Effect of salt, phosphate and protein content on the techno-functionality of plant-based proteins for hybrid meat product formulation

Salt, phosphate and protein concentration within ranges relevant for hybrid meat products may affect the techno-functional properties of plant-based protein products but this is not well documented. In the present study, combinations of NaCl (0-3.5%), phosphate (0-0.5%) and pea protein isolate (PPI) or sunflower pit flour (SPF) (0.05–15%), generated by mixture design, were tested for protein solubility (PS), emulsion capacity (EC) and gel penetration force (PF). The impact of these ingredients was assessed by regression models. Changes within the proteins’ secondary structure were revealed by Fourier-Transform Infrared (FTIR) spectra. Interpretation of the models and the FTIR spectra demonstrated that higher protein concentrations result in significantly better EC and PF, due to more proteins being present to participate in emulsion and gelling activities. PS could be significantly elevated by increasing NaCl concentration, leading to the formation of Na+-hydration screens surrounding proteins. This effect was most profound for SPF (with r = 1 between PS and NaCl) due to its lower initial NaCl concentration and the disruption of protein-carbohydrate complexes caused by the presence of NaCl, leading to more available protein. Phosphate was significantly incorporated within the secondary structure of PPI proteins, which was caused by the higher concentrations of serine and lysine. Still, the effect on proteins’ techno-functionality remained minimal. These findings may aid efforts to improve the (textural) quality of hybrid meat products.