Effect of ultrasound followed by high pressure processing on prebiotic cranberry juice.

This work evaluated the effect of high pressure processing (HPP) and ultrasound (US) on the quality of prebiotic cranberry juice fortified with fructo-oligosaccharides (FOS). The juice was subjected to HPP for 5min (450MPa) and to ultrasonic treatment for 5min (600 and 1200W/L) followed by HPP for 5min (450MPa). Chemical analyses were carried out to identify and quantify the anthocyanins, and to quantify FOS, organic acids, instrumental color, soluble solids, pH and antioxidant capacity. Both non-thermal treatments preserved the FOS content maintaining the prebiotic property of the juice. The retention of organic acids was high (>90%) and an increase in anthocyanin content (up to 24%) was observed when ultrasound was followed by HPP. The changes in instrumental color, soluble solids content and pH were negligible. The use of HPP and ultrasound processing has been proven satisfactory to treat prebiotic cranberry juice.