Abstract
The effectiveness of different postharvest wash treatments at two levels (10 and 20 g/l) for different dipping times was determined to remove chlorpyrifos from date fruits treated at concentration of 2 mg/l. The recovered amount of chlorpyrifos was extracted based on the solid phase extraction (SPE) method and then analyzed by gas chromatography with mass spectrometry (GC-MS). The results demonstrate that the removal of chlorpyrifos increased in the order of acetic acid (AA)> citric acid (CA)> hydrogen peroxide (H
2
O
2
)> potassium permanganate (KMnO
4
)> running water (H
2
O), and the percent of pesticide residue on date fruits depended on the concentration of tested washing treatments and dipping time without the formation of the toxic by-product, chlorpyrifos-oxon. Kinetic studies revealed that chlorpyrifos was found to be more easily removable from date fruits treated with the tested chemical solutions with t
1/2
values of 12–29 min compared with roughly 53 min in case of running water. The impact of these washing treatments on quality of date fruits illustrated that all treatments exerted a little negative effect on total sugars content but H
2
O
2
and KMnO4 at level of 2 % had more drastic effect. Whereas, running water, 10 and 20 g/l CA caused significant increases in total phenolic contents, during all the tested contact times compared with control. Except the insignificant effect of KMnO
4
treatments, antioxidant capacity of date fruits tended to increase in all wash treatments, when the contact times were 5 or 15 min.