The influence of sterilization with EnbioJet® Microwave Flow Pasteurizer on composition and bioactivity of aronia and blue-berried honeysuckle juices

In this study, fruit juices that are rich sources of anthocyanins, obtained from aronia (Am. chokeberry, Aronia melanocarpa) and blue-berried honeysuckle (Lonicera caerulea L. var. edulis) were used to examine the preservation of plant phytochemicals and bioactivity upon sterilization—either thermal, or with an EnbioJet® Microwave Flow Pasteurizer. The chemical properties verified included determinations of anthocyanins and other polyphenols by HPLC, total antioxidant activity, and profiles of antioxidants by post-column derivatization. Compared to heat treatment, the higher stability of aronia and blue-berried honeysuckle phytocomplexes during processing with the EnbioJet® device for temperatures ensuring microbial purity (range investigated 90–130 °C) was demonstrated. In the same batches of juices submitted to heating at 100 °C, the rapid decline of anthocyanin content accompanied by lowered antioxidant activity was observed. The changes in chemical composition were reflected in altered biological activity. Both cytotoxicity and protection of DNA against oxidative damage were higher for microwaved juices than for juices processed by the heating method that caused degradation of bioactive phytochemicals.