Hydrophobic Research Articles

The effect of biochar in a specialty adsorbent on enhanced PFAS removal from surface water

An enhanced specialty adsorbent, referred to as biochar-based iron and perlite-integrated green environmental media (BIPGEM), was designed to simultaneously remove both long-chain PFAS mainly including perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS) from surface water matrices. Batch-scale experiments using BIPGEM revealed that the removal efficiencies for PFOA and PFOS exceeded 98 % when treating a mixture of 3 short-chain PFAS, including perfluorobutanoic acid (PFBA), perfluorobutane sulfonic acid (PFBS), and hexafluoropropylene oxide dimer acid (GenX Chemicals). Additionally, a fixed-bed column study using BIPGEM revealed that the removal efficiencies of PFOA and PFOS were over 85 % within the first 12 h whereas the removal efficiency of PFBA was over 40 % at the fortieth hour. It was confirmed that the critical role of biochar in the removal of long-chain PFAS, particularly PFOA, can be attributed to the following factors: (1) the morphological structure and pore size of biochar restrict PFAS mobility, (2) the extensive specific surface area of biochar, with a positive charge (point of zero charge = 10.7) at the experimental condition, enhances the adsorption likelihood with the negatively charged hydrophilic heads of PFOA and PFOS, and (3) the presence of non-polar aromatic rings with high hydrophobicity in biochar facilitates the removal of PFAS through hydrophobic interactions with the functional groups of PFAS.

Enhancing soy protein isolate flexibility through non-covalent ferulic acid modification: implications for interfacial characteristics and protein-based emulsion performance

This study aims to enhance the flexibility of soy protein isolate (SPI) to improve its functional properties, focusing on the investigated the effects of ferulic acid (FA) on the structure, interfacial behaviour and emulsification performance of SPI. Our study showed that FA induces SPI structures to depolymerization and unfolding primarily through hydrogen bonding and hydrophobic interactions, thereby increasing the flexible structures (random coils and β-turns) of protein. These changes enhanced the interfacial functional properties of SPI, with 150 μmol/g of FA-modified SPI exhibiting the best molecular flexibility, and its emulsification and emulsification stability were improved by 21.26% and 39.86%, respectively, compared to unmodified SPI. In addition, non-covalently modified FA significantly improved emulsions stability. Emulsions stabilized by SPI-FA150 complexes exhibited better storage, heat, and freeze-thaw stability than SPI, with a significant reduction in oxidation products. This relationship between flexibility and function reveals the importance of structural modification in enhancing protein functionality. These discoveries shed new light on flexible protein processing technologies and the application of FA in protein functional modification.

Investigating the non-covalent interactions between rutin and superoxide dismutase: Focus on thermal stability, structure, and in vitro digestion

Rutin is prone to degradation during processing, highlighting the need for a suitable protein system for its delivery. This study evaluated the effects of pH and concentration ratios on the interaction between rutin and superoxide dismutase (SOD), aiming to develop a suitable non-covalent delivery system. The highest thermal stability was observed at pH 4 with a rutin-to-SOD concentration ratio of 5:1, where the melting temperature (Tm) reached 67.8 °C, and the half-life was 176 min. Infrared spectroscopy and particle size analysis revealed that rutin has minimal impact on the secondary structure of SOD; however, high concentrations of rutin influence the quaternary structure of SOD, leading to aggregation. Molecular docking and molecular dynamics simulations further confirmed that the interaction between rutin and SOD occurs through hydrogen bonding and hydrophobic interactions, with pH altering their binding sites. At pH 5 and pH 6, the digestive stability of the SOD-rutin complex was the highest. This study provides a theoretical basis for the preparation of highly stable SOD-rutin complexes and identifies a new protein system for the stabilization of rutin.

