Competitive adsorption and dilatational rheology of pork myofibrillar and sarcoplasmic proteins at the O/W emulsion interface

The competitive adsorption behavior of pork sarcoplasmic (SP) and myofibrillar (MP) proteins, alone or mixed (ratios 6:4, 5:5 and 4:6, w/w) in 0.6 M NaCl, at the oil-water interface was investigated. SP adsorbed more rapidly than MP at the oil surface establishing a ~10 mN/m dynamic interfacial pressure (π). However, the dilatational elasticity (E_d) of the SP film was low when compared with MP. For corn oil emulsions prepared with mixed proteins, the poor interfacial adsorption (29%) and low emulsifying activity (3.42 m²/g) of SP were overcome by substitutions with MP that strongly bound to oil. Unabsorbed proteins were mostly SP and secondarily tropomyosin and C-protein from MP. Smaller droplets were observed in MP emulsions than in SP emulsions. Therefore, while both SP and MP contributed to the formation of O/W emulsions, MP played a far more competitive role due to its stronger interfacial adsorption and adhesion properties.