Physicochemical Properties of Honey from Marche,Central Italy: Classification of Unifloral and Multifloral Honeys by Multivariate Analysis

Abstract

The purpose of this study was the physicochemical characterization and classification of Italian honey from Marche Region with a chemometric approach. A total of 135 honeys of different botanical origins [acacia (Robinia pseudoacacia L.), chestnut (Castanea sativa), coriander (Coriandrum sativum L.), lime (Tilia spp.), sunflower (Helianthus annuus L.), Metcalfa honeydew and multifloral honey] were considered. The average results of electrical conductivity (0.14 – 1.45 mS cm⁻¹), pH (3.89 – 5.42), free acidity (10.9 – 39.0 meq_NaOH kg⁻¹), lactones (2.4 – 4.5 meq_NaOH kg⁻¹), total acidity (14.5 – 40.9 meq_NaOH kg⁻¹), proline (229–665 mg kg⁻¹) and 5-(hydroxy-methyl)-2-furaldehyde (0.6–3.9 mg kg⁻¹) content show wide variability among the analysed honey types, with statistically significant differences between the different honey types. Pattern recognition methods such as principal component analysis and discriminant analysis were performed in order to find a relationship between variables and types of honey and to classify honey on the basis of its physicochemical properties. The variables of electrical conductivity, acidity (free, lactones), pH and proline content exhibited higher discriminant power and provided enough information for the classification and distinction of unifloral honey types, but not for the classification of multifloral honey (100% and 85% of samples correctly classified, respectively).