High pressure processing (HPP) of aronia berry purée: Effects on physicochemical properties, microbial counts, bioactive compounds, and antioxidant capacities

The effect of high pressure processing (HPP) at 200 to 600 MPa for 2.5 or 5 min on physicochemical properties (color, pH, titratable acidity, total soluble solids content/TSSC, pulp content, particle size distribution, and viscosity), microbial counts (aerobic bacteria, yeast and mold counts), bioactive compounds (total phenolic and anthocyanin contents), and antioxidant capacities (DPPH radical scavenging capacity and ferric reducing antioxidant power) of aronia berry purée were investigated. All measurements were compared between HPP treated and untreated purées. TSSC and viscosity decreased significantly when pressurized above 400 MPa for 2.5 min and at all HPP conditions, respectively. Other physicochemical properties changed insignificantly after HPP. Pressurization at 400 and 600 MPa both effectively reduced yeasts and molds to below 1 log CFU/g, and reduced aerobic bacteria to <2 log CFU/g only when pressurized for 5 min. No significant reduction in phenolic contents or antioxidant capacities in pressurized purée was observed.