Effect of Inorganic Additive Strategy on the Stability of VO2+ in Vanadium Redox Flow Battery Electrolyte by Molecular Dynamics.

Inorganic ions are considered to be effective additives to improve the temperature stability of all-vanadium redox flow batteries. In this study, molecular dynamics simulation has been performed to study the solvation structure and dynamic properties of VO2+ in the positive electrolyte by doping Na+, K+, and NH4+ in the presence of V2O5 precipitation. The results show that VO2+ ions aggregate into chainlike clusters in the electrolyte due to the induction of SO42-. The additives, which are stable in the solvation layers of VO2+, can work as protective shells to inhibit cluster growth. NH4+ is a superior dispersant compared with Na+ and K+ as it can stably exist in both the first solvation layer and the second solvation layer of VO2+. This work performed the molecular dynamics simulation of the electrolyte of vanadium redox flow batteries, and it gives some insights into the theoretical study of the modification of the cathode electrolyte.

A Comprehensive Review of the Mechanism and Modification Strategies of V2O5 Cathodes for Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (AZIBs) have attracted wide attention due to their affordability, inherent safety, and environmental friendliness, recognized as one of the most ideal next generation energy storage systems. Vanadium-based cathodes have garnered significant interest in the field of AZIBs, presenting vast application prospects in stationary energy storage. Among them, layered vanadium pentoxide (V2O5) stands out a promising material due to its high theoretical capacity, drawing extensive research efforts. However, the research on V2O5 is greatly hindered by issues such as cathode material dissolution, low conductivity, and byproduct formation. Therefore, this review starts from the characteristics of V2O5 materials, summarizes the energy storage mechanism of Zn2+, and elucidates the main challenges faced by V2O5. Subsequently, current modification strategies are summarized based on these challenges, along with the relationships between the issues and strategies. Finally, further challenges and directions faced by each modification strategy are proposed. It is expected to provide researchers with information to quickly familiarize themselves with the current applications and inspiring prospects of V2O5 in AZIBs.

Deficiency of leap2 promotes somatic growth in zebrafish: Involvement of the growth hormone system.

Purpose: Liver-expressed antimicrobial peptide-2 (LEAP2) is identified as an endogenous antagonist and inverse agonist of the growth hormone secretagogue receptor type 1a (GHSR1a), its effect on the GHSR1a is contrary to the role of GHRELIN. Growth hormone (GH) is a crucial hormone for early development. Previous studies report that LEAP2 dose-dependently attenuates ghrelin-induced GH secretion, and Leap2-knockout mice exhibit increased plasma GH levels after GHRELIN administration. Clinical data revealed a possible correlation between LEAP2 and height development. However, the role of LEAP2 in early development remains unclear. This study aimed to investigate the role of LEAP2 in early development using leap2 mutant zebrafish larvae as a model. Method: We analyzed the conservation of LEAP2 peptide across multiple species and generated leap2 mutants in zebrafish by CRISPR-Cas9, dynamically observed and measured the growth and development of zebrafish larvae from fertilization to 5 day post fertilization (dpf). In situ hybridization, transcriptome sequencing, quantitative real-time PCR and Western blot were used to detect the expression levels of GH and its signaling in early stage of embryonic development. Result: Our data demonstrate that zebrafish with a knockout of the leap2 gene display a significant increase in hatching rate, body length, and the distance between their eyes, all without visible developmental defects in the early stages of development. In addition, both RNA and protein analyses revealed a significant increase in GH expression in leap2 mutant. Conclusion: In general, this study demonstrates that LEAP2 regulates the expression of GH during early development, particularly influencing body length.

Efficient Desulfurizer Recycling during Spent Lead-Acid Batteries Paste Disposal by Zero-Carbon Precursor Hypothermic Smelting.

Recycling of spent lead-acid batteries (LABs) is extremely urgent in view of environmental protection and resources reuse. The current challenge is to reduce high consumption of chemical reagents. Herein, a closed-loop spent LABs paste (SLBP) recovery strategy is demonstrated through Na2MoO4 consumption-regeneration-reuse. Experimental and DFT calculations verify that MoO4 2- competes Pb/Ca ions and weakens the metal-oxygen bond of PbSO4/CaSO4.2H2O in SLBP, facilitating PbMoO4/CaMoO4 formation and 99.13 wt% of SO4 2- elimination. Pb of 99.97 wt% is obtained as zero-carbon precursors (PbO2 and PbMoO4) by green leaching coupled with re-crystallization. The regeneration of Na2MoO4 is realized at 600 ℃ using LABs polypropylene shells and NaOH as reagents. Compared with the traditional smelting technologies, the temperature is reduced from ＞1000 to 600 °C. The extraction of Na2MoO4 require only water, and satisfactory re-used desulfurization efficiency (98.67 wt%) is achieved. For the residual Na2MoO4 after first SLBP desulfurization, the desulfurization efficiency remains above 97.36 wt% after adding fresh reagents for two running cycles. The new principle enables the reuse of 99.83 wt% of Na2MoO4 and the recycling of 95.27 wt% of Pb without generating wastewater and slags. The techno-economic analysis indicates this strategy is efficient, economical, and environmentally-friendly.