Trehalose-6-phosphate phosphatase expression and enzymatic properties of Fusariumgraminearum

This study presents an exhaustive characterization of the enzymatic attributes and structural properties of trehalose-6-phosphate phosphatase (TPP) derived from Fusarium graminearum. Enzyme activity was evaluated through a meticulously designed enzymatic assay. The findings indicate that the molecular weight of the enzyme is approximately 99.8 kDa, with an optimal reaction temperature and pH of 40 °C and 6.5, respectively. Magnesium ions (Mg2+) markedly enhance the enzymatic activity, resulting in a specific activity of 1.795 U/μg. Kinetic analysis revealed a Km value of 0.96 μmol/L and a Vmax of 15.79 μmol/L/min. Subsequent computational analysis elucidated the three-dimensional architecture of the enzyme and identified the binding site for the substrate trehalose-6-phosphate (T6P). T6P was found to form hydrogen bonds with TPP at residues Lys754, Arg720, His665, Glu758, and Asn756. Additionally, hydrophobic interactions were observed between T6P and residues Phe802, Ile610, Asp801, Pro752, and Gly753. The binding energy calculated for the T6P-TPP complex stood at −5.7 kcal/mol.

Gel properties of mung bean protein‑sodium caseinate hybrid yogurt: Physicochemical properties, microstructure, and intermolecular interactions

The study aimed to evaluate the gel properties of mung bean protein (MP)/sodium caseinate (NaCas) hybrid yogurt at various mixing ratios, such as rheology, texture, water holding capacity, microstructure, and formation mechanism. The gel hardness, storage modulus (G′) and water holding capacity of MP/NaCas yogurt increased and subsequently decreased as the NaCas level increased, maximum at a MP/NaCas ratio of 70:30. Meanwhile, as the MP/NaCas ratio was 70:30, the hybrid yogurt gel formed tighter and finer network structure. Moreover, the MP/NaCas hybrid yogurt slowed down the acidification rate with increasing NaCas ratio. Especially when NaCas was added at 50 %, the blend sample presented the longest fermentation time (280 min). Results showed that the optimal physicochemical characteristics of the yogurt gel were obtained when MP/NaCas ratio was mixed at 70:30. The results of the intermolecular forces indicated that hydrophobic interactions were the main factor causing yogurt gel formation.

Neural stem cell-derived extracellular vesicles purified by monolith chromatography retain stimulatory effect on in vitro scratch assay.

BackgroundExtracellular vesicles (EVs) have gained traction as potential cell-free therapeutic candidates. Development of purification methods that are scalable and robust is a major focus of EV research. Yet, there is still little in the literature which evaluates purification methods against potency of the EV product. AimsIn the present study, we examine two monolith chromatography methods with a focus on assessing the ability of purified EVs to retain stimulatory effects on firbroblasts to connect scalable purification methods with product outputs. MethodsWe characterised EVs recovered from CTX0E03 (CTX) neural stem cell-conditioned medium in terms of biomarker distribution, functional capacity, and purity. We evaluated the ability of EVs to promote wound closure in an in vitro scratch assay prior to, and following two monolith chromatography steps (anion exchange, and hydrophobic interaction) to determine whether these options may better serve EV bioprocessing. ResultsEVs from CTX cells were successful in initiating wound repair on a fibroblast scratch assay over 72 hours with a single 20μg dose. EV preparations presented the markers CD9, CD81, CD63, but also contained culture albumin and DNA as process impurities. EVs recovered by tangential flow filtration could be successfully purified further by both monolith chromatography steps. Post-monolith EV stimulation was conserved. ConclusionThe results indicate that monolith chromatography is a viable purification method for EVs derived from cell culture that doesn't detract from the product's ability to stimulate fibroblasts, suggesting that product functionality is conserved. Further work is needed in developing suitable downstream processes and analytics to achieve clinically relevant purities for injectable biologics.

