The phenolic content in the truffles methanolic extracts was
estimated by means of the Folin-Ciocalteu assay described by
Singleton and Rossi (1965) with minor modifications for mushroom
samples (Palacios et al., 2011). The absorbance was read at
725 nm in a Jenway 6305 spectrophotometer (Bibby Scientific
Limited, UK). Gallic acid was used to calculate the standard curve
(0.01 to 0.8 103 M; r2 > 0.999). The results were expressed as
mg of gallic acid equivalents per g of dried truffle.