Influence of short-term hypoxia exposure on dynamic visual acuity.

Background: To quantify the changes in dynamic visual acuity (DVA) and explain the hidden reasons after acute exposure to hypobaric hypoxia status. Methods: The study group comprised 18 healthy male and 15 healthy female participants aged 20-24 years old. DVA was measured with the self-developed software of Meidixin (Tianjin) Co., Ltd. Measurements were taken at eight altitudes. Data analysis was performed using the Kolmogorov-Smirnov test, paired sample T-test, and two-way repeated measures analysis of variance (ANOVA) for repeated measurements. Results: At constant altitude, DVA showed an overall decreasing trend with increasing angular velocity and a fluctuating decrease at the vast majority of altitudes. At constant angular velocities, DVA gradually increased with altitude, with the most pronounced increase in DVA at altitude 5, and thereafter a gradual decrease in DVA as altitude increased. Finally, as altitude decreased, DVA increased again and reached a higher level at the end of the experiment, which was superior to the DVA in the initial state. Conclusion: Under a hypobaric hypoxic environment at high altitude, DVA was affected by the angular velocity and the degree of hypoxia, manifesting as an increase or decrease in DVA, which affects the pilot's observation of the display and control interfaces during the driving process, acquisition of information, and decision-making ability, which in turn may potentially jeopardize the safety of the flight.

AnnoSM: An Automated Annotation Tool for Determining the Substituent Modes on the Parent Skeleton Based on a Characteristic MS/MS Fragment Ion Library.

Mass spectrometry (MS) is a powerful technology for the structural elucidation of known or unknown small molecules. However, the accuracy of MS-based structure annotation is still limited due to the presence of numerous isomers in complex matrices. There are still challenges in automatically interpreting the fine structure of molecules, such as the types and positions of substituents (substituent modes, SMs) in the structure. In this study, we employed flavones, flavonols, and isoflavones as examples to develop an automated annotation method for identifying the SMs on the parent molecular skeleton based on a characteristic MS/MS fragment ion library. Importantly, user-friendly software AnnoSM was built for the convenience of researchers with limited computational backgrounds. It achieved 76.87% top-1 accuracy on the 148 authentic standards. Among them, 22 sets of flavonoid isomers were successfully differentiated. Moreover, the developed method was successfully applied to complex matrices. One such example is the extract of Ginkgo biloba L. (EGB), in which 331 possible flavonoids with SM candidates were annotated. Among them, 23 flavonoids were verified by authentic standards. The correct SMs of 13 flavonoids were ranked first on the candidate list. In the future, this software can also be extrapolated to other classes of compounds.

Molecular Dynamics Simulations of Supramolecular Polymers within Nanoconfinements for Enhanced Oil Recovery.

Supramolecular polymers offer promising potential for enhanced oil recovery (EOR) advancing techniques. Current instrumental analyses face limitations in capturing instantaneous intracomplex motions due to temporal and spatial constraints. The molecular mechanism of supramolecular polymer transport behavior within nanoconfinement is not yet fully understood. Therefore, the self-assembly mechanism of ß-cyclodextrin (ß-CD) and adamantane (ADA)-modified supramolecular polymers (p-AA-ß-CD-ADA) was delved into in this work. Further exploration focuses on the translocation dynamics of p-AA-ß-CD-ADA within nanoconfinement under external driving forces. Results suggest that ß-CD and ADA in p-AA-ß-CD-ADA were assembled into nodes in the form of a host and a guest, combining with a "node-rebar-cement" interaction model encapsulating the formation mechanism of these supramolecular polymers. The heightened density of the hydrate layers at the nanoscale pore throats acts as a constraining factor, resulting in restricted mobility and altered dynamics of the supramolecular polymers. During passage through nanopore throats, host-guest molecules within the supramolecular polymer experience noncovalent dissociation. Notably, these supramolecular polymers exhibit remarkable self-healing capabilities, reinstating their assembly state upon traversing pore throats. This work provides a molecular-level comprehension of the potential utility of supramolecular polymers in EOR processes, offering valuable information for the molecular design of polymers employed for EOR in low-permeability reservoirs.

