Blood factor XIII is a transglutaminase that occurs as a enzymogen in plasma, placenta and platelets. Transglutaminase was first extracted from bovine blood in 1983, in order to improve the binding ability of fresh meat products at chilling temperature. It showed how myosin was cross-linked by TGase. An important property of the TGase reaction was documented when cross-linking between myosin and proteins (soy, casein and gluten), all commonly used in meat processing, was found. Moreover, the restructured meat products can be processed without heating, and their salt and phosphate content reduced, by the addition of TGase from animal blood.