Colour of hard cheese .1. Description of colour properties and effects of maturation

During ripening, body colour of Emmental cheeses was evaluated by tristimulus reflectance measurements. Tristimulus primaries were transformed to the Helmholtz system and into CIELAB-coordinates in order to obtain interpretable results. Apart from lightness decreasing with increasing maturation time, it was found by using both systems that, (1) colourfulness increased continuously up to a cheese age of approximately 10 weeks and then remained constant, and (2) the hue of the cheese body shifted towards a slightly more orange colour in the last stage of ripening. The yellowness index, which represents a one-dimensional measure calculated from tristimulus primaries, is proposed as a simple and adequate measure of cheese body colour, and interrelations with CIELAB-values commonly used in food science are outlined.