Flow Behavior of Mixed-Protein Incipient Gels

Abstract

Strong protein gel networks may result from synergistic interactions with other proteins or food materials above that are not achievable with a single protein alone. The varying flow and viscoelastic behavior of calcium caseinate or whey protein isolate mixed with egg albumin, fish protein isolate, soy protein isolate, or wheat gluten in a model system with wheat flour and glycerol as starch and oil surrogates was determined. Temperature sweeps revealed peak tan δ values as the proteins aggregated. Single protein gels of calcium caseinate, soy protein isolate, and wheat gluten were predominantly elastic, while egg albumin and whey protein isolate gels were mostly viscous. For example, egg albumin steady shear viscosities were: 0.0145 Pa s (0.5 min) and 0.1331 Pa s (45 min), and whey protein isolate 0.0003 Pa s (0.5 min) and 0.0024 Pa s (45 min); but combined with whey protein isolate (whey protein isolate/egg albumin: 10/5 wt%), the apparent viscosity values dropped to 0.0053 Pa.s (0.5 min) and 0.0221 Pa s (45 min), respectively.