“We eat with our eyes first,” says one article on baking,1 with color so important for baking success that companies actually make meters to measure it. Egg products can contribute to product color in two ways; browning on the product exterior in the case of baked goods, or the product itself such as coloring mayonnaise or muffin interiors.
The proteins within eggs can participate in the Maillard reaction when exposed to heat, producing a desirable brown color. The Maillard reaction is responsible for the golden crust of baked products such as yellow batter cake,2 meat browning and the dark color of roasted coffee.3
In addition, egg yolk contributes rich color to various foods via xanthophyll, a carotenoid with a yellow-orange pigment that gives the yolk its characteristic color.4 Egg yolks impart a rich yellow color to cakes and are often used to fortify whole egg products within formulations to yield a more intense color or increased emulsifying action. The pleasing color that eggs impart to baked foods has long been accepted as a mark of superior quality.5
The beautiful yellow/orange hues of egg yolk, or the xanthophyll it contains, add “richness in color,” which aids perceived quality and freshness for products from mayonnaise to baking applications.6,7 The xanthophyll content, the major pigment in egg yolk, is stable under most conditions encountered in food processing.4
While color is an important factor in food product development, it is “rare for eggs to be used as an ingredient in food products for their color contribution alone,” says one author, since eggs possess multiple functional benefits beyond this coloring ability.6