Distribution of phthalic acid esters in propolis ethanolic extract and capsuled propolis

Phthalate esters (PAEs), commonly used in food packaging materials, pose a potential health risk due to their migration into food matrices. Propolis, a resinous bee product widely consumed for its health benefits, is often packaged in plastics, raising concerns about PAE contamination. However, the occurrence of PAEs within propolis has been scarcely investigated. This study quantified PAE contamination profiles in propolis ethanolic extracts (PE) and propolis capsules (PCs) from China. The GC-MS/MS analysis of 20 PAEs demonstrated high linearity, indicating the reliability of the method. The limits of quantification (LOQ) ranged from 1.3 to 26.2 µg/kg, and the limits of detection (LOD) ranged from 0.4 to 8.6 µg/kg. Matrix effects ranged between 9% and 33%. Five PAEs were detected in PE samples: dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP), dibutyl phthalate (DBP) and bis(2-ethylhexyl)phthalate (DEHP). Seventeen PAEs were detected in PC samples, with 15 consistently present in all samples (100% positivity). Diallyl phthalate (DAP), dipropyl phthalate (DPrP) and di-n-octyl phthalate (DNOP) were not detected in any sample. The total mean concentration of the 17 detected PAEs (∑17 PAEs) in the capsules ranged from 0.87 mg/kg to 23.71 mg/kg. This study found that PE and PC had the highest DBP (0.24 mg/kg) and di-heptyl phthalate (DHP: 2.29 mg/kg) levels on average, respectively. While PC showed higher PAE levels than PE. Therefore, this study provides insight into PAE contamination of raw propolis extract and encapsulated propolis.