Integrative pathway-based metabolomics and statistical correlation unravel key flavor formation in pecans

This study explored the mechanisms underlying raw pecan flavor biosynthesis using pathway-based metabolomics and statistical correlation analysis. Three pecan cultivars-'Avalon,' 'Desirable,' and 'Sumner'-were collected and evaluated. Ten major flavor formation pathways were identified and targeted, including glycolysis, sucrose metabolism, the citric acid cycle, 2,3-butanedione and 3-penten-2-one biosynthesis, valine-derived volatiles, terpenoid backbone biosynthesis, lipoxygenase pathway, flavonoid biosynthesis, phenylpropanoid pathway, and shikimic acid pathway. Overall, consistent metabolic linkages were observed between flavor precursors, intermediates, and their corresponding flavor products. For example, lipoxygenase-derived aldehydes and glycolysis-related precursors, along with downstream 2,3-butanedione, were consistently abundant in 'Sumner,' while the precursor chlorogenic acid and downstream flavonoids were observed predominantly in 'Desirable.' These results, together with odor and taste activity values, revealed key pathways and mechanisms responsible for flavor formation in raw pecans. This work provides a valuable foundation for future research and breeding programs aimed at improving or maintaining pecan flavor quality.