Detailed investigation of the composition and transformations of phenolic compounds in fresh and fermented Vaccinium floribundum berry extracts by high-resolution mass spectrometry and bioinformatics

Introduction:Blueberries are known for their very high content of biologically activephenolic compounds; nonetheless, differently from the North American andEuropean species of blueberries, Neotropical blueberries have not been extensivelystudied yet.Objectives:In the present paper, the phenolic composition ofVacciniumfloribundumKunth, which is endemic to the Andean regions and grows 1,600to 4,500 meters above sea level, was investigated by ultra-high-performanceliquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS). Native and fermented berries were compared in terms of phenoliccomposition as well as antioxidant activity, total phenolic content, and totalanthocyanin content.Materials and Methods:V. floribundumnative and fermented berries were extractedand analyzed by UHPLC-HRMS. The acquired datasets were processed by Com-pound Discoverer 3.1 using a dedicated data analysis workflow that was specificallyset up for phenolic compound identification.Results:In total, 309 compounds were tentatively identified, includinganthocyanins, flavonoids, phenolic acids, and proanthocyanidins. The moleculartransformations of phenolic compounds during fermentation were comprehen-sively investigated for the first time, and by a customized data processingworkflow, 13 quinones and quinone methides were tentatively identified in thefermented samples. Compared to other species of the genusVaccinium, a peculiarphenolic profile is observed, with low abundance of highly methylatedcompounds.