From the article: "But Impossible Foods thinks the essence of a meat lies in a compound called heme, which gives ground beef its color and vaguely metallic tast

From the article: "But Impossible Foods thinks the essence of a meat lies in a compound called heme, which gives ground beef its color and vaguely metallic taste—thanks to iron in the heme molecule. In blood, heme lives in a protein called hemoglobin; in muscle, it's in myoglobin." The blood might cook out of the final burger, but it affects the taste and texture. In that respect it's not unlike cooking with wine, liquor, or cider, with which the alcohol will cook out.