Influence of sonication and high hydrostatic pressure on the quality of carrot juice

Summary The combined effects of ultrasound ( US ) and high hydrostatic pressure ( HHP ) on enzymes, micro‐organisms, colouring pigments, total polyphenols, ascorbic acid and physicochemical properties of carrot juice were investigated. Carrot juice was treated with sonication (20 kHz, 70% amplitude) and HHP (250, 350, 450 MPa) at room temperature for 10 min. For comparison, fresh carrots were water blanched ( WB ) at 100 °C for 4 min and carrot juice was then extracted. As results, highest improvements in colouring pigments were observed in WB and US ‐ HHP 450 treatments, which also completely inactivated micro‐organisms. The highest reduction in enzymes was observed in WB treatment followed by US ‐ HHP 450. Total polyphenol contents increased significantly in US , HHP and US ‐ HHP treatments with the highest increase in US ‐ HHP 450, but it decreased significantly in WB treatment. Ascorbic acid contents significantly decreased in WB and HHP 450, while increased in US and US ‐ HHP treatments. Results indicate that US ‐ HHP 450 treatment improves the quality of carrot juice and serves as a good alternative for blanching treatment.