2.3.5. Homemade Jam (HJ)

The jam production was based on a local recipe. The peels of the orange samples were gently grated and removed. In order to remove the bitterness of the outer thin layer on the fruit pulp, the pulps were boiled in water 3 times for 15 min. For each time, boiling water was replaced with fresh. Then, the fruits were sliced into 2-cm-thick cubes with a knife. Sugar syrup was prepared by dissolving sugar in water at 1:1 concentration (*w*/*w*) followed by boiling for 30 min. Orange juice (1 mL) was added to the syrup at the end of the boiling step. The fruits were added in to the syrup and cooked at 95 ◦C for 30 min until the jam reached a proper consistency. The hot jam was put into the glass jars. Subsequently, the jars were turned upside down for cap sterilizations and kept in this form until they were cool. pH of the jam was measured as 3.45 ± 0.06 and water-soluble dry matter (Brix) was determined as 72.65 ± 0.64/100 g (RA-500 Model Kyoto Electronics Manufacturing Co. Ltd., Kyoto, Japan).

Samples were stored at −20 ◦C until further analysis.

#### *2.4. Pesticide Residue Analysis*

Acetonitrile, glacial acetic acid, methanol, formic acid (with a quality of sufficient purity that is free of interfering compounds in LC/MS/MS) were obtained from Merck (Germany). Neat reference standards with purity >99% were obtained from Dr. Ehrenstorfer (Germany). Deionized pure water was used (Milli Q purification system, Merck, Germany) for the analysis. The standard solutions were prepared with 1% acetic acid acetonitrile and stored at −18 ◦C. Regarding chopping of the laboratory samples, each unit of the laboratory samples was divided into four, and two cross sections were homogenized until a final particle size of 2–3 mm was obtained (RechtGM 200, Haan, Germany). On the other hand, the laboratory sample coded as HJ was entirely homogenized, and the laboratory samples FJ and GP were not subjected to homogenization. Two analytical portions from each analytical sample were taken and stored for one month at −20 ◦C in capped polypropylene sample vials until further analysis was performed.

The QuEChERS (fast, easy, cheap, effective, robust, and safe) extraction method was applied [20]. The details of the method, including LC-MS/MS identification and equipment parameters, were provided by Acoglu and Yolci Omeroglu [2].

All household processes were repeated three times, and pesticide residue analyses including LC-MS/MS injections were performed in duplicates for each analytical sample. Results were presented as mean ± standard error.
