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Platinum-based intermetallic compounds (IMCs) play a vital role as electrocatalysts in a range of energy and environmental technologies, such as proton exchange membrane fuel cells. However, the synthesis of IMCs necessitates recombination of ordered Pt-M metallic bonds with high temperature driving, which is generally accompanied by side effects for catalysts' structure and performance. In this work, we highlight that semimetal atoms can trigger covalent interactions to break the synthesis-temperature limitation of platinum-based intermetallic compounds and benefit fuel-cell electrocatalysis. Attributed to partial fillings of p-block in semimetal elements, the strong covalent interaction of d-p π backbonding can benefit the recombination of ordered Pt-M metallic bonds (PtGe, PtSb and PtTe) in the synthesis process. Moreover, this covalent interaction in metallic states can further promote both electron transport and orbital fillings of active sites in fuel cells. The semimetal-Pt IMCs were obtained with a temperature 300 K lower than that needed for the synthesis of metal-Pt intermetallic compounds and reached the highest CO-tolerant oxygen reduction activity (0.794 A mg−1 at 0.9 V and 5.1% decay under CO poisoning) among reported electrocatalysts. We anticipate that semimetal-Pt IMCs will offer new insights for the rational design of advanced electrocatalysts for fuel cells. [ABSTRACT FROM AUTHOR]

Proteins and polyphenols are abundant in the daily diet of humans and their interactions influence, among other things, the texture, flavor, and bioaccessibility of food. There are two types of interactions between them: non-covalent interactions and covalent interactions, the latter being irreversible and more powerful. In this review, we systematically summarized advances in the investigation of possible mechanism underlying covalent polyphenols-proteins interaction in food processing, effect of different processing methods on covalent interaction, methods for characterizing covalent complexes, and impacts of covalent interactions on protein structure, function and nutritional value, as well as potential bioavailability of polyphenols. In terms of health promotion of the prepared covalent complexes, health effects such as antioxidant, hypoglycemic, regulation of intestinal microbiota and regulation of allergic reactions have been summarized. Also, the possible applications in food industry, especially as foaming agents, emulsifiers and nanomaterials have also been discussed. In order to offer directions for novel research on their interactions in food systems, nutritional value, and health properties in vivo, we considered the present challenges and future perspectives of the topic.

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The harsh working environments of proton exchange membrane fuel cells (PEMFCs) pose huge challenges to the stability of Pt‐based alloy catalysts. The widespread presence of metallic bonds with significantly delocalized electron distribution often lead to component segregation and rapid performance decay. Here we report L10−Pt2CuGa intermetallic nanoparticles with a unique covalent atomic interaction between Pt−Ga as high‐performance PEMFC cathode catalysts. The L10−Pt2CuGa/C catalyst shows superb oxygen reduction reaction (ORR) activity and stability in fuel cell cathode (mass activity=0.57 A mgPt−1 at 0.9 V, peak power density=2.60/1.24 W cm−2 in H2‐O2/air, 28 mV voltage loss at 0.8 A cm−2 after 30 000 cycles). Theoretical calculations reveal the optimized adsorption of oxygen intermediates via the formed biaxial strain on L10−Pt2CuGa surface, and the durability enhancement stems from the stronger Pt−M bonds than those in L11−PtCu resulted from Pt−Ga covalent interactions. [ABSTRACT FROM AUTHOR]

Rutin is a biologically active polyphenol, but its poor water solubility and low bioavailability limit its application to the food industry. We investigated the effect of ultrasound treatment on the properties of rutin (R) and whey protein isolate (WPI) using spectral and physicochemical analysis. The results revealed that there was covalent interaction between whey protein isolate with rutin, and the binding degree of whey isolate protein with rutin increased with ultrasound treatment. Additionally, solubility and surface hydrophobicity of WPI-R complex improved with ultrasonic treatment, and a maximum solubility of 81.9 % at 300 W ultrasonic power. The ultrasound treatment caused the complex to develop a more ordered secondary structure, resulting in a three-dimensional network structure with small and uniform pore sizes. This research could provide a theoretical reference for studying protein–polyphenol interactions and their applications in food delivery systems.

A series of di‐ and polymetal complexes involving closed‐shell, heavy main‐group atoms and ions shows a selection of special physical properties. These involve short metal–metal contacts, low entropies of formation and, most interestingly, strong Raman bands at low wavenumbers. These results together with the constitution of the coordination compounds, where the majority of electrons are assembled on the highly polarizable metal atoms and ions, experimental results have been interpreted in terms of direct, partial covalent metal–metal bonding. Previous theoretical studies have challenged this view and instead attributed the obvious attractive forces involved to secondary‐type of interactions, such as dispersion. This study utilizes a multitude of theoretical tools, such as natural bond order (NBO) and natural energy decomposition analysis (NEDA), non‐covalent interaction (NCI) analysis, electron localization functions (ELFs), and atoms‐in‐molecules (AIM) to characterize the interactions in models comprising closed‐shell dimers, as well as experimentally studied ring and cage systems constituting the main reason for the hypotheses on metal–metal interactions. The results show that all experimental results can be attributed to the covalent interactions between the electron‐rich, metal centers and the bridging anions in ring and cage coordination compounds of high symmetry, where the experimentally observed effects can be traced to the combination of covalent interactions between the metal centers and the anions along the edges of the ring and cage systems in combination with the cooperative effects generated by the high symmetry of these ring and cage systems. [ABSTRACT FROM AUTHOR]

