Metabolomics analysis reveals the bitter active ingredients in Lonicera caerulea L.

Introduction: L.) is a nutritionally valuable cold-climate berry characterized by a considerable bitter taste. While bitter compounds in plant foods are often associated with favorable physiological activities, their specific identities in blue honeysuckle remain unclear. Methods: This study combined sensory evaluation, electronic tongue analysis, and untargeted metabolomics based on ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) to identify and compare bitter compounds in three cultivars of blue honeysuckle. Results: A total of 73 bitter metabolites were identified in blue honeysuckle, predominantly flavonoids, amino acids and derivatives, phenolic acids, lipids, and tannins. The highest-bitterness variety, Chaoxian (CX) exhibited specific accumulation of l-valine, l-leucine, l-histidine, l-phenylalanine, eriodictyol, trifolin, isoorientin, naringin, and eriocitrin compared to Luohuotan (LHT) and Lanjingling (LJL). The KEGG enrichment analysis implicated the biosynthesis of amino acids (ko01230) and flavonoid biosynthesis (ko00941) as primary contributors to inter-varietal bitterness divergence. Discussion: These findings provide important information for retaining bioactive bitter metabolites in blue honeysuckle and optimizing its flavor profile to enhance market acceptability.