Botanical traceability of unifloral honeys by chemometrics based on head-space gas chromatography

The botanical origin of honey is subjected to severe controls by Food Control Institutions, both for health protection and for frauds prevention. The complexity of honey makes it very difficult to verify the botanical origin. Among the available validated methods, sensory analysis and melissopalynology are the most widely employed. These methods require a long time and deep consolidated expertise. To shorten analysis time while simplifying the analytical procedure, head-space flash gas chromatography was applied in the present study. Chromatographic peak areas were processed by chemometrics (in particular principal components analysis and linear discriminant analysis). Three hundred and thirty-nine honey samples from twelve categories of unifloral honey were analyzed: acacia, citrus, chestnut, thistle, tree heath, eucalyptus, sunflower, rhododendron, lime, French honeysuckle, fir honeydew, and wood honeydew. Each sample was a priori classified by sensory analysis. The multivariate models were validated by cross validation and test-set validation, with predictive abilities always higher than 80%: good results were obtained both in calibration and in prediction mode, showing a good agreement between this new approach and the traditional one for the determination of the botanical origin of honey.