Color measurement of rosemary honey in the solid state by reflectance spectroscopy with black background.

A colorimetric method was developed to measure the color of rosemary honeys in the solid state, without liquefaction. The color of 20 solid samples of rosemary honeys was measured by reflectance spectroscopy with white and black background in cells of 1 cm pathlength. The Kulbelka-Munk theory of turbid media was applied to calculate the spectral distribution of reflectivity, internal transmittance, and coefficients of absorbance and scattering of light. From these spectral distributions, 2 different types of honey were found. The honey colors measured from reflectivity and internal transmittance are well grouped. The colors obtained from reflectivity and those obtained from reflectance with black background show high linear correlation (r2 > 0.99). As a practical application, measurements of reflectance with black background in cells of 1 cm pathlength can be used to determine the color of these honeys in the solid state.