Abstract This study systematically investigated the binding patterns and interaction mechanisms between protein amyloid fibrils formed via acid-heat treatment from different sources (soybean, pea, rice, gluten) and 2,5-dimethylpyrazine. The results indicated that fibrillation modification of proteins significantly enhanced their binding capacity for aroma molecules. However, differences in microscopic morphology, structural characteristics, and physicochemical properties among amyloid fibrils from different protein sources directly affected their binding capacity and the thermal stability of binding to 2,5-dimethylpyrazine. Among them, pea amyloid fibrils (PAFs) exhibited a high binding ratio of 36.64% and demonstrated good binding thermal stability across different temperatures (50–120 °C). The superior aroma-binding capability of PAFs was closely associated with their high surface hydrophobicity, abundant β-sheet content, and regular aggregation-state morphology. Spectroscopic and thermodynamic analyses further revealed distinct binding mechanisms among the different protein amyloid fibrils and the aroma molecule: hydrophobic interactions dominated for SAFs, van der Waals forces and hydrogen bonds were primary for PAFs, while electrostatic interactions were predominant for RAFs and GAFs. This research provides a theoretical basis for the design and screening of aroma stabilization in plant-based meat, holding significant application value for improving the flavor quality of plant-based foods.

Quick and sensitive monitoring of Carbosulfan (CBF) residues in food is of great significance to guarantee food safety. This study developed a simple, portable, and enzyme-free sodium alginate hydrogel probe (SA-Hydrogel probe) for the colorimetric and fluorescent rapid detection of CBF. Iron single-atom nanozyme (Fe-N/C SANs) with excellent oxidase-like activity was synthesized via high-temperature pyrolysis, which catalyzed the oxidation of 3,3 ',5,5 '-tetramethylbenzidine (TMB) into a blue product (oxTMB). Red-emissive carbon dots (R-CDs) with aggregation-induced emission property were introduced as a reference signal, and the generated oxTMB quenched the red fluorescence of R-CDs through the inner filter effect (IFE). However, acidified CBF inhibited the enzyme-like activity of Fe-N/C SANs by producing reductive sulfide ([SH]), leading to a reduction in oxTMB generation. Additionally, the weakened IFE led to the recovery of R-CDs's fluorescence. The probe exhibited a good linear response to CBF within the range of 0.05-20 mu g/mL, with calculated limits of detection (LODs) of 0.025 mu g/mL and 0.012 mu g/mL based on the color parameter (G+B)/2 R (colorimetric) and R (fluorescent), respectively. This study not only innovatively constructed an enzyme-free dual-mode sensing platform for the rapid identification of CBF but also provides new insights for the development of portable pesticide residue detection devices.

Incorporation of carrageenan (Car) offers an effective approach to modulate the assembly and functionality of protein-based nanocomplexes; however, the role of Car sulfate ester motifs has not been fully clarified. Here, κ-Car, ι-Car, and λ-Car with distinct sulfate content and distributions were used to construct Car/TP-Cur nanocomplexes. The sulfate ester motifs regulated intermolecular interactions and protein conformation, leading to distinct assembly structures. In κ-Car/TP-Cur and ι-Car/TP-Cur nanocomplexes, the interaction between TP and Cur was dominated by hydrogen bonding and hydrophobic interaction, whereas λ-Car/TP-Cur complex was mainly governed by hydrophobic interactions. Notably, ι-Car produced the most compact and stable structure, achieving curcumin encapsulation efficiency of 83.33% and bioaccessibility of 34.59%. Moreover, sulfate ester motifs significantly affected antioxidant activity and emulsion properties. These findings clarify how Car sulfate motifs regulate the assembly behavior and functional properties of protein-polysaccharide complexes and provide guidance for designing efficient natural delivery carriers.

