QUALITY CHANGES IN APPLE JUICE AS RELATED TO NONTHERMAL PROCESSING

ABSTRACT Fresh apple juice was preserved using ultrafiltration and high voltage pulsed electric fields as nonthermal preservation techniques. Changes in quality attributes such as soluble solids, pH, acidity and color were verified for both processes. Changes were tested in terms of membrane pore, transmembrane pressure and recovery percentage for the ultrafiltration treatments, as well as in terms of electric field strength and number of pulses for the pulsed electric fields experiments. Among the quality attributes investigated, soluble solids, pH and acid content did not show significant differences, while color was significantly different for both nonthermal techniques. For the ultrafilteredjuice, a browning trend was observed, whereas for the pulsed electric treated juice an opposite, lightening, tendency was present.