Interaction and binding mechanism of cyanidin-3-O-glucoside to ovalbumin in varying pH conditions: A spectroscopic and molecular docking study

Mechanistic insights into betanin-protein interactions: Structural and thermal stability enhancement by non-covalent binding with animal- and plant-derived proteins

This study evaluated animal- and plant-derived proteins (whey protein isolate, ovalbumin, soy protein isolate, pea protein) for enhancing betanin's thermal stability. Protein-betanin complex formation was confirmed via particle size, SEM, and UV-Vis spectroscopy. Multi-spectroscopy and molecular dynamics simulations revealed static quenching dominated WPI/ovalbumin-betanin interactions, driven by hydrogen bonds and van der Waals forces, evidenced by negative ΔH0, ΔS0, and ΔG0 values, indicating spontaneous, exothermic binding. Reduced free amino groups, intrinsic tryptophan fluorescence, surface hydrophobicity, and α-helix content, alongside increased β-sheet structures, highlighted the roles of hydrophobic and electrostatic interactions. These forces unfolded proteins, altered tryptophan microenvironments, and stabilized complexes. Findings provide mechanistic insights into betanin stabilization and demonstrate the potential of diverse proteins as effective carriers, broadening betanin's application scope in food and pharmaceuticals.

New insights into the interactions between the antibiotic enrofloxacin and fish protein by spectroscopic, thermodynamic, and theoretical simulation approaches

In this study, myofibrillar proteins (MPs) from crucian carp were utilized as a model to investigate the binding mechanism between fish proteins and antibiotic residues. Fluorescence quenching confirmed the static quenching (Ksv = 1.89 × 104 M-1 s-1, Kq = 1.89 × 1012 M-1 s-1) and effective binding (Kb = 5.66 × 106 M-1) of Enrofloxacin (ENRO) to MPs. Fourier-transform infrared spectroscopy and circular dichroism spectroscopy revealed that ENRO binding altered the secondary structure of MPs. The interaction mechanism, primarily driven by hydrogen bonding, electrostatic, and hydrophobic interactions (ΔH0 < 0, ΔS0 > 0), was elucidated using isothermal titration calorimetry. The ΔH0, -TΔS0 and ΔG0 values of the binding reaction between MPs and ENRO were -5.98 kJ/mol, -32.57 kJ/mol and -38.55kJ/mol. Molecular docking further verified the interaction forces, identifying key amino acid residues (Phe-40, His-93, and Lys-42) involved in ENRO binding. Additionally, protein carbonylation results demonstrated that even at maximum residue limits, ENRO accelerated MPs oxidation, further confirming the binding of the two. This study can provide theoretical support for the research of the dissipation fate of bound state residues in aquatic products.

Interactions between polyphenols and polysaccharides/proteins: Mechanisms, effect factors, and physicochemical and functional properties: A review

Polyphenols have attracted much attention in the food industry and nutrition because of their unique biological activities. However, the health benefits of polyphenols are compromised due to their structural instability and sensitivity to the external environment. The interaction between polyphenols and polysaccharides/proteins largely determines the stability and functional characteristics of polyphenols in food processing and storage. Hence, this topic has attracted widespread attention in recent years. This review initially outlines the basic properties of polyphenols and their applications in food. Subsequently, the interaction mechanisms between polyphenols and polysaccharides/proteins are discussed in detail including non-covalent bonding, covalent modification, and conformational changes. These interactions can display profound impacts on the nutritional value, taste, stability, and safety of food. Additionally, this article also systematically reviews the influencing factors (type, concentration, temperature, pH, and other factors) of interaction between polyphenols and proteins/polysaccharides. Finally, this paper also summarizes systematically the effects of the interaction between polyphenols and polysaccharides/proteins on the physicochemical and functional properties of polyphenols/proteins. The findings provide prospects for the application of composite materials in food preservation, functional food development, and nanocarrier development, which can provide theoretical references for the in-depth development of polyphenols in the food industry.

Characteristics of exopolysaccharides - egg white protein composite gel and its application in low - fat sausage

A composite gel was developed by integrating antioxidant extracellular polysaccharides (EPS) derived from Pediococcus acidilactici S1 with egg white protein (EWP), aiming to evaluate its potential as a viable alternative to animal fat in pork sausages. The results indicated that the EPS - EWP gel exhibited a lower free water content, an enhanced water - holding capacity, a higher apparent viscosity, and increased storage and loss modulus. Molecular interactions were strengthened, resulting in a more stable structure characterized by the transition of secondary structure from random coils to ordered β - sheets. Molecular docking (MD) analysis revealed favorable binding conformations and strong binding energies between ovalbumin (OVA) and EPS, particularly through the formation of specific pockets involving interactions with residues such as Lysine (Lys) and Aspartic acid (Asp). Hydrophobic and electrostatic forces were identified as the primary driving forces for this energetic combination. Additionally, low - fat sausages showed a significant 32.87 % improvement in inhibiting fat oxidation.

Exploring the binding mechanism and functional properties of lactoferrin-berberine complex: Based on multispectral analysis, molecular docking, and dynamics simulations

Denaturation and/or aggregation of proteins under adverse environmental conditions can greatly impair their bioactivity and functional properties. Based on this, this study aims to improve the functional properties of lactoferrin by complexing with berberine and investigate the mechanism using multispectral techniques, molecular docking and dynamics simulations. The results showed that berberine bound to lactoferrin through hydrogen bonding and van der Waals forces and altered its conformation, surface hydrophobicity, amino acid microenvironment, and secondary structure. Molecular docking and dynamics simulations further revealed that berberine inhibited the drastic changes in the lactoferrin structure, contributing to the complex stability. Consequently, the denaturation temperature and degradation temperature (224 °C to 230 °C) and the tolerance to extreme pH, high temperature, and ions of the lactoferrin-berberine complex were improved. This study systematically revealed the mechanism of berberine to improve the functional properties of lactoferrin, contributing to the development and application of novel functional ingredients.

Metal-free production of natural blue colorants through anthocyanin-protein interactions

INTRODUCTION

The scarcity of naturally available sources for blue colorants has driven reliance on synthetic alternatives. Nevertheless, growing health concerns have prompted the development of naturally derived blue colorants, which remains challenging with limited success thus far. Anthocyanins (ACNs) are known for providing blue colors in plants, and metal complexation with acylated ACNs remains the primary strategy to generate stable blue hues. However, this approach can be costly and raise concerns regarding potential metal consumption risks.

OBJECTIVES

Our study aims to introduce a metal-free approach to achieve blue coloration in commonly distributed non-acylated 3-glucoside ACNs by exploring their interactions with proteins and unveiling the underlying mechanisms.

METHODS

Using human serum albumin (HSA) as a model protein, we investigated the structural influences of ACNs on their blue color generation using visible absorption spectroscopy, fluorescence quenching, and molecular simulations. Additionally, we examined the bluing effects of six proteins derived from milk and egg and identified the remarkable roles of bovine serum albumin (BSA) and lysozyme (LYS).

RESULTS

Our findings highlighted the importance of two or more hydroxyl or methoxyl substituents in the B-ring of ACNs for generating blue colors. Cyanidin-, delphinidin- and petunidin-3-glucoside, featuring two neighboring hydroxyl groups in the B-ring, exhibited blue coloration when interacting with HSA or LYS, driven primarily by favorable enthalpy changes. In contrast, malvidin-3-glucoside, with two methoxyl substituents, achieved blue coloration through interactions with HSA or BSA, where entropy change played significant roles.

