Identification and Quantification of Antioxidant Components of Honeys from Various Floral Sources

Identification and Quantification of Antioxidant Components of Honeys from Various Floral Sources

Journal of Agricultural and Food Chemistry
2002, Vol. 50, No. 21, pp.5870-5877
The objective of this study was to quantify and characterize the antioxidants and some of the isolated phenolic compounds and/or fractions of honeys from seven different floral sources (acacia, buckwheat, clover, fireweed, Hawaiian Christmas berry, tupelo, and soybean). Chromatograms of the phenolic nonpolar fraction of the honeys indicated that most honeys contain similar types but quantitatively different phenolic contents. The primary flavinoids identified were the flavanones pinobanksin, and pinocembrin and the flavones chrysin and galangin. A linear correlation between phenolic content and ORAC activity was demonstrated (R(2) = 0.963, p < 0.0001). Honeys were separated by solid-phase extraction into four fractions to identify the relative contribution of each fraction to the antioxidant activity of honey. Antioxidant analysis of the different honey fractions suggested that the water-soluble fraction contained most of the antioxidant components, including protein; gluconic acid; ascorbic acid; hydroxymethylfuraldehyde; and the combined activities of the enzymes glucose oxidase, catalase and peroxidase. Of these components, a significant correlation could be established only between protein content and ORAC activity (R(2) = 0.674, p = 0.024). These results suggest that the antioxidant capacity of honey is a product of the combined activity of a wide range of compounds including phenolics, peptides, organic acids, enzymes, Maillard reaction products, and possibly other minor components.