The superficial appearance and color of foods are the first parameters of quality evaluated by consumers and are thus critical factors for acceptance of the food item by the consumers. The colour of these products is likely to change when exposed to air (e.g. oxidation, greying). The characterization of this colour change over time is a necessity in order to evaluate the acceptability of a genotype by the consumer. The present document aims at describing step by step a standardized procedure to characterize this color change over time. The principle relies on repeated image acquisition of the same RTB product over time followed by image analysis to characterize RTB product colour evolution at each timestamp. After image acquisition, the first step aims at identifying the pixel coordinates of the RTB product using segmentation based on RGB values of the first image. This procedure allows to subtract the background from all images of a series. The RTB product colour is then characterized at each timestamp allowing to estimate colour difference indices and colour change dynamic.