Production of soluble pea protein/sodium caseinate co-dispersions using ultrasonication and their acid coagulation properties

Abstract

This research investigated the influence of pH-shifting and ultrasonication on the formation of pea protein isolate (PPI)/sodium caseinate (NaCas) co-dispersion and the acid coagulation properties of PPI/NaCas blends. The results showed that pH-shifting could not form stable PPI/NaCas dispersions. A combination of pH-shifting and ultrasonication successfully produced PPI/NaCas dispersions with different ratios. All dispersions had an average particle size of around 270 nm and a zeta potential value of around −35 mV. More importantly, they all exhibited excellent solubility and colloidal stability. Rheological results indicated that dispersions with different PPI/NaCas ratios have various gelation behavior. The gelation time decreased with increasing PPI concentration in the blends. The elastic modulus of PPI/NaCas gels decreased with increasing PPI concentration when the percentage of PPI was lower than 50%. Increasing PPI concentration to higher than 50% resulted in the gradual increase of elastic modulus. The gel formed at the PPI/NaCas ratio of 1:1 had the weakest structure and lowest hardness, which ruptured during the frequency sweep. The incorporation of PPI prevented the synesis and increased the water-holding capacity of NaCas gel. The gels produced with different PPI/NaCas ratios exhibited various textural properties. By controlling the PPI/NaCas ratio in the blends, it is feasible to produce PPI/NaCas co-gels with desirable textural properties.