Milk allergy is a global health issue, which affects the quality of life and can even be life threatening. According to epidemiological investigation, 2%–6% of infants are sensitive to beta-lactoglobulin (β-LG) in milk. Avoiding allergens is still the first-rank option for vulnerable group because immunization therapy is hardly available. Therefore, exploring the allergic mechanism of β-LG and applying appropriate antiallergic treatments are the key to solving the problem of milk allergy. This review describes the occurrence of β-LG, including the type, structure, epitopes of β-LG, the performance of gastrointestinal digestion, the mechanism and allergy consequence of β-LG allergic responses. Then, various methods to reduce the sensitization of β-LG were summarized, including covalent and non-covalent interactions, non-thermal processing technologies (fermentation, irradiation, pulsed electric field, ultrasound), thermal processing technology (microwave), and combination therapies. Key findings and conclusions : β-LG allergy is an immediate type I hypersensitivity reaction involving immunoglobulin (IgE) dependent antibody responses that cause a variety of clinical symptoms, such as asthma, eczema, gastrointestinal disorders, and anaphylactic shock in severe cases. To reduce the allergenicity of the β-LG, it is necessary to adopt novel processing strategies with higher efficiency. This review covers the covalent or non-covalent binding of polyphenols, polysaccharides, metal ions and nanoparticles to β-LG, as well as emerging technologies, and finds that structural modifications and conformational epitope changes of β-LG are associated with immunomodulatory properties. The combination of various approaches is a potential new way to reduce β-LG hypersensitivity. • Specificity between IgE antibodies and epitopes is indicator of β-LG allergy. • Any technique that alters the β-LG epitopes can reduce the antigenicity of β-LG. • Dietary molecules, metal ions and nanoparticles bind to β-LG by covalent interaction. • Preparation of β-LG conjugates regulate the antigenicity and digestibility of β-LG. • Novel processing techniques for β-LG to alleviate allergic symptoms are reviewed. [ABSTRACT FROM AUTHOR]

Whey proteins were conjugated with polyphenols (caffeic and ferulic acid) using different methods viz. noncovalent (pH 3, 5 and 7) and covalent (alkaline, chemical coupling and free radical grafting method). The binding of polyphenols was higher in the covalent conjugates (maximum in free radical grafting) than the noncovalent conjugates (maximum seen at pH 7). The conjugation was confirmed by decreased intrinsic fluorescence intensity (>30%), increased UV–visible absorbance and changed intensity of peaks in amide I region of Fourier transform infrared spectroscopy (FTIR). The conjugates that were prepared by the covalent (free radical grafting) and noncovalent (pH 7) methods exhibited much better emulsifying activity and emulsion stability than the alkaline conjugates for both caffeic and ferulic acid. [ABSTRACT FROM AUTHOR]

Plant-based proteins represent a more sustainable alternative, the approaches to modify and enhance their functionality and application are focused on. Covalent interaction could significantly modify the structure and function properties of protein. This study investigated the effects of covalent interaction between wheat gluten and tea polyphenols on the structure, aggregation, stability, and digestive properties of their covalent complex, as well as the possible action mechanism. The results showed that tea polyphenols could interact with gluten via covalent bonds (CN and/or CS), while tea polyphenols also acted as a bridge connecting gluten molecules, thus making covalent complex to show the larger particle sizes. This covalent interaction significantly changed the secondary structure, tertiary structure, and surface hydrophobicity of gluten. Moreover, covalent complex exhibited the high polyphenols bioaccessibility during in vitro digestion. The peptide bonds of covalent complex were mainly broken in gastric digestion, while the covalent bonds between tea polyphenols and gluten were completely destroyed in intestinal digestion. In addition, their digestates exhibited excellent antioxidant capability. All results suggest that wheat gluten have potential to prepare functional carrier for transporting active compounds and protecting them during digestion., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2024. Published by Elsevier B.V.)

The rising demand for energy density of cathodes means the need to raise the voltage or capacity of cathodes. Transition metal (TM) doping has been employed to enhance the electrochemical properties in multiple aspects. The redox voltage of doped cathodes usually falls in between the voltage of undoped layered cathodes. However, we found anomalous redox features in NaTi1−yVyS2. The first discharge platform potential (2.4 V) is significantly higher than that of undoped NaTiS2 and NaVS2 (both around 2.2 V), and the energy density is raised by 15 %. We speculate that the anomalous voltage is mainly attributed to the strong hybridization in the Ti−V−S system. Ti3+ and V3+ undergo charge transfer and form a more stable Ti (t2g0eg0) and V (t2g3eg0) electronic configuration. Our results indicate that higher voltage of cathode materials could be achieved by strong TM‐ligand covalency, and this conclusion provides possible opportunities to explore high voltage materials for future layered cathodes. [ABSTRACT FROM AUTHOR]

Sericin, as an inexpensive byproduct of the silk industry, has drawn increasing attention due to its good biocompatibility and various bioactivities. Covalent interactions between proteins and phenolic compounds are ubiquitous and can affect the functional properties of proteins, but little is known about the interactions between sericin and phenolic compounds. In our research, hydroquinone and pyrogallol were selected as model phenolic compounds to investigate the interaction between sericin and phenolic compounds. UV spectroscopy and SEC-HPLC confirmed that sericin and oxidized phenolic compounds formed conjugates, which were primarily the result of covalent interactions. The covalent binding of phenolic compounds changed the secondary structure and thermal behavior of sericin and increased its surface hydrophobicity. The covalent interaction had a positive effect on the emulsifying activity of sericin. Likewise, the antioxidant activity and anti-inflammatory activity of sericin were enhanced in the presence of phenolic compounds. Sericin-phenolic conjugates would be used as multifunctional ingredients in cosmetics, food, and other industries due to their improved emulsifying, antioxidant, and anti-inflammatory properties. [Display omitted] • Sericin was modified with hydroquinone and pyrogallol. • Covalent binding of phenolics changed the physicochemical properties of sericin. • Covalent interaction had a positive effect on the emulsifying activity of sericin. • Antioxidant activity of sericin was enhanced in the presence of phenolics. • Anti-inflammatory activity of sericin was enhanced in the presence of phenolics. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenides (TMDCs) are widely used in biosensing applications due to their excellent physical and chemical properties. Due to the properties of biomaterial targets, the biggest challenge that biosensors face now is how to improve the sensitivity and stability. A lot of materials had been used to enhance the target signal. Among them, TMDCs show excellent performance in enhancing biosensing signals because of their metallic and semi-conducting electrical capabilities, tunable band gap, large specific surface area and so on. Here, we review different functionalization methods and research progress of TMDCs-based biosensors. The modification methods of TMDCs for biosensor fabrication mainly include two strategies: non-covalent and covalent interaction. The article summarizes the advantages and disadvantages of different modification strategies and their effects on biosensing performance. The authors present the challenges and issues that TMDCs need to be addressed in biosensor applications. Finally, the review expresses the positive application prospects of TMDCs-based biosensors in the future.

