Ascorbic acid in orange juice-based beverages processed by pulsed electric fields

Citrus fruits have been widely used as ingredients in fruit juices and beverages. However, vitamin C content may be reduced by thermal processing, thus reducing beneficial health effects. For this reason, the degradation kinetics of ascorbic acid were determined in orange juice based beverages after treatment by pulsed electric field, a novel emerging technology with increasing interest in the conservation of juices. The orange juice and orange-carrot juice mixture fitted a linear model, while the orange juice- milk beverage followed an exponential model. The degradation constants obtained in the orange juice were 0.00046±1•10-4, -0.00051±5•10-5, -0.00074±8•10-5, and - 0.00095±1•10-4 μs-1 for fields of 25, 30, 35, and 40 kV/cm, respectively. In the case of the orange-carrot juice they were -0.00037±3•10-5, -0.00042±5•10-5, -0.00119±7•10-5, and -0.00091±2•10-4 μs-1 for fields of 25, 30, 35, and 40 kV/cm, respectively, and for the orange juice-milk beverage they were -0.00012±3•10-5, -0.00022±5•10-5, - 0.00042±7•10-5, and -0.00061±6•10-5 μs-1 for fields of 15, 25, 35, and 40 kV/cm, respectively, demonstrating the use of PEF as an alternative to pasteurization treatments. The D value increased with electric field strength, and the ZE values were 42.9, 30.6, and 35.1 kV/cm for the orange juice, orange-carrot mixture, and orange juice-milk beverage, respectively. Therefore, the orange juice was more resistant to changes in electric field strength in PEF treatment, while the treatment time required to produce the same degradation of ascorbic acid was greater in the orange juice-milk beverage than for the orange juice or the orange-carrot juice mixture, showing the need to optimize treatment conditions whenever there is a change in the food matrix.