In this paper, the dose-effect relationship and molecular mechanism of tea residue derived cellulose nanocrystals (CNC) to improve the gel behavior of pea protein-derived amyloid fibrils (PAFs) were studied. The results showed that the gel strength and water holding capacity of PAFs+1.5 % CNC gel increased respectively by 21.40 % and 37.50 % compared with PAFs gel (p < 0.05). At the same time, CNC promoted the aggregation of PAFs to form protein aggregates with large size and uniform distribution. In addition, compared with PAFs gel, the relative content of alpha-helix in PAFs+1.5 % CNC gel decreased by 14.90 % (p < 0.05), while the relative content of beta-sheet increased by 6.50 % (p < 0.05). With the increase of CNC addition, the ionic bonds, hydrogen bonds and disulfide bonds were strengthened in the PAFs-based composite gel, while the hydrophobic interactions were weakened. Gradient CNC could change the aggregation behavior and multi-scale structure of PAFs molecules to different degrees, promote the exposure of functional groups and strengthen the interaction between molecules, and realize the targeted regulation of PAFs-based gel strength and water holding capacity. This study provided a theoretical reference for the wide application of PAFs-CNC composite gel system in functional protein substrates and food ingredients.

Functional short- and long-chain acyl triacylglycerols oleogels were developed using three different gelators. The mechanism of introducing short-chain fatty acids to the glycerol skeleton influencing the self-assembly of oleogels was investigated. Compared to camellia oil oleogels, the thermal stability and mechanical strength of short- and long-chain acyl triacylglycerols oleogels decreased by 1.17-1.37 J/g-1 and 0.27-0.39 N, respectively. The crystalline sizes, distance between molecules and the final sub-cell size in short- and long-chain acyl triacylglycerols oleogels were increased, while hydrogen bonding and van der Waals interactions were weakened, resulting in a weak crystal network structure. Besides, free fatty acids release by short- and long-chain acyl triacylglycerols oleogels (28.83 %-64.91 %) was higher than that by camellia oil oleogels (21.01 %-55.99 %). These findings indicate that short- and long-chain acyl triacylglycerols oleogels exhibiting a weaker structure but a higher lipolysis degree, facilitated fatty acid absorption.

This study systematically investigated the interaction behaviors and conformational changes of the tea protein (TP) with three flavonoids (chrysin, apigenin, and luteolin) through various experiments and computational simulations. Notably, TP formed stable and homogeneous complexes with all three flavonoids, with TP-luteolin complex being the most stable. Surface hydrophobicity and multispectral analyses revealed that flavonoid binding significantly changed the TP surface properties and conformational rearrangements. Fluorescence spectroscopy revealed a static quenching mechanism, with quenching abilities in the following order: Luteolin > apigenin > chrysin. Thermodynamic analysis confirmed the spontaneous nature of the interactions, which were primarily driven by hydrogen bonding and van der Waals forces. Infrared spectroscopy further confirmed the protein conformation changes. Molecular docking and simulations provided complementary insights into the binding mechanisms at the atomic level. Overall, our findings provide structural insights into TP-flavonoid interactions.

This study investigated the properties of a novel medicinal starch isolated from the roots of Trichosanthes kirilowii (TKRS). The multiscale structural and physicochemical properties of TKRS were characterized and compared with two common starches, sweet potato starch (SPS) and kudzu starch (KS), to elucidate the influence of structural characteristics on the physicochemical properties of these root starches. TKRS granules exhibited elliptical and irregular polygonal shapes, with the largest median particle size (14.48 mu m). TKRS had a lower amylose content (15.03 %) and a lower molecular weight (8.40 x 107 g/mol). XRD analysis confirmed a C-type crystallinity pattern, with a higher crystallinity degree (21.51 %) and a high degree of short-range ordered structure. Further analysis of the chain length distribution revealed that TKRS contained a larger proportion of long-chain amylopectin. Compared to SPS and KS, TKRS showed a lower gelatinization temperature (72.65 degrees C) but a higher peak viscosity (7351 cP). Additionally, despite its relatively lower water retention capacity, TKRS exhibited higher storage modulus and loss modulus than conventional tuber starches. In vitro digestibility analysis indicated that TKRS had a lower rapidly digestible starch content and a higher resistant starch content, highlighting its potential for processing into healthy starch-based food products.

