Retention of polyphenols and vitamin C in cranberrybush purée (Viburnum opulus) by means of non-thermal treatments.

The effects of high pressure processing (HPP; 200-600 MPa for 5 or 15 min) and pulsed electric field (PEF; 3 kV/cm, 5-15 kJ/kg) treatment on physicochemical properties (conductivity, pH and total soluble solids content), bioactive compounds (vitamin C, total phenolic (TPC), total flavonoid (TFC), total anthocyanin (TAC) and chlorogenic acid contents), antioxidant capacities (DPPH and CUPRAC assays) and polyphenol oxidase (PPO) activity of cranberrybush purée were evaluated immediately after processing. The results were compared to an untreated purée. According to the results, conductivity increased significantly after PEF (15 kJ/kg) treatment. PEF and HPP treatments resulted in a better retention of bioactive compounds (increase in TPC in the range of ~4-11% and ~10-14% and TFC in the range of ~1-5% and ~6-8% after HPP and PEF, respectively) and antioxidant activity (as measured with CUPRAC method) compared to untreated sample. HPP reduced residual enzyme activity of PPO comparatively better than PEF.