High pressure processing technique and its application for shelf life extension of aronia berry purée

High pressure processing (HPP) is one of the most attractive non-thermal food preservation processes as it can inactivate pathogens and reduce the numbers of spoilage microorganisms, resulting in extended product shelf life. In this study, changes in microbial population and physicochemical properties of aronia purée treated by HPP (400 MPa for 5 min) and stored at 4 oC for 8 weeks was monitored. Results showed that high pressure treatment of 400 MPa reduced the aerobic plate count (APC) from 4.8 to 2.3 log CFU/g. The APC did not change significantly during the eight-week storage period for both untreated and high pressure treated samples. High pressure treatment resulted in reduction of molds and yeasts to below the detection limit (1 log CFU/g), and no regrowth was observed during eight weeks of storage. In contrast, yeasts in unpressurized aronia purée increased from 4.7 to 6.1 log CFU/g during eight-week storage. Physicochemical properties of aronia purée did not have noticeable change after high pressure treatment. During 8 weeks of storage, lightness, viscosity, total soluble solid content, and pH value did not have significant change, while the redness, yellowness, and titratable acidity had statistically significant but slight changes. HPP could be an effective preservation technique for microbial population reduction, quality retention and shelf life extension of aronia purée.