Özet:

In this study, 9 active substances that could be analysed by Gas Chromatography-Mass Spectrometer (GC/MS) were used. Changes in these pesticide residues were determined after strawberries were washed, pasteurized, stored in cold and washed on different days. In addition, strawberry puree was stored at -18±2ºC and pasteurized puree was stored at different temperatures. The highest and lowest processing factors in the pasteurization process were determined in tebufenpyrad (Pf:1.20) and tetraconazole (Pf:0.81), respectively. During cold storage, kresoxim-methyl degradation was found statistically significant (p<0.05). At the end of cold storage, penconazole was below the quantification limit while pyrimethanil and tebufenpyrad did not change; however, azoxystrobin, boscalid, tetraconazole and kresoxim-methyl residues decreased by 3.8, 10.9, 25.0 and 36.4%, respectively. Washing process did not reduce tebufenpyrad residues. On the other hand, reduction rates were 3.8, 4.2, 4.5 and 9.1% for azoxystrobin, pyrimethanil, bupirimate and kresoxim-methyl, respectively while they were 10.9% for boscalid and 16.7% for tetraconazole. During long-term storage, the highest and the fastest decrease in pesticide residues was observed at 20±2ºC, and this decrease slowed down with the effect of pasteurization. Pesticide degradation rates at the end of one-year storage period in the samples stored at -18±2 ºC following pasteurization were 20, 23, 26, 27, 37 and 41% for tetraconazole, pyrimethanil, azoxystrobin, kresoxim-methyl, boscalid and bupirimate, respectively. As a result, it was found that pesticide degradation was dependent upon the chemical nature of pesticides, initial concentration, agricultural commodity, processing and storage conditions.

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