Transglutaminase Cross‐linking of Whey/Myofibrillar Proteins and the Effect on Protein Gelation

Transglutaminse (TGase)‐catalyzed interactions of whey (WPI)/myofibrillar (MPI) protein isolates were investigated under 5 conditions: (1) ionic strengths; (2) calcium/ethylenediaminetetra‐acetic acid (EDTA); (3) enzyme:substrate ratio; (4) WPI:MPI ratio; and (5) preheating of WPI (80 °C). TGase treatments of MPI in distilled water converted myosin heavy chain and actin into lower‐molecular‐weight polypeptides. The reaction, accelerated by the presence of WPI but diminished by NaCl, was completely reversed upon extended incubation. There was no visible WPI/MPI cross‐linking; and the enzyme:substrate or WPI:MPI ratio, preheating, calcium, and EDTA did not influence the enzyme reaction. TGase treatment did not alter the melting pattern of WPI/MPI mixtures, but markedly enhanced their thermal gelling ability.