CONCLUSION

Our work, for the first time, demonstrates the remarkable capability of widely distributed 3-glucoside ACNs to generate diverse blue shades through interactions with certain proteins. This offers a promising and straightforward strategy for the production of ACN-based blue colorants, stimulating further research in this field.

Effect of rutin on the structural and functional properties of ovalbumin

Phenolic substances affect protein functionality. This study aimed to examine how rutin influences the gel properties, antioxidant activity, and structure of ovalbumin (OVA). Increasing rutin concentration enhanced the gel hardness of OVA but reduced soluble protein content with no significant effect on water retention. At 0.25 % rutin concentration, the gel hardness of OVA increased from 109.33 g to 292.60 g, while soluble protein content decreased from 1.08 mg/mL to 0.97 mg/mL. Rutin modification significantly increased the storage and loss moduli of OVA gel, making its structure more compact. At 0.25 % rutin, antioxidant analysis showed increases in the DPPH radical scavenging rate (127 %), ABTS radical scavenging rate (112 %), hydroxyl radical scavenging rate (4167 %), and reducing power (101 %) of OVA. Fluorescence spectroscopy, surface hydrophobicity, free sulfhydryl content, and circular dichroism spectra revealed that higher rutin concentrations reduced fluorescence intensity and surface hydrophobicity while increasing the free sulfhydryl content of OVA. The α-helix content of OVA decreased, while β-sheet content increased. In addition, it was confirmed that OVA and rutin were bound by hydrophobic interaction. The quenching mechanism was static quenching. Rutin alters the structure and functional properties of OVA, providing a theoretical foundation for developing antioxidant and high-gel OVA variants.

Improved encapsulation efficiency and storage stability of lutein by soy protein isolate nanocarriers with thermal and trypsin treatments

BACKGROUND

Encapsulation of bioactive compounds within protein-based nanoparticles has garnered considerable attention in the food and pharmaceutical industries because of its potential to enhance stability and delivery. Soy protein isolate (SPI) has emerged as a promising candidate, prompting the present study aiming to modify its properties through controlled thermal and trypsin treatments for improved encapsulation efficiency (EE) of lutein and its storage stability.

RESULTS

The EE of lutein nanoparticles encapsulated using SPI trypsin hydrolysates (SPIT) with three varying degrees of hydrolysis (4.11%, 6.91% and 10.61% for SPIT1, SPIT2 and SPIT3, respectively) increased by 12.00%, 15.78% and 18.59%, respectively, compared to SPI. Additionally, the photostability of SPIT2 showed a remarkable increase of 38.21% compared to SPI. The superior encapsulation efficiency and photostability of SPIT2 was attributed to increased exposure of hydrophobic groups, excellent antioxidant activity and uniform particle stability, despite exhibiting lower binding affinity to lutein compared to SPI. Furthermore, in SPIT2, the protein structure unfolded, with minimal impact on overall secondary structure upon lutein addition.

CONCLUSION

The precise application of controlled thermal and trypsin treatments to SPI has been shown to effectively produce protein nanoparticles with substantially improved encapsulation efficiency for lutein and enhanced storage stability of the encapsulated lutein. These findings underscore the potential of controlled thermal and trypsin treatments to modify protein properties effectively and offer significant opportunities for expanding the applications of protein-based formulations across diverse fields. © 2024 Society of Chemical Industry.

The application of emerging technologies for the quality and safety evaluation of oilseeds and edible oils

Oilseeds and edible oils are an indispensable part for the human diet and provide nutritional support for the human health. It has been reported a total of above 170 million tons per annum of edible oils consumption were consumed worldwide. Safety and quality of oilseeds and edible oils cannot be ignored, which can pose risk to human health and cause agro-economic loss. Classical techniques widely used to detect the safety and quality attributes of oilseeds and edible oils often involve time-consuming and tedious operation; therefore, the development of low cost, rapid and non-destructive detection method is necessary. This review presents applications of four emerging spectroscopic techniques in recent ten years, such as Raman spectroscopy, fluorescence spectroscopy, fourier transform infrared spectroscopy and near-infrared spectroscopy for determining the quality and safety of oilseeds and edible oils. Meanwhile, the technical challenges and future prospects of these non-destructive spectroscopic technologies are also discussed.

Regulation of catechins with different structure characteristics on the physicochemical properties of casein and the structure-activity relationship

Regulation of catechins with different structure characteristics on the physicochemical properties of casein were investigated, and the structure-activity relationship was further explored. All testing catechins effectively modulated the physicochemical properties of casein, and esterified catechins showed the stronger binding affinity to casein than non-esterified catechins. Catechins significantly altered the secondary and tertiary structures of casein. Fluorescence spectroscopy and thermodynamic analyses indicated that the fluorescence quenching mechanism of casein by the four catechins was static. The Gibbs free energies (ΔG) for the interactions between EC, ECG, EGC, and EGCG with α-casein were - 14.16, -25.41, -22.23, and - 24.48 kJ/mol, respectively. For β-casein, ΔG were - 17.91, -29.85, -17.34, and - 19.33 kJ/mol, respectively. All negative ΔG values suggested that the interactions between catechins and casein occurred spontaneously. At 297 K, the binding constants for catechins with α-casein followed the order: ECG (29.51 × 103 L/mol) > EGCG (20.23 × 103 L/mol) > EGC (8.13 × 103 L/mol) > EC (0.31 × 103 L/mol). For β-casein, the order was: ECG (177.83 × 103 L/mol) > EGCG (2.51 × 103 L/mol) > EC (1.41 × 103 L/mol) > EGC (1.12 × 103 L/mol). Molecular docking combined with multispectral analysis further demonstrated that hydrogen bonds, van der Waals forces, and hydrophobic interactions governed the interactions between catechins and casein, and hydrogen bonds were the predominant force. All results indicate that the amount of hydroxyl groups and the presence of galloyl group significantly affect the capability of catechins to interact with casein.

Effect and mechanisms of thermal sterilization methods on the in vitro phenolic bioaccessibility of rose tea with milk

Rose polyphenols, key functional components in roses, require adequate bioaccessibility for their health benefits, subject to influence by food components and processing. Investigating the impact of various thermal sterilization methods on the bioaccessibility of rose polyphenols in rose tea with milk and the underlying mechanisms, our findings indicated a significant increase in bioaccessibility following treatment at 85 °C/30 min. Conversely, 121 °C/15 min treatment decreased bioaccessibility. Examining the interaction between β-casein in milk and rose polyphenols under different sterilization conditions, SEM and particle size analysis revealed binding, with fluorescence spectroscopy indicating non-covalent bonds. Binding forces followed the order 121 °C > 85 °C > 25 °C. Notably, at 85 °C, non-covalent binding improved polyphenol bioaccessibility, while the intensified binding at 121 °C decreased it. SDS-PAGE and amino acid analysis confirmed no covalent bond. This study establishes a theoretical basis for selecting thermal sterilization temperatures for milk-flower combinations, considering polyphenol bioaccessibility.