Structuring chicken breast analogs via high moisture extrusion of dairy-plant proteins blends

Chicken analogs were structured using binary blends of soy protein isolate (SPI) and wheat gluten (WG) or whey protein concentrate (WPC), as well as trinary blends of SPI-WG-WPC via high moisture extrusion. Chicken analogs with anisotropic structures were achieved (anisotropic index >1). Although adding WPC increased hardness, by varying the ratio of SPI to WG in the trinary blends, comparable texture profile properties as cooked chicken breast were achieved. The drivers of the fiber structure formation were non-covalent protein-protein interactions like hydrogen bonds and hydrophobic interactions, and to a lesser extent, inter-protein disulfide bonds formation. β-sheets were the dominant secondary structure, and adding WPC increased the proportion of α-helix while adding WG increased the proportion of β-turns in the meat analog (MA). This study offered strategies on structuring extruded chicken analogs with WPC, a high-quality protein source, and provided insights into mechanisms underlying the formation of fiber structures.

Myosin supramolecular self-assembly: The crucial precursor that manipulates the covalent aggregation, emulsification and rheological properties of myosin

The transformation of molecular conformation and self-assembly properties of myosin during the heating process at different ionic strengths (0.2 M, 0.4 M and 0.6 M NaCl) and its effect on rheological behavior and emulsification properties were investigated. Under incubation temperatures between 40 °C and 50 °C, myosin underwent a supramolecular self-assembly stage dominated by noncovalent forces (hydrogen bonding, ionic bonding and hydrophobic interactions). Higher ionic strength facilitated molecular rearrangement through enhanced swelling of myosin heads and head-to-head assemblies, which contributed to enhanced ordering and homogeneity of myosin covalent aggregates (above 60 °C) and manifested itself macroscopically as enhanced gel viscoelasticity and emulsion stability. In contrast, at lower ionic strength, the tail-to-tail assemblies of myosin led to the preferential formation of covalent cross-links in the tails, which resulted in the inability of molecular rearrangement and the formation of disordered aggregates and finally led to the deterioration of the gel and the destabilization of the emulsion. In conclusion, the supramolecular self-assembly behavior of myosin, as an intermediate process in myosin’s sol–gel transition, is crucial for the orderliness of myosin assemblies, gel network strengthening, and emulsion stability. The obtained insight provides a reference for the precise implementation of quality improvement strategies for meat products.

Effective magnetic nanoadsorbent based on natural carboxymethyl cellulose/polyaniline nanotube/graphene oxide for aflatoxin B1 and B2 adsorption in rice utilizing a novel synthesis method

A magnetic nanoadsorbent was prepared via a novel one-pot magnetization method by employing natural carboxymethyl cellulose (CMC), polyaniline (PANI) nanotube, and graphene oxide (GO) for the effective adsorption of aflatoxins B1 (AFB1) and B2 (AFB2) from rice samples. This synthesized adsorbent combines the multifunction of CMC, PANI, and GO and shows improved extraction performance. FT-IR, XRD, FE-SEM, VSM, and TGA analyses were used to investigate the successful synthesis of the nanocomposite. The adsorption mechanism was ascribed to π-π interactions, hydrogen bonding, and hydrophobic interactions. Under optimized conditions, the method achieved extraction recoveries ranging from 78 % to 89 %. Low limits of detection (LODs) and quantification (LOQs) were obtained in the ranges of 0.07 and 0.01 ng g−1, and 0.20 and 0.04 ng g−1 for AFB1 and B2, respectively. This method showed an acceptable precision with intra- and inter-day relative standard deviations (RSDs) of less than 15 %. Comparative studies with other adsorbents used in extraction methods such as solid phase extraction (SPE), magnetic dispersive solid phase extraction (MDSPE), and matrix solid-phase dispersion (MSPD) demonstrated that the proposed method outperforms the existing procedures; it is promising in efficient AFs monitoring in rice.