[Display omitted] • The asymmetric orbital hybridization improves adsorption of heavy metal cations. • The polarizations of ions with 3 s 3 p 3 d are stronger than that with 3 s 3 p hybridization. • Polarization-induced covalent bonds exist at siloxane surfaces due to asymmetric response. • The contribution of asymmetric response to total adsorption energy was quantified. The interactions between heavy metal cations and charged surfaces are major processes responsible for the deactivation/activation of heavy metals, attracting special interest in both agricultural and environmental issues. The traditional view argues that the interactions between heavy metal and hydroxyl surface are primarily controlled by electrostatic forces and coordination-covalent bonds, while the interactions between heavy metal and siloxane surface are solely determined by electrostatic forces. A theory of asymmetric orbital hybridization was applied in this study to investigate the interactions between metal cations and charged surfaces. New surface reactions, polarization-enhanced induction forces (PEIF) and polarization-induced covalent bonds (PICB) between heavy metal cations (Cu2+ and Zn2+) and O atoms of charged siloxane surfaces, were discovered, and their respective contributions were quantified using asymmetric orbital hybridization theory. Both PEIF and PICB for metal cations with 3 s 3 p z 3 d z2 hybridization are stronger than those with sp z hybridization. For example, the proportion of covalent bonds in the overall adsorption energy is lower for Ca2+ with 3 s 3 p z hybridization (28.92 %) compared to Cu2+ with 3 s 3 p z 3 d z2 (32.77 %). The new surface reactions based on asymmetric orbital hybridization determine the adsorption selectivity of heavy metal cations and strongly affect their removal in wastewater. The removal efficiency of heavy metals can be regulated through the enhancements of hydroxyl groups, electric field strength, and orbital hybridization effects at the clay mineral surfaces. [ABSTRACT FROM AUTHOR]

The reactivity of amino acid residues in proteins towards quinones, along with the concentration of quinones, may play a crucial role in determining the specific sites of reaction between quinones and proteins. The reaction efficiencies of 20 different α-carbon amine group blocked amino acids with 4-methylbenzoquinone (4MBQ) were investigated at pH 7.0 by cyclic voltammetry. Among these, Nα-acetyl- l -lysine, Nα-Boc- l -histidine, Nα-acetyl- l -arginine, and Nα-acetyl- l -cysteine exhibited reactivity towards 4MBQ, with the reactivity sequence being: Nα-acetyl- l -cysteine > Nα-acetyl- l -lysine > Nα-acetyl- l -arginine > Nα-Boc- l -histidine. In addition, the reactivity of Nα-acetyl- l -cysteine towards 4MBQ was over 50-fold greater than that of Nα-acetyl- l -lysine, Nα-Boc- l -histidine and Nα-acetyl- l -arginine. Adducts formed from the reaction of 4MBQ with Nα-acetyl- l -lysine and Nα-acetyl- l -arginine were identified as quinone adducts. In contrast, those formed with Nα-acetyl- l -cysteine and Nα-Boc- l -histidine were identified as phenol adducts through UPLC-QTOF-MS/MS analysis. Irrespective of whether the molar ratio of 4MBQ to protein free thiol groups was 1:2 or 2:1, the residues of cysteine, lysine, arginine and histidine in β-lactoglobulin (β-Lg) invariably engaged in the reaction with 4MBQ. This work may provide valuable information for design polyphenol-protein covalent conjugates which can be further applied as functional additives in food industry by choosing protein with different proportion of lysine, histidine, arginine and cysteine residues. • 4MBQ reacted with protein via cysteine, arginine, histidine, and lysine residues. • 4MBQ concentration did not affect its reaction sites with β-Lg. • The reaction of 4MBQ with lysine and arginine residues formed quinone adducts. • The reaction of 4MBQ with cysteine and histidine residues formed phenol adducts. [ABSTRACT FROM AUTHOR]

Enzymes are the precious gift of nature to humans. The wise utilization of enzymes may reduce energy needs of humans and the Immobilization technique can help a lot in this regard. This aspect overcomes limitations of the enzymes, therefore providing an opportunity to explore enzymatic chemistry further. In the present context, it is quite cumbersome & costly to identify the amino acid of enzymes involved in the covalent mode of Immobilization. In the present study, molecular modeling techniques were used to do this difficult task. The present work used molecular modeling methods to extract information about the immobilization of α-Amylase (E.C.3.2.1.1) on Dialdehyde Cellulose. The Lysine residue is the most probable residue to interact with Dialdehyde Cellulose. In the present work, a total of 23 lysine residues were used to study covalent binding behavior with α-Amylase. It was found that if Lys142 is involved in binding with Dialdehyde Cellulose then binding affinity (−6.1 & −5.9 kcal mol−1), as well as the involvement of amino acids of both free α-Amylase and Lys142 immobilized α-Amylase with the starch substrate, were found to be similar. The technique reported here is used for the identification of amino acid residue for the Immobilization of enzymes. [Display omitted] • Molecular modeling techniques were used to identify residue involved in bonding. • Docking & visualization software were used in the present study. • Studies were carried out using the concept of stepwise exclusion of individual lysine residue. • Lys142 was involved for immobilization of α-Amylase on Dialdehyde Cellulose. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The conjugation of protein and chlorogenic acid was expected to change protein structure and improve protein functional properties. The study investigated the effect of covalent interactions of soy protein isolate (SPI) and chlorogenic acid (CA) at different concentrations (20, 40, 60, 80, 100 μmol/g protein) on the interface-related functions and antioxidant activities. The results showed that the conjugation rate was directly proportional to the CA concentration. The results of SDS-PAGE analysis revealed that covalent complexes were formed. The intrinsic fluorescence spectroscopy and ultraviolet spectroscopy indicated that CA tended to unfold the structure of SPI. Correspondingly, the flexibility was greatly enhanced by 183.06%, and a significant decrease (26.06%) in the surface hydrophobicity was caused. In addition, the DPPH and ABTS radical scavenging activities constantly increased by 10.87% and 33.08 μmol Trolox Equivalent (TE)/g protein with CA of 100 μmol/g protein. However, the solubility, emulsifying stability and foaming properties increased first and then decreased with the increase of CA concentration. They all reached the maximum when CA was 80 μmol/g protein, respectively, 47.77 ± 0.15%, 39.55 ± 1.27 min, and 3155.76 ± 52.02%. And the particle size was the smallest at this time, particles smaller than 10 nm had the largest volume fraction. In summary, SPI had the greatest improvement in the interface-related functional properties and excellent antioxidant activities with CA of 80 μmol/g protein. This work elucidates that SPI-CA covalent conjugates can be used as a new food ingredient in emulsion food systems to improve food quality. [ABSTRACT FROM AUTHOR]

