Integration of volatilomics, non-targeted metabolomics, and electronic sensory technologies reveals the flavor evolution mechanism in ‘Queen Nina’ table grapes during ripening

Abstract

‘Queen Nina’ grapes are renowned for their distinctive “fruity”, “cheesy”, and “vinous” aromas, yet the metabolic mechanisms driving these traits during ripening remain elusive. This study integrated volatile metabolomic, non targeted metabolomic, and electronic sensory technologies to profile flavor evolution across three developmental stage. We identified 44 core differential volatile organic compounds (VOCs) closely associated with the transition of profiles. Specifically, (Z)-3-hexen-1-ol declined, while esters including (E)-2-hexen-1-ol acetate and ethyl 3-hydroxybutanoate accumulated. ROAV analysis identified ethyl butanoate and hexanoate as key aroma-active compounds. Furthermore, the downregulation of 355 non-volatile metabolites (amino acids, lipids) may serve as potential biosynthetic precursors for VOCs, whereas upregulated flavonoids are associated with enhanced coloration. A constructed metabolic pathway map revealed how primary metabolism fuels secondary pathways to orchestrate flavor development. These findings elucidate the metabolic basis of the distinctive aroma characteristics of ‘Queen Nina’ grapes and provide theoretical insights for further investigation into the quality characteristics and formation mechanisms in table grapes.