Xanthine oxidase inhibitors: Virtual screening and mechanism of inhibition studies

Xanthine oxidase (XO), which plays a key role in purine metabolism, is an important target enzyme for the prevention and treatment of hyperuricemia. Inhibitory activity against XO is a common criterion for the screening of compounds with potential anti-hyperuricemic activity. In this study, 22 XO inhibitors were used to construct a 3D-QSAR pharmacophore model. Subsequently, molecular docking and in vitro activity evaluations were used to identify strong XO inhibitors from a list of 2000 natural compounds. The interaction mechanisms of these compounds with XO were analyzed based on inhibition kinetics and multi-spectral analyses. The pharmacophore model was composed of three hydrogen bond receptors and a hydrophobic center. The screened compounds - Diosmetin, Fisetin, and Genistein - all showed good XO inhibitory activity, with IC50 values of 1.86 ± 0.11 μM, 5.83 ± 0.08 μM, and 7.56 ± 0.10 μM, respectively. Kinetic analysis, fluorescence quenching assays, and molecular docking experiments showed that Diosmetin, Fisetin, and Genistein docked near the same active site of XO, mainly affecting the microenvironment of tryptophan residues. These molecules showed static binding to XO via hydrogen bonds, hydrophobic interactions, and van der Waals forces. Diosmetin and Genistein were competitive inhibitors, whereas Fisetin was a mixed inhibitor. Infrared spectroscopy showed that Diosmetin, Fisetin, and Genistein increased the α-helix content of XO from 7.4 % to 16.6 %, 21.4 %, and 11.2 %, respectively, thereby enhancing its stability. In summary, the pharmacophore model constructed in this study was accurate. The flavonoids Diosmetin, Fisetin, and Genistein effectively inhibited the activity of XO, and the amino acid residues LEU257, ILE353, and VAL259 played a key role in the interaction between the flavonoids and XO. These findings are of great significance for the screening and development of new XO inhibitors.

Caseinate-coated zein nanoparticles as potential delivery vehicles for guavinoside B from guava: Molecular interactions and encapsulation properties

Guavinoside B (GUB) is a characteristic constituent from guava with strong antioxidant activity; however, its low water solubility limits its utilization. Herein, we investigated the interaction between GUB and zein, a prolamin with self-assembling property, using multiple spectroscopic methods and fabricated GUB-zein-NaCas nanoparticles (GUB-Z-N NPs) via the antisolvent coprecipitation approach. GUB caused fluorescence quenching to zein via the static quenching mechanism. Fourier-transform infrared spectroscopy and computational analysis revealed that GUB bound to zein via van der Waals interaction, hydrogen bond, and hydrophobic forces. The GUB-Z-N NPs were in the nanometric size range (< 200 nm) and exhibited promising encapsulation efficiency and redispersibility after freeze-drying. These particles remained stable for up to 31 days at 4 °C and great resistance to salt and pH variation, and displayed superior antioxidant activity to native GUB. The current study highlights the potential of zein-based nanoparticles as delivery vehicles for GUB in the food industry.

Harnessing the health benefits of purple and yellow-fleshed sweet potatoes: Phytochemical composition, stabilization methods, and industrial utilization- A review

Purple-fleshed sweet potato (PFSP) and yellow-fleshed sweet potato (YFSP) are crops highly valued for their nutritional benefits and rich bioactive compounds. These compounds include carotenoids, flavonoids (including anthocyanins), and phenolic acids etc. which are present in both the leaves and roots of these sweet potatoes. PFSP and YFSP offer numerous health benefits, such as antioxidant, anti-inflammatory, anti-cancer, and neuroprotective properties. The antioxidant activity of these sweet potatoes holds significant potential for various industries, including food, pharmaceutical, and cosmetics. However, a challenge in utilizing PFSP and YFSP is their susceptibility to rapid oxidation and color fading during processing and storage. To address this issue and enhance the nutritional value and shelf life of food products, researchers have explored preservation methods such as co-pigmentation and encapsulation. While YFSP has not been extensively studied, this review provides a comprehensive summary of the nutritional value, phytochemical composition, health benefits, stabilization techniques for phytochemical, and industrial applications of both PFSP and YFSP in the food industry. Additionally, the comparison between PFSP and YFSP highlights their similarities and differences, shedding light on their potential uses and benefits in various food products.

Exploring high hydrostatic pressure effects on anthocyanin binding to serum albumin and food-derived transferrins

This study investigated the effects of high hydrostatic pressure (HHP) on the binding interactions of cyanindin-3-O-glucoside (C3G) to bovine serum albumin, human serum albumin (HSA), bovine lactoferrin, and ovotransferrin. Fluorescence quenching revealed that HHP reduced C3G-binding affinity to HSA, while having a largely unaffected role for the other proteins. Notably, pretreating HSA at 500 MPa significantly increased its dissociation constant with C3G from 24.7 to 34.3 μM. Spectroscopic techniques suggested that HSA underwent relatively pronounced tertiary structural alterations after HHP treatments. The C3G-HSA binding mechanisms under pressure were further analyzed through molecular dynamics simulation. The localized structural changes in HSA under pressure might weaken its interaction with C3G, particularly polar interactions such as hydrogen bonds and electrostatic forces, consequently leading to a decreased binding affinity. Overall, the importance of pressure-induced structural alterations in proteins influencing their binding with anthocyanins was highlighted, contributing to optimizing HHP processing for anthocyanin-based products.

Stabilization effect and interaction mechanism of mannoprotein on anthocyanins in mulberry juice

This study aimed to investigate the problem of color instability in mulberry juice, examine the effect of mannoprotein (MP) dosage on improving the stability of anthocyanins in mulberry juice, and explore the molecular binding mechanism between them. As the mass ratio of anthocyanins to MP of 1.07 × 10-3: 1-1.65 × 10-3: 1, the retention rates of anthocyanins in mulberry juice and simulated system were significantly improved in the photostability experiment, with the highest increase of 128.89 % and 24.11 %, respectively. In the thermal stability experiment, it increased by 7.96 % and 18.49 %, respectively. The synergistic effect of combining MP with anthocyanins has been demonstrated to greatly enhance their antioxidant capacity, as measured by ABTS, FRAP, and potassium ferricyanide reduction method. Furthermore, MP stabilized more anthocyanins to reach the intestine in simulated in vitro digestion. MP and cyanidin-3-glucoside (C3G) interacted with each other through hydrogen bonding and hydrophobic interactions. Specific amino acid residues involved of MP in binding process were identified as threonine (THR), isoleucine (ILE) and arginine (ARG). The identification of the effective mass concentration ratio range and binding sites of MP and anthocyanins provided valuable insights for the application of MP in mulberry juice.

