Improving gel properties of purified Chlorella protein extract by alkali and TGase modifications combined with Ca2+: A study on the multidimensional regulatory mechanisms of gel properties.

Controlled thermal unfolding of soy protein isolate modulates transglutaminase-induced gelation and network structure of fish gelatin.

Mixed-protein gel systems have emerged as an effective strategy for tailoring textural and structural properties in sustainable food systems. In this study, the effects of varying ratios (1:1, 2:1, 4:1) and thermal pretreatment (75, 85, 95 °C) of soy protein isolate (SPI) on the gelation behavior of transglutaminase (TGase)-crosslinked fish gelatin (FG) were systematically investigated. The results showed that TGase-induced FG-SPI complexes exhibited strengthened intermolecular interactions. However, the globular structure of native SPI constrained the formation of a dense and continuous porous microstructure characteristic of TGase-crosslinked FG, thereby reducing the gel strength of the mixed gels. Preheating SPI at 75 °C promoted partial unfolding of the protein, generating additional TGase-accessible reactive sites and intensifying hydrophobic interactions and disulfide bonding, which collectively improved the gel strength and textural properties of the FG-SPI gels. These findings provide a robust framework for designing tunable, sustainable mixed-protein gels for diverse food applications.

Modifying Structure–Functionality of Common Bean ( Phaseolus vulgaris L.) Protein via Cold Atmospheric Plasma Processing and Maillard Reaction

Structural and functional modifications of common bean (Phaseolus vulgaris L.) protein were investigated using cold atmospheric plasma (CAP) and Maillard reaction (MR) with pectin. CAP treatment (20 kV, 1–5 min) significantly enhanced protein solubility and emulsifying activity. Conversely, MR (90 °C, 0.5–3 h) reduced solubility and foaming properties but improved gelling capacity, achieving the lowest gelation concentration (LGC) at 2–3 h of heating. Conformational shifts in secondary structures (α-helix, β-turn, and β-sheet) were confirmed by FTIR and correlated with protein unfolding and structural modifications, as characterized by SDS-PAGE. Zeta potential measurements indicated that CAP improved colloidal stability, whereas extended MR heating decreased stability. These findings demonstrate that CAP is an effective nonthermal tool for enhancing protein functionality, while MR is better suited for developing stable gel-based food matrices, lowering the LGC from 8% to 5%.

Valence-dependent evolution of hierarchical structure and functional properties in soy protein isolate-potato protein composite hydrogels.

Understanding how ionic valence regulates the hierarchical structure evolution of composite plant protein gels is essential for the rational design of functional food hydrogels. In this study, soy protein isolate (SPI)-potato protein (PP) hydrogels were employed as a model system to investigate the effects of ionic valence on multiscale structural characteristics and functional properties. Na+ at 100 mM formed a homogeneous dense network via electrostatic shielding, achieving peak water-holding capacity (WHC, 99.41%) and hardness among the Na+ series, accompanied by increased β-sheet content and hydrogen bonding. Ca2+ induced strong aggregation via ionic bridging, constructing a reinforced and elastic network at 20 mM, with the highest proportion of strongly bound water (9.20%). Fe3+ induced charge reversal at high concentrations through excessive charge neutralization, triggering rapid heterogeneous aggregation and increasing α-helix content, which ultimately caused deterioration in water retention and mechanical stability. Intermolecular force analysis revealed that ion treatment further strengthened the already dominant hydrophobic interactions while weakening electrostatic interactions.

Process-dependent structural and functional modification of yeast protein: Alkaline extraction-acid precipitation versus high-pressure homogenization-assisted pH shifting.

Multivariate analysis indicated β-turn content, surface hydrophobicity, and reactive-group content were positively associated with selected functional properties that support ASAP as a promising route, while validation across additional raw materials remains necessary.

Alcalase hydrolysis enhances solubility and foaming properties of perilla protein isolate through structural modification

Comparative Effects of Protein Glutaminase and Transglutaminase on Fermentation-Induced Gelation of Pea, Faba Bean, and Soy Protein Isolates

Pea, faba bean, and soy protein isolates (PPI, FPI, SPI) are increasingly used as primary ingredients for developing plant-based gels for cheese and meat analogues. A major challenge is their limited functionality, including low solubility, poor emulsifying capacity, and restricted molecular flexibility, which together constrain their ability to form strong and cohesive gels. Controlled protein modification and optimized processing conditions are therefore required to tailor their gelation behaviour. This study aimed to modify the gelation properties of PPI, FPI, and SPI using protein glutaminase (PG) and transglutaminase (TG), and to evaluate fermentation-induced gelation in emulsion-based systems relevant for future plant-based food applications. PG treatment resulted in 12–16% deamidation across the three proteins but increased solubility only in SPI, while zeta potential remained unchanged, indicating minimal changes in net surface charge. Lactic-acid bacteria fermentation enhanced gelation for all proteins, yielding gel hardness values of 46–102 g and confirming that acidification is the primary driver of network formation. TG addition during fermentation markedly increased gel hardness in all proteins (128–402 g), with the strongest effect observed in SPI. PG treatment alone did not affect the hardness of fermented gels, but it modulated TG-induced gelation in a protein-specific manner. In SPI, PG reduced TG-induced gel hardness to 303 g, likely due to increased soluble proteins and water retention, whereas FPI showed no change and PPI exhibited a slight increase to 176 g. These findings highlight the interplay between PG-induced deamidation and TG-mediated cross-linking and demonstrate that these interactions are strongly protein dependent.