The Mitogen-Activated Protein Kinase Hog1 Regulates Fungal Development, Pathogenicity, and Stress Response in Botryosphaeria dothidea.

The high-osmolarity glycerol mitogen-activated protein kinase (HOG-MAPK) pathway plays a central role in environmental stress adaptation in eukaryotes. However, the biological function of the HOG-MAPK pathway varies in different fungi. In this study, we investigated the HOG-MAPK pathway by inactivation of the core element Hog1 in Botryosphaeria dothidea, the causal agent of Botryosphaeria canker and apple ring rot. Targeted deletion of BdHOG1 resulted in the loss of conidiation ability and significant reduction of virulence. In addition, the ΔBdHog1 mutant exhibited hypersensitivity to osmotic stress but resistance to phenylpyrrole and dicarboximide fungicides. Comparative transcriptome analysis revealed that inactivation of BdHog1 influenced multiple metabolic pathways in B. dothidea. Taken together, our results suggest that BdHog1 plays a crucial role in development, virulence, and stress tolerance in B. dothidea, which provides a theoretical basis for the development of target-based fungicides.

A structural similarity networking assisted collision cross-section prediction interval filtering strategy for multi-compound identification of complex matrix by ion-mobility mass spectrometry.

Ion mobility coupled with mass spectrometry (IM-MS), an emerging technology for analysis of complex matrix, has been facing challenges due to the complexities of chemical structures and original data, as well as low-efficiency and error-proneness of manual operations. In this study, we developed a structural similarity networking assisted collision cross-section prediction interval filtering (SSN-CCSPIF) strategy. We first carried out a structural similarity networking (SSN) based on Tanimoto similarities among Morgan fingerprints to classify the authentic compounds potentially existing in complex matrix. By performing automatic regressive prediction statistics on mass-to-charge ratios (m/z) and collision cross-sections (CCS) with a self-built Python software, we explored the IM-MS feature trendlines, established filtering intervals and filtered potential compounds for each SSN classification. Chemical structures of all filtered compounds were further characterized by interpreting their multidimensional IM-MS data. To evaluate the applicability of SSN-CCSPIF, we selected Ginkgo biloba extract and dripping pills. The SSN-CCSPIF subtracted more background interferences (43.24%∼43.92%) than other similar strategies with conventional ClassyFire criteria (10.71%∼12.13%) or without compound classification (35.73%∼36.63%). Totally, 229 compounds, including eight potential new compounds, were characterized. Among them, seven isomeric pairs were discriminated with the integration of IM-separation. Using SSN-CCSPIF, we can achieve high-efficient analysis of complex IM-MS data and comprehensive chemical profiling of complex matrix to reveal their material basis.

Concentration-dependent effect of eugenol on porcine myofibrillar protein gel formation.

The effects of different concentrations of eugenol (EG = 0, 5, 10, 20, 50, and 100 mg/g protein) on the structural properties and gelling behavior of myofibrillar proteins (MPs) were investigated. The interaction of EG and MPs decreased free thiol and amine content, and reduced tryptophan fluorescence intensity and thermal stability, but enhanced surface hydrophobicity and aggregation of MPs. Compared with the control (EG free), the MPs' gels treated with 5 and 10 mg/g of EG had a higher storage modulus, compressive strength, and less cooking loss. A high microscopic density was observed in these EG-treated gels. However, EG at 100 mg/g was detrimental to the gelling properties of the MPs. The results indicate that an EG concentration of 20 mg/g is a turning point, i.e., below 20 mg/g, EG promoted MPs gelation, but above 20 mg/g, it impeded gelation by interfering with protein network formation. The EG modification of MPs could provide a novel ingredient strategy to improve the texture of comminuted meat products.

Ghrelin regulates hyperactivity-like behaviors via growth hormone signaling pathway in zebrafish (Danio rerio).

