Sources of color in soybean “lecithin”

Summary The color of soybean lecithin is due to carotenoids, brown pigments, and occasionally porphyrins. In the water‐washing of crude oil xanthophylls are preferentially removed with the gums, and carotene is practically absent in lecithin. Lutein is the principal carotenoid, comprising about three‐quarters of the carotenoids in lecithin. Hydrogen peroxide bleaching destroys all the color to some extent, but by far the greater effect is on the carotenoids. The brown color is very likely an aldehyde amine reaction product. It is largely formed by heating of the oil during the solvent‐stripping operation. It is not increased by drying the gums under vacuum for 3 hours at 80°C. but it is increased on heating at 100° C. under the same conditions. The formation of the brown color is not prevented by removal of free sugars or by hydrogenation of the lecithin.