Improving the functional properties of bovine serum albumin-glucose conjugates in natural deep eutectic solvents

Discrepant Effects of Hydrated and Neat Reline on the Conformational Stability of a Knotted Protein

Although knotted proteins are rare in number, their peculiar topology has long intrigued the scientific community. In this study, we have explored the conformational stability of a trefoil-knotted protein, YbeA, in reline (choline chloride:urea in a 1:2 ratio), a well-characterized deep eutectic solvent, using classical molecular dynamics simulation. Deep eutectic solvents (DESs) are explored as a reliable alternative to conventional solvents, effectively altering a protein's structural stability and activity, either stabilizing its native state or disordering its conformation depending on the relevant interactions involved. Here, using pure and hydrated concentrations of reline, we observe the conflicting effect of the DES on the knotted protein's stability. Our studies at room temperature and elevated temperatures show that in pure reline, the protein is conformationally stable and rigid. In contrast, the protein tends to lose its structural integrity in hydrated reline. The stable knotted topology also gets untied as the protein, solvated in hydrated reline, is exposed to an elevated temperature. Using Minimum Distance Distribution Functions and Kirkwood-Buff Integrals, we analyzed the solvation pattern of the DES constituents around the protein. We expect that this study will lead to more effective strategies in developing tailored solvent systems for comprehending the conformational behavior of knotted proteins.

Structural and functional changes induced by different ultrasound-frequency-assisted xylose-glycation inhibits lysinoalanine formation in Tenebrio molitor protein

We explored the effects of sonication-assisted xylose (Xyl) grafting on the structure and functionality of Tenebrio molitor protein (MP). Different ultrasound frequencies (20, 25, 28, 20/25, 20/28, 25/28, 20/25/28 kHz) were used, and the inhibition mechanism of ultrasound-assisted Xyl grafting on the formation of lysinoalanine (LAL) was explored. The results suggested that the turbidity and browning products of MP significantly increase, with MP-Xyl-20 kHz exhibiting the highest grafting degree (43.78 %). Compared with MP, the total sulfhydryl content of MP-Xyl and MP-Xyl-20 kHz was significantly improved by 21.90 % and 98.80 % (P < 0.05). Circular Dichroism, Fourier Transform Infrared Spectroscopy, SEM, and AFM analysis showed changes in MP conformation following various frequencies ultrasound-assisted glycosylation. Notably, emulsifying capacity, stability, and foaming ability of MP-Xyl-20 kHz were significantly enhanced by 97.08 %, 48.03 %, and 55.01 %, respectively, compared with MP. The glycol-conjugated MP treated with ultrasound-assisted glycosylation (MP-Xyl-25/28 kHz) had the lowest LAL content (7.19 μg/mg), representing a 56.56 % and 46.70 % decrease compared to the control MP and MP-Xyl, respectively. The content of LAL exhibited a positive correlation with surface hydrophobicity, whereas it demonstrated a negative correlation with sulfhydryl and carbonyl groups. These findings indicated that sonication-assisted xylose improved the functional characteristics of MP, and the inhibition effect on LAL formation. The outcome of the study could be very beneficial in the modification of MP for food industrial applications.

Glycation-mediated pea protein isolate-curcumin conjugates for uniform walnut oil dispersion: enhancing oxidative stability and shelf life

BACKGROUND

Traditional methods for fabricating protein-polyphenol conjugates have not preserved the structural and functional integrity essential for the food industry effectively. This research introduces an advanced encapsulation methodology designed to overcome these limitations, with the potential to enhance the stability of edible oil matrices significantly, leading to improved preservation techniques and extended shelf life.

RESULTS

Glycated pea protein isolate-curcumin conjugates (gPPI-CUR) were developed, demonstrating a marked improvement in the oxidative stability of walnut oil (WO), a proxy for edible oil matrices. Characterized by a Z-average diameter of 158.37 nm and an encapsulation efficiency of 80.94%, these conjugates demonstrated exceptional performance in reducing lipid oxidation and aldehyde formation. Molecular docking analysis confirmed the formation of robust bonds with curcumin, thereby amplifying antioxidant activity. The uniform distribution of gPPI-CUR throughout the walnut oil matrix, as validated by confocal microscopy, ensured sustained bioactivity and mitigated the risk of localized oxidation. Electron spin resonance spectroscopy corroborated the superior antioxidant properties of the conjugates, which translated into a substantial 19-day increase in the shelf-life of the oil.

