Effect of Ohmic heating on functionality of sodium caseinate - A relationship with protein gelation.

Sodium caseinate (NaCAS) is widely used in the food industry to provide nutritional and functional benefits. This work deals with the effects of applying moderate electric fields (MEF) of different intensity - ranging from 2 V·cm to 17 V·cm - on the physical and functional properties of NaCAS solutions during Ohmic heating (OH) at 95 °C. Self-standing gels were produced regardless the heating technique applied (i.e. conventional or OH), and these gels were much more prone to physical rupture when compared with the ones produced from unheated NaCAS. Interestingly, OH treatment formed gels with lower values of strain at rupture and water holding capacity than unheated samples; this pattern was not observed for gels obtained through the conventional heating treatment (at 0 V·cm). These effects may be linked with disturbances of the distribution of random coil structures and enhanced solubility of NaCAS at its isoelectric point, reducing aggregation and impairing the development of a more compact protein network. Results show that OH presents potential to be used as volumetric heating tool for NaCAS solubilization and for the production of distinctive acidified systems.