Microwave-assisted technology offers an efficient and eco-friendly method for starch modification. In this study, sorghum starch (SS) was treated under varying microwave durations and complexed with caffeic acid (CA) to form SS-CA complexes. Microwave treatment significantly reduced crystallinity (24.07 % to 3.51 %), disrupted short-range order, and caused granule swelling, aggregation, and decreased thermal stability. Complexation induced a V-type inclusion structure. The SS-CA (120 s) complex showed a 9.17 % reduction in rapidly digestible starch (RDS) and a 14.40 % increase in resistant starch (RS). Molecular docking and DFT analyses confirmed that hydrogen bonding and van der Waals forces dominated SS-CA interactions. During 0-7 days of storage, free water content in the SS-CA gel increased only 1.58 % compared to 5.93 % in native SS, indicating reduced retrogradation. The SS-CA complex displayed lower gelatinization enthalpy and improved phase stability. These findings suggest the potential of microwave-assisted SS-CA complexes in developing low-glycemic starch-based foods.

The aim of this study was to alleviate the adverse effects of wheat germ (WG) addition on the quality of Chinese steamed bread (SB). WG was first coated with milk protein, and the effects of WG, WG and milk protein (WG + P), milk protein-coated WG (PCWG) additions on dough rheology and SB quality were investigated. The addition of WG to wheat flour significantly weakened the dough strength and decreased the quality of SB. However, the addition of 5 % or 10 % WG + P and PCWG resulted in a stronger dough and a higher-quality SB than the addition of WG. Compared with the dough with the WG + P addition, Mixolab results showed that the dough with the PCWG addition had a higher mixing stability and C2 value, a lower peak viscosity (C3 value), and a lower retrogradation degree (C5 value). An SB-making test revealed that, the SB with the PCWG addition exhibited a larger specific volume, higher lightness, lower hardness, higher consumer acceptability, and lower starch retrogradation degree after 24 h of storage than the SB with the WG + P addition. Hence, this study indicates that a stronger dough and higher-quality SB can be produced when using PCWG than when using WG or WG + P.

This study was conducted to investigate the effect of tea residue cellulose nanocrystal (CNC) in coordination with Ca2+ on the thermal gelation of pea protein amyloid fibrils (PAFs) and its potential mechanism. The results showed that CNC (0.12%) inhibited the aggregation of PAFs molecules, reduced the surface hydrophobicity and increased the solubility of the solution, and further formed PAFs-based gels with high water holding capacity and high gel strength. However, Ca2+ (400 mM) promoted the aggregation of PAFs molecules, which made the solution have high surface hydrophobicity and low solubility, and finally formed a PAFs-based gel with low water holding capacity and high gel strength. The intermolecular force of PAFs-CNC/Ca2+ gel was enhanced, and the content of beta-sheet conformation was increased. CNC fragments bound to specific amino acid sites of PAFs through non-covalent forces (hydrogen bonding and van der Waals forces), and Ca2+ might enhance the crosslinking and interaction between CNC and protein, thus making the two synergies enhance the gel strength and viscoelasticity of PAFs. The research results will provide a new perspective for the diversified regulation of PAFs gel properties and the design and development of PAFs gel-based products.

