Blueberries, besides having commonly-recognized taste properties, are also a valuable source of health-promoting bioactive compounds. For several decades, blueberries have gained in popularity all over the world, and recent years have seen not only an increase in fresh consumption, but also in the importance of blueberries for the processing industry. Blueberry processing mostly consists of freezing and juicing. Recently, more attention has been drawn to dewatering and drying, which are promising areas for developing novel blueberry products. Processing affects each biologically-active compound in a different way, and it is still unknown what changes those compounds undergo at the molecular level after the application of different processing technologies. This work presents the most recent state of knowledge about the pre-treatment and processing methods applied to blueberries and their influence on the content of biologically-active compounds. The presentation of methods is preceded by a brief overview of the characteristics of the blueberry species, a description of the chemical composition of the fruit and a short note about the main growing areas, production volumes and the management of fruit crops.

This study compared the mineral content and bioactive properties of flowers and fruit coming from wild elderberry plants with those of flowers and fruit harvested from elderberry cultivars grown in an orchard. Elderberry fruit and flowers were analyzed for the content of selected minerals, phenolic compounds, and anthocyanins, as well as for antioxidant activity. Mineral content was determined by the atomic absorption spectrometry method, while antioxidant activity and the content of polyphenols and anthocyanins were determined by spectrophotometric methods. Flowers were found to contain more total ash and much higher content of most of minerals, except magnesium which was present in high concentrations in fruit. Fruit showed significantly higher antioxidant activity than flowers, whereas the total phenolic content varied depending on the growing location or cultivar. The material obtained from selected cultivars growing in an orchard had higher antioxidant activity and polyphenol and anthocyanin content than the material obtained from wild plants. Fruit of the ”Haschberg” cultivar and flowers of the ”Sampo” cultivar had the best bioactive properties of the studied samples.