CONCLUSION

The gPPI-CUR conjugates enhanced the oxidative stability of walnut oil significantly, as demonstrated by the increased shelf life and reduced lipid oxidation. This study introduced an effective encapsulation method that improved the stability and extended the shelf life of edible oils, aligning with consumer demands for high-nutrition food products. The results indicate that the gPPI-CUR conjugates could serve as a promising antioxidant strategy for food preservation, offering a practical approach to enhance food quality and safety. © 2025 Society of Chemical Industry.

Reducing the bitterness of angiotensin-I-converting enzyme (ACE) inhibitory peptides from soybean protein by NADES-driven Maillard reaction

Soybean peptide (SP) exhibits significant angiotensin-I-converting enzyme inhibitory (ACEI) activity, however, its strong bitterness restricts its use in food industry. This study aimed to reduce the bitterness of SP by natural deep eutectic solvent (NADES)-driven Maillard reaction (MR). Results showed that both the mixtures of Glucose-NADES and the Glucose-Xylose-NADES formed the hydrogen bonds and shown good thermal stability analyzed by using Fourier transform infrared (FTIR), Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). Compared with Glucose-NADES, Glucose-Xylose-NADES exhibited higher reaction activity, while lower ACEI-activity and higher bitterness were observed in its Maillard reaction products (MRPs). It also indicated that NADES's excellent ability to increase umami free amino acid (FAAs) and reduce bitter FAAs during MR, were key factors in reducing bitterness. Some amino acids (Glu, Asp, Leu and Ala) were considered to have a higher contribution to change the bitterness of MRPs. This study is expected to provide a theoretical basis for preparing functional peptides with high activity and good taste.

Enthalpy-Driven Interaction between Bovine Serum Albumin and Biomass-Derived Low-Melting Mixture Solvents (LoMMSs) for Efficient and Green Purification of Protein

Green separation of protein (e.g., bovine serum albumin (BSA)) by low-melting mixture solvents (LoMMSs) depends on the underlying mechanism between BSA and LoMMSs. Here, we for the first time find that eco-friendly biomass-derived LoMMSs could be potentially used for the efficient and green purification of BSA protein by enthalpy-driven interactions. Biomass-derived LoMMSs possess the merits of high biocompatibility, high degradability, high abundance, and low cost. A single high-affinity binding site via hydrogen bonding and van der Waals forces is observed between BSA and LoMMSs by fluorescence and thermodynamic analysis. Experimental results from circular dichroism and infrared spectra demonstrate that the addition of LoMMSs stabilizes the secondary structure of the BSA protein. This work provides a valuable indication for the design of eco-friendly and cost-effective LoMMSs for the purification of protein.

Enhancement of Physicochemical and Functional Properties of Chicken Breast Protein Through Polyphenol Conjugation: A Novel Ingredient for Protein Supplements

Polyphenol conjugation has emerged as a promising approach to enhance the technological properties and physiological benefits of food proteins. This study investigated the effects of polyphenol conjugation on the technological properties, antioxidant capacity, and in vitro digestibility of chicken breast (CB) proteins. Conjugation with (-)-epigallocatechin 3-gallate (EGCG) and tannic acid (TA) significantly reduced sulfhydryl content. EGCG conjugates exhibited higher turbidity and greater molecular weight aggregates (>245 kDa). Fourier-transform infrared spectroscopy (FTIR) revealed alterations in protein secondary structures, with shifts in amide I and II bands. Polyphenol conjugation significantly enhanced the water-holding capacity of chicken muscle proteins, particularly for CB-TA (3.29 g/g) and CB-EGCG (3.13 g/g) compared to the control (2.25 g/g). The emulsion stability index improved notably in CB-EGCG (96.23 min) and CB-TA (87.24 min) compared to the control (69.05 min). Color analysis revealed darker and more intense hues for CB-EGCG, while CB-TA maintained a lighter appearance, making it potentially preferable for industrial applications requiring neutral-colored powders. Moreover, polyphenol conjugation could enhance antioxidant capacity, particularly in conjugates with EGCG (p < 0.05). In vitro protein digestibility remained comparable across treatments (p > 0.05). Our findings could indicate the potential of chicken muscle protein-polyphenol conjugates as innovative ingredients for high-quality protein supplements.

