Wild bilberry, blackcurrant, and blackberry by-products as a source of nutritional and bioactive compounds

This study aimed to investigate the nutritional and antioxidant composition of dried wild bilberry, blackcurrant, and blackberry pomaces by evaluating the proximate content, titratable acidity, color, total phenolics, total flavonoids, total anthocyanins content, and antioxidant activity. In addition, fatty acid and polyphenolic profiles were assessed using chromatographic methods. Higher fiber, fat, and mineral contents were found in blackberry as compared with bilberry and blackcurrant pomaces. The fatty acid profile revealed high concentrations of monounsaturated (16.7-18.7%) and polyunsaturated fatty acids (72.3-77.4%). The lowest n-6/n-3 ratio was found in bilberry pomace (0.90) followed by blackcurrant (1.28) and blackberry pomaces (4.26). Bilberry pomace showed the highest total phenolic (36.7 mg GAE/g dw) and total anthocyanin content (28.35 mg CGE/g dw). The phenolic profile of the bilberry pomace was dominated by ellagic acid and catechin while in blackberry and blackcurrant pomaces the major phenolic compounds were epigallocatechin and catechin, respectively. High levels of procyanidins B1 have been also quantified in bilberry and blackcurrant pomaces. Due to their healthy lipid profile and richness in antioxidant compounds, berry pomaces are good candidates as food ingredients for enhancing the functionality of food products and for contributing to the sustainability of the food industry.