Leachables in pharmaceutical products may react with biomolecule active pharmaceutical ingredients (APIs), for example, monoclonal antibodies (mAb), peptides, and ribonucleic acids (RNA), potentially compromising product safety and efficacy or impacting quality attributes. This investigation explored a series of in silico models to screen extractables and leachables to assess their possible reactivity with biomolecules. These in silico models were applied to collections of known leachables to identify functional and structural chemical classes likely to be flagged by these in silico approaches. Flagged leachable functional classes included antimicrobials, colorants, and film-forming agents, whereas specific chemical classes included epoxides, acrylates, and quinones. In addition, a dataset of 22 leachables with experimental data indicating their interaction with insulin glargine was used to evaluate whether one or more in silico methods are fit-for-purpose as a preliminary screen for assessing this biomolecule reactivity. Analysis of the data showed that the sensitivity of an in silico screen using multiple methodologies was 80%-90% and the specificity was 58%-92%. A workflow supporting the use of in silico methods in this field is proposed based on both the results from this assessment and best practices in the field of computational modeling and quality risk management., (© PDA, Inc. 2024.)

Allergenicity of soybean 7S protein (7S) troubles many people around the world. However, many processing methods for lowering allergenicity is invalid. Interaction of 7S with phenolic acids, such as chlorogenic acid (CHA), to structurally modify 7S may lower the allergenicity. Hence, the effects of covalent (C-I, periodate oxidation method) and noncovalent interactions (NC-I) of 7S with CHA in different concentrations (0.3, 0.5, and 1.0 mM) on lowering 7S allergenicity were investigated in this study. The results demonstrated that C-I led to higher binding efficiency (C-0.3:28.51 ± 2.13%) than NC-I (N-0.3:22.66 ± 1.75%). The C-I decreased the α-helix content (C-1:21.06%), while the NC-I increased the random coil content (N-1:24.39%). The covalent 7S-CHA complexes of different concentrations had lower IgE binding capacity (C-0.3:37.38 ± 0.61; C-0.5:34.89 ± 0.80; C-1:35.69 ± 0.61%) compared with that of natural 7S (100%), while the noncovalent 7S-CHA complexes showed concentration-dependent inhibition of IgE binding capacity (N-0.3:57.89 ± 1.23; N-0.5:46.91 ± 1.57; N-1:40.79 ± 0.22%). Both interactions produced binding to known linear epitopes. This study provides the theoretical basis for the CHA application in soybean products to lower soybean allergenicity.

A theoretical approach used in the work—the theory of generalized charges—is an asymptotic approximation of quantum mechanics for interatomic forces. To some extent it is similar to the Thomas–Fermi model of inhomogeneous electron gas. The well-known consequence of Teller's theorem about the impossibility of applying the Thomas–Fermi model to interatomic forces is circumvented by replacing the electric field with the field of generalized charges. To clarify the origin of generalized charges, the concept of covalent bond function is introduced through the overlap integral of the electronic wave functions of interacting atoms. The proposed approach is convenient to explain two types of interatomic interactions (covalent and van der Waals) and to derive the expressions for their energies. It is shown that the covalent bond function is involved in the electronic balance and associated with generalized charges and wave vectors of electrons. New analytical relationships, restrictions and regularities for the length and potential of a homopolar covalent bond are deduced. In particular, expressions are obtained for the covalent radii and bond distances of homonuclear molecules in the ground state. The theory of generalized charges also has excellent prospects for describing the binding energy, which will be shown independently. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this research, the physicochemical, structural and functional properties of soybean protein isolate (SPI) as well as controlled hydrolysates (HSPI) were investigated by treatment with different concentrations of phlorotannins (PT) (0, 0.2, 0.5, 1.0, 2.0, mg/mL) through covalent and non-covalent interactions. Native/SDS-PAGE confirmed the formation of covalent and non-covalent complexes between PT and SPI/HSPI, and the presence of covalent bonds other than disulfide bonds in the covalent complexes (C–N, C–S bonds). After binding to PT, the secondary and tertiary structures of SPI/HSPI were changed. The secondary structure of complexes was transformed from β-sheet and β-turn to α-helix and random coil, and higher rates of transformation for covalent complexes. With the increase of PT concentration, the fluorescence and UV intensity of covalent/non-covalent complexes gradually reduced and rose, respectively; covalent complexes had lower fluorescence and higher UV intensity at equal concentrations. The particle size and ζ-potential of covalent/non-covalent complexes rose with PT concentration, and the PDI decreased and then rose, reaching a minimum value of 0.21 (HSPI-PT covalent) at PT of 0.5 mg/mL. TEM showed PT addition induced the aggregation of the complexes to increase. Meanwhile, surface hydrophobicity reduced while the antioxidant activity rose. Solubility, foaming activity and emulsifying activity of HSPI-PT covalent complexes first rose and then declined, and were optimal at PT of 0.5 mg/mL, with 78%, 250% and 97 m2/g, respectively. These will provide references for the improvement of soy protein properties and the application of complexes in formulated foods. [Display omitted] • The loose structure of HSPI made it more favorable for binding to PT. • Covalent complexes had higher molecular weights. • HSPI-PT covalent complexes had better functional properties and more stable. [ABSTRACT FROM AUTHOR]

