Role of myofibrillar proteins in water-binding in brine-enhanced meats

Brine-incorporated meats have become major novelty food items in the present fresh meat retail market in the United States. Brines are used to “enhance” products' moistness and juiciness; however, the physicochemical processes involved in water-binding and entrapment in the meat protein matrix have not been completely elucidated. This paper describes our recent studies on the mode of water-binding in chicken and pork muscle foods following phosphate, NaCl, and enzyme-hydrolyzed soy protein brine treatments. The results showed that the dynamics of brine penetration into muscle fibrils were specific to phosphate types, with pyrophosphate and tripolyphosphate having the highest efficacy. Both phosphate treatments produced a transverse expansion of the myofibrils with a simultaneous extraction of myosin from the ends of the A-band in the sarcomere. These structural/biochemical changes resulted in substantial swelling of muscle fibers, i.e., an enhanced water uptake and immobilization. Furthermore, depending on the type of proteases employed, soy protein hydrolysates or peptides interacted differently with myofibrillar proteins, producing an array of morphologies and rheologies of protein gels that played a major role in water-immobilization in salted pork products.