Phenolic acids and Flavonoid Profiles of Vitis vinifera L. var. Apyrena Grapes across Four Consecutive Harvest Years

Vitis vinifera L. var. Apyrena is a seedless black grape variety that, besides its consumption as table grape, serves as the exclusive raw material for the production of Corinthian currants. While the phenolic composition of Corinthian currant has been documented, the fresh grape phenolic content remains largely uncharacterized. In this study, the phenolic composition of Apyrena grapes was profiled over four consecutive harvest years (2021–2024) using high-resolution mass spectrometry (LC–HRMS). A diverse range of phenolic acids, flavonols, stilbenes, and anthocyanins was found. Caftaric acid (8.15 ± 1.36 mg/100 g), malvidin-3- O -glucoside (1.89 ± 0.78 mg/100 g), and quercetin derivatives were among the dominant constituents in 2023. Complementary suspect screening analysis revealed over 50 additional phenolic constituents, including glycosylated flavonoids and acylated anthocyanins, not previously reported in this variety. This is the first longitudinal phenolic profiling of Vitis vinifera var. Apyrena grape, additionally establishing a compositional reference for future studies on Corinthian currant quality and valorization. • First comprehensive phenolic profiling of Vitis Vinifera L. var. Apyrena fresh grapes. • Targeted and suspect LC-HRMS revealed over 70 phenolic compounds. • Caftaric acid, malvidin-3- O -glucoside and quercetin derivatives predominated. • Quercetin and peonidin derivatives were consistently detected across all samples. • Interannual phenolic variation linked to climatic conditions.