Introduction: Ghrelin is originally identified as the endogenous ligand for the growth hormone secretagogue receptor (GHSR) and partially acts by stimulating growth hormone (GH) release. Our previous studies have identified GHRELIN as a novel susceptibility gene for human attention-deficit hyperactivity disorder (ADHD), and ghrelin-depleted zebrafish (Danio rerio) display ADHD-like behaviors. However, the underlying molecular mechanism how ghrelin regulates hyperactivity-like behaviors is not yet known. Results: Here, we performed RNA-sequencing analysis using adult ghrelin Δ/Δ zebrafish brains to investigate the underlying molecular mechanisms. We found that gh1 mRNA and genes related to the gh signaling pathway were significantly reduced at transcriptional expression levels. Quantitative polymerase chain reaction (qPCR) was performed and confirmed the downregulation of gh signaling pathway-related genes in ghrelin Δ/Δ zebrafish larvae and the brain of adult ghrelin Δ/Δ zebrafish. In addition, ghrelin Δ/Δ zebrafish displayed hyperactive and hyperreactive phenotypes, such as an increase in motor activity in swimming test and a hyperreactive phenotype under light/dark cycle stimulation, mimicking human ADHD symptoms. Intraperitoneal injection of recombinant human growth hormone (rhGH) partially rescued the hyperactivity and hyperreactive-like behaviors in ghrelin mutant zebrafish. Conclusion: Our results indicated that ghrelin may regulate hyperactivity-like behaviors by mediating gh signaling pathway in zebrafish. And the protective effect of rhGH on ghrelin Δ/Δ zebrafish hyperactivity behavior provides new therapeutic clues for ADHD patients.

Economical and Sustainable Synthesis of Small-Pore Chabazite Catalysts for NOx Abatement by Recycling Organic Structure-Directing Agents.

The application of small-pore chabazite-type SSZ-13 zeolites, key materials for the reduction of nitrogen oxides (NOx) in automotive exhausts and the selective conversion of methane, is limited by the use of expensive N,N,N-trimethyl-1-ammonium adamantine hydroxide (TMAdaOH) as an organic structure-directing agent (OSDA) during hydrothermal synthesis. Here, we report an economical and sustainable route for SSZ-13 synthesis by recycling and reusing the OSDA-containing waste liquids. The TMAdaOH concentration in waste liquids, determined by a bromocresol green colorimetric method, was found to be a key factor for SSZ-13 crystallization. The SSZ-13 zeolite synthesized under optimized conditions demonstrates similar physicochemical properties (surface area, porosity, crystallinity, Si/Al ratio, etc.) as that of the conventional synthetic approach. We then used the waste liquid-derived SSZ-13 as the parent zeolite to synthesize Cu ion-exchanged SSZ-13 (i.e., Cu-SSZ-13) for ammonia-mediated selective catalytic reduction of NOx (NH3-SCR) and observed a higher activity as well as better hydrothermal stability than Cu-SSZ-13 by conventional synthesis. In situ infrared and ultraviolet-visible spectroscopy investigations revealed that the superior NH3-SCR performance of waste liquid-derived Cu-SSZ-13 results from a higher density of Cu2+ sites coordinated to paired Al centers on the zeolite framework. The technoeconomic analysis highlights that recycling OSDA-containing waste liquids could reduce the raw material cost of SSZ-13 synthesis by 49.4% (mainly because of the higher utilization efficiency of TMAdaOH) and, meanwhile, the discharging of wastewater by 45.7%.

Baicalein exerts anxiolytic and antinociceptive effects in a mouse model of posttraumatic stress disorder: Involvement of the serotonergic system and spinal delta-opioid receptors.

Post-traumatic stress disorder (PTSD) is a serious mental disease featured by a stress dysfunction that occurs after an individual has faced intense mental stress, often accompanied by anxiety and chronic pain. Currently, the mainstream drug for PTSD is serotonin reuptake inhibitors (SSRIs), however, their pain management for patients is limited. Baicalein, a Chinese traditional herbal medicine, has shown promising results in treating anxiety, depression, and pain. In this study, we found that baicalein may alleviate single prolonged stress (SPS)-induced PTSD-like behaviors in mice without altering baseline nociceptive sensitivity or activity. Meanwhile, baicalein increased the noradrenaline (NE) and serotonin (5-HT) content and decreased the ratio of 5-hydroxyindoleacetic acid (5-HIAA)/5-HT by inhibiting the activity of monoamine oxidase A (MAO-A) in SPS-induce mice. The anxiolytic and antinociceptive effects induced by baicalein were totally abolished by 5-HT depleting agents. Moreover, the anxiolytic effects of baicalein could be abolished by the 5-HT1A receptor antagonist WAY-100635, and the analgesic effects could be abolished by delta-opioid receptor antagonists in the spinal. Taken together, our study provides compelling evidence that baicalein reversed anxiety-like behaviors and neuropathic pain in PTSD through serotonergic system and spinal delta-opioid receptors.