To design a novel emulsifier capable of enhancing the bioavailability of curcumin (Cur)-loaded emulsions in the gastrointestinal tract, soy protein-based ternary composite nanoparticles (SEPn) were fabricated by transacylation reaction. The results showed that SEPn was formed by the covalent binding of the carboxyl groups in PGA to the amino groups in SEC through multiple forces. SEPn-1:1 was determined to be the optimal condition for preparing Cur-loaded emulsions. Additionally, SEPn-1:1 had superior emulsifying capacity as formed plastic-state emulsion gel with φ as low as 0.5. Moreover, the rise in oil content promoted the development of gel, thus increasing the apparent viscosity, gel strength, and stability of Cur-loaded emulsions. Furthermore, SEPn-1:1 emulsion exhibited excellent gastric stability and higher free fatty acid (FAA) release rates in the small intestine phase compared with that of SECcon (SEC control sample) and Mixture emulsion, thus leading to the highest bioavailability of Cur (28.57 ± 1.91 %).

Herein, cellulose nanocrystals (CNCs) from Camellia oleifera Abel seed shell (COASS) were prepared to strengthen starch-based films for extending shrimp shelf life. The morphology, crystal structure and thermal properties of CNCs were characterised. The rheological properties, moisture distribution and micro-morphology of the film-forming solution were analysed. The mechanical properties, water vapour/oxygen permeability, formation mechanism and shrimp preservation of the CNC-starch films were investigated. COASS-CNCs had a type I cellulose structure. The crystal granules were rod-shaped, with an average length of 135.91 nm and a width of 11.55 nm. The rheological properties, moisture distribution and micro-morphology suggested that the addition of COASS-CNCs improved the matrix network structure and stabilised the moisture of the film-forming solution. When COASS-CNCs were added at 8 %, the tensile strength, water vapour permeability and oxygen barrier ability of the composite film increased by 71.96 %, 16.20 % and 34.29 %, respectively. Molecular docking technology shows that the number of hydrogen bonds in the system increases with the increase of COASS-CNCs, accompanied by a phase transition behavior, the binding free energy reaches the maximum with 6 % COASS-CNCs addition. The composite film has potential applications in shrimp preservation. This study provides another reference for the practical application of COASS-CNCs in biodegradable films.

With the increasing prevalence of diabetes, the search for natural compounds with potential anti-hyperglycemic effects has become a key focus in food and nutrition research. L-theanine (THE) and epigallocatechin gallate (EGCG) from tea are gaining attention due to their antioxidant and metabolic regulation properties. Although they have been shown to have an effect on glucose metabolism, their synergistic effect on starch digestive properties and the mechanism remain unclear. Here, we explored that THE and EGCG synergistically regulated starch digestive properties in ultrasound treatment through two different perspectives. At specific THE/EGCG ratios (THE/EGCG1:1), maize starch granules exhibited significant aggregation and densification. THE promoted the ordered arrangement of starch molecular chains through hydrogen bonding, and the polyphenolic structure of EGCG further stabilised this ordered structure, thus enhancing the crystallinity and short-range ordering of starch. It meant that THE and EGCG further reduced starch digestibility by synergistically modulating the multi-scale structure of starch. In addition, THE and EGCG exhibited significant synergistic inhibition of α-amylase activity (1.6 mM THE and 0.05 mg/mL EGCG). The multi-spectral results showed that the addition of THE and EGCG enhanced the conformational change of the enzyme, leading to the change of the secondary structure, and the synergistic effect might originate from the multiple interactions of THE and EGCG with different amino acid residues in the digestive enzyme (e.g., THR-163, GLN-63, ASP-197, etc), which strengthened the inhibition, and the molecular dynamics simulations further supported the findings. This work promotes the further development and utilisation of endogenous substances in tea and provides some references for the development of food ingredients with potential hypoglycaemic functions.

