Naslov
The influence of temperature and solid matter content on the viscosity of whey protein concentrates and skim milk powder before and after tribomechanical treatment

Autori
Herceg, Zoran ; Lelas, Vesna

Izvornik
Journal of Food Engineering (0260-8774) 66 (2005), 5; 433-438

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
tribomechanical micronisation; rheological properties; whey protein concentrate; skim milk powder

Sažetak
In this work the influence of temperature and solid matter content on the viscosity of model systems prepared with tribomechanicaly treated as well as untreated whey proteins and skim milk powder was investigated. The rheological properties of model systems were determined using a rotational rheometer Rheometric Scientific RM-180, and described by the Ostwald de Waele &laquo ; ; ; power law&raquo ; ; ; . Signigicantly higher viscosity was found for model systems prepared with tribomechanicaly treated materials compared to those prepared with untreated materials. Systems with higher protein content (WPC-80) exihibited greated viscosity than those with lower protein content (WPC-60). The lowest viscosity was found for systems prepared with skim milk powder. The correlation between viscosity and temperature (0-600C) was determined by an Arrhenius model. Because of a very high regression coefficient (0.91 to 0.98) achieved for the investigated systems, the Arrhenius model can completely describe the viscosity change in the given temperature range. Activation energy of viscous flow was significantly higher for all tribomechanicaly treated systems, because tribomechanical micronisation decreases particles size and enables their better hydration.

Izvorni jezik
Engleski

Znanstvena područja
Prehrambena tehnologija

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