Exploring the effect of natural deep eutectic solvents on zein: Structural and functional properties

This study evaluated the effects of chemical modification, including ethanol, acetic acid, and natural deep eutectic solvents (NADES), on the secondary and tertiary structures, hydrophobicity, free amine content, protein-protein interactions, and functional properties of zein. The NADES used included choline chloride: oxalic acid, choline chloride: urea, choline chloride: glycerol, and glucose: citric acid. The results reveal that the NADES system significantly altered zein's structures, as evidenced by Fourier transform infrared spectroscopy, fluorescence, and Ultraviolet-Visible Spectroscopy analysis. Circular dichroism spectroscopy analysis indicated significant conformational change in modified zein, with decreased α-helix and increased random coil content. Notably, the NADES system leads to greater disruption of hydrogen bonds and facilitates the exposure of hydrophobic regions compared to water, ethanol, and acetic acid systems. This resulted in enhanced solubility, surface hydrophobicity, and free amine content in zein, indicating a more significant change in protein structure. In contrast, water and acetic acid solvents maintained more stable disulfide bonds within zein, which correlates with lower solubility and less unfolding. The NADES system promoted interactions between zein and its solvent components, improving emulsifying properties. Water, ethanol, and acetic acid systems had higher solubility in urea, thiourea, and dithiothreitol than the NADES system, revealing disruption of both covalent and noncovalent bonds in zein modified by NADES. Overall, this study highlights the superior ability of the NADES system to modify zein's structure and functionality compared to conventional solvents, suggesting its potential for enhancing protein applications in the industrial production of foods.

Structural and sensory characteristics of ultrasonic assisted wet-heating Maillard reaction products of Giant salamander protein hydrolysates

BACKGROUND

Chinese giant salamander protein hydrolysates (CGSPH) are beneficial to human health as a result of their high content of amino acids and peptides. However, the formation of bitter peptides in protein hydrolysates (PHs) would hinder their application in food industry. The ultrasound assisted wet-heating Maillard reaction (MR) is an effective way to improve the flavor of PHs. Thus, the effect of ultrasonic assisted wet-heating MR on the structure and flavor of CGSPH was investigated in the present study.

RESULTS

The results indicated that the ultrasound assisted wet-heating MR products (MRPs) exhibited a higher degree of graft and more significant changes in the secondary and tertiary structures of CGSPH compared to traditional wet-heating MRPs. Moreover, ultrasound assisted wet-heating MR could significantly increase the content of small molecule peptides and reduce the content of free amino acids of CGSPH, which resulted in more significant changes in flavor characteristics. The changed in flavor properties after MR (especially ultrasound assisted wet-heating MRPs) were mainly manifested by a significant reduction in bitterness, as well as a significant increase in the content of aromatic aldehyde ester compounds such as furan-2-carbaldehyde, butanal, benzaldehyde, furfural, etc. CONCLUSIONS: Ultrasound assisted wet-heating MR between CGSPH and xylose could be a promising way to improve the sensory characteristics of CGSPH. © 2024 Society of Chemical Industry.

Enhancing vitamin D3 bioaccessibility: Unveiling hydrophobic interactions in soybean protein isolate and vitamin D3 binding via an infant in vitro digestion model

