Bilberries are processed into different food products and beverages. Therefore, we studied how various bilberry items (puree, infusion, liqueur, and fresh and pasteurized juices) differ in secondary metabolites as compared to the fresh fruit. For this purpose, we identified phenolics with a liquid chromatography-mass spectrophotometry (LC-MS) system and compared phenolic profiles and phenolic contents in various bilberry products prepared from the same raw material. Our results show that processing significantly affected the biochemical pattern and levels of phenolics. Total analyzed phenolics decreased with processing, mostly due to anthocyanins, which had the highest share in phenolic profile of all bilberry-based products. The highest differences among products in flavanol (63.7-fold), followed by flavonol contents (26.3-fold). Fresh fruits had the highest content of total anthocyanins (5,190 mg/100 g dry weight [DW]), followed by puree (2,719 mg/100 g DW), infusion (2,469 mg/100 g DW), and liqueur (1,830 mg/100 g DW), whereas fresh and pasteurized juices had the lowest content of total anthocyanins (921 and 1,099 mg/100 g DW).
Practical application: Although we confirmed the common belief among consumers that the consumption of fresh berries is more beneficial than consuming processed products, this study showed that various bilberry-derived products can also be valuable source of phenolic compounds all year round.
Keywords: Vaccinium myrtillus L; anthocyanins; beverages; bilberries; phenolics.
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