Influence of extraction pre-treatments on some phytochemicals and biological activity of Transylvanian cranberries (Vaccinium vitis-idea L.)

Cranberries (Vaccinium spp.) are rich sources of phytochemicals, but their bioactivity depends on cultivar, harvesting time, processing, or extraction procedure. Thus, a wider variety of subspecies needs to be characterized, and the effects of treatments prior to consumption or extraction need to be determined. This study aims to phytochemically characterize pre-treated (fresh, frozen, and dried) Transylvanian cranberries (Vaccinium vitis-idea L.) and to evaluate their bioactivity. The profile and content of individual anthocyanins were analyzed by HPLC-PDA, total phenolics and flavonoids were determined spectrophotometrically, and antioxidant activity was evaluated by ABTS(+) radical cation assay. Their antibacterial activity against Staphylococcus aureus, Escherichia coli, and Salmonella Typhimurium was assessed by disk diffusion. Total identified anthocyanins ranged from 11.14 to 123.02 mg cyanidin-3-O-galactoside/100 g fresh weight. Cranberries were rich in polyphenols and flavonoids, with the highest content in fresh berries; they inhibited E. coli and S. Typhimurium. Freezing enhanced their antibacterial activity. The significance of this study lies in the evaluation of how pre-treatments affect some novel natural food-grade antimicrobials from cranberries with the potential to replace synthetic food preservatives and to deliver phytochemicals with health benefits.