Tartary buckwheat protein-rutin/quercetin covalent complex was synthesized in alkaline oxygen-containing environment, and its binding sites, conformational changes and functional properties were evaluated by multispectral technique and proteomics. The determination of total sulfhydryl and free amino groups showed that rutin/quercetin can form a covalent complex with BPI and could significantly reduce the group content. Ultraviolet-visible spectrum analysis showed that protein could form new characteristic peaks after binding with rutin/quercetin. Circular dichroism spectrum analysis showed that rutin and quercetin caused similar changes in the secondary structure of proteins, both promoting β-sheet to α-helix, β-ture and random coil transformation. The fluorescence spectrometry results showed that the combination of phenols can cause the fluorescence quenching, and the combination of rutin was stronger than the quercetin. Proteomics showed that there were multiple covalent binding sites between phenols and protein. Rutin had a high affinity for arginine, and quercetin and cysteine had high affinity. Meanwhile, the combination of rutin/quercetin and protein had reduced the surface hydrophobic ability of the protein, and improved the foaming, stability and antioxidant properties of the protein. This study expounded the mechanism of the combination of BPI and rutin/quercetin, and analysed the differences of the combination of protein and phenols in different structures. The findings can provide a theoretical basis for the development of complexes in the area of food. [Display omitted] • The mechanism of covalent interaction between phenols and BPI was investigated. • The structure of BPI can be changed by the binding of phenols. • The covalent binding sites were identified by proteomics. • The glycoside group of phenol can affect the binding affinity of phenol to BPI. [ABSTRACT FROM AUTHOR]

The glycol alkoxysilanes, tetrakis(2‐hydroxyethyl)silane (THEOS), and tris(2‐hydroxyethyl)methyl silane (MeTHEOS) are water soluble derivatives of tetraethoxysilane (TEOS) and methyltriethoxysilane (MeTEOS) and precursors of the system silane–chitosan reviewed in this work. The glycol modified alkoxysilanes are obtained by transesterification reaction of TEOS or MeTEOS with ethylene glycol. The reaction evolution is monitored by 29Si NMR. It is possible to observe the formation of the various species of glycol alkoxysilanes in equilibrium as the reaction proceeds showing that the oligomers formation is favored at longer reaction times with the final product tendency to gel keeping the complete water solubility. The glycol alkoxysilanes are synthesized at moderated reaction conditions, by using the Piers–Rubinsztajn (PR) reaction. Additionally, it is already known that THEOS is compatible with different natural polysaccharides as chitosan and the same behavior has been demonstrated in this work for MeTHEOS. Several reports refer studies regarding the system THEOS–polysaccharides to synthesize hybrid materials. The system THEOS–chitosan is known but the characterization as well as the way silane–chitosan interact has not been studied in detail. In the present report, chemical evidence of the covalent interactions THEOS– and MeTHEOS–chitosan based on NMR studies (13C and 29Si) are presented as intended. [ABSTRACT FROM AUTHOR]

In recent years, the synthesis and application of green and sustainable products have become global ecological and societal issues. Based on the principles of green chemistry, the application of different biocatalysts not only produce target products and decreases side effects but also enhances the selectivity and activity. Enzyme-based biocatalysts are very interesting due to their high catalytic performance, eco-friendly reaction systems, and selectivity. Immobilization is demonstrated as a favorable approach to improve the stability and recyclability of enzymes. Among different supports, porous and crystalline materials, covalent organic frameworks (COFs), represent an interesting class of support matrices for the immobilization of different enzymes. Owing to tunable physicochemical characteristics, a high degree of crystallinity, large specific surface area, superior adsorption capacity, pre-designable structure and marked stability, COFs might consider as perfect host materials for improving the desirable properties of enzymes, such as poor stability, low operational range, lack of repeatability, and products/by-products inhibition for large-scale applications. The enzyme-incorporated COFs have emerged as one of the hopeful ways to constitute tailor-made biocatalytic systems, which can be employed in an array of reactions. Highly porous nature of many COFs led to increased process output in contrast to other micro/nanoparticles. The enzymes can be integrated into COFs through different techniques, including physical adsorption and direct covalent attachment between the enzyme molecules and COFs or through a cross-linking agent. Herein, we discuss and highlight the synthesis methods, properties, and functionalization of COFs and the recent literature for the application of these materials in enzymes immobilization. Main approaches for immobilization of enzymes into COFs and the catalytic applications of these materials are also presented. This study offers new avenues to address the limitations of traditional enzyme immobilization supports as well as delivers new possibilities to construct smart biocatalytic systems for diverse biotechnological applications. [ABSTRACT FROM AUTHOR]

Proteins and polyphenols are abundant in the daily diet of humans and their interactions influence, among other things, the texture, flavor, and bioaccessibility of food. There are two types of interactions between them: non-covalent interactions and covalent interactions, the latter being irreversible and more powerful. In this review, we systematically summarized advances in the investigation of possible mechanism underlying covalent polyphenols-proteins interaction in food processing, effect of different processing methods on covalent interaction, methods for characterizing covalent complexes, and impacts of covalent interactions on protein structure, function and nutritional value, as well as potential bioavailability of polyphenols. In terms of health promotion of the prepared covalent complexes, health effects such as antioxidant, hypoglycemic, regulation of intestinal microbiota and regulation of allergic reactions have been summarized. Also, the possible applications in food industry, especially as foaming agents, emulsifiers and nanomaterials have also been discussed. In order to offer directions for novel research on their interactions in food systems, nutritional value, and health properties in vivo , we considered the present challenges and future perspectives of the topic., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zhang, Huang, Wang, Wan and Wang.)

