Interfacial properties and inter-relationship of sarcoplasmic and myofibrillar proteins in simulated muscle protein extracts: Effect of salt reduction and pea protein

Sodium reduction in meat products has been a strategic goal for decades, but the progress has been slow due to compromised functionality of myofibrillar protein (MP). The present study attempted to accentuate emulsifying activity of sarcoplasmic protein (SP) and understand the inter-relationship of SP and MP in mixed soluble muscle protein (SMP) extracted under simulated salt-reducing meat processing conditions. The SMP extracts with various “in situ” SP:MP ratios and structurally modified (ultrasound and pH12-shifting) pea protein supplements were subjected to interfacial analysis and emulsion preparation at salt concentrations of 0.1–0.6 M NaCl. In low-salt conditions (0.1–0.3 M NaCl), the SP-rich SMP exhibited strong initial interfacial adsorptivity compared with high-salt conditions (0.4–0.6 M NaCl), and the inclusion of 2% pea protein further improved (P < 0.05) the surface hydrophobicity (170–260%), interfacial pressure (2–11%), emulsifying activity (11–65%), and emulsion stability (7–35%). SP was responsible for emulsifying properties of SMP at < 0.4 M NaCl and had no appreciable effect on emulsifying activity of MP-dominated meat extract under higher-salt conditions. Results from this simulated SP/MP extract study indicate the feasibility to produce low-salt meat emulsions when aided by structurally modified pea protein.