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The differences in the gelling properties of soy protein isolate (SPI) and soy protein isolate amyloid fibrils (SAFs) as well as the role of cellulose nanocrystals (CNC) in regulating their gel behaviors were investigated in this study. The binding of CNC to β-conglycinin (7S), glycinin (11S), and SAFs was predominantly driven by non-covalent interactions. CNC addition reduced the particle size, turbidity, subunit segments, and crystallinity of SPI and SAFs, promoted the conversion of α-helix to β-sheet, improved the thermal stability, exposed more tyrosine and tryptophan residues, and enhanced the intermolecular interactions. A more regular and ordered lamellar network structure was formed in the SAFs-CNC composite gel, which could be conducive to the improvement of gel quality. This study would provide theoretical reference for the understanding of the regulatory mechanism of protein amyloid fibrils gelation as well as the high-value utilization of SAFs-CNC complex as a functional protein-based material or food ingredient in food field. [Display omitted] [ABSTRACT FROM AUTHOR]

This study systematically investigated the dose-effect relationship and regulatory mechanism of theanine on the gelling properties of soy protein isolate (SPI). The results indicated that the strength and water holding capacity of 0.10% theanine-SPI gel increased by 238.80% and 1.13% compared with pure SPI gel, respectively. Hydrogen bonds and van der Waals forces mainly promoted the binding of theanine to β-conglycinin and glycinin. This binding could further change the protein aggregation state (reducing particle size and irregular aggregation), functional groups (exposing more hydrophilic amino acid residues and sulfhydryl groups), and molecular structure (α-helix and β-turn transforming into β-sheet). Furthermore, a more uniform and dense three-dimensional gel network was formed in the composite gels, offering the structural basis for improving the performance of the SPI gel. The results will provide theoretical basis and technical support for the precise regulation of gel properties of the functional amino acid-SPI complex as well as the efficient creation of new SPI-based foods. [Display omitted] • Theanine improved gel strength and water holding capacity of soy protein isolate. • Theanine bound to 7S and 11S globulin by hydrogen bonds and van der Waals forces. • Moderate theanine changed protein conformation and enhanced molecular interaction. [ABSTRACT FROM AUTHOR]

This study focused on the dose-effect relationship and molecular mechanism of cellulose nanocrystals (CNC) in improving the gel property of pea protein isolate (PPI). The addition of 0.75% CNC enabled PPI molecules to form a dense and orderly network structure, and gel strength and water holding capacity were increased by 391.68% and 11.65% compared with the control (p < 0.05). Meanwhile, CNC reduced the production of irregularly protein aggregates and their particle size. Hydrogen bonds and van der Waals were found to be the mainly driving interaction of CNC binding to specific amino acids of 11 S Legumin and 7 S Vicilin. Moreover, CNC changed the microenvironment of amino acid and promoted the transformation of α-helix to β-sheet. Finally, the composite gel modified by 0.75% CNC had the potential to delay the release of tea flavor substances, and it could be applied to the development of pea protein-based products with tea flavor. This study provides a theoretical reference for the structural modification and functional application of pea protein. [Display omitted] • CNC specifically bound to Legumin and Vicilin mainly via non-covalent interaction. • The presence of CNC changed protein conformation and enhanced molecular interaction. • The composite gel modified by 0.75% CNC delayed the release of tea flavor. [ABSTRACT FROM AUTHOR]

The low solubility limits the utilization of other functional characteristics of wheat gluten (WG). This study effectively improved the solubility of WG through protease modification and explored the potential mechanism of protease modification to enhance the solubility of WG, further stimulating the potential application of WG in the food industry. Solubility of WG modified with alkaline protease, complex protease, and neutral protease was enhanced by 98.99%, 54.59%, and 51.68%, respectively. Notably, the content of β-sheet was reduced while the combined effect of hydrogen bond and ionic bond were increased after protease modification. Meanwhile, the reduced molecular size and viscoelasticity as well as the elevated surface hydrophobicity, thermostability, water absorption capacity, and crystallinity were observed in modified WG. Moreover, molecular docking indicated that protease was specifically bound to the amino acid residues of WG through hydrogen bonding, hydrophobic interaction, and salt bridge. [Display omitted] • Solubility of wheat gluten (WG) was improved after treatment by three proteases. • WG bound to proteases mainly through non-covalent interactions at specific sites. • Protease modification induced β-sheet changed into α-helix, β-turn and random coil. • Proteases enhanced the combined effect of hydrogen bond and ionic bond in WG. [ABSTRACT FROM AUTHOR]