Thiol concentration, structural characteristics and gelling properties of bovine heart protein concentrates

Consumer demand for proteins from animal sources has been increasing with economic growth of the populations. Freeze-dried ground bovine heart was treated using supercritical-CO₂ (SC–CO₂) at different pressures (20, 30 and 40 MPa) and hexane to produce a protein concentrate. Thiol concentration, structural and gelling properties of the control bovine heart and bovine heart protein concentrates (BHPCs) were investigated. SC-CO₂ treatment at 20 MPa led to an increased (p < 0.05) thiol (–SH) content (74.08 nmol/mg protein) than those for the control and other BHPCs. Fourier–transform infrared (FT–IR) spectroscopy showed increased secondary structure of α–helix and parallel β–sheet content for SC-CO₂–treated bovine heart protein when compared to the control and hexane–treated bovine heart protein. Integrated light scattering in protein suspension showed SC-CO₂–treated samples had higher cumulative values (Q3) and density (q3) for the particle size distribution. SC-CO₂–treated BHPC had better physicochemical properties without structural deterioration of proteins resulting in increased functional properties such as solubility (31.08 g/100 g bovine heart), viscosity and gelling capacity (least gelation concentration 10 g/100 mL water). Bovine heart proteins may serve as a good source of quality proteins for different food applications.