Construction of fatty acid-ovalbumin binary complexes to improve the water dispersibility, thermal/digestive stability and bioaccessibility of lutein: A comparative study of different fatty acids

Lipids are increasingly being incorporated into delivery systems due to their ability to facilitate intestinal absorption of lipid-soluble nutrients through molecular solubilization and micellization. In this work, self-assembled complexes of ovalbumin (OVA) and nine dietary fatty acids (FAs) were constructed to improve the processability and absorbability of lutein (LUT). Results showed that all FAs could form stable hydrophilic particles with OVA under the optimized ultrasound-coupled pH conditions. Fourier infrared spectroscopy and transmission electron microscopy analysis showed that these binary complexes effectively encapsulated LUT with an encapsulation rate > 90.0 %. Stability experiments showed that these complexes protected LUT well, which could improve thermal stability and in vitro digestive stability by 1.66-3.58-fold and 1.27-2.74-fold, respectively. Besides, the bioaccessibility of LUT was also enhanced by 7.16-24.99-fold. The chain length and saturation of FAs affected the stability and absorption of LUT. Therefore, these results provided some reference for the selection of FAs for efficient delivery of lipid-soluble nutrients.

Research Progress on the Extraction and Purification of Anthocyanins and Their Interactions with Proteins

Anthocyanins, as the most critical water-soluble pigments in nature, are widely present in roots, stems, leaves, flowers, fruits, and fruit peels. Many studies have indicated that anthocyanins exhibit various biological activities including antioxidant, anti-inflammatory, anti-tumor, hypoglycemic, vision protection, and anti-aging. Hence, anthocyanins are widely used in food, medicine, and cosmetics. The green and efficient extraction and purification of anthocyanins are an important prerequisite for their further development and utilization. However, the poor stability and low bioavailability of anthocyanins limit their application. Protein, one of the three essential nutrients for the human body, has good biocompatibility and biodegradability. Proteins are commonly used in food processing, but their functional properties need to be improved. Notably, anthocyanins can interact with proteins through covalent and non-covalent means during food processing, which can effectively improve the stability of anthocyanins and enhance their bioavailability. Moreover, the interactions between proteins and anthocyanins can also improve the functional characteristics and enhance the nutritional quality of proteins. Hence, this article systematically reviews the extraction and purification methods for anthocyanins. Moreover, this review also systematically summarizes the effect of the interactions between anthocyanins and proteins on the bioavailability of anthocyanins and their impact on protein properties. Furthermore, we also introduce the application of the interaction between anthocyanins and proteins. The findings can provide a theoretical reference for the application of anthocyanins and proteins in food deep processing.

Unveiling the impact of high-pressure processing on anthocyanin-protein/polysaccharide interactions: A comprehensive review

Anthocyanins, natural plant pigments responsible for the vibrant hues in fruits, vegetables, and flowers, boast antioxidant properties with potential human health benefits. However, their susceptibility to degradation under conditions such as heat, light, and pH fluctuations necessitates strategies to safeguard their stability. Recent investigations have focused on exploring the interactions between anthocyanins and biomacromolecules, specifically proteins and polysaccharides, with the aim of enhancing their resilience. Notably, proteins like soy protein isolate and whey protein, alongside polysaccharides such as pectin, starch, and chitosan, have exhibited promising affinities with anthocyanins, thereby enhancing their stability and functional attributes. High-pressure processing (HPP), emerging as a non-thermal technology, has garnered attention for its potential to modulate these interactions. The application of high pressure can impact the structural features and stability of anthocyanin-protein/polysaccharide complexes, thereby altering their functionalities. However, caution must be exercised, as excessively high pressures may yield adverse effects. Consequently, while HPP holds promise in upholding anthocyanin stability, further exploration is warranted to elucidate its efficacy across diverse anthocyanin variants, macromolecular partners, pressure regimes, and their effects within real food matrices.

Allergenicity Modulation of Casein with the Modifications of Linearization, Cross-Linking, and Glycation via the Regulation of Th1/Th2 Homeostasis

Casein (CN) is the primary allergenic protein in cow's milk, contributing to the worldwide escalating prevalence of food allergies. However, there remains limited knowledge regarding the effect of structural modifications on CN allergenicity. Herein, we prepared three modified CNs (mCN), including sodium dodecyl sulfate and dithiothreitol-induced linear CN (LCN), transglutaminase-cross-linked CN (TCN), and glucose-glycated CN (GCN). The electrophoresis results indicated widespread protein aggregation among mCN, causing variations in their molecular weights. The unique internal and external structural characteristics of mCN were substantiated by disparities in surface microstructure, alterations in the secondary structure, variations in free amino acid contents, and modifications in functional molecular groups. Despite the lower digestibility of TCN and GCN compared to LCN, they significantly suppressed IL-8 production in Caco-2 cells without significantly promoting their proliferation. Moreover, GCN showed the weakest capacity to induce LAD2 cell degranulation. Despite the therapeutic effect of TCN, GCN-treated mice displayed the most prominent attenuation of allergic reactions and a remarkably restored Th1/Th2 imbalance, while LCN administration resulted in severe allergic phenotypes and endotypes in both cellular and murine models. This study highlighted the detrimental effect of linear modifications and underscored the significance of glycation in relation to CN allergenicity.

Natural Biomolecule Ovomucin-Chitosan Oligosaccharide Self-Assembly Nanogel for Lutein Application Enhancement: Characterization, Environmental Stability and Bioavailability

As an essential nutrient, lutein (LUT) has the ability to aid in the prevention of eye diseases, cardiovascular diseases, and cancer. However, the application of LUT is largely restricted by its poor solubility and susceptibility to oxidative degradation. Thus, in this study, LUT-loaded nanogel (OVM-COS-LUT) was prepared by a self-assembly of ovomucin (OVM) and chitosan oligosaccharide (COS) to enhance the effective protection and bioavailability of LUT. The nanogel had excellent dispersion (PDI = 0.25) and an 89.96% LUT encapsulation rate. XRD crystal structure analysis confirmed that the encapsulated LUT maintained an amorphous morphology. In addition, the nanogel showed satisfactory stability with pH levels ranging from 2 to 9 and high ionic strengths (>100 mM). Even under long-term storage, the nanogel maintained an optimistic stabilization and protection capacity; its effective retention rates could reach 96.54%. In vitro, digestion simulation showed that the bioaccessibility and sustained release of OVM-COS-LUT nanogel was superior to that of free LUT. The nanogel provided significant antioxidant activity, and no significant harmful effects were detected in cytotoxicity analyses at higher concentrations. In summary, OVM-COS-LUT can be utilized as a potential safe oral and functional carrier for encapsulating LUT.

Interactions between phosvitin and aldehydes affect the release of flavor from Russian sturgeon caviar

The release mechanism of flavor during caviar storage was studied by the interaction between phosvitin and four aldehydes. Gas chromatography-mass spectrometry showed that the binding rate of phosvitin with 3-methylbutanal, nonanal, (E,Z)-2,6-nonadienal, and (E)-2-octenal decreased with an increase in the aldehyde concentrations. Among them, (E,Z)-2,6-Nonadienal (0.5 mM) had the highest binding rate (84.47%). The main quenching mechanism of (E,Z)-2,6-nonadienal with phosvitin was static quenching and the binding force comprised spontaneous hydrophobic interactions. An increase in the aldehyde concentrations reduced the α-helix content of phosvitin and led to aggregation of the microstructure of phosvitin. The results of molecular docking showed that tyr residue contributed the most to the binding of phosvitin to aldehydes. This study has elucidated the mechanism of the effect of caviar protein on changes in the caviar flavor during storage and provides effective strategies for regulation of caviar flavor during storage.

