Chemical factors contributing to orosensory profiles of bilberry (Vaccinium myrtillus) fractions

The effects of fractionation on the sensory profile of bilberry (Vaccinium myrtillus) were studied. The berries were fractionated by juice pressing, four ethanol extractions and ethanol evaporation. High-performance liquid chromatography and gas chromatography were used to analyze phenolic compounds, sugars and organic fruit acids of the fractions, and sensory properties of the fractions were studied using generic descriptive analysis. The majority of the phenolic compounds were anthocyanins, and they were mainly found to be located in the press residue. Anthocyanins and other phenolic compounds dissolved in ethanol, and the extracts were perceived as astringent and bitter as the sensory profile of the press residue was very mild. The juice was dominant in sweetness because it contained most of the sugars and fruit acids. Many flavonol glycosides and hydroxycinnamic acid conjugates were discovered to be the compounds contributing to astringency and bitterness, especially myricetin-3-O-arabinoside, myricetin-3-O-glucoside, myricetin-3-O-galactoside and an unknown caffeoyl quinic acid derivative. By supplementing the juice fraction with extracts, the content of phenolic compounds was significantly increased without altering the sensory profile of the juice.