Effect of high hydrostatic pressure on ascorbic acid, phenolic compounds and antioxidant activity of Pera Rio orange juice.

Orange juice is the most popular juice in the world, representing an important source of bioactive compounds in diet. High hydrostatic pressure (HHP) is an alternative technology that does not use high temperature, being able to preserve flavor and nutritional characteristics of the juice. The influence of HHP treatment conditions, pressure (100-600 MPa), temperature (30- 60°C) and time (30-360 s), on ascorbic acid, phenolic compounds and antioxidant activity of orange juice was investigated using response surface methodology. Analysis of variance showed that quadratic polynomial models fitted well with the experimental data for ascorbic acid (R²=0.92, p<0.01) and antioxidant activity using the ABTS*+ assay (R²=0.91, p<0.01). The increase in time and temperature of HHP treatment promoted the reduction of ascorbic acid content and antioxidant activity in orange juice. HHP treatment reduced the ascorbic acid content and antioxidant activity of orange juice. The HHP treatment conditions of 100 to 250 MPa, 30 to 40°C and 30 to 125 s were able to produce orange juice with more than 70% of the initial ascorbic acid content and 80% of the antioxidant activity.