Improving gelation properties of low concentration peanut protein isolate by phosphorylation

Low concentration (10 %) peanut protein isolate (PPI) could not form an ideal gel structure. However, phosphorylation is a convenient and cost-effective method to enhance gelation properties of proteins. Therefore, this paper aimed to improve gelation properties of low concentration PPI using sodium tripolyphosphate (STP). Gelation and structural properties of phosphorylated peanut protein isolate gel (P-PPIG) were analyzed by SEM, analysis of texture and rheology, water holding capacity (WHC), LF-NMR, intermolecular forces, surface hydrophobicity, FTIR, etc. Surface hydrophobicity of P-PPIG increased, but total content of α-helix and β-sheet decreased as STP concentration increased. The results of intermolecular forces manifested STP boosted hydrophobic interactions and disulfide bonds, which were crucial forces for forming P-PPIG. P-PPIG with 3 % STP had the most ordered network structure, the largest hardness (175.75 g), chewiness (132.71 g), final storage modulus (678,000 Pa) with temperature scanning, and the highest storage modulus and loss modulus with frequency scanning among all samples. Moreover, the analysis of LF-NMR indicated 3 % STP caused the lowest mobility of water with the highest WHC (97.51 %) of P-PPIG among all samples. The findings exhibited STP could promote gelation properties of P-PPIG, especially 3 % STP, providing data references for application of STP in protein gelation.