Work

Mechanochemical unfolding facilitates protein-glutaminase deamidation and charge remodeling of myofibrillar protein to reduce low-salt-induced aggregation tendency

Year: 2026

Type: article

Abstract: Low-salt-induced aggregation tendency of myofibrillar protein (MP) reduces its solubility and functional performance under low ionic strength conditions. This study investigated whether high-pressure microfluidization(HPM)-induced mechanochemical unfolding could facilitate protein-glutaminase (PG) deamidation and charge remodeling of MP to reduce low-salt-induced aggregation tendency. MP dispersed under low-salt conditions (0.1 mol/L NaCl) was treated with HPM at 52, 69, 86 and 103 MPa, followed by PG deamidation, and its degree of deamidation, solubility, particle characteristics, surface charge, conformational changes, molecular interactions, and assembly morphology were analyzed. HPM disrupted the highly cross-linked MP structure and promoted conformational unfolding, thereby improving substrate accessibility for PG-mediated deamidation. Sequential HPM-PG treatment markedly improved low-salt MP dispersion with increased DD from 5.94% to 11.45% after HPM pretreatment, increasing solubility from 34.5% in untreated MP to 71.2-71.94% in MP-15000H-PG. This improvement was associated with a reduction in particle size, with MP-10000H-PG and MP-15000H-PG decreasing to 1408.67 and 1254.67 nm, respectively. Moreover, the ζ-potential shifted from -11.63 to -25.96 mV, indicating that PG-mediated conversion of glutamine (Gln) residues to glutamic acid (Glu) residues might have remodeled MP charge. Secondary structure, fluorescence, sulfhydryl, TEM, and asymmetrical flow field-flow fractionation analyses further showed that sequential treatment disrupted filamentous aggregates, exposed reactive groups, and prevented it from aggregating into coarse myofibrillar structures. These findings clarified that mechanochemical unfolding-assisted PG deamidation can convert low-salt-reassembled MP into a charge-stabilized dispersed state, providing a molecular strategy for developing highly soluble meat protein ingredients for salt-reduced food systems.

Source: Current Research in Food Science

DOI: 10.1016/j.crfs.2026.101606