Determination of Trace Metals and Polyphnols in Honey from South and North Wollo Zones, Ethiopia

Abstract

Honey is a natural product valued for its nutritional and antioxidant properties, which are influenced by its mineral composition and polyphenolic content. This study aimed to determine the concentrations of selected trace metals (Fe, Ni, Mn, Cu, and Zn) and total polyphenols in honey samples collected from six districts of North Wollo (Wadal, Meket, and Gubalafo) and South Wollo (Ambasel, Delanta, and Tehuledere), Ethiopia. The concentrations of metals were determined by using flame atomic absorption spectroscopy after acid digestion of the honey samples. Total polyphenol contents were determined using the Folin–Ciocalteu method with UV–Vis spectroscopy and results expressed as milligrams of gallic acid equivalents per kilogram (mg GAE/kg). The concentrations of Fe, Ni, Mn, Cu, and Zn in the honey samples ranged from 24.2–85.8 mg/kg, 5.6–15.1 mg/kg, 14.9–25.8 mg/kg, 5.1–16.6 mg/kg, and 12.2–53.5 mg/kg, respectively. The limits of detection (LOD) for Fe, Ni, Mn, Cu, and Zn were 4.2, 1.2, 2.3, 1.4, and 2.1 mg/kg, respectively. Except for samples from Wadal, Fe was the most abundant metal followed by Zn. Method accuracy was evaluated using spiked honey samples, and the mean percentage recoveries ranged from 83.9% to 112.5%, indicating acceptable analytical performance. The polyphenol content of the honey samples ranged from 519.8 to 1221.7 mg GAE/kg. The mean total polyphenol content was higher in honey from North Wollo (893.5 mg GAE/kg) than from South Wollo (707.3 mg GAE/kg). The results indicate that honey from the study areas contains appreciable levels of essential trace metals and bioactive polyphenols, suggesting its potential nutritional and antioxidant benefits.