Phenolic profile of sercial and Tinta Negra Portuguese varieties: Novel phenolic compounds in Vitis vinifera L. grape

Grapes from Vitis vinifera L. belong to the world's largest fruit crops, and are consumed by population and applied, mainly, on wine production. This study represents the first phytochemical research of phenolic components of Sercial and Tinta Negra V. vinifera L. from Madeira Island (Portugal). The phenolic profiles of Sercial and Tinta Negra V. vinifera L. grape skins (white and red varieties, respectively) were established using high performance liquid chromatography-diode array detection-electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI-MSⁿ), at different ripening stages (véraison and maturity). A total of 40 phenolic compounds were identified, from these, as far as we know, 10 compounds were reported for the first time in V. vinifera L. grapes, namely protocatechuic acid-glucoside, p-hydroxybenzoyl glucoside, caftaric acid vanilloyl pentoside, p-coumaric acid-erythroside, naringenin hexose derivate, eriodictyol-glucoside, taxifolin-pentoside, quercetin-glucuronide-glucoside, malylated kaempferol-glucoside, and resveratrol dimer. This data represents valuable information that may be useful to oenological management and to valorise these varieties as sources of bioactive compounds.