Covalent modification using polyphosphates improves the structural and functional properties of spirulina protein: effects of polyphosphate type and concentration

Abstract The objective of this study was to investigate the feasibility of enhancing the functional properties of spirulina protein (SPP) through polyphosphate covalent modification. The results indicated that the introduction of polyphosphates did not result in the degradation of the primary subunits of SPP, but rather increased its surface electronegativity and reduced particle size. Additionally, an increase in surface hydrophobic groups and free sulphhydryl groups was observed in polyphosphate-treated SPP, which can be attributed to changes in the secondary structure and tertiary conformation of SPP. Functional property analysis revealed that polyphosphate treatment could enhance the solubility, oil holding capacity, emulsifying capacity, and foaming ability of SPP. Moreover, the types and concentrations of polyphosphates significantly influenced these functional properties. Specifically, treatment with 8% sodium tripolyphosphate (STP) improved the solubility, emulsifying capacity, and foaming ability of SPP by 39.4%, 28.9%, and 30.9%, respectively. These findings suggest that STP treatment is a promising approach for improving the functional properties of SPP.