Viscous properties of microparticulated dairy proteins and sucrose.
Slurries of whey protein concentrate (WPC) or sodium caseinate (Na-CN) mixed with sucrose (36% T.S.) were subjected to microparticulation by a high shear homogenizer operated at 27,000 rpm for 2, 4, and 6 min to facilitate gel formation. After microparticulation treatment, the milk protein and sucrose slurries were evaporated at 85 degrees C for 60 min under a partial vacuum (20 to 45 mm of Hg) to form composite gels. Particle sizes and viscoelastic properties were determined before microparticulation treatment. Microparticulation reduced the particle size of WPC-sucrose slurries from an average size of 330 to 188 nm after 4 min and NaCN-sucrose slurries from 270 to 35 nm after 2 min. The WPC-sucrose composites were gel-like, but NaCN-sucrose composites did not gel. Viscoelastic properties of heated WPC-sucrose composites were liquid-like, exhibiting significant reduction in storage modulus and complex viscosity. Microparticulation reduced particle sizes, which resulted in softer gels as time of shearing increased.
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US Department of Agriculture, ARS, Eastern Regional Research Center, Wyndmoor, PA 19038, USA. Conulata@arserrc.gov
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D000818:Animals; D002364:Caseins / Q000737:chemistry; D002614:Chelating Agents / Q000737:chemistry; D005524:Food Technology; D005782:Gels; D008855:Microscopy, Electron, Scanning; D008894:Milk Proteins / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D012212:Rheology; D013395:Sucrose / Q000737:chemistry*; D014783:Viscosity
D002364:Caseins; D002614:Chelating Agents; D005782:Gels; D008894:Milk Proteins; D013395:Sucrose