Characterization and classification of commercial thyme honeys produced in specific Mediterranean countries according to geographical origin, using physicochemical parameter values and mineral content in combination with chemometrics

The aim of the present study was to provide information on physicochemical (pH, free, lactonic, and total acidity, electrical conductivity, moisture, ash, lactonic/free acidity), colour parameters (L*, a*, b*), and mineral content (Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sb, Se, Si, Ti, Tl, V, Zn) of 34 commercial thyme honeys produced in Egypt, Morocco, Greece, and Spain, in terms of characterization and geographical discrimination using MANOVA/LDA, chemometric analyses. Conventional physicochemical and colour parameters were determined using official methods of analysis. Minerals were quantified using inductively coupled plasma optical emission spectroscopy (ICP-OES). Results showed that all honey samples analysed met the standard quality criteria set by the EU. In order to classify honeys according to geographical origin, MANOVA and LDA were applied in sequence. Respective classification rates based on cross-validation method were: 91.2, 76.5, and 88.2%, using 10 physicochemical and colour parameters, 12 minerals, and their combination, respectively. Testing whether the determined physicochemical parameters of commercial Mediterranean thyme honeys could be applied to routine quality control serving as honey origin predictors showed positive results. Finally, such a combination of data enhances honey quality control and authentication efforts, at an international level.