Molecular insights on the binding of chlortetracycline to bovine casein and its effect on the thermostability of chlortetracycline

Bovine casein was selected as a model protein to evaluate the impact of food matrix on the thermal degradation of antibiotics. Fluorescence quenching and isothermal titration calorimetry experiments revealed that chlortetracycline (CTC) could spontaneously bind to casein via hydrogen bonding and hydrophobic interactions. The amino acid residues forming the binding pocket were further identified using molecular docking, while saturation transfer difference NMR deciphered that the binding of CTC engages its -N(CH3)2 group. Moreover, the degradation behavior of free CTC versus that bound in casein-CTC complex was compared during thermal treatment. Compared with free CTC, a lower first-order rate constant was observed in the presence of casein. Removal of casein shortened the half-life of CTC by at least 48.1% at low concentrations. Elucidating that the formation of protein-antibiotic complexes alters the amenability of antibiotics to degradative reactions, which could help eliminate residual antibiotics and guarantee the safety of dairy products.

Investigation on the interaction mechanisms for stability of preheated whey protein isolate with anthocyanins from blueberry

Proteins and anthocyanins coexist in complex food systems. This research mainly studied the steady-state protective design and mechanism of the preheated protein against anthocyanins. Multispectral and molecular dynamics are utilized to illustrate the interaction mechanism between preheated whey protein isolate (pre-WPI) and anthocyanins. The pre-WPI could effectively protect the stability of anthocyanins, and the effect was better than that of the natural whey protein isolate (NW). Among them, NW after preheating treatment at 55 °C showed better protection against anthocyanin stability. Fluorescence studies indicated that pre-WPI there existed a solid binding affinity and static quenching for malvidin-3-galactoside (M3G). Multispectral data showed a significant variation in the secondary structure of pre-WPI. Furthermore, molecular dynamics simulation selects AMBER18 as the protein force field, and the results showed that hydrogen bonding participated as an applied force. Compared with NW, pre-WPI could better wrap anthocyanins and avoid damage to the external environment due to tightening of the pockets. Protein protects anthocyanins from degradation, and this protective effect is influenced by the preheating temperature of protein and the structure of protein. On the basis of the above results, it is possible to pinpoint the interaction mechanism between preheated proteins and anthocyanins.

Stabilization of anthocyanins by simultaneous encapsulation-copigmentation via protein-polysaccharide polyelectrolyte complexes

This study prepared a series of polyelectrolyte complexes (PECs) composed of heated whey protein isolate (HWPI) and different polysaccharides for simultaneous encapsulation and copigmentation of anthocyanins (ATC) and their ultimate stabilization. Four polysaccharides including chondroitin sulfate, dextran sulfate, gum arabic, and pectin were chosen due to their abilities to simultaneously complex with HWPI and copigment ATC. At pH 4.0, these PECs were formed with an average particle size of 120-360 nm, the ATC encapsulation efficiency of 62-80%, and the production yield of 47-68%, depending on the type of polysaccharides. The PECs effectively inhibited the degradation of ATC during storage and when exposed to neutral pH, ascorbic acid, and heat. Pectin had the best protection, followed by gum arabic, chondroitin sulfate, and dextran sulfate. The stabilizing effects were associated with the hydrogen bonding, hydrophobic and electrostatic interactions between HWPI and polysaccharides, conferring dense internal network and hydrophobic microenvironment in the complexes.

Computational insight into stability-enhanced systems of anthocyanin with protein/peptide

Anthocyanins, which belong to the flavonoid group, are commonly found in the organs of plants native to South and Central America. However, these pigments are unstable under conditions of varying pH, heat, etc., which limits their potential applications. One method for preserving the stability of anthocyanins is through encapsulation using proteins or peptides. Nevertheless, the complex and diverse structure of these molecules, as well as the limitation of experimental technologies, have hindered a comprehensive understanding of the encapsulation processes and the mechanisms by which stability is enhanced. To address these challenges, computational methods, such as molecular docking and molecular dynamics simulation have been used to study the binding affinity and dynamics of interactions between proteins/peptides and anthocyanins. This review summarizes the mechanisms of interaction between these systems, based on computational approaches, and highlights the role of proteins and peptides in the stability enhancement of anthocyanins. It also discusses the current limitations of these methods and suggests possible solutions.

Research on the interaction of astragaloside IV and calycosin in Astragalus membranaceus with HMGB1

BACKGROUND

High mobility group box 1 protein (HMGB1), a lethal late inflammatory mediator, contributes to the pathogenesis of diverse inflammatory and infectious diseases. Astragaloside IV and calycosin as active ingredients in Astragalus membranaceus, possess potent regulatory ability on HMGB1-induced inflammation, however, the interaction between these two phytochemicals and HMGB1 has not been elucidated yet.

METHODS

To further investigate the interaction of astragaloside IV, calycosin with HMGB1 protein, surface plasma resonance (SPR) and a series of spectroscopic methods, including UV spectra, fluorescence spectroscopy, circular dichroism (CD), were used. Molecular docking was also carried out to predict the atomic level's binding modes between two components and HMGB1.

RESULTS

Astragaloside IV and calycosin were found to be able to bind HMGB1 directly and affect the secondary structure and environment of the chromogenic amino acids of HMGB1 to different extents. In silico, astragaloside IV and calycosin showed a synergistic effect by binding to the two independent domains B-box and A-box in HMGB1, respectively, where hydrogen and hydrophobicity bonds were regarded as the crucial forces.

CONCLUSION

These findings showed that the interaction of astragaloside IV and calycosin with HMGB1 impaired its proinflammatory cytokines function, providing a new perspective for understanding the mechanism of A. membranaceus in treating aseptic and infectious diseases.

Effects of whey protein isolate and ferulic acid/phloridzin/naringin/cysteine on the thermal stability of mulberry anthocyanin extract at neutral pH

In this study, the effects of whey protein isolate (WPI) and four copigments, including ferulic acid (FA), phloridzin, naringin, and cysteine (Cys), on the thermal stability (80 °C/2h) of mulberry anthocyanin extract (MAE) pigment solution at pH 6.3 were studied. WPI addition or copigment (except for Cys) addition alone could protect anthocyanin from degradation to a certain degree, and FA exhibited the best effect among copigments. Compared with the MAE-WPI and MAE-FA binary systems, ΔE of the MAE-WPI-FA ternary system decreased by 20.9% and 21.1%, respectively, and the total anthocyanin degradation rate decreased by 38.0% and 39.3%, respectively, indicating the best stabilizing effect. Remarkably, interactions between anthocyanins and Cys, which generate four anthocyanin derivatives with 513-nm UV absorption during heat treatment, did not alter the color stability of MAE solution; however, they accelerated anthocyanin degradation. These results favor the combined use of multiple methods to stabilize anthocyanins at neutral conditions.

The comparison between zein-anthocyanins complex and nanoparticle systems: Stability enhancement, interaction mechanism, and in silico approaches

This research aimed to compare and characterize the physicochemical properties and interaction mechanism of zein and anthocyanins (ACNs) from experimental and theoretical perspectives. Zein-ACNs complex (ZACP) was prepared by mixing ACNs with different concentrations of zein, and zein-ACNs nanoparticles (ZANPs) were formed using ultrasound-assisted antisolvent precipitation method. The hydrated particle sizes of the two systems were 590.83 nm and 99.86 nm, respectively, and observed to be spherical under transmission electron microscopy (TEM). The multi-spectroscopy approaches confirmed hydrogen bonding and hydrophobic forces were the dominant forces for stabilizing ACNs. The retention of ACNs, color stability and antioxidant activities were also improved in both systems. Furthermore, molecular simulation results were consistent with the multi-spectroscopy findings, which clarified the contribution of van der Waals forces to the binding of zein and ACNs. This study provided a practical approach for stabilizing ACNs and expanding the utilization of plant proteins as stabilization systems.

