A while back, Spinning Straw into Gold provided a link to this article, Snow White and the Philosopher's Stone, by John Patrick Pazdziora, which sheds light on the color symbolism in Snow White. Christie and her readers go on in the comments to consider the colors in Little Red Riding Hood as alchemical as well. From the article:
Eleanor Vere Boyle
Recently, reader Kelli Orazi of The Middle Page wrote an excellent post which looked at Beauty and the Beast as a potential alchemical tale.
As Christie and Kelli point out, this was not necesssarily the author's intentions when writing the tales, but something to consider, especially when looking at earlier versions of fairy tales. It would certainly help to explain why the colors black, white, red, and gold are so prevalent across stories from multiple cultures.