Mild oxidation promotes protein network formation and enhances gelation of myofibrillar protein under normal salt and pH conditions used in meat processing. This oxidative effect, which involves disulfide linkages, is somewhat similar to that in bakery product processing where oxidants are used to improve dough performance through gluten protein interaction.

Fresh prawns were subjected to five freeze-thaw cycles (Ϫ29ЊC 22ЊC) → ← and associated physicochemical changes in muscle were determined. Shear force to break prawn tails was dependent on prawn size, more on weight (r ϭ 0.75-0.81) than on diameter (r ϭ 0.56-0.66). No change (P Ͼ 0.05) in shear force was observed in raw prawns after five freeze-thaw cycles. However, shear force of cooked prawns decreased after three freeze-thaw cycles which coincided with accelerated lipid oxidation in raw prawns. Electrophoretic analysis revealed gradual decreases in myosin, actin, and most other myofibrillar proteins with each successive freeze-thaw cycle. Enthalpy of protein denaturation decreased from 16.6 J/g (fresh) to 13.5 J/g after one freeze-thaw cycle with minor changes thereafter.

No abstract

Dynamic rheological properties were investigated during gelation of chicken myofibrillar protein as influenced by heating procedures, Thermal scan (l"C/min) of myofibril suspensions in 0.6M NaCl @H 6.0) induced a major transition in storage modulus (G', peak 48°C) preceded by a transition in protein-protein aggregation (46°C) and accompanied by a marked reduction in actomyosin solubility. Preheating at 50°C diminished the transition and resulted in increased final G' value. Isothermal heating produced complex, temperature-dependent rheological changes'@ and phase angles), particularly within 43-58°C. The rheological transitions of myofibrillar protein were probably related to kinetic changes during formation of elastic gel networks. Such rheological data on gel formation can help predict and control muscle food responses to specific thermal processes.