Orosensory contributing compounds in crowberry (Empetrum nigrum) press-byproducts

Berries of crowberry (Empetrum nigrum) were fractionated by juice pressing, ethanol extraction, solvent evaporation and supercritical fluid extraction. Phenolic compounds, sugars and acids in the fractions were analysed by high-performance liquid chromatography and gas chromatography. The sensory characteristics of the fractions were studied by using generic descriptive analysis. Most of the sugars were located in the juice and this was perceived as the sweetest of the fractions. The majority of the phenolic compounds were anthocyanins, located in the press residue. Ethanol extracted nearly all the phenolic compounds from the press residue. The extracts were the most bitter and astringent of the fractions. Eight flavonol glycosides and two flavonol aglycones were discovered to contribute particularly to bitterness and astringency. After ethanol extraction, only fibres and seeds were left, and the supercritical fluid extraction removed only a small amount of compounds from this fraction, which did not have any impact on sensory properties. This study shows that crowberries are rich in different nutrients and some of them are contributing to orosensory properties. The sequential fractionation by ethanol ended up in products with substantial differences in their orosensory characteristics and nutrient composition. Stepwise fractionation empowers versatile and beneficial ways to exploit the berries in food industry.