Membrane fouling remains a notorious problem in microfiltration (MF) and ultrafiltration (UF), and a systematic understanding of the fouling mechanisms is fundamental for solving this problem. Given a wide assortment of fouling studies in the literature, it is essential that the numerous pieces of information on this topic could be clearly compiled. In this review, we outline the roles of membrane-foulant and foulant-foulant intermolecular interactions in MF/UF organic fouling. The membrane-foulant interactions govern the initial pore blocking and adsorption stage, whereas the foulant-foulant interactions prevail in the subsequent build-up of a surface foulant layer (e.g., a gel layer). We classify the interactions into non-covalent interactions (e.g., hydrophobic and electrostatic interactions), covalent interactions (e.g., metal-organic complexation), and spatial effects (related to pore structure, surface morphology, and foulants size for instance). They have either short- or long-range influences on the transportation and immobilization of the foulant toward the membrane. Specifically, we profile the individual impacts and interplay between the different interactions along the fouling stages. Finally, anti-fouling strategies are discussed for a targeted control of the membrane-foulant and foulant-foulant interactions.

Many food ingredients such as polyphenols, phenolic acids (e.g. present in fruit and vegetables) and organosulphur compounds (e.g. present in mustard, garlic and chives) covalently interact with meat, egg, dairy and plant-based proteins. The results of those interactions are manifold and range from altered technological properties (in emulsions, foams, gels) to sensory changes (colour formation, altered taste and smell) and different biological activity (allergy, antimicrobial effects, hydrolysis). The present review discusses both the positive and the negative side effects of such interactions and explores the potential to fine-tune protein functionality during processing not only in model solutions but also in more complex foods. Traditionally, studies have focused on the negative effects of interactions between protein and plant ingredients (e.g. discolouration and solubility changes), but more recent studies highlight positive effects (e.g. enhanced emulsifying capacity, reduced allergy and targeted production of protein pigments). By controlling food processing conditions (e.g. protein nativity) and the food matrix (e.g. presence of antioxidative compounds or thiol groups, pH value during storage), the observed effects can be prevented or induced. On the basis of the listed findings, future processes can be developed that take such interactions into account to enable targeted co-processing of plant compounds with proteins. A better understanding of these interactions opens up a wealth of novel utilization potential. [ABSTRACT FROM AUTHOR]

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New expressions for the energy and the length of interatomic bonds depending on atomic number, bond order, and angular momentum are derived within the theory of generalized charges, which is an asymptotic approximation for interatomic forces in the quantum-statistical model of a multicomponent electron gas. In particular, expressions for bond energies and bond lengths in hydrides are derived as functions of atomic numbers. As a consequence of the developed theory, hydrogen bonding is viewed as a one-electron covalent bonding, which is used to derive corresponding quantitative relations. The energy of hydrogen bonding cannot be lower than some specific value determined by the charge of the bonded atom. The region of existence of hydrogen bonding is established. The boundaries of the region are determined by the classes of substances distinguished by their ability to form hydrogen bonding. Quantitative estimations are used to explain the ability or inability of substances containing electronegative atoms to dissolve in water. [ABSTRACT FROM AUTHOR]

The covalent interactions between proanthocyanidins (PAs) and pectin during thermal processing was investigated. An acid-butanol assay clearly showed that PAs were covalently bound to pectin. Computational studies indicated that a nucleophilic substitution reaction occurred between the carbocation generated by the PAs and carboxyl or hydroxyl groups on the pectin, leading to the formation of PAs-pectin adducts. Thermal processing and PAs significantly affected the physicochemical, functional, and biological properties of pectin. Thermal processing reduced the molecular weight and increased the gelling properties of pectin, whereas PAs increased both the molecular weight and the gelling properties. Finally, we found that the covalent attachment of PAs to pectin greatly enhanced its antioxidant, prebiotic, and α-glucosidase inhibitory activity. Overall, our results suggest that the thermal processing of fruits has the potential to induce a covalent interaction between PAs and pectin, which would impact the physicochemical characteristics and functional properties of pectin.

Novel graphitic carbon nitride nanocones (g-CNNCs) were synthesized for the first time in this study. The SEM, TEM, XPS and FT–IR were used to research the structure of the g-CNNCs. We found that the g-CNNCs showed high selective and sensitive for fluorescence enhancement detection of Pb2+ ion via covalent interaction. In addition, the g-CNNCs exhibit stable and specific concentration-dependent fluorescence intensity in the presence of Pb2+ ion in the range of 1–200 μmol·dm−3, and the limit of detection was estimated to be 0.0438 μmol·dm−3 (3S/k). More importantly, the g-CNNCs were used to detect practical samples with satisfactory results. Schematic illustration of graphitic carbon nitride nanocones fluorescence enhanced sensing Pb2+ ion. Unlabelled Image • Graphitic carbon nitride nanocones (g-CNNCs) were synthesized for the first time. • Pb2+ ion can enhance g-CNNCs fluorescence intensity. • g-CNNCs displayed excellent selectivity and sensitivity for lead ion. • g-CNNCs were used to detect lead ion with high accuracy comparing with AAS. [ABSTRACT FROM AUTHOR]

Summary: We investigated the function and molecular mechanisms of 2-desoxy-4β-propylcarbamate-pulchellin (P-13), a sesquiterpene lactone derivative of 2-desoxy-4-epi-pulchellin from the traditional Chinese medicinal herb Carpesium abrotanoides L, in regulating STAT3 signaling and cancer cell growth. We found that P-13 inhibited the IL-6-induced, as well as the constitutive, STAT3 activation in a dose and time-dependent manner. In vitro kinase activity analyses demonstrated that P-13 directly inhibited JAK2 kinase activity. The inhibitory effects of P-13 on JAK2/STAT3 signaling could be blocked by reducing agents dithiothreitol (DTT) or glutathione (GSH), indicating an involvement of the thiol-reactive α-β unsaturated carbonyl group in P-13. Further analyses with mass spectrograph, as well as molecular docking, revealed that P-13 covalently bound with the C452 in the SH2 domain of JAK2. Furthermore, P-13 inhibited growth and induced death of many cancer cell lines, particularly those expressing constitutively activated STAT3. It also inhibited in vivo growth of human cancer cell xenografts. Taken together, these findings revealed P-13 as a novel covalent inhibitor of JAK2, uncovered a new mechanism to inhibit JAK2, and provided a promising anti-cancer drug candidate. [ABSTRACT FROM AUTHOR]

