Nutritional value of Sorbus domestica L. bark, fruits and seeds: minerals and phenolics

The aim of this study was to i) investigate the content of inorganic (macro- and microelements) and organic compounds (total phenolics, total flavonoids and total tannins) and ii) evaluate the antioxidant activities of total phenolics and total tannins in S. domestica L. bark, fruits (separately exocarp and mesocarp) and seeds using phytochemical analyses. Results revealed all the tested service tree samples were rich in potassium. Bark, among the tested samples, was the best source of calcium and zinc, while seeds were the best source of magnesium. Extracts of immature exocarp and bark contained the highest amounts of total phenolics. Ripening significantly decreased the amount of phenolics in fruits (both exocarp and mesocarp). Exocarp was significantly richer in total flavonoids than mesocarp, bark or seeds. The highest antioxidant activity showed phenolics from immature exocarp and then from bark. The antioxidant activity of phenolics and tannins from exocarp, but not from mesocarp, was significantly decreased after ripening. Based on the data we conclude that service tree bark and seeds are significantly better sources of macro- and microelements than fruits, while exocarp and bark are better sources of total phenols and flavonoids. We suggest that under-utilized species Sorbus domestica L. could be used as a great source of mineral elements and antioxidants important for human diet.