and 97.5–100.0%, respectively. The efficiency of this methodology was compared with that of spectrophotometric and mass-spectrometric quantitative methods, and was assessed in the light of previous studies. The ERG contents in different mushrooms were 12.69–234.85 mg/kg wet weight basis. Dietary supplementation with extracts from mushroom processing waste significantly improved ERG bioavailability in the blood of yellowtail fish and muscle tissue of cattle.