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The investigation focused on the batter properties, baking performance, and retrogradation behavior of gluten-free sponge cakes after partial (15%, 30%, and 45%) substitution of glutinous rice flour with exogenous protein, including whey protein isolates (WPI), egg white protein (EWP), and soy protein isolate (SPI). The viscoelastic properties and apparent viscosity of batter positively correlated with substitution levels, with SPI superior to WPI and EWP. WPI could produce batter with smaller and more evenly distributed cells, contributing to an enhanced specific volume of the cake due to its stabilizing effect of gas cells to form viscoelastic films. The gelatinization of starch granules proved to be constrained by the incorporation of WPI and SPI, as evidenced by elevated gelatinization temperature and reduced enthalpy change values. The restriction could be attributed to the strengthened hydrogen bonding between the starch and protein, which subsequently alleviated the retrogradation and water redistribution of cake during storage. An unpleasant eggy or beany flavor of cake was generated at 45% substitutions of EWP and SPI. In comparison, 30% WPI contributed to an appealing aroma and mouthfeel, making it a nutritional supplement to enhance its protein content while maintaining its fine sensory attributes of gluten-free sponge cake. [Display omitted] • Whey protein isolate exhibited the most pronounced stabilizing effect on batter gas cells. • Both whey protein and soy protein effectively constrain the gelatinization of starch granules. • The alleviation of starch retrogradation and water redistribution was protein-dose dependent. • Hydrogen bonds between starch and three exogenous proteins were strengthened. [ABSTRACT FROM AUTHOR]

Spherical curcumin/polyvinylpyrrolidone nanocapsules (CurNC) with the improved water solubility and thermal stability than native curcumin (Cur) were synthesized. Subsequently, soy protein isolate-based pH-sensitive multifunctional packaging films reinforced with cellulose nanocrystals (CNC), CurNC, CNC/CurNC, and CNC/Cur were developed for shrimp freshness detection. It was found that adding the CNC-containing agents improved the tensile strength, hydrogen bond interactions, thermal stability, and crystalline structure of the film and decreased its water solubility and water vapor and oxygen permeability. The Cur-containing agents decreased the L* (lightness/darkness) and a* (redness/greenness) values and increased the b* (yellowness/blueness) and ΔE (total color difference) values of the film. A more dense and uniform matrix of the nanocomposite films was likely responsible for delaying the release of Cur from the film matrix. Interestingly, CNC/CurNC film displayed higher antiradical scavenging activity than CNC/Cur film, as well as remarkable color responsiveness to pH changes and NH 3 presence. Moreover, the CNC/CurNC film was able to decrease the total volatile basic nitrogen of stored shrimp and visually monitor shrimp freshness in real-time. [Display omitted] • Curcumin nanocapsules (CurNC) had improved water solubility and stability than Cur. • pH-sensitive antioxidant film based on soy protein isolate was developed. • Cellulose nanocrystals (CNC) delayed the release of Yu et al., 2017, 2018 curcumin from film matrix. • CNC/CurNC film showed good antioxidant activity and color response to pH and NH 3. • The film loaded with CNC/CurNC can visually monitor shrimp freshness in real-time. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mechanism of cellulose nanocrystals (CNC) to improve film properties was proposed. • Adding CNC restricted water mobility and improved the viscoelasticity of films. • Incorporation of CNC enhanced hydrophobic and hydrogen bonding interactions. • CNC-induced conformational modifications promoted to form stronger film structures. • The obtained nanocomposite films can be used for pork and strawberry preservation. This study aimed to evaluate the effects of cellulose nanocrystals (CNC) on the basic properties of soy protein isolate films, and especially to propose the corresponding formation mechanism. Tensile strength, barrier properties, and water resistance were effectively improved after the formation of nanocomposite films. Incorporating CNC could restrict water mobility and improve the viscoelastic properties of films. Appropriate content of CNC (0.50% and 0.75%) promoted the construction of a more homogeneous and compact film structure, which may be attributed to the CNC-induced conformational modifications and the enhanced hydrophobic and hydrogen-bond interactions. While excessive CNC (1.00%) was not conducive to the integrity and continuity of film structures, resulting in the weakened functional properties. The obtained films were able to decrease total viable counts and total volatile basic nitrogen of stored pork, and extend the shelf-life of strawberry. This work offers a theoretical basis for the application of CNC in packaging industry. [ABSTRACT FROM AUTHOR]