Soy Protein Isolate Interacted with Acrylamide to Reduce the Release of Acrylamide in the In Vitro Digestion Model

Acrylamide (AA), a common carcinogen, has been found in many dietary products.. This study aimed to explore the interaction of soybean protein isolate (SPI) with AA and further research the different effects of SPI on the AA release due to interactions in the in vitro digestion model. Analysis of variance was used to analyze the data. The results suggested that AA could bind with SPI in vitro, leading to the variation in SPI structure. The intrinsic fluorescence of SPI was quenched by AA via static quenching. The non-covalent (van der Waals forces and hydrogen bonding) and covalent bonds were the main interaction forces between SPI and AA. Furthermore, the release of AA significantly decreased due to its interaction with SPI under simulated gastrointestinal conditions. SPI had different effects on the AA release rate after different treatments. The thermal (80, 85, 90, and 95 °C for either 10 or 20 min) and ultrasound (200, 300, and 400 W for either 15, 30, or 60 min) treatments of SPI were useful in reducing the release of AA. However, the high pressure-homogenized (30, 60, 90, and 120 MPa once, twice, or thrice) treatments of SPI were unfavorable for reducing the release of AA.

Fabrication, Characterization, and Emulsifying Properties of Complex Based on Pea Protein Isolate / Pectin for the Encapsulation of Pterostilbene

In this study, pectin (PEC) and pea protein isolate(PPI) was successfully used to create complexes as a novel delivery system for pterostilbene (PT). When the mass ratio of PEC to PPI was 0.5, the particle size and ζ-potential of PPI-PEC-PT were 119.41 ± 5.68 nm and -23.26 ± 0.61 mV, respectively, and the encapsulation efficiency (EE) of PT was 90.92 ± 2.08%. The photochemical stability of PT was enhanced after encapsulation. The results of the molecular docking and multispectral analysis demonstrated that the PPI and PT binding was spontaneous and mostly fueled by hydrophobic interactions. The hydrophobicity of PPI was significantly decreased and the emulsification activity and emulsion stability were significantly improved after production with PEC and PT. The best emulsification impact was demonstrated by the PPI-PEC-PT complex. PPI-PEC is an effective PT delivery material, and the PPI-PEC-PT complex is a new functional emulsification material with significant potential in liquid and semi-liquid food and health products.

Curcumin-encapsulated hydrophilic gelatin nanoparticle to stabilize fish oil-loaded Pickering emulsion

Herein, pH-cycle method was explored to prepare curcumin-encapsulated hydrophilic bovine bone gelatin (BBG/Cur) nanoparticle and then the obtained nanoparticle was applied to stabilize fish oil-loaded Pickering emulsion. The nanoparticle had a high encapsulation efficiency (93.9 ± 0.5 %) and loading capacity (9.4 ± 0.1 %) for curcumin. The nanoparticle-stabilized emulsion had higher emulsifying activity index (25.1 ± 0.9 m²/g) and lower emulsifying stability index (161.5 ± 18.8 min) than BBG-stabilized emulsion. The pH affected the initial droplet sizes and creaming index values of the Pickering emulsions: pH 11.0 < pH 5.0 ≈ pH 7.0 ≈ pH 9.0 < pH 3.0. Curcumin provided obvious antioxidant effect for the emulsions, which was also dependent on pH. The work suggested pH-cycle method could be used to prepare hydrophobic antioxidant-encapsulated hydrophilic protein nanoparticle. It also provided basic information on the development of protein nanoparticles for Pickering emulsion stabilization.

The Interactional Characterization of Lentil Protein Isolate (LPI) with Cyanidin-3-O-Glucoside (C3G) and Their Effect on the Stability and Antioxidant Activity of C3G

The interaction between lentil protein isolate (LPI) and cyanidin-3-O-glucoside (C3G) was investigated via with UV−vis spectroscopy, circular dichroism, and fluorescence spectroscopy and the stability of anthocyanin was also evaluated. After LPI mixed with C3G, the turbidity and foaming capacity increased and the particle size and surface charge did not change significantly, while the surface hydrophobicity decreased significantly (p < 0.05). The fluorescence results indicated that C3G quenched the intrinsic of LPI by static quenching and LPI bound with C3G via hydrophobic effects with Ka of 3.24 × 106 M−1 at 298 K. The addition of LPI significantly (p < 0.05) slightly decreased the thermal and oxidation degradation of C3G by up to 90.23% and 54.20%, respectively, while their antioxidant activity was inhibited upon mixing. These alterations of physicochemical properties might be attributed to their structural changes during the interaction. The obtained results would be of help in stabilizing bioactive compounds and the development of functional foods.

Multispectroscopic and Computational Investigations on the Binding Mechanism of Dicaffeoylquinic Acids with Ovalbumin

Recently, studies on the interactions between ovalbumin (OVA) and polyphenols have received a great deal of interest. This study explored the conformational changes and the interaction mechanism of the binding between OVA and chlorogenic acid (CGA) isomers such as 3,4-dicaffeoylquinic acids (3,4-diCQA), 4,5-dicaffeoylquinic acids (4,5-diCQA), and 3,5-dicaffeoylquinic acids (3,5-diCQA) using multispectroscopic and in silico analyses. The emission spectra show that the diCQAs caused strong quenching of OVA fluorescence under different temperatures through a static quenching mechanism with hydrogen bond (H-bond) and van der Waals (vdW) interactions. The values of binding constants (OVA-3,4-diCQA = 6.123 × 10⁵, OVA-3,5-diCQA = 2.485 × 10⁵, OVA-4,5-diCQA = 4.698 × 10⁵ dm³ mol^-1 at 298 K) suggested that diCQAs had a strong binding affinity toward OVA, among which OVA-3,4-diCQA exhibits higher binding constant. The results of UV-vis absorption and synchronous fluorescence indicated that the binding of all three diCQAs to OVA induced conformational and micro-environmental changes in the protein. The findings of molecular modeling further validate the significant role of vdW force and H-bond interactions in ensuring the stable binding of OVA-diCQA complexes. Temperature-dependent molecular dynamics simulation studies allow estimation of the individual components that contribute to the total bound free energy value, which allows evaluation of the nature of the interactions involved. This research can provide information for future investigations on food proteins' physicochemical stability and CGA bioavailability in vitro or in vivo.