Natural products are gaining attention as α-glucosidase (α-GLU) inhibitors owing to their safety and multifunctionality. L-theanine (THE) and epigallocatechin gallate (EGCG) in tea have inhibitory effects, but whether their synergistic inhibition of α-GLU remains unclear. This study investigated the synergistic mechanism of THE and EGCG in inhibiting α-GLU activity using spectral analysis and computational simulation. The results showed that a combination of 1.6 mM THE and 0.11 mM EGCG significantly enhanced α-GLU inhibition. Fluorescence quenching experiments revealed that EGCG did not alter the static quenching pattern of THE on α-GLU. However, it promoted enzyme conformational changes. Multi-spectral analysis and molecular dynamics simulations further demonstrated that THE and EGCG interacted non-covalently with key α-GLU residues (ASP-242, PHE-303, and PRO-312, etc.), disrupting the active site structure, reducing its catalytic efficiency. These findings provide valuable insight into the synergistic inhibition of α-GLU by natural active ingredients, with potential applications in functional foods.

With the increasing number of patients with type II diabetes associated with starchy foods, the inhibition of starch digestion has become one of the most important strategies for limiting postprandial glucose elevation. However, indirect inhibition of starch digestibility through the starch digestive enzymes pathway remains poorly studied. Based on this, we found that L-theanine (THE) had the potential to inhibit starch digestive enzyme activity and investigated the mechanism based on multi-spectral and computer simulations. The results showed that the half-inhibitory concentration (IC50) values of THE on alpha-amylase and alpha-glucosidase were 1.22 mmol/L and 2.77 mmol/L, respectively, which exhibited a mixed type of inhibition. Fluorescence quenching results and analyses showed that the mechanism of inhibition of THE with digestive enzymes had both static quenching, mainly based on non-covalent interactions such as van der Waals forces and hydrogen bonding, with binding energies of -3.19 and -7.76 kcal/mol, respectively (Molecular docking results). The multi-spectral analysis showed that the binding of THE changed the secondary structure of starch digestive enzymes and the conformation of polypeptide chains, thus inhibiting the activity. The findings of this study are expected to guide the development of food products with hypoglycaemic function using THE.

In this study, aloe emodin and β-d-glucose pentaacetate were added into potato starch/polyvinyl alcohol for the construction of colorimetric/fluorescent dual-pass intelligent response labels. Inspired by the lotus leaf structure, retained the advantages of the label itself and solved the hydrophilic problem of the label, and further developed a multi-functional dual-channel smart label with hydrophobicity and self-adhesion. The water contact angle of the prepared T-AEB label was 120.1 ± 0.8°, and the adhesion was 8 to 12 kPa. After burying T-AEB label in the soil for 35 days, the degradation rate reached 85 %, reflecting excellent ecological security. At pH (7-13) and volatile ammonia (25 to 25,000 ppm) conditions, the label's own color would change dramatically to indicate the effect. In sunlight, as the ammonia concentration increases, the color of the label changed from yellow to purplish red. Correspondingly, the fluorescent color of the label changed from yellow to blue. Under a 365 nm UV lamp. In addition, the label was successfully used for freshness monitoring of shrimp and razor clams during storage at 4 °C, 25 °C and - 20 °C. The smart label was a novel, economical, convenient and food freshness dual monitoring system, which was of great significance to improve food safety and quality monitoring.

With the growing demand for functional foods, protein-flavonoid interactions offer a promising strategy to enhance food structure and bioactivity. Whey protein isolate (WPI), known for its emulsifying, gelling, and carrier capabilities, is widely applied to form functional complexes. This study explored the interaction of WPI with three structurally distinct flavonoids (chrysin (Chr), apigenin (Api), and luteolin (Lut)), focusing on their conformational changes and effects on protein functionality and anti-inflammatory activity. Fluorescence quenching and thermodynamic analyses confirmed static quenching and spontaneous binding, mainly driven by hydrogen bonding and van der Waals forces. Multi-spectral analyses and molecular docking revealed that flavonoid hydroxyl groups induced local conformational changes in WPI, increasing molecular flexibility. Functionally, complexation improved the emulsifying and foaming properties of WPI and enhanced its antioxidant capacity. Among the complexes, WPI-Lut showed the highest radical scavenging activity, with DPPH and ABTS clearance rates of 71.47 % and 45.96 %, respectively. In LPS-stimulated RAW 264.7 cells, all complexes significantly reduced intracellular reactive oxygen species (ROS) levels (p < 0.05) and maintained mitochondrial membrane potential. Notably, the WPI-Lut complex reduced ROS by 23.97 % compared to the control group, indicating strong protection against oxidative stress. This work elucidates the conformational regulation and synergistic functional enhancement of WPI-flavonoid complexes, supporting their potential in high-activity protein-polyphenol formulations.

