Effect of orange juice processing on postharvest pesticides residues: incorporation of UV irradiation as a decontamination strategy

Abstract

Residues of imazalil, propiconazole, and pyrimethanil were assessed. The current Maximum Residue Limits established in the European Union for these compounds are 4, 0.01, and 8 mg/kg, respectively. Samples analyzed included juice with pulp, pulp-free juice, pulp, pasteurized juice, and concentrated juice, to assess the influence of each processing stage on pesticide concentrations. A UV-C (ultraviolet light in the C range, 200–280 nm) radiation stage was evaluated to be incorporated into the process with the aim of a greater reduction on pesticide residues. A modified QuEChERS, followed by gas chromatography-mass spectrometry method was used. Different extraction and reconstitution solvents and clean-up adsorbents were tested. The method demonstrated strong linearity (r² >0.9956), recoveries ranging from 97.3 to 115.6%, and relative standard deviations below 8.1%. The concentration stage results in the greatest reduction of pesticides, with reduction rates of 94.7% for propiconazole, 97.9% for imazalil, and 93.4%, for pyrimethanil. In contrast, the pulping stage shows the lowest reduction. UV-C light treatments resulted in a reduction ranging from 20.9 to 83.3%, depending on the presence of pulp, with a treatment duration of 35 min. These findings demonstrate that conventional juice processing steps contribute to a reduction in pesticide residues, with UV-C treatment showing the greatest degradation rates. Therefore, integrating UV-C exposure as an additional step may enhance the safety of citrus juice by significantly lowering pesticide concentrations.