Palynological, physico-chemical and colour characterization of Moroccan honeys: I. River red gum (Eucalyptus camaldulensis Dehnh) honey

The melissopalynological, physico-chemical and colour characteristics of Eucalyptus honeys from Morocco were studied. It is generally accepted that a minimum content of 70% of Eucalyptus pollen is necessary to classify an Eucalyptus honey as unifloral. Twenty-eight physico-chemical and five colour parameters were measured, including the content of sugars and minerals, proline, water content, pH, acidity, hydroxymethylfurfural, diastase activity, ash, electrical conductivity, colour coordinates (L*, a*, b*), chroma (C*ab) and hue angle (hab). Pollen analysis was included, and samples contained a mean of six pollen types (range 2–12). The majority of the samples (75%) contained more than 90%Eucalyptus pollen. The presence of Quercus, Plantago and Thymelaea pollen allows the differentiation of these honeys from those with a different geographical origin. Physico-chemical analysis showed that there was a low percentage of sucrose ( = 0.01%) and trisaccharides. Mineral analysis showed a low percentage of Mg ( = 25.99 ppm) and K ( = 205 ppm), while electrical conductivity ( = 721 μS cm−1) and diastase activity ( = 39.05 °Gothe) showed medium-high values. The colour parameters lightness (L*) and chroma (C*ab) showed relatively low values.