Effect of limited hydrolysis on the structure and gel properties of soybean isolate proteins: A comparative study of papain or/and trypsin

Plant protein's gelation is crucial in various food applications, and hydrolysis may enhance their gelation properties. In this study, we prepared soybean protein isolate hydrolysates (SPIH) using trypsin and/or papain, and found significant improvement in the solubility and gelling properties. These proteases broken down the peptide bonds and caused the exposure of hydrophobic groups as well as the unfolding of protein. Low molecular weight (<35 kDa) SPIHs were generated by the two-step enzymatic hydrolysis, showing significant improvements in storage modulus (G′), loss modulus (G″), viscosity, strength, and water-holding capacity (WHC). Among, PT-10 exhibited the highest WHC (61.72 ± 0.36 %), gel strength (4.67 ± 0.12 g), and network cross-linking density (0.33 ± 0.01 mol/m3), while its solubility was also significantly increased up to 254 %. According to the results of gel molecular force interactions, disulfide bonds, hydrophobic interactions and hydrogen bonds involved in the gel network formation. These findings reveal that the appropriate hydrolysis modification may improve SPI gel's properties and expand its application in gel foods.

Fabrication and characterization of curcumin-encapsulated composite nanoparticles based on soybean protein isolate hydrolysate/soybean polysaccharides: Interaction mechanism, stability and controlled release properties

This study developed a stable nanoparticle (CUR-SPIH/SSPS) using soybean protein isolate hydrolysate (SPIH) and soybean polysaccharides (SPSS) to protect curcumin (CUR) from degradation during storage and exposure to light and heat conditions, achieving controlled release. The SPIH to SPSS mass ratio of 5:1 gave the CUR-SPIH/SPSS nanoparticles with the highest CUR encapsulation efficiency (95.60 ± 3.00 %) and the strongest antioxidant capacity (90.26 ± 2.42 % and 66.78 ± 1.89 % for ABTS•+ and DPPH radical scavenging ability, respectively), and CUR was successfully encapsulated within the CUR-SPIH/SPSS as evidenced by X-ray diffraction. FTIR and fluorescence spectroscopy analysis confirmed that the interactions in CUR-SPIH/SPSS are primarily driven by electrostatic, hydrogen bonding, and hydrophobic interactions. Moreover, the CUR-SPIH/SPSS nanoparticles significantly enhanced CUR's thermal and UV light stability. The UV degradation kinetics showed that the half-life of CUR-SPIH/SPSS (247.55 min) was 1.61 times longer than that of free CUR (154.03 min). The release rate of CUR incorporated into CUR-SPIH/SPSS was significantly delayed during in vitro gastrointestinal digestion. This study introduces an innovative nanoparticle strategy for the stable delivery of lipophilic compounds.

In Silico Drug Encapsulation Using 2-Hydroxypropyl-β-CD, Tyrosine Kinase and Tyrosinase Inhibition of Dinuclear Cu(II) Carboxylate Complexes

In recent years, copper carboxylate complexes have garnered significant interest for biological applications. This study focuses on 20 Cu(II) carboxylate complexes selected from our previous research. Due to the hydrophobic nature of these complexes, the 2-hydroxypropyl-β-cyclodextrin (2HPβCD) was employed as a carrier to reduce toxicity and increase solubility for controlling drug delivery. Monte Carlo calculations were performed to confirm the interaction between the optimized structures of Cu(II) complexes and 2HPβCD, forming a host-guest system. All the structures were simulated and optimized using DFT-D calculations in Material Studio 2017. The results indicated that a neutral medium is more favorable for the adsorption of these complexes into 2HPβCD. More negative binding energy values suggested strong and energetically favorable adsorption on 2HPβCD. Complexes 4, 5, and 7 exhibited the highest interaction, making them excellent candidates for drug delivery systems. DFT-D calculations were also used to investigate the release of complexes, revealing that complexes 5, 14, and 19 were difficult to release due to their lowest energy. In contrast, complexes 8, 9, and 16 were found to be most efficient to release due to weak non-covalent interactions with 2HPβCD as we can predict from binding energy obtained by DFT-D. No specific trend was observed in the interaction of the complexes with 2HPβCD. Additionally, the effects of these complexes on c-kit tyrosine kinase and Mushroom tyrosinase were studied by molecular docking. The results demonstrated that all the complexes interacted with the active site of respective receptors through hydrophobic interactions. Complexes containing 1,10-phenanthroline and 2,2-bipyrdine were identified as having a strong, spontaneous binding ability with receptors.

