Identification and quantification of ergosterol and phenolic compounds occurring in Tuber spp. truffles

A study was conducted to quantify the mycochemical composition of the truffles Tuber melanosporum, Tuber aestivum and Tuber indicum in terms of ergosterol and phenolic contents. The ergosterol concentration ranged from 1.28 to 1.80 mg/g of dried matter. An ergosteryl ester was found in all truffles, and the concentration was considerably higher in T. aestivum (0.36 mg of ergosterol equivalents/g of dried matter) in comparison to T. melanosporum (0.10 mg/g) and T. indicum (0.09 mg/g). The total phenolic content was determined by the Folin-Ciocalteu assay, and the truffles contained between 1 and 2 mg of phenolics per g of dried matter. The individual phenolic compounds were separated and identified by high performance liquid chromatography. Diverse phenolic acids, namely gallic, homogentisic, protocatechuic, p-hydroxybenzoic, o- and p-coumaric acids and other phenolic derivatives, such as 3,4-dihydroxybenzaldehyde, were found. The profile and content depended on the truffle species; thus, the hydroxycinnamic acid derivatives, o- and p-coumaric acids, were only detected in T. aestivum. All the truffles showed inhibition of lipid oxidation, being T. aestivum the most effective (24% inhibition) followed by T. indicum (23% inhibition) whereas T. melanosporum was the truffle with the lowest antioxidant activity (18% inhibition). (C) 2012 Elsevier Inc. All rights reserved.