Physicochemical Variability and Quality of Honey from the Zagreb Region: The Role of Botanical Origin and Spatial Structure

The physicochemical composition of honey reflects its botanical origin, environmental conditions, and post-harvest handling; however, studies that combine long-term monitoring data with multivariate and spatial analyses at a metropolitan scale remain limited. This study analyzed acacia, chestnut, flower, and meadow honeys from the Zagreb metropolitan region, Croatia, using a long-term physicochemical quality dataset from the Zzzagimed International Honey Quality Competition collected between 2007 and 2019. From a total database of 351 samples, 82 georeferenced samples from the City of Zagreb and Zagreb County were selected and evaluated for moisture, electrical conductivity, free acidity, and hydroxymethylfurfural (HMF). Most samples met general honey quality requirements: only three samples exceeded the moisture threshold of 20%, and no samples exceeded the limits for HMF or free acidity. Electrical conductivity and free acidity provided the clearest differentiation among honey types, ranging from 0.22 to 1.47 mS/cm and from 9.77 to 27.38 meq/kg, respectively. Multivariate analysis showed that physicochemical variability was structured primarily by honey type, with the first two principal components explaining 62.8% of the total variance. Spatial analyses revealed weak to moderate spatial structure, with residual autocorrelation retained only for free acidity. Honeys from the Zagreb region showed good physicochemical quality, and their variability was driven mainly by declared botanical origin rather than by broad City–County differences.