Evaluation of imazalil dissipation/migration in postharvest papaya using low-temperature partition extraction and GC-MS analysis.

Methods involving solid-liquid extraction with low-temperature partition and analysis by gas chromatography coupled to mass spectrometry (GC-MS) were validated to investigate the dissipation/migration of residues of the postharvest fungicide imazalil in papaya skin, pulp, and seeds. The fruits were stored for 23 days (14 °C). Every two days, fruits from the control group and those treated with imazalil had their skin, outer pulp, inner pulp, and seeds separated and then analyzed by GC-MS. After the 23rd day, about 70% of the imazalil had dissipated. Most of the remaining residue was found in the skin; however, the small amount migrating into the pulp was above the maximum residue levels allowed by the regulatory agencies. Imazalil residue was also detected in seeds at concentrations lower than the LOQ (0.025 mg kg-1). Mass loss was the only quality parameter that showed a significant difference between the fruits of the control and study groups.

The efficacy of washing strategies in the elimination of fungicide residues and the alterations on the quality of bell peppers.

Food safety problems caused by pesticide residues in vegetables have become a top issue to raise public concern. In this study, bell peppers were grown in an experimental field and sprayed with two systemic (azoxystrobin and difenoconazole) and one contact (chlorothalonil) fungicides. Ozone (ozonated water and water continuously bubble with ozone) or conventional domestic (washing with distilled water, detergent, acetic acid, sodium bicarbonate, and sodium hypochlorite solutions) procedures were investigated to identify the most effective way to remove fungicide residues in bell peppers. The residues in the fruits and the washing solutions were determined by solid-liquid extraction with a low-temperature partition (SLE/LTP) and liquid-liquid extraction with a low-temperature partition (LLE/LTP), respectively, and analyzed by gas chromatography. Water continuously bubbled with ozone a concentration of 3 mg L-1 was the most efficient treatment with removal of fungicides residues ranging from 67% to 87%. However, similar treatment at a lower concentration (1 mg L-1) did not only efficiently removed fungicide residues (between 53% and 75%) but also preserving the quality of the fruit along a storage time of 13 days. Among the conventional solutions, sodium bicarbonate at 5% showed good efficiency removing between 60% and 81% of the fungicide residues from bell peppers, affecting the color quality of the fruit. Overall, the most affected physicochemical parameters in bell peppers after the treatments were weight loss, color, and vitamin C content.