Technique de réflectométrie usuelle pour la mesure de la couleur des mielsS. Auberta, M. Gonnetb and P. Jourdanc
a INRA, station de technologie des produits végétaux, BP 91, domaine Saint-Paul, 84143 Montfavet cedex, France
b INRA, station de recherches de zoologie-apidologie, BP 91, domaine Saint-Paul, 84143 Montfavet cedex, France
c ADAPI, maison des Agriculteurs, 22, avenue H-Pontica, 13126 Aix-en-Provence, France
Abstract - Conventional color-grading techniques of honey
Differences between well-defined colors of honeys (liquid clear, redissolved, turbid or crystallized) can be recognized and standardized using a conventional Cielab 1976 (CIE, 1978) system. This system is less complicated than the classical tristimulative official method of Hardy (1936), with a few allowances for the relative sensitivity detection of human eyes. Colorimetric comparisons of honeys using a bidimensional graphical projection with luminance L* and chromaticity C* (or b*) terms is proposed. Measurements in conventional Petri dishes with a regular reflectometric chromameter were analysed for different colored honey samples. The characterization of the origin of unifloral genuine honey (table I) using the classic Hardy system (fig 1) new or conventional criteria (fig 2) gave the same results. Variability between the measured values for the samples depends on the geometry of commercial container, but is smaller than the annual parameters. The influence of sample collection conditions of lavender honey (table II, fig 3), and the change with added yellow typical sunflower honey (table III, fig 4) were analyzed as having different chromatic values. Observations on the crystallization on the bottom of the container (fig 5) or on the side wall of the commercial container also gave good results on color perception, but measurements in conventional Petri dishes were better.
Key words: honey / colorimetry / crystallization / blend / characterization