In the domain of infant nutrition, optimizing the absorption of crucial nutrients such as vitamin D3 (VD3) is paramount. This study harnessed dynamic-high-pressure microfluidization (DHPM) on soybean protein isolate (SPI) to engineer SPI-VD3 nanoparticles for fortifying yogurt. Characterized by notable binding affinity (Ka = 0.166 × 105 L·mol-1) at 80 MPa and significant surface hydrophobicity (H0 = 3494), these nanoparticles demonstrated promising attributes through molecular simulations. During simulated infant digestion, the 80 MPa DHPM-treated nanoparticles showcased an impressive 74.4% VD3 bioaccessibility, delineating the pivotal roles of hydrophobicity, bioaccessibility, and micellization dynamics. Noteworthy was their traversal through the gastrointestinal tract, illuminating bile salts' crucial function in facilitating VD3 re-encapsulation, thereby mitigating crystallization and augmenting absorption. Moreover, DHPM treatment imparted enhancements in nanoparticle integrity and hydrophobic properties, consequently amplifying VD3 bioavailability. This investigation underscores the potential of SPI-VD3 nanoparticles in bolstering VD3 absorption, thereby furnishing invaluable insights for tailored infant nutrition formulations.

The effect of rice protein-polyphenols covalent and non-covalent interactions on the structure, functionality and in vitro digestion properties of rice protein

The characteristics of the crosslinking between rice protein (RP) and ferulic acid (FA), gallic acid (GA), or tannin acid (TA) by covalent binding of Laccase and non-covalent binding were evaluated. The RP-polyphenol complexes greatly improved the functionality of RP. The covalent effect with higher polyphenol binding equivalence showed higher emulsion activity than the non-covalent effect. The solubility, and antioxidant activity of covalent binding were higher than that of non-covalent binding in the RP-FA group, but there was a contrasting behavior in the RP-GA group. The RP-FA was most soluble in conjugates, while the RP-GA had the highest solubility in mixtures. It was found that the covalent complexes were more stable in the intestinal tract. The content of polyphenols in the RP-TA group was rapidly increased at the later intestinal digestion, which indicated the high polyphenol-protective effect in this group. Meanwhile, the RP-TA group showed high reducing power but low digestibility.

Glucose-modified BSA/procyanidin C1 NPs penetrate the blood-brain barrier and alleviate neuroinflammation in Alzheimer's disease models

Alzheimer's disease (AD) is a chronic neurodegenerative disease with high prevalence, long duration and poor prognosis. The blood-brain barrier (BBB) is a physiologic barrier in the central nervous system, which hinders the entry of most drugs into the brain from the blood, thus affecting the efficacy of drugs for AD. Natural products are recognized as one of the promising and unique therapeutic approaches to treat AD. To improve the efficiency and therapeutic effect of the drug across the BBB, a natural polyphenolic compound, procyanidin C-1 (C1) was encapsulated in glucose-functionalized bovine serum albumin (BSA) nanoparticles to construct Glu-BSA/C1 NPs in our study. Glu-BSA/C1 NPs exhibited good stability, slow release, biocompatibility and antioxidant properties. In addition, Glu-BSA/C1 NPs penetrated the BBB, accumulated in the brain by targeting Glut1, and maintained the BBB integrity both in vitro and in vivo. Moreover, Glu-BSA/C1 NPs alleviated memory impairment of 5 × FAD mice by reducing Aβ deposition and Tau phosphorylation and promoting neurogenesis. Mechanistically, Glu-BSA/C1 NPs significantly activated the PI3K/AKT pathway and inhibited the NLRP3/Caspase-1/IL-1β pathway thereby suppressing neuroinflammation. Taken together, Glu-BSA/C1 NPs could penetrate the BBB and mitigate neuroinflammation in AD, which provides a new therapeutic approach targeting AD.

Glutenin-chitosan 3D porous scaffolds with tunable stiffness and systematized microstructure for cultured meat model

A glutenin (G)-chitosan (CS) complex (G-CS) was cross-linked by water annealing with aim to prepare structured 3D porous cultured meat scaffolds (CMS) here. The CMS has pore diameters ranging from 18 to 67 μm and compressive moduli from 16.09 to 60.35 kPa, along with the mixing ratio of G/CS. SEM showed the porous organized structure of CMS. FTIR and CD showed the increscent content of α-helix and β-sheet of G and strengthened hydrogen-bondings among G-CS molecules, which strengthened the stiffness of G-CS. Raman spectra exhibited an increase of G concentration resulted in higher crosslinking of disulfide-bonds in G-CS, which aggrandized the bridging effect of G-CS and maintained its three-dimensional network. Cell viability assay and immuno-fluorescence staining showed that G-CS effectively facilitated the growth and myogenic differentiation of porcine skeletal muscle satellite cells (PSCs). CLSM displayed that cells first occupied the angular space of hexagon and then ring-growth circle of PSCs were orderly formed on G-CS. The texture and color of CMS which loaded proliferated PSCs were fresh-meat like. These results showed that physical cross-linked G-CS scaffolds are the biocompatible and stable adaptable extracellular matrix with appropriate architectural cues and natural micro-environment for structured CM models.

