Roasting　is　pivotal　for　enhancing　the　flavor　of　Wuyi　rock　tea　(WRT).　A　study　investigated　a　novel　compound　that　enhances　the　umami　taste　of　WRT.　Metabolomics　of　Shuixian　tea　(SXT)　and　Rougui　tea　(RGT)　under　light　roasting　(LR),　medium　roasting　(MR),　and　heavy　roasting　(HR)　revealed　significant　differences　in　nonvolatiles　compounds.　Compared　LR　reducing　sugars　and　amino　acids　notably　decreased　in　MR　and　HR,　with　l-alanine　declining　by　69%.　Taste-guided　fractionation　identified　fraction　II-B　as　having　high　umami　and　sweet　intensities.　A　surprising　taste　enhancer,　N-(1-carboxyethyl)-6-(hydroxymethyl)　pyridinium-3-ol　(alapyridaine),　was　discovered　and　identified.　It　formed　via　the　Maillard　reaction,　positively　correlated　with　roasting　in　SXT　and　RGT.　Alapyridaine　levels　were　highest　in　SXT　among　the　five　oolong　teas.　Roasting　tea　with　glucose　increased　alapyridaine　levels,　while　EGCG　inhibited　its　formation.　HR-WRT　exhibited　enhanced　umami　and　sweet　taste,　highlighting　alapyridaine＇s　impact　on　WRT＇s　flavor　profile.　The　formation　of　alapyridaine　during　the　roasting　process　provides　new　insights　into　the　umami　and　sweet　perception　of　oolong　tea.