Effect of wax separation on macro- and micro-elements, phenolic compounds, pesticide residues, and toxic elements in propolis

Abstract

Propolis, a natural product with many biological activities, is a resinous material produced by honeybees. It contains not only valuable components but also some possible contaminants in varying amounts. Hence, this study aimed to examine how the process step of wax separation affects certain elements, pesticide residues, and phenolic compounds in propolis. Total phenolics, elements, and some pesticide residues were analyzed in the crude propolis (CP samples), wax portion (W samples), and remaining propolis fraction (PF samples) after wax separation. Total phenolics of the CP samples were determined in the range of 31.90–45.00 mg GAE g−1 sample, while those of the PF samples were in the range of 54.97–162.09 mg GAE g−1 sample. Loss/reduction values by means of wax separation for phenolics were calculated as 10.88% and 17.89%, respectively. Pb contents of all PF samples were low (0.232–1.520 mg kg−1), but it was also noteworthy that nearly 40% or even more of Cr, As, Cd, and Pb were removed by wax separation. Removal of significant amounts of carbendazim (38.09%–67.35%), metalaxyl (81.57%–72.67%), tebuconazole (65.99%–78.36%), and propargite (88.46%–83.05%) was also achieved. Wax separation enables the removal of toxic substances from crude propolis without causing huge losses in phenolic compounds.