Protective effect of colchicine on albumin glycation and cellular oxidative stress: Insights into diabetic cardiomyopathy

The present work elucidates the role of colchicine (COL) on albumin glycation and cellular oxidative stress in diabetic cardiomyopathy (DCM). Human serum albumin (HSA) was glycated with methylglyoxal in the presence of COL (2.5, 3.75, and 5 µM), whereas positive and negative control samples were maintained separately. The effects of COL on HSA glycation, structural and functional modifications in glycated HSA were analyzed using different spectroscopical and fluorescence techniques. Increased fructosamine, carbonyl, and pentosidine formation in glycated HSA samples were inhibited in the presence of COL. Structural conformation of HSA and glycated HSA samples was examined by field emission scanning electron microscopy, circular dichroism, Fourier transform infrared, and proton nuclear magnetic resonance analyses, where COL maintained both secondary and tertiary structures of HSA against glycation. Functional marker assays included ABTS•+ radical scavenging and total antioxidant activities, advanced oxidative protein product formation, and turbidimetry, which showed preserved functional properties of glycated HSA in COL-containing samples. Afterward, rat cardiomyoblast (H9c2 cell line) was treated with glycated HSA-COL complex (400 μg/mL) for examining various cellular antioxidants (nitric oxide, catalase, superoxide dismutase, and glutathione) and detoxification enzymes (aldose reductase, glyoxalase I, and II) levels. All three concentrations of COL exhibited effective anti-glycation properties, enhanced cellular antioxidant levels, and detoxification enzyme activities. The report comprehensively analyzes the potential anti-glycation and properties of COL during its initial assessment.

Glycation-induced enhancement of yeast cell protein for improved stability and curcumin delivery in Pickering high internal phase emulsions

Pickering high internal phase emulsions (HIPEs) have gained significant attention for various applications within the food industry. Yeast cell protein (YCP), derived from spent brewer's yeast, stands out as a preferred stabilizing agent due to its cost-effectiveness, abundance, and safety profile. However, challenges persist in utilizing YCP, notably its instability under high salt concentration, thermal processing, and proximity to its isoelectric point. This study aimed to enhance YCP's emulsifying properties through glycation with glucose and evaluate its efficacy as a stabilizer for curcumin (CUR)-loaded HIPEs. The results revealed that glycation increased YCP's surface hydrophobicity, exposing hydrophobic groups. This augmentation, along with steric hindrance from grafted glucose molecules, improved emulsifying properties, resulting in a thicker interfacial layer around oil droplets. This fortified interfacial layer, in synergy with steric hindrance, bolstered resistance to pH changes, salt ions, and thermal degradation. Moreover, HIPEs stabilized with glycated YCP exhibited reduced oxidation rates and improved CUR protection. In vitro digestion studies demonstrated enhanced CUR bioaccessibility, attributed to a faster release of fatty acids. This study underscores the efficacy of glycation as a strategic approach to augment the applicability of biomass proteins, exemplified by glycated YCP, in formulating stable and functional HIPEs for diverse food applications.

