Determination of the bioactive properties, mineral and phenolic composition of different solvent-based propolis extracts and their evaluation according to existing regulations

Abstract

Introduction. The propolis is a natural remedy and a popular food supplement worldwide. Botanical origin of raw propolis, bee types, extraction methods, parameters and solvents effect the propolis extract bioactivity and attributes. In this study, 14 propolis extracts (water and ethanol based) were analyzed and compared with the results evaluated according to current regulations. Materials and methods. The physicochemical properties (pH, titration acidity, color, degrees Brix), antioxidant activity (inhibition %), total phenolic content, and phenolic and mineral compositions were determined, and the results were statistically compared (p<0.05). Additionally, the sensory profiles of the propolis extracts were evaluated using principal component analysis. Results and discussion. A significant (p<0.05) correlation was identified between the degrees Brix values of the samples and their total phenolic content, suggesting that the degrees Brix value could serve as an initial indicator for estimating the polyphenol content in propolis extracts. Among the phenolic compounds, chrysin, apigenin, and caffeic acid phenyl ester were found to be the most abundant. The study showed that phenolic content was generally higher in alcohol-based samples compared to water-soluble ones. None of the propolis extracts complied with the "phenolic content" requirement set out in the Turkish Food Codex (TFC) Bee Products Communiqu & eacute;. Potassium and calcium were identified as the most prevalent minerals across all samples, while lead and cadmium were present within the limits specified by TFC regulations on contaminants. Although arsenic is not regulated in the national legislation, it was detected, particularly in alcohol-based samples. Conclusions. It was recommended to establish a limit for As content in bee product regulations. Additionally, similar to the regulations in countries such as Brazil and Ukraine, it was suggested to include standards for total phenolic content or total flavonoid content as quality classification criteria in bee product regulations.