30A-29 |
Characterization of the antioxidants in honeys from different floral sources |
N. GHELDOF1, X. Wang, and N. Engeseth. (1) Dept. of Food Science & Human Nutrition, Univ. of Illinois, Urbana-Champaign, 259 ERML, 1201 W. Gregory Dr., Urbana, IL 61801 Since ancient times, honey has been valued as a flavorful sweetener, but also for its therapeutic and medicinal uses. Recently, consumer's demand for natural, healthy products has driven renewed interest in health benefits of honey. Previous research demonstrated that honeys from various floral sources exhibited a range of antioxidant activities. Antioxidant properties of honey were effective against deteriorative oxidation reactions in foods. Little is known about individual honey components that are responsible for its protective effects. The major objective of this study was to characterize the antioxidant content of seven different honeys. Specific antioxidant components, including phenolic compounds, ascorbic acid, and the enzymes glucose oxidase, catalase and peroxidase were identified and/or quantified. Antioxidant properties of honey were confirmed by using the ORAC assay. Ascorbic acid and phenolic compounds of various honeys were analyzed by RP-HPLC. Total phenolic content was measured by the Folin-Ciocalteau method. The combined activity of glucose oxidase, catalase and peroxidase in honey was assessed by measuring peroxide accumulation. Chromatograms of phenolic fractions of honeys indicated that most honeys have similar but quantitatively different phenolic profiles. Unique distributions of phenolics to individual honeys were highlighted. Enzyme activity and ascorbic acid were very low, if not undetectable, in all honeys. ORAC values ranged from 3.1 to 16.3 mmol Trolox equivalent /g honey, the darkest colored honey having the highest ORAC value. A linear correlation was observed between total phenolic content and ORAC activity for honeys (R2=0.9352). The antioxidant capacity of the honeys appeared to be primarily due to their phenolic composition as opposed to enzymatic antioxidants and ascorbic acid. Characterization of the honeys helps in understanding their antioxidant behavior and hence promotes their use as a natural food ingredient and as a source of antioxidants in the human diet.
Session 30A, Food Chemistry: Lipids
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