Why cow ghee is yellow?
The color yellow comes from the fact that the cow's milk fat contains a pigment called the Beta-carotene, the carotenoid which is a precursor of vitamin-A. The color yellow in ghee variants stands true only if the cows have been taken care of well and fed good fodder.
The white variety of ghee is made from buffalo's milk, the yellow one is made from cow's milk.
yellowish
The real colour of pure desi ghee is yellowish or golden. The granular part of ghee that settles down at the bottom is whiter than the liquid golden part of ghee that floats at the top.
Always check for mold or discoloration before using ghee. It has gone rancid. Rancidity occurs when ghee oxidizes, or gets exposed to moisture, heat, light, or air for too long. Rancid ghee has a sour flavor and an unpleasant odor and may appear white instead of yellow.
One of the simplest measures is to heat a teaspoon of ghee in a vessel. If the ghee melts immediately and turns dark brownish in colour, then it is of pure quality. However, if it takes time to melt and turns light yellow in colour, it is best avoided.