Hydrolytic Quinoa Protein and Cationic Lotus Root Starch-Based Micelles for Co-Delivery of Quercetin and Epigallo-catechin 3-Gallate in Ulcerative Colitis Treatment

The accumulation and sustained release of drugs in the colonic inflammatory region are the favorable strategy for treating ulcerative colitis (UC). In this study, we developed a synergistic anti-inflammatory drug (quercetin/EGCG)-loaded micelle using hydrolytic quinoa protein (HQP) and cationic lotus root starch (CLRS) by a layer-by-layer assembly method. The encapsulation efficiency of quercetin and EGCG in the Que-HQP-EGCG-CLRS micelles reached 91.5 and 89.4%, respectively. This composite micelle exhibited a core-shell structure, where Que-HQP-EGCG was the core and CLRS was the coating shell. Moreover, the in vitro experiments indicated that these micelles can make Que/EGCG pass through gastric environments stably and delay their release in the intestine. Animal experiments further confirmed that the Que-HQP-EGCG-CLRS micelles can efficiently accumulate in the colonic inflammatory region and enable sustained release of drugs (more than 24 h), thus notably alleviating the symptoms of UC. These results suggested that Que-HQP-EGCG-CLRS micelles have good gastric stability, colonic inflammatory-accumulated effect, and sustained drug release ability, which are a promising co-delivery system for UC treatment.

Action mechanisms of two key xanthine oxidase inhibitors in tea polyphenols and their combined effect with allopurinol

BACKGROUND

Tea polyphenols have been reported to have the effect of lowering uric acid. However, there are few studies on the inhibitory effects and molecular mechanisms of specific catechins on the urate-metabolizing enzyme xanthine oxidase (XO). In this research, multiple spectroscopic methods and computer simulations were used to determine the inhibitory ability and mechanisms of epigallocatechin gallate (EGCG) and gallocatechin gallate (GCG) on XO.

RESULTS

Herein, EGCG and GCG reversibly inhibited XO activity in a mixed manner, with IC₅₀ values of 40.50 ± 0.32 and 33.60 ± 0.53 μmol L^-1 , and also decreased the superoxide anion radical (O₂ ^- ) of the catalytic system by reducing the XO molecule and inhibiting the formation of uric acid. The combination of EGCG or GCG with allopurinol showed synergistic inhibition on XO. The binding of EGCG or GCG to XO with moderate affinity formed a stable complex by hydrogen bonds and van der Waals forces. The presence of EGCG and GCG made the structure of XO more stable and compact. The two inhibitors bound to the vicinity of flavin adenine dinucleotide (FAD) in XO, hindering the entry of substrate; thus the activity of XO was suppressed.

CONCLUSION

Both EGCG and GCG are excellent natural XO inhibitors, and inhibited the activity of XO by occupying the channel of the substrate to enter the active center and interfering with the dual substrate reaction catalyzed by XO. These findings provide a scientific basis for the application of catechins in dietary supplements and medicines with lowering uric acid effects. © 2022 Society of Chemical Industry.

Exploring the Inhibition of Quercetin on Acetylcholinesterase by Multispectroscopic and In Silico Approaches and Evaluation of Its Neuroprotective Effects on PC12 Cells

This study investigated the inhibitory mechanism of quercetin in acetylcholinesterase (AChE) and its neuroprotective effects on β-amyloid_25-35-induced oxidative stress injury in PC12 cells. Quercetin inhibited AChE in a reversible mixed manner with an IC₅₀ of 4.59 ± 0.27 µM. The binding constant of quercetin with AChE at 25 °C was (5.52 ± 0.05) × 10⁴ L mol^-1. Hydrogen bonding and van der Waals forces were the main interactions in forming the stable quercetin-AChE complex. Computational docking revealed that quercetin was dominant at the peripheral aromatic site in AChE and induced enzymatic allosterism; meanwhile, it extended deep into the active center of AChE and destabilized the hydrogen bond network, which caused the constriction of the gorge entrance and prevented the substrate from entering the enzyme, thus resulting in the inhibition of AChE. Molecular dynamics (MD) simulation emphasized the stability of the quercetin-AChE complex and corroborated the previous findings. Interestingly, a combination of galantamine hydrobromide and quercetin exhibited the synergistic inhibition effect by binding to different active sites of AChE. In a β-amyloid_25-35-induced oxidative stress injury model in PC12 cells, quercetin exerted neuroprotective effects by increasing the glutathione level and reducing the malondialdehyde content and reactive oxygen species levels. These findings may provide novel insights into the development and application of quercetin in the dietary treatment of Alzheimer's disease.

Boosting the Bioaccessibility of Dietary Bioactives by Delivery as Protein-Polyphenol Aggregate Particles

Protein-polyphenol aggregate particles concurrently fortify a functional food product with healthy dietary proteins and concentrated polyphenols. However, what impact does ingestion of aggregate particles have on ultimate health relevance of either the polyphenolic molecules in the matrix or the protein molecules? Because human health benefits are contingent on bioavailability after ingestion, the fate of these molecules during transit in the gastrointestinal tract (GIT) will dictate their utility as functional food ingredients. This brief review explores diverse applications of protein-polyphenol particles in the food industry and the bioaccessibility of both bioactive polyphenolic compounds and edible proteins. Evidence to date suggests that complexation of phytoactive polyphenolics effectively enhances their health-relevant impacts, specifically because the phytoactives are protected in the protein matrix during transit in the GIT, allowing intact, non-degraded molecules to reach the colon for catabolism at the gut microbiome level, a prerequisite to realize the health benefits of these active compounds.

Development of cobalt oxyhydroxide-aptamer-based upconversion sensing nano-system for the rapid detection of Staphylococcus aureus

Staphylococcus aureus (S. aureus) is a common pathogen that is dangerous to humans' health. Herein, a novel upconversion fluorescent biosensor based on fluorescence resonance energy transfer from aptamer-labeled upconversion nanoparticles (UCNPs-apt) as donor and cobalt oxyhydroxide (CoOOH) nanosheets as acceptor was designed to detect S. aureus in complex matrices. The principle of the work relies on fluorescence resonance energy transfer as UCNPs-apt can self-assemble on CoOOH nanosheet surfaces by van der Waals forces to effectively quench the fluorescence. When S. aureus was added, the aptamer was able to preferentially capture the target, resulting in the dissociation of donor and acceptor and the recovery of fluorescence. The structure and morphology of the nanostructures were assigned in detail by a series of characterizations, and the energy transfer mechanism was evaluated by time-resolved lifetime measurements. Under the optimal conditions, a linear calibration plot was obtained in a concentration range of 45-4.5 × 10⁶ CFU/mL with a limit of detection of 15 CFU/mL. In addition, the proposed biosensor was used for S. aureus detection in real samples (e.g., pork, beef), and the detection result showed no significant difference (p > 0.05) compared with the conventional plate count approach. Hence, the fabricated biosensor holds a potential application for S. aureus in food analysis and public health.

Interaction and binding mechanism of lipid oxidation products to sturgeon myofibrillar protein in low temperature vacuum heating conditions: Multispectroscopic and molecular docking approaches

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A comparative study of the effects of malondialdehyde and 4-hydroxy-2-nonenal on protein oxidation.

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Interaction mechanism between lipid oxidation production and protein at temperatures were firstly studied.

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Hydrogen bonding was the main driving force for bonding.

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Malondialdehyde had a strong ability to bind MP and accelerated protein oxidation.