Pulsed electric field enhances glucose glycation and emulsifying properties of bovine serum albumin: Focus on polarization and ionization effects at a high reaction temperature

Previous studies demonstrated that the non-thermal effects of pulsed electric fields can promote protein glycation below 40 °C, but it does not always enhance the emulsifying properties of proteins, such as in the bovine serum albumin/glucose model. Therefore, the aim of this study was to investigate the impact of non-thermal effects on the glucose glycation and emulsification properties of bovine serum albumin at 90 °C. The results of circular dichroism, surface hydrophobicity, and molecular dynamics simulations showed that the polarization effect increased the degree of glycation of bovine serum albumin-glucose conjugates from 12.82 % to 21.10 % by unfolding protein molecule, while the emulsifying stability index was increased from 79.17 to 100.73 compared with the control. Furthermore, the results of principal component analysis and Pearson correlation analysis indicated that the ionization effect and the free radicals generated by pulsed electric fields significantly (p < 0.05) inhibited browning and reduced free sulfhydryl content. This study demonstrated that pulsed electric fields combined with heating can prepare glycated proteins with good emulsifying properties in a short period of time and at temperatures lower than conventional heating while reducing energy consumption. This processing strategy has potential applications in improving the emulsifying performance of highly stable proteins.

Synergistic effect of residual sugar on freeze-thaw stability of high internal phase emulsions using glycosylated cod protein as interface stabilizer

Nowadays, glycosylated protein seems to be one of the most effective stabilizers for preparing freeze-thaw stabile emulsion; nevertheless, few papers mentioned the relationship between the residual free sugars after the glycosylation reaction and the freeze-thaw stability of high internal phase emulsions (HIPEs). Herein, glucose was used to prepare glycosylated cod proteins (GCPs). The synergistic effect was related to the grafting degree of GCP, and the amount of glucose added to prepare freeze-thaw stable HIPEs was reduced from 20% to 4% when the grafting degree of GCP increased from 0% to 31.58% (i.e. 12% GCP). This might be due to fewer ice crystals forming in water phase or less destruction of emulsion droplets by ice crystals. The obtained results in this study will allow developing freeze-thaw stable HIPEs or new frozen ingredients.

Physicochemical and functional characteristics of glycated collagen protein from giant salamander skin induced by ultrasound Maillard reaction

Chinese giant salamander skin collagen (CGSSC) was successfully conjugated with glucose (Glu)/xylose (Xy) by ultrasound Maillard reaction (MR) in nature deep eutectic solvents (NADES). The effects of ultrasound and reducing sugar types on the degree graft (DG) of MR products (MRPs), as well as the influence of DG on the structure and functional properties of MRPs were investigated. The results indicated that the ultrasound assisted could markedly enhance the MR of CGSSC, and low molecular weight reducing sugars were more reactive in MR. The ultrasound MR significantly changed the microstructure, secondary and tertiary structures of CGSSC. Moreover, the free sulfhydryl content of MRPs were increased, thus enhancing the surface hydrophobicity, emulsifying properties and antioxidant activity, which were positively correlated with DG. These findings provided theoretical insights into the effects of ultrasound assisted and different sugar types on the functional properties of collagen induced by MR.

Enhancing the solubility and emulsion properties of rice protein by deamidation of citric acid-based natural deep eutectic solvents

The characteristics of rice protein deamidated (DRP) by choline chloride-citric acid and glucose-citric acid natural deep eutectic solvents (C-C NADES, G-C NADES) at different dilutions were investigated. Compared with the effect of citric acid deamidation on the structural and functional properties of the protein, the DRP from the NADESs led to remarkable differences in the degree of hydrolysis (DH), SDS-PAGE, morphology, surface hydrophobicity, average particle size, intrinsic fluorescence, amino acid compositions, and emulsion activity. The results of SDS-PAGE, DH, and SEM showed the NADESs reduced the occurrence of uncontrolled hydrolysis of protein during acid deamidation. DRP from C-C and G-C NADESs was found to significantly improve solubility. DRP prepared by C-C NADES showed a more than 40 % solubility over a wide pH range associated with its higher emulsifying activity (37.62-44.19 m2/g) and emulsifying stability (73.76-86.9 min), as well as a better deamidation effect while lower DH. Thus, these findings showed that acid-based NADESs had great potential as a deamidation solvent to expand the application of protein.

Targeted treatment of atherosclerosis with protein-polysaccharide nanoemulsion co-loaded with photosensitiser and upconversion nanoparticles

Macrophages are the most abundant cell group in atherosclerosis (AS) lesions and play a vital role in all stages of AS progression. Recent research has shown that reactive oxygen species (ROS) generation from photodynamic therapy (PDT) induces macrophage autophagy to improve abnormal lipid metabