Rheological and nuclear magnetic resonance characterization of porcine plasma protein-stabilized gel-like emulsion affected by pH and heating

- Gel-like characteristics of high oil phase porcine plasma protein emulsion were studied.
- Emulsions show elasticity characteristics and has satisfied stability after 48 h storage.
- pH should be higher than 5.5 for structuring gel-like characteristics based on NMR and WHC results.

In the present work, gel-like characteristics of porcine plasma protein oil-in-water (O/W; 52/48, g/100 g) emulsion has been studied under the influence of pH and heating. Viscosity analyses indicated that emulsions exhibited shear-thinning behaviors. Viscosity at pH6.5 and pH7.0 was significant higher than that of pH5.0 (P < 0.05). After 48 h storage, emulsions showed higher stability than 91.07%. From pH 5.0 to 7.0, final storage modulus and final loss modulus showed increase trend; compared with latter, former had always higher value which means more elasticity characteristics. Increase of pH caused a significant hardness strengthened effect (P < 0.05). Within the tested range, water holding capacity ranged from 94.02% to 96.97% indicating good thermal stability. Nuclear magnetic resonance test showed that pH higher than 5.5 bring non-heating emulsion higher T22 fraction which means more non-mobility water (P < 0.05). Cooking exhibited significant positive effects on the non-mobility status of water proton on samples at pH 5.0 and 5.5.Overall, gel-like characteristics of porcine plasma protein emulsion can be modified by pH and heating. Taking into account all factors, plasma protein emulsion should be adjusted to pH higher than 5.5 for the structuring of gel-like characteristics.