Effects of pulsed magnetic field on microbial and enzymic inactivation and quality attributes of orange juice

Abstract

Pulsed magnetic field (PMF, 5–7 T, 5–30 pulses) was applied to orange juice to evaluate its effects on inactivation of microbiota and enzyme and quality attributes. PMF decreased the activities of mesophilic baceria and yeast and mold by the highest log reduction of 0.61 at 7 T with 20 pulses and 0.36 at 7 T with 30 pulses, respectively. Peroxidase (POD) and pectin methylesterase (PME) activities were partially inactivated. PMF showed a good potential to inactivate PME and the lowest residual activity of PME was 50.28% obtained at 6 T with 20 pulses. No significant change in soluble solids and small changes in the pH, titratable acidity, and color were observed after PMF treatment. PMF brought about a slight decrease of ascorbic acid, phenolic compounds, and antioxidant capacity (DPPH​ and ABTS) in orange juice. Therefore, PMF appears to be a promising technogy involving microbial and enzymic inactivation with small changes in juice quality. Novelty Impact Statement Pulsed magnetic field could inactivate mesophilic bacteria and yeast and mold in orange juice. Pulsed magnetic field had a good potential to inactivate pectin methylesterase in orange juice. The minor quality degradation in orange juice was observed after pulsed magnetic field treatment.