This study aimed to develop soy protein isolate (SPI)-based active nanocomposite films reinforced with cellulose nanocrystals (CNC), zinc oxide nanoparticles (ZnONP), CNC/ZnONP mixture (physical mixing), or CNC@ZnONP nanohybrids (in situ growth). The tensile strength, oxygen and water vapor barrier properties, water resistance ability, and thermal stability were substantially improved by the incorporation of nano reinforcements, particularly the CNC-containing agents. However, the nanocomposite films displayed a lower elongation at break, surface hydrophobicity, and transmittance compared with the pure SPI-based film. The filling effect of reinforcements and their hydrogen bonds with the film matrix contributed to the formation of a compact and homogeneous film structure. The ZnO-containing films obviously inhibited the growth of foodborne pathogens (Escherichia coli and Staphylococcus aureus) and also reduced the total viable counts and the total volatile basic nitrogen values in a pork sample. Furthermore, the CNC@ZnONP film prevented the migration of zinc from the film into the food system. Therefore, the obtained nanocomposite films have broad application prospects in the field of active food packaging. Image 1 • Cellulose nanocrystals@ZnO nanoparticles (CNC@ZnONP) nanohybrids were synthesized. • Soy protein isolate-based antibacterial nanocomposite films were developed. • CNC improved the tensile strength, barrier ability, and thermal stability of films. • The films containing ZnONP had potential to extend the shelf-life of fresh pork. • The CNC@ZnONP film prevented the migration of zinc from film to the food system. [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]

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]

• Wheat bran cellulose (WBC) strengthened heat-induced soy protein isolate (SPI) gel. • WBC improved gel properties by stabilizing water phase and filling effect. • WBC induced the formation of a regular three-dimensional gel network. • A conformation conversion from α-helix to β-sheet found in the composite gels. • The thermal stability of SPI gel was enhanced after WBC incorporation. The effect and mechanism of wheat bran cellulose (WBC) on the gelling characteristics of soy protein isolate (SPI) were evaluated. It was found that the water holding capacity, gel strength, and viscoelasticity of SPI gel were improved with the increase of WBC concentration. The addition of WBC (0.5–2.0%, w/v) stabilized the moisture phase and induced the construction of the regular and homogenous three-dimensional gel network. The Raman spectroscopy revealed that WBC addition caused a significant reduction in α-helix percentage (28.92–63.08%) (p < 0.05) with a concomitant increase in β-sheet (16.92–34.37%) (p < 0.05) and β-turn (8.09–13.54%) (p > 0.05) percentages of the pure SPI gel. Additionally, hydrogen-bonding interaction between SPI and WBC and the enhanced thermal stability were proposed in the composite gels. Overall, WBC is effective in improving the gel properties of SPI, suggesting its potential application as novel gel modifier in the food industry. [ABSTRACT FROM AUTHOR]

This study aims to elucidate the changes and corresponding mechanisms of storage stability of soy protein isolate (SPI) films strengthened via wheat bran cellulose (WBC) and cellulose nanocrystals (CNC). The incorporation of WBC and CNC improved the mechanical strength, water resistance, water vapor and visible light barrier abilities of stored SPI-based films to varying degrees. Higher crystallinity and lower water mobility were observed in the composite films. WBC molecules reduced the irregular pores and cracks within the internal structure of the film through physical filling and non-covalent interactions, involving hydrogen bond and van der Waals force. In contrast, uniformly distributed CNC cross-linked with amino acid residues at specific binding sites under non-covalent forces. Furthermore, CNC induced the secondary conformation of proteins to transform from α-helix to β-sheet and enhanced the hydrophobic interaction, which promoted the establishment of a stable network structure and thus extended the storage stability of SPI-based films. [Display omitted] • Cellulose and cellulose nanocrystals improved storage stability of protein film. • Cellulose improved structural integrity by filling and non-covalent interaction. • Binding sites of cellulose chains and proteins were analyzed via molecular docking. • Nanocellulose modified protein conformation and enhanced intramolecular interaction. [ABSTRACT FROM AUTHOR]