In this work, the binding mechanism of myofibrillar protein (MP) with malondialdehyde and 4-hydroxy-2-nonenal under low temperature vacuum heating was investigated via multispectroscopic and molecular docking. The results showed that binding interaction and increasing temperature caused significant changes in the conformations as well as a decrease in the value of protein intrinsic fluorescence, surface hydrophobicity, and fluorescence excitation-emission matrix spectra. Furthermore, the decrease in α-helix and β-turn, increase in β-sheet and a random coil of MP, imply the MP molecules to be more unfolded. Isothermal titration calorimetry and molecular docking results showed that main driving force for binding with MP was hydrogen bond, and the binding ability of malondialdehyde was superior to that of 4-hydroxy-2-nonenal. Moreover, increasing the heating temperature was beneficial to the binding reaction and intensified the conformational transition of MP. These results will provide a reference for further studies on the lipid and protein interaction of sturgeon.

Electrospun nanofibrous membrane with antibacterial and antiviral properties decorated with Myoporum bontioides extract and silver-doped carbon nitride nanoparticles for medical masks application

Public health safety issues have been plaguing the world since the pandemic outbreak of coronavirus disease (COVID-19). However, most personal protective equipments (PPE) do not have antibacterial and anti- toxicity effects. In this work, we designed and prepared a reusable, antibacterial and anti-toxicity Polyacrylonitrile (PAN) based nanofibrous membrane cooperated with Ag/g-C₃N₄ (Ag-CN), Myoporum.bontioides (M. bontioides) plant extracts and Ag nanoparticles (NPs) by an electrospinning-process. The SEM and TEM characterization revealed the formation of raised, creased or wrinkled areas on the fiber surface caused by the Ag nanoparticles, the rough surface prevented the aerosol particles on the fiber surface from sliding and stagnating, thus providing excellent filtration performance. The PAN/M. bontioides/Ag-CN/Ag nanofibrous membrane could be employed as a photocatalytic bactericidal material, which not only degraded 96.37% of methylene blue within 150 min, but also exhibited the superior bactericidal effect of 98.65 ± 1.49% and 97.8 ± 1.27% against E. coli and S. aureus, respectively, under 3 hs of light exposure. After 3 cycles of sterilization experiments, the PAN/M. bontioides/Ag-CN/Ag nanofibrous membrane maintained an efficient sterilization effect. Molecular docking revealed that the compounds in M. bontioides extracts interacted with neo-coronavirus targets mainly on Mpro and RdRp proteins, and these compounds had the strongest docking energy with Mpro protein, the shortest docking radius, and more binding sites for key amino acids around the viral protein targets, which influenced the replication and transcription process of neo-coronavirus. The PAN/M.bontioides/Ag-CN/Ag nanofibrous membrane also performed significant inhibition of influenza A virus H3N2. The novel nanofiber membrane is expected to be applied to medical masks, which will improve human isolation and protection against viruses.

Acidified glycerol as a one-step efficient green extraction and preservation strategy for anthocyanin from blueberry pomace: New insights into extraction and stability protection mechanism with molecular dynamic simulation

In present work, green and efficient glycerol solvent system was coupled with pulse-probe ultrasonication for one-step extraction and preservation of anthocyanin from blueberry pomace. Under optimal conditions (40 min, 174 W, 18.6 mL/g, 20% of glycerol fraction), extraction yield was 23.07 ± 0.09 mg C3GE/g DW. The extracted anthocyanins were characterized by UPLC-Triple-TOF/MS and 10 anthocyanins compounds were tentatively identified. Stability of anthocyanins influenced by solvents were evaluated in varying temperature, pH and light exposure conditions, demonstrating higher stability of anthocyanins in glycerol solvent system than methanol one. Furthermore, mechanism of high efficiency extraction and stability of anthocyanin using glycerol were investigated by quantum chemical calculation with molecular dynamic simulation. Larger solvent accessible surface area (127.16 nm²), hydrogen bonds number (228.16) and hydrogen bonds lifetime (4.35 ps), and lower intermolecular interaction energy (-1080.48 kJ/mol) between anthocyanin and glycerol were responsible for better extraction and preservation of anthocyanins using glycerol system.

An updated review on the stability of anthocyanins regarding the interaction with food proteins and polysaccharides

The health benefits of anthocyanins are compromised by their chemical instability and susceptibility to external stress. Researchers found that the interaction between anthocyanins and macromolecular components such as proteins and polysaccharides substantially determines the stability of anthocyanins during food processing and storage. The topic thus has attracted much attention in recent years. This review underlines the new insights gained in our current study of physical and chemical properties and functional properties in complex food systems. It examines the interaction between anthocyanins and food proteins or polysaccharides by focusing on the "structure-stability" relationship. Furthermore, multispectral and molecular computing simulations are used as the chief instruments to explore the interaction's mechanism. During processing and storage, the stability of anthocyanins is generally influenced by the adverse characteristics of food and beverage, including temperature, light, oxygen, enzymes, pH. While the action modes and types between protein/polysaccharide and anthocyanins mainly depend on their structures, the noncovalent interaction between them is the key intermolecular force that increases the stability of anthocyanins. Our goal is to provide the latest understanding of the stability of anthocyanins under food processing conditions and further improve their utilization in food industries. Practical Application: This review provides support for the steady-state protection of active substances.

Formation, Structure and stability of high internal phase Pickering emulsions stabilized by BSPI-C3G covalent complexes

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The HIIPPE was stabilized by BSPI-C3G covalent particles.

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HIPPEs stabilized with 74% (v/v) oil phase fraction have a stable gel-like state.

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HIPPEs stability was the best with the 3 % (w/v) BSPI-C3G particle concentration.

Food-grade high internal phase Pickering emulsions (HIPPEs) are stabilized by protein-based particles, which have attracted extensive attention due to their good gel-like structure. The black soybean isolate protein/cyanidin-3-O-glucoside (BSPI-C3G) covalent particles were used as a particulate emulsifier to form stable HIPPEs with oil phase fractions (74 % v/v) and low particle concentrations (0.5 %–3 % w/v) The particle size distribution and microstructure demonstrated that the BSPI-C3G covalent particles acted as an interfacial layer and surrounded the oil droplets. As the concentration of BSPI-C3G particles increased from 0.5 % to 3 %, the droplet size, elasticity, antioxidant capacity of the heated or stored HIPPEs more stable. So, the HIPPEs had the best stability with the BSPI-C3G particle at 3 % (w/v) concentration. These findings may extend the application of BSPI and C3G in foods and provide the guidelines for the rational design of food-grade HIPPEs stabilized by protein/anthocyanin complexes.

Exploring the interaction mechanism of dietary protein ovalbumin and folic acid: A combination research of molecular simulation technology and multispectroscopy

This study aims to reveal the mechanism of the interaction between folic acid (FA) and egg ovalbumin (OVA) through the method of multi-spectroscopic, molecular docking, and molecular dynamics simulation in order to probe OVA as the possibility of a carrier of unstable vitamins. The results of the fluorescence spectra indicated a static quenching in the OVA-FA with a strong affinity of 6.998 × 10⁴ M^-1. At the same time, the complex formed by FA and OVA has changed the microenvironment. The measurement results of circular dichroism and particle size showed that FA and OVA gradually formed larger particles without changed the secondary structure of the protein. In addition, the results of molecular simulations indicated that the interaction between OVA and FA is mainly stabilized by strong hydrophobic and hydrogen bonds. This research was expanded the application prospect of dietary protein OVA as a transportation and protection system of vitamin substances.