Aberrant activation of the signal transducer and activator of transcription 3 (STAT3) and the nuclear factor‐κB (NF‐κB) signalling pathways is associated with the development of cancer and inflammatory diseases. JAKs and IKKs are the key regulators in the STAT3 and NF‐κB signalling respectively. Therefore, the two families of kinases have been the major targets for developing drugs to regulate the two signalling pathways. Here, we report a natural compound xanthatin from the traditional Chinese medicinal herb Xanthium L. as a potent inhibitor of both STAT3 and NF‐κB signalling pathways. Our data demonstrated that xanthatin was a covalent inhibitor and its activities depended on its α‐methylene‐γ‐butyrolactone group. It preferentially interacted with the Cys243 of JAK2 and the Cys412 and Cys464 of IKKβ to inactivate their activities. In doing so, xanthatin preferentially inhibited the growth of cancer cell lines that have constitutively activated STAT3 and p65. These data suggest that xanthatin may be a promising anticancer and anti‐inflammation drug candidate. [ABSTRACT FROM AUTHOR]

Previously, a universal relation for the energy and length of homopolar covalent bond has been derived with the use of the theory of generalized charges, which represents an asymptotic approximation for interatomic forces of the quantum-statistical model of a multicomponent electron gas. The article discusses the new implications of the theory, obtained to describe the donor-acceptor bond. The bond energy includes the contribution of the donor atom characteristic of a homopolar bond and the Coulomb interaction of the atoms, with allowance for the probability of fixation of the bond electrons on the acceptor. Regularities for the donor-acceptor bond length and energy have been discovered. In particular, for the particular case realized in hydrides, expressions are obtained for the length and bond energy versus the atomic number of the acceptor. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dynamic microfluidic-assisted transglutaminase dual modification of soy protein isolate-chitosan adducts showed significant improvement in their structural and functional properties. • The solubility and the degree of binding of the adducts were significantly increased. • The magnitude of the change in the secondary structure of the protein in the adduct was increased. • The surface hydrophobicity of the adduct was increased and the average particle size was reduced. • After in vitro digestion, the antioxidant activity of the adducts was significantly enhanced. In this study, soy protein isolate (SPI)-chitosan (CS) adducts were prepared by using dynamic microfluidic-assisted transglutaminase (TGase) modification. It was shown that the solubility and degree of binding of SPI-CS adducts prepared by dynamic microfluidic-assisted TGase modification were better. After the samples were treated twice at 400 bar, the degree of binding for SPI-CS adducts increased to 31.97 ± 1.31%, and the solubility increased to 66.25 ± 1.10%. With the increase of microfluidic pressure, the exposed free sulfhydryl groups increased, the particle size reduced, and the surface hydrophobicity first increased and then decreased. Under the action of the pressure generated by microfluidics, the structure of the protein in the SPI-CS adduct was unfolded and transformed from an ordered structure to a disordered one. The SPI-CS adducts prepared with assisted dynamic microfluidic treatment showed significantly higher ABTS radical scavenging rate, DPPH radical scavenging rate and reducing power after in vitro digestion compared with that of SPI-CS adducts prepared with TGase alone. This result indicated that appropriate dynamic microfluidic treatment improved the structural and functional properties of TGase-modified SPI-CS adducts and significantly increased the antioxidant activity after in vitro digestion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Different ternary complexes were prepared by SPI, DG and MC. • The combinations of SPI, DG and MC were studied to evaluate the stability of emulsion. • Delivery efficiency of β-carotene was compared in different emulsions. A β-carotene rich emulsion with improved physical and chemical stability was obtained in this study, using different types of protein-polysaccharide-polyphenol ternary complexes as novel emulsifiers. The ternary complexes were prepared by covalent or non-covalent binding of soy protein isolate (SPI), β-glucan (DG) and myricetin (MC), which were evidenced to be stable. It was indicated that the emulsion stabilized by covalent complex of SPI, DG and MC, exhibited higher zeta-potential and smaller particle size than those stabilized by non-covalent complex. Furthermore, the covalent complexes prepared from different addition sequences showed different efficiencies in stabilizing the emulsion, in which SPI-DG-MC and SPI-MC-DG-stabilized emulsions possess better stability, emulsifying activity and storage resistance under adverse environmental treatment, with CI values of 62.7% and 64.3% after 25 days, respectively. According to oxidative stability and rheology analysis of the emulsions, it was found that the SPI-MC-DG complex prepared at the ratio of 4:2:1 was more stable with relatively less lipid oxidation products and a tighter stacking structure, and the final LH value was 39.98 mmol/L and the MDA value was 6.34 mmol/L. These findings implied that the ternary complex has the potential to deliver fat-soluble active ingredient by means of emulsion, but which depends on the mode and sequence of the molecular interactions. [ABSTRACT FROM AUTHOR]

The aim of this study is the effects of (+)-catechin (CC) covalent cross-linking (CCCI) (0.05–0.25 %, w / v) on the physicochemical properties, rheological properties, and oxidative stability of rice bran protein (RBP) emulsion. Analysis of particle size, ζ-potential, circular dichroism, fluorescence spectroscopy, surface hydrophobicity, and emulsifying properties demonstrated that a concentration of 0.15 % (w / v) CCCI facilitated protein structure unfolding, resulting in reduced particle size, enhanced electrostatic repulsion, and improved emulsion stability. Moreover, the covalent complexes of RBP-0.15 %CC (w / v) exhibited increased viscosity and shear stress, reflected by the highest G′ and G″ values, ultimately enhancing the oxidative stability. Furthermore, analysis using atomic force microscopy and confocal laser scanning microscopy revealed that the RBP-0.15 %CC complexes exhibited the smallest particle size (164 nm) and displayed greater homogeneity. An increase in CC concentration to 0.25 % (w / v) resulted in a higher emulsion aggregation. The emulsions stabilized by CCCI exhibited superior rheological properties and enhanced oxidation stability compared to the control. In conclusion, an appropriate amount of CC can enhance the rheology and oxidation stability of the RBP emulsion, while CCCI treatment holds potential for expanding the utility of RBP in various applications. [Display omitted] • A more homogeneous rice bran protein (RBP) emulsion was encouraged by (+)-catechin covalent cross-linking (CCCI). • The apparent viscosity of RBP emulsion increased after CCCI. • The emulsion rheological properties of (+)-catechin covalent binding RBP were significantly improved. • The RBP emulsion oxidation stability was improved by CCCI, which depended on metering. [ABSTRACT FROM AUTHOR]

