Interpretation of the color due to the ubiquitous nonenzymatic browning phenomena in foods

Abstract

Many foods are subject to browning by heat treatment or long storage times. Either if it is a sign of quality decrease or a desirable feature, it is necessary to characterize fully the color of what is perceived as “brown.” In this paper, we define three stages of browning in foods, ranging from yellow, reddish-brown to dark brown, showing that the commonly employed indexes are not sufficient to describe the later stages of browning, corresponding to the darker colors. Frequently absorbance at a single wavelength, two-dimensional (2D) diagrams, browning index depending on one chromatic coordinate or just L* are employed to describe color in the browning processes in food systems. While these tools are adequate enough to define the evolution of the reaction, they fail to properly characterize the brown color quality: they evaluate either lightness (1D) or the chromatic aspects (2D). In this work, we fully characterized browning in 3D color spaces. The limits for the appropriate use of the different indexes were also defined, according to the browning stage.