ABSTRACT This study is dedicated to explore the effect of cellulose nanocrystal (CNC) on the film formability of pea protein isolate (PPI) and propose the regulation mechanism from the perspective of water phase stabilization. Compared with PPI film, the CNC‐PPI composite films showed the improvement in mechanical properties and barrier properties of water/air. CNC reduced the proportion of free water in the PPI film and induced its conversion to immobilized water. From the microscopic observation of the films, it could be found that 0.25%–0.75% CNC made the dispersion of PPI more uniform, and formed more compact film structure. Meanwhile, the exposure of tyrosine and tryptophan in PPI molecules and the increase in the content of β‐sheet resulted in the improvement of film‐forming properties of PPI. The enhanced stability of water phase induced by CNC restrained the formation of water channels, thus improving the structural integrity of gel network and the film‐forming properties of PPI. This work provided a theoretical reference for regulation of the film‐forming properties of PPI with CNC, which was expected to improve the product performance of PPI films and enrich the application scenarios of PPI.

The aim of this study was to investigate the effects of loaded natural polyphenols on the structure of short- and long-chain acyl triacylglycerols oleogels. In this study, five representative polyphenolic compounds, gallic acid (hydroxycinnamic acid), tannic acid (tannins), dihydromyricetin (dihydroflavonols), kaempferol (flavonols) and luteolin (flavones) were selected. The microstructural and macroscopic effects of different polyphenols on the oleogels were examined by polarized light microscopy, infrared spectroscopy, X-ray diffraction, and rheometry. Oleogels loaded with the flavonol or the flavone showed increased oil binding capacity (2.12 % and 2.3 %, respectively) and hardness (0.23 N and 0.25 N, respectively), which corresponded to the formation of the strongest crystalline network structure with the highest crystal density and thermal stability. Additionally, all five polyphenols significantly improved the oxidative stability of the oleogels. Overall, flavones or flavonols were most effective in enhancing the properties of SLCT oleogels by increasing their crystal density and strengthening hydrogen bond forces.

This study aimed to elucidate the pathways through which covalent and non-covalent interactions between deamidated gliadin (DG) and tannic acid (TA) on influence the stability of Pickering emulsions. The interactions induced protein unfolding, as evidenced by increased ultraviolet absorption and a red shift in fluorescence emission. DG-TA composite nanoparticles effectively stabilized high internal phase emulsions, whereas DG nanoparticles alone did not. Covalent DG-TA nanoparticle stabilized Pickering emulsions (C-DGTAE) retained a consistent mean droplet size after 30 d of storage. Lipid hydroperoxide and malondialdehyde levels in C-DGTAE and N-DGTAE were reduced by 59.1 %-69.5 % and 38.9 %-44.4 %, respectively. Furthermore, the retention of β-carotene in the emulsions was significantly enhanced. All emulsions exhibited elastic behavior, characterized by higher G' than G″. Notably, N-DGTAE demonstrated the highest apparent viscosity, G' and G″, attributed to the connected nanoparticles around the droplets. Confocal laser scanning microscopy revealed that C-DGTAE droplets possessed the thickest layer, corroborated by the highest interfacial nanoparticle content of 76 % and an interfacial thickness of 441 nm. These findings suggest that covalent interactions enhance the interfacial nanoparticle layer, while non-covalent interactions promote nanoparticle networking, providing valuable insights for optimizing the stability of Pickering emulsions.