Evaluation of pulsed electric field and high-pressure processing on the overall quality of refrigerated Concord grape juice

Consumers' demands for minimally processed juices are prompting the expansion of refrigerated, cold-pressed juice market. To develop a nutritious, cold-pressed Concord grape juice, high pressure processing (HPP, 600 MPa, 3 min, 5 degrees C) and pulsed electric field (PEF, 0.85 kV/cm, 300 pulses) were utilized and the resultant juice was compared with the heat treated (HT, 63 degrees C, 3 min) juice. HPP was able to preserve the physicochemical properties, reduce microbial load and extend the shelf-life of juice under refrigeration. PEF treatment significantly increased the juice yield (p < 0.01), antioxidants contents and antioxidant activity (p < 0.05). Macroscopic observation indicated that the skin cell structure was altered after PEF. PEF + HPP treated juice had significantly higher purchase intent, appearance and aroma likings (p < 0.05). Combination of PEF and HPP can produce a superior cold-pressed Concord grape juice that meets consumers' demands for fresh and nutritious fruit juices.