Rheological and Microstructural Properties of Porcine Myofibrillar Protein–Lipid Emulsion Composite Gels

Abstract

The objective of the study was to investigate the role of emulsified fat (lard) and oil (peanut oil) in the rheology and microstructure of porcine myofibrillar protein (MP) gels. Heat-induced composite gels were prepared from 2% MP with 0% to 15% pre-emulsified lipids at 0.6 M NaCl, pH 6.2. Dynamic rheological testing upon temperature sweeping (20 to 80 degrees C at 2 degrees C/min) showed substantial increases in G' (an elastic modulus) of MP sols/gels with the addition of emulsions. Gel hardness was markedly enhanced (P < 0.05) by incorporating >or=10% emulsions, and the composite gel with 15% lard was 33% more rigid (P < 0.05) than that with 15% peanut oil. Incorporation of both emulsions at 10% or higher levels improved the water holding capacity of the gels by 28% to 44% (P < 0.05). Light microscopy revealed a compact gel structure filled with protein-coated fat/oil globules that interacted with the protein matrix via disulfide bonds. The results indicated that both physical and chemical forces contributed to the enhancements in the rheology, moisture retention, and lipid stabilization in the MP-emulsion composite gels.

Rheology and microstructure of myofibrillar protein–plant lipid composite gels: Effect of emulsion droplet size and membrane type

“…MP was extracted from thawed pork muscle samples at 2-4°C using an isolation buffer consisting of 0.1 M NaCl, 10 mM sodium phosphate, 2 mM MgCl 2 , 1 mM EGTA, pH 7.0, as described previously (Wu et al, 2009). Isolated MP pellets were washed two times each by suspension in 4 vol of 0.1 M NaCl, adjusting the pH of the suspension to 6.2, followed by centrifugation at 2000g.…”

“…In a previous study, we investigated the effects of animal fat and vegetable oil at different lipid concentrations on the rheological properties of myofibrillar protein (MP) gels (Wu et al, 2009). We noted that pre-emulsified lipids (lard and peanut oil) significantly improved the dynamic rheological performance of the MP gel network with emulsified lard having a stronger influence on the MP gels than emulsified peanut oil.…”

Effect of pre-emulsified sesame oil on physical-chemical and rheological properties of pork batters

“…When heated from 20 °C to 41 °C, G' decreased slowly, and then at a slightly increase from 41 °C to 50 °C, because the meat protein denaturation occurred, and gelation at 45-50 °C was initiated after protein-protein interaction had taken place (Xiong & Brekke;1990). Due to the denaturation of the myosin tails, and this changes could disruption of the protein network that had previously formed at lower temperatures, G' had a moderate decline from 53 °C to 56 °C (Wu et al, 2009b;Álvarez et al, 2012). This was immediately followed by a phase where a rapid increase in G' occurred as the temperature approached 80 °C, because of the transformation of the viscous sol into an elastic gel network (Álvarez, 2012).…”

Preparation, Characterization, andin VitroGastrointestinal Digestibility of Oil-in-Water Emulsion-Agar Gels

“…7) Wu et al have investigated the effects of animal fat and vegetable oil at different lipid compositions on the rheological properties of myofibrillar protein gels. 9) Their results have suggested the feasibility of totally or partially replacing animal fat by vegetable oil in the processing of cholesterol-reduced comminuted muscle foods.…”