The utilization rate of proteins can be effectively improved through the interaction between proteins and polyphenols. In this study, non-covalent and covalent whey protein concentrate (WPC)-quercetin (Q) complexes were prepared. The binding principle between WPC and Q and the structural and functional properties alteration of WPC on binding with different concentrations of Q were evaluated. Fluorescence spectroscopy results demonstrated significant structural alterations of WPC characterised by fluorescence quenching and a red-shifted maximum wavelength of emission peak after the interaction between WPC and Q, and a significant decrease in β-sheet and a remarkable increase in random curl content with the increase of Q concentration in fourier transform infrared spectroscopy (FTIR). Moreover, WPC and Q were more likely to form covalent complexes rather than non-covalent ones, which was featured with higher Q binding quantity and lower sulfhydryl group content at the same Q content. The binding sites number under covalent interaction mode was about 4.75 times that of the non-covalent counterparts. Combination of Q to WPC decreased surface hydrophobicity and improved foaming capability and emulsifying activity as well as antioxidant capability both for non-covalent and covalent interaction. However, non-covalent binding increased foam stability and emulsifying stability and decreased the protein solubility characterised by protein aggregation, while opposite trends were found for covalent interaction. The interfacial stability index variations were explained by the changes of zeta-potential of complexes with the increase of Q concentration. This study provides clarifies the principle behind the binding of WPC with Q and the possible application of WPC-Q complexes in food. [Display omitted] • Whey protein concentrate (WPC)-quercetin complex characteristics were studied. • Secondary structural variations had similar trends via the two interaction modes. • WPC and quercetin were more likely to form stable covalent complexes. • Covalent interaction improved WPC solubility while non-covalent impaired it. • Interfacial stability was related to zeta-potential and depended on interaction type. [ABSTRACT FROM AUTHOR]

• Biotinylated caffeic acid (BioC) was synthesized for the identification of protein-phenol adducts. • MHC-BioC and Actin-BioC adducts were purified and quantified in myofibrillar proteins system. • Secondary structures of MP were changed by covalent binding with caffeic acid. • Caffeic acid binding showed negative correlation with gel properties of myofibrillar proteins. In this study, the effects of covalent interactions between myofibrillar proteins (MP) and caffeic acid (CA) were investigated. Protein-phenol adducts were identified by biotinylated caffeic acid (BioC) used as a substitution of CA. The total sulfhydryls and free amines content were decreased (p < 0.05). The α-helix structure of MP increased (p < 0.05) and MP gel properties enhanced slightly at low dosages of CA (10 and 50 μM), and both were impaired significantly (p < 0.05) at high dosages of CA (250 and 1250 μM). Two prominent adducts of myosin heavy chain (MHC)-BioC and Actin-BioC were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), which gradually increased at low concentrations of BioC (10 and 50 μM), and raised significantly at the concentration of 1250 μM. According to the correlation analysis, MHC-BioC and Actin-BioC adducts showed a significant negative correlation with gel properties, such as G', hardness, and water holding capacity (WHC) (p < 0.01), which indicated that the covalent interactions between MP and CA significantly affected the quality of meat products. [ABSTRACT FROM AUTHOR]

[Display omitted] • A unique N---S covalent interaction enhances the photo and thermal stability. • The designed systems are efficient for high-performance organic solar cells. • Low excitation and binding energy values have been observed. • High mobility of the hole and electron has been observed. Organic photovoltaics with prolonged photo stability need further attention from researchers around the world. In this report, a new series of photostable acceptor molecules for possible applications in organic photovoltaics have been presented. In these molecules, a robust carbon–carbon single bond initiates a unique N---S covalent interaction that enhances the photo and thermal stability of the studied designed systems. In this regard, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) have been employed at different appropriate levels. The position of frontier molecular orbitals (FMOs) reduces the band gap with maximum charge transportation. Further, the modeled systems have also shown light absorption in the near infra-red (IR) region with easy excitation of the exciton. High electron and hole mobilities towards the respective electrodes are also noted for the studied systems (SSFL-1 to SSFL-4). Finally, enhanced fill factor (FF%) along with high power conversion efficiency (PCE) of 21.36 % is noted in the designed systems. [ABSTRACT FROM AUTHOR]

• The WPI-R complex was prepared by pH-driven method (pH-DM) combined with ultrasonic treatment. • The interaction between whey protein and rutin is covalent, and appropriate ultrasonic treatment could promote degree of polyphenol binding and grafting between whey protein isolate and rutin. • The ultrasonic treatment increased the WPI-R complex's solubility while decreasing its surface hydrophobicity and free sulfhydryl. • The secondary structure of the complex was improved with ultrasonic treatment, which results in three-dimensional honeycomb structures with small and uniform pore sizes. Rutin is a biologically active polyphenol, but its poor water solubility and low bioavailability limit its application to the food industry. We investigated the effect of ultrasound treatment on the properties of rutin (R) and whey protein isolate (WPI) using spectral and physicochemical analysis. The results revealed that there was covalent interaction between whey protein isolate with rutin, and the binding degree of whey isolate protein with rutin increased with ultrasound treatment. Additionally, solubility and surface hydrophobicity of WPI-R complex improved with ultrasonic treatment, and a maximum solubility of 81.9 % at 300 W ultrasonic power. The ultrasound treatment caused the complex to develop a more ordered secondary structure, resulting in a three-dimensional network structure with small and uniform pore sizes. This research could provide a theoretical reference for studying protein–polyphenol interactions and their applications in food delivery systems. [ABSTRACT FROM AUTHOR]