evaluating the quality and physicochemical properties of honey commercialized in iran

this study was intended to evaluate the quality of 30 honey samples, in terms of physicochemical properties such as moisture content, electrical conductivity, ash content, reducing sugars and sucrose, free acidity, ph, diastase activity, and hydroxymethylfurfural (hmf) content. moreover, three methods recommended by the international honey commission for the determination of hmf, including 1) high performance liquid chromatography (hplc), 2) white spectrophotometry and 3) winkler spectrophotometry methods, were compared. the average moisture content ranged from 12.08±0.36 to 19.36±0.11%. the electrical conductivity values (0.43±0.00 to 0.77±0.00 ms/cm), ash content (0.24±0.01 to 0.74±0.03%), ph values (3.37±0.01 to 5.21±0.16), free acidity (29.60±0.36 to 39.66±0.37 meq/kg of honey), total reducing sugar (52.28±0.09 to 88.01±0.63%), sucrose content (2.21±0.07 to 7.55±0.35%), diastase activity (2.07±0.28 to 29.01±0.50), and hmf content (17.33±0.18 to 834.46±0.30 mg/kg) were observed. thirteen out of 30 samples (43%) showed hmf content higher than standard limits. results obtained from the current study revealed that except for hmf and diastase activity, all physicochemical properties of samples met the national and international standard limits. moreover, three methods applied for determination of hmf showed good recovery values and standard deviation. however, winkler and white methods gave higher hmf value in honey sample than hplc method.