Revealing the off-flavors in hydro-distilled essential oils of sweet orange (Citrus sinensis) by flavoromics strategy and computational simulation

Citrus essential oils (EOs) are renowned for their aroma, but thermal extraction methods can introduce undesirable cooking and pungent odors. The specific compounds responsible for these off-flavors and their perception mechanisms remain unclear. This study investigated the flavor differences between cold pressing (CP) and hydro-distilled (HD) extracted essential oils from sweet oranges (SEOs) using flavoromics strategy. The results indicated that increased levels of alcohol compounds, particularly terpinen-4-ol, β-citronellol, geraniol, trans-carveol, and α-terpineol, were primarily responsible for the off-flavors in HD-extracted SEOs. Furthermore, molecular docking and dynamics simulations revealed that off-flavor compounds bind to olfactory receptors through hydrogen bonding and hydrophobic interactions, inducing slight structural and conformational changes that facilitate odor recognition and activate downstream signaling events. This study offers crucial insights into the mechanisms underlying off-flavor development in citrus EOs, providing valuable knowledge for optimizing extraction methods, controlling SEOs quality, and advancing flavor science.

Enhancing flocculation and dewatering performance of fine phosphate tailings: A sustainable approach for water resources management

The sustainable recovery of water from fine phosphate tailings (FPTs) is essential for reducing water consumption and mitigating the environmental risks associated with phosphate beneficiation operations, particularly during tailings storage. Dewatering through enhanced flocculation techniques is among the most sustainable management practices in the mining industry. However, the interactions between phosphate tailings and polymers remain insufficiently explored, particularly in the context of the flocculation process. To address this, the present study investigates the improvement of dewatering performance through optimized flocculation techniques. Fourteen flocculants, including anionic, nonionic, and cationic types, were assessed for their effectiveness in enhancing water recovery, sedimentation rates, and turbidity reduction. Among the tested flocculants, polyethylene oxide (PEO 4 M) and anionic polyacrylamide (AN923) exhibited superior performance, achieving water recovery rates exceeding 84 %, solid contents above 38 %, and settling rates over 13.9 cm/min, along with significant turbidity reductions to below 4.40 NTU. Insights into the adsorption mechanisms, derived from zeta potential measurements and Fourier-transform infrared spectroscopy, revealed that anionic polyacrylamide (APAM) induces flocculation primarily through hydrogen bonding and polymer bridging, whereas polyethylene oxide (PEO) operates via hydrophobic interactions and charge neutralization. These findings lay the groundwork for more sustainable water management strategies in phosphate mining, enhancing both resource efficiency and environmental protection.

Structure-based design and screening of hydrogel copolymer/Fe3O4 composite microspheres for magnetic solid phase extraction of bisphenol A from aqueous samples

It is of great significance to monitor bisphenol A (BPA) in the environment because of its potential environmental and health risks. However, the detection of trace or ultratrace BPA in complicated environmental samples is challenging due to the relatively low affinity and poor selectivity of existing adsorbents used in sample pretreatment. Herein, we report a high-affinity, low environment-dependent and strong interference-resistant abiotic affinity ligand, a N-methacryloyl-l-lysine-NH2 (MLys)-based hydrogel copolymer (HP 17) screened from a small focused polymer library engineered by incorporating various combinations and ratios of candidate functional monomers. The selection of these monomers was guided by molecular mechanism between BPA and the ligand-binding pocket of its estrogen receptors. The BPA–HP17 binding is mainly a synergistic effect of π-cation and hydrophobic interactions. The screened HP 17 has high adsorption capacity (349.4 mg/g) for BPA under wide pH (3.0–10.0) and ionic strength (0–150 mM) range. To improve its practicability, a hydrogel copolymer/Fe3O4 composite microspheres (Fe3O4@HP 17) was synthesized and applied for magnetic solid phase extraction–high-performance liquid chromatography (MSPE–HPLC) analysis of BPA in tap water, lake water and industrial effluents. The method shows wide linear range (2.5⁓100 ng/mL), high sensitivity (detection limit of 0.22 ng/mL even without further concentration after desorption), high accuracies (92.6⁓103.0 %) and good precisions (0.57⁓4.53 %), indicating a great potential of this material and method in the detection of trace or ultratrace BPA in complex environmental water samples.