Advances in dietary proteins binding with co-existed anthocyanins in foods: Driving forces, structure-affinity relationship, and functional and nutritional properties.

Anthocyanins, which are the labile flavonoid pigments widely distributed in many fruits, vegetables, cereal grains, and flowers, are receiving intensive interest for their potential health benefits. Proteins are important food components from abundant sources and present high binding affinity for small dietary compounds, e.g., anthocyanins. Protein-anthocyanin interactions might occur during food processing, ingestion, digestion, and bioutilization, leading to significant changes in the structure and properties of proteins and anthocyanins. Current knowledge of protein-anthocyanin interactions and their contributions to functions and bioactivities of anthocyanin-containing foods were reviewed. Binding characterization of dietary protein-anthocyanins complexes is outlined. Advances in understanding the structure-affinity relationship of dietary protein-anthocyanin interaction are critically discussed. The associated properties of protein-anthocyanin complexes are considered in an evaluation of functional and nutritional values.

Ammonia Abatement via Selective Oxidation over Electron-Deficient Copper Catalysts.

Selective catalytic ammonia-to-dinitrogen oxidation (NH3-SCO) is highly promising for the abatement of NH3 emissions from flue gas purification devices. However, there is still a lack of high-performance and cost-effective NH3-SCO catalysts for real applications. Here, highly dispersed, electron-deficient Cu-based catalysts were fabricated using nitrogen-doped carbon nanotubes (NCNT) as support. In NH3-SCO catalysis, the Cu/NCNT outperformed Cu supported on N-free CNTs (Cu/OCNT) and on other types of supports (i.e., activated carbon, Al2O3, and zeolite) in terms of activity, selectivity to the desired product N2, and H2O resistance. Besides, Cu/NCNT demonstrated a better structural stability against oxidation and a higher NH3 storage capacity (in the presence of H2O vapor) than Cu/OCNT. Quasi in situ X-ray photoelectron spectroscopy revealed that the surface N species facilitated electron transfer from Cu to the NCNT support, resulting in electron-deficient Cu catalysts with superior redox properties, which are essential for NH3-SCO catalysis. By temperature-programmed surface reaction studies and systematic kinetic measurements, we unveiled that the NH3-SCO reaction over Cu/NCNT proceeded via the internal selective catalytic reaction (i-SCR) route; i.e., NH3 was oxidized first to NO, which then reacted with NH3 and O2 to form N2 and H2O. This study paves a new route for the design of highly active, H2O-tolerant, and low-cost Cu catalysts for the abatement of slip NH3 from stationary emissions via selective oxidation to N2.

Synthetic liver fibrotic niche extracts achieve in vitro hepatoblasts phenotype enhancement and expansion.

It is still a challenge for synthesizing 'cellular niche-mimics' in vitro with satisfactory reproducibility and fidelity to recreate the natural niche components (e.g., extracellular matrices and soluble factors) for stem cell cultivation. Inspired by the massive amplification of hepatic progenitor cells during liver fibrosis in vivo, here we optimized the in vitro liver fibrotic niches and subsequently harvested their bioactive ingredients as niche extracts (NEs). The fibrosis-relevant NE marginally outperformed Matrigel for phenotype maintenance of human embryonic stem cell (hESC)-derived hepatoblasts (HBs) and recapitulation of the pathological angiogenesis of hESC-derived endothelial cells both in 2D culture and 3D liver organoids. Finally, defined NE components (i.e., collagen III, IV, IL-17, IL-18 and M-CSF) were resolved by the quantitative proteomics which exhibited advantage over Matrigel for multi-passaged HB expansion. The pathology-relevant and tissue-specific NEs provide innovative and generalizable strategies for the discovery of optimal cellular niche and bioactive niche compositions.

Electrical conductivity: A simple and sensitive method to determine emulsifying capacity of proteins.

