Color changes during storage of honeys in relation to their composition and initial color

The causes of darkening in honey have been attributed to Maillard reaction, fructose caramelization and reactions of polyphenols, however, no systematic studies exist on this subject. The influence of composition and initial color on the rate of darkening of several Argentine honeys submitted to storage at 37 degrees C during 90 days was evaluated through spectrocolorimetric measurements. The most suitable color functions to evaluate darkening of honeys [lightness (L-ab*), browning index (BI), metric chroma (C-ab*), metric hue (H-ab*) and 1/Z] increased linearly as storage time increased, after an initial induction period of very low browning development. The slope of the linear browning development zone with time was an index of browning rate, and it was analyzed in relation to the initial color and the composition of honeys (moisture content, total nitrogen, total lipids and polyunsaturated fatty acids, fructose and glucose content). Of the analyzed variables, the initial color was the parameter which better defined the rate of darkening of honeys. (C) 1999 Published by Elsevier Science Ltd on behalf of the Canadian Institute of Food Science and Technology. All rights reserved.