What are the yellow crystals that sometimes form in canned asparagus?
The yellow crystals that sometimes form in canned asparagus are deposits of rutin, a pigment which occurs naturally in asparagus. If the vegetable was packed in water with a high iron content, the precipitated rutin may be grey or black rather than yellow. Either way, it is harmless.
Barbara Willenberg, Nutritional Sciences, University of Missouri-Columbia
Last update: Tuesday, May 05, 2009