Emulsifying capacity (EC) of proteins is a benchmark standard widely used to evaluate the quality of protein ingredients in emulsion foods. EC (mL of oil emulsified per g of protein) is usually measured by a sudden drop in electrical resistance (phase transition) with the continuous addition of oil to a specific protein solution. However, little is known about electrochemical mechanisms behind this process because resistance, measured with an ohmmeter, is not sensitive enough to monitor changes in the concentration of protein electrolytes. Here, pea (PPI), myofibrillar (MPI), and whey (WPI) protein isolates were vigorously homogenized with oil at a series of oil/protein ratios to prepare emulsions with different final protein concentrations. The conductivity was closely monitored using a conductivity meter. A linear relationship was discovered between conductivity and the final protein concentrations. At higher oil fractions, the migration of proteins from the aqueous phase to the oil-water interface limited protein mobility, leading to a conductivity drop. EC was calculated from the regression lines; when the starting protein concentration was raised from 0.5% to 2.0%, the EC of PPI, MPI, and WPI decreased from 717, 782, 1339 to 219, 303, and 540 mL oil/g protein, respectively. The dependence of EC on the initial protein concentration and the sensitivity of conductivity to the depleting protein electrolytes suggest that protein concentration is an important factor to consider when determining EC for a given protein or comparing EC among different proteins. PRACTICAL APPLICATION: The simple and sensitive electrical conductivity test described in this paper allows for the accurate determination of emulsifying capacity of proteins. It may be adopted by the food industry to compare the emulsifying properties of different protein ingredients.

Inhibition Effect of Phosphorus Poisoning on the Dynamics and Redox of Cu Active Sites in a Cu-SSZ-13 NH3-SCR Catalyst for NOx Reduction.

Phosphorus (P) stemming from biodiesel and/or lubricant oil additives is unavoidable in real diesel exhausts and deactivates gradually the Cu-SSZ-13 zeolite catalyst for ammonia-assisted selective catalytic NOx reduction (NH3-SCR). Here, the deactivation mechanism of Cu-SSZ-13 by P-poisoning was investigated by ex situ examination of the structural changes and by in situ probing the dynamics and redox of Cu active sites via a combination of impedance spectroscopy, diffuse reflection infrared Fourier transform spectroscopy, and ultraviolet-visible spectroscopy. We unveiled that strong interactions between Cu and P led to not only a loss of Cu active sites for catalytic turnovers but also a restricted dynamic motion of Cu species during low-temperature NH3-SCR catalysis. Furthermore, the CuII ↔ CuI redox cycling of Cu sites, especially the CuI → CuII reoxidation half-cycle, was significantly inhibited, which can be attributed to the restricted Cu motion by P-poisoning disabling the formation of key dimeric Cu intermediates. As a result, the NH3-SCR activity at low temperatures (200 °C and below) decreased slightly for the mildly poisoned Cu-SSZ-13 and considerably for the severely poisoned Cu-SSZ-13.

Myoprotein-phytophenol interaction: Implications for muscle food structure-forming properties.

Phenolic compounds are commonly incorporated into muscle foods to inhibit lipid oxidation and modify product flavor. Those that are present in or extracted from plant sources (seeds, leaves, and stems) known as "phytophenols" are of particular importance in the current meat industry due to natural origins, diversity, and safety record. Apart from these primary roles as antioxidants and flavorings, phytophenols are now recognized to be chemically reactive with a variety of food constituents, including proteins. In processed muscle foods, where the structure-forming ability is critical to a product's texture-related quality attributes and palatability, the functional properties of proteins, especially gelation and emulsification, play an essential role. A vast amount of recent studies has been devoted to protein-phenol interactions to investigate the impact on meat product texture and flavor. Considerable efforts have been made to elucidate the specific roles of phytophenol interaction with "myoproteins" (i.e., muscle-derived proteins) probing the structure-forming process in cooked meat products. The present review provides an insight into the actions of phytophenols in modifying and interacting with muscle proteins with an emphasis on the reaction mechanisms, detection methods, protein functionality, and implications for structural characteristics and textural properties of muscle foods.

Myofibrillar Protein Cross-Linking and Gelling Behavior Modified by Structurally Relevant Phenolic Compounds.

Protein gelation is an important phenomenon in processed meats. The present study investigated the structure-activity relationship of six phenolic compounds, that is, gallic acid (GA), chlorogenic acid (CA), propyl gallate (PG), quercetin (QT), catechin (CC), and (-)-epigallocatechin-3-gallate (EGCG) in a myofibrillar protein (MP) gelling system under controlled oxidative conditions. All phenolics induced unfolding and promoted cross-linking of MP via sulfhydryl or amine groups. At an equal molar concentration, EGCG boosted the elastic MP gel network more than other phenolics except PG. However, all three monophenols (GA, CA, and PG) and the diphenol QT increased the MP gel strength more than CC (diphenol) and EGCG (triphenol). The flavanol structure appeared to interfere with the protein gel structure development. All phenolics retarded lipid oxidation in MP-emulsion composite gels during refrigerated storage with the least polar phenolic compounds, PG and QT, showing the greatest efficacy.