7-(Diethylamino) coumarin-3-carboxylic acid as a novel antibrowning agent: Activity and mechanism

Browning caused by polyphenol oxidase (PPO) and microorganisms significantly impacts the nutritional quality of fruits and vegetables. This study identified 7-(Diethylamino) coumarin-3-carboxylic acid (7-DCCA) as an effective inhibitor of both PPO and bacteria. Enzyme assays revealed that 7-DCCA competitively inhibits PPO activity with an IC50 value of 0.275 ± 0.002 mM. Fluorescence and molecular simulation methods demonstrated that 7-DCCA forms a complex with PPO through hydrogen bonding and hydrophobic interactions, altering the enzyme's structure and reducing its activity. Thermogravimetric and differential scanning calorimetry (DSC) assays showed that 7-DCCA stabilizes PPO, delaying its thermal decomposition. Antibacterial tests proved that 7-DCCA inhibits Staphylococcus aureus and Escherichia coli by disrupting cell membranes. Additionally, 7-DCCA suppressed PPO and peroxidase activities, delaying phenolic oxidation and preventing browning in fruits and vegetables. Cytotoxicity assays confirmed its safety, with over 85 % cell viability at concentrations up to 0.1 mM. Stability experiments verified that 7-DCCA had greatly light and thermal stability. This study highlighted 7-DCCA as a promising antibrowning agent with potential application in food preservation.

Design, synthesis of antipyrine-based Schiff bases and investigation of their cholinesterase and carbonic anhydrase activities by in vitro and in silico approaches

In this study, a series of antipyrine-based Schiff bases (1-10) was designed, synthesized, and evaluated as potential inhibitors of various metabolic enzymes, including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and human erythrocyte carbonic anhydrase I and II (hCA I and hCA II). The target molecules were characterized by UV-Vis, FT-IR, 1H NMR, 13CNMR, LC-HRMS, and elemental analysis. All tested derivatives demonstrated low nanomolar inhibition with Ki values of in the range of 20.58 ± 0.35 to 53.11 ± 1.02 nM against AChE, 21.84 ± 0.40 to 54.41 ± 1.05 nM against BChE, 27.45 ± 0.41 to 48.22 ± 0.91 nM against cytosolic hCA I isoform associated with epilepsy, and 6.02 ± 0.11 to 29.32 ± 0.54 nM against cytosolic hCA II isoform associated with glaucoma. In general, most these molecules, except for a few, inhibited these enzymes more than acetazolamide (AZA) and neostigmine. Among them, compounds 5, 7, 8, and 9 showed the best inhibitory activities against AChE, BChE, hCA I, and hCA II, respectively. Docking results were calculated for the compounds that showed the best inhibitory activity against these enzymes and for reference compounds. Based on the molecular docking results, they were determined to have high binding energies, including hydrogen bonds, electrostatic interactions, and hydrophobic interactions. Absorption, distribution, metabolism, and excretion (ADME) parameters determined that all the synthesized pyrazolone ring-bearing Schif base derivatives (1-10) have the expected physicochemical properties in terms of drug-likeness and can be evaluated as orally active potential. Properties such as the electrophilicity index and chemical hardness were also investigated by density functional theory (DFT) at the B3LYP/6-311G** level of theory.

Fabrication of functional interface on magnetic beads via various amino acids and their application in chemiluminescent immunoassay as carrier

Magnetic polymer microspheres with superparamagnetism, high specificity, and monodispersity play a crucial role in the field of in vitro diagnostics. However, the surface modification process of magnetic beads is often complex, and it remains a significant challenge to prepare high-performance magnetic beads easily. To overcome these drawbacks, herein we fabricated functional interface on magnetic bead with the various amino acid via the ring-opening reaction of amino acids with epoxy groups, with attempt to produce carboxylated magnetic beads (MPS-GA) in a convenient way. Results indicate that when compared to other amino acids, the phenylalanine magnetic beads (MPS-GA1) developed in this study exhibit strong adsorption for mouse immunoglobulin (IgG), streptavidin (SA), and protamine (PA), with an IgG adsorption capacity of 53.5μg/mg and a coupling capacity of 52.5μg/mg. It is found that electrostatic forces and hydrophobic interactions are key factors influencing biomolecular interactions. Additionally, these magnetic beads can generate strong chemiluminescent signals, significantly reducing background levels by up to 99.7%. Therefore, the magnetic beads proposed in this paper can serve as carriers for chemiluminescent immunoassay (CLIA), providing new insights into the synthesis of high-quality magnetic bead.

Deacetylation enhances the structure and gelation properties of konjac glucomannan/soy protein isolate cold-set gels

This study aimed to investigate the effect of the deacetylated konjac glucomannan (DKGM), with varying degree of deacetylation (DD), on the physicochemical and structural properties of transglutaminase-induced soy protein isolate (SPI) cold-set gels. Compared with native konjac glucomannan (KGM), DKGM significantly enhanced the gel strength, water-holding capacity, and thermal stability of the composite gels, with DK3 (DKGM with 65.85 % deacetylation) showing the most significant improvement. The secondary and tertiary structures of SPI in the DK3 group were the most stable. Compared with the KGM group, the DK3 group showed a 58.32 % increase in hydrophobic interaction and a 37.98 % decrease in free sulfhydryl content. The microstructure results demonstrated that DK3 was uniformly dispersed within the SPI network, promoting the formation of a continuous and dense network structure. This was mainly due to DK3 having a moderate particle size and low viscosity. Therefore, DKGM with a moderate DD is conducive to forming a more ordered and dense gel network structure, imparting optimal gel performance to the SPI cold-set gel.

Inhibition mechanisms of α-glucosidase by eight catechins: Kinetic, molecular docking, and surface plasmon resonance analysis.

α-Glucosidase is considered to be one of the effective targets for the treatment of type 2 diabetes. This study examined the inhibitory mechanisms of eight catechins on α-glucosidase, including both the free forms (C, EC, GC, EGC) and esterified forms (CG, ECG, GCG, EGCG). Enzyme kinetics and molecular docking studies demonstrated that catechins primarily inhibit α-glucosidase by binding through hydrogen bonds and hydrophobic interactions, with esterified catechins exhibiting stronger inhibitory effects. The structural changes of the proteins following binding were further explored using fluorescence spectroscopy and atomic force microscopy (AFM). Fluorescence spectroscopy revealed that catechins altered the microenvironment around the fluorescent amino acids within the enzyme (such as tyrosine and tryptophan), resulting in slight unfolding of the protein structure. AFM further confirmed that catechin binding to α-glucosidase induced protein aggregation, with esterified catechins exhibiting a more pronounced effect. All of the above findings were based on static model studies. Moreover, the binding kinetics of catechins with α-glucosidase were innovatively investigated using surface plasmon resonance (SPR), revealing that esterified catechins bound more rapidly and displayed higher affinity. The presence of the gallate group in esterified catechins was identified as crucial for their binding to α-glucosidase, resulting in a more significant inhibitory effect. These findings suggested that dietary intake of catechins, especially esterified form, may more effectively inhibit the activity of α-glucosidase.