Impact of alternative and thermal preservation on microbiological, enzymatical, and chemical properties of blackcurrant juice

The general objective of this study was to assess the processing impact of selected advanced and conventional thermal technologies on the microbiological quality and selected physical and chemical parameters of blackcurrant juice (Ribes nigrum L.). In addition, the juice was extracted using an innovative spiral filter press operating under a low-oxygen atmosphere and vacuum pressing of the juice. Obtained blackcurrant juice was treated with selected technologies at a pilot scale: pulsed electric fields (PEF, 90 kJ/l, 15 kV/cm), high hydrostatic pressure (HHP, 400 MPa, 1 min), and thermal treatment (74 °C, 3 s). The processing effects were investigated directly after the treatments and during 8 weeks of refrigerated storage at 4 ± 1 °C. Different technologies and storage time affected mostly parameters like concentration of sugars, vitamin C, antioxidant capacity, total phenolic content, and total anthocyanins. The overall effect of PEF and HHP under the investigated conditions has had only a minor impact on selected quality parameters of the blackcurrant juices compared to the thermal treatment.