Processed elderberry (Sambucus nigra L.) products: A beneficial or harmful food alternative?

• Elderberries contain beneficial and also harmful compounds.
• During processing selected components transfer into elderberry products.
• Contents of selected compounds were different between different elderberry products.
• Phenolics and cyanogenic glycosides decreased during processing.

Elderberry fruit and its food products are not only a rich source of phenolics, boosting their antioxidant activity, but also contain harmful cyanogenic glycosides. In order to assess the potential positive/negative effects of consuming elderberry-based products their biochemical profile and levels of individual compounds were identified with the aid of high-performance liquid chromatography (HPLC) coupled with mass spectrophotometry (MS). Cyanidin-3-sambubioside and cyanidin-3-glucoside were the prevalent compounds among phenolics and sambunigrin among cyanogenic glycosides in all analyzed elderberry products. Processing considerably affects the content of elderberry phenolics and cyanogenic glycosides. The levels of phenolics decreased from 958 mg/kg in unprocessed control berries to 343 mg/kg in elderberry liqueur, 337 mg/kg in spread, 162 mg/kg in tea and 114 mg/kg in elderberry juice. Higher temperatures not only reduced the content of beneficial compounds, but also decreased the levels of harmful cyanogenic glycosides for 44% in elderberry juice, for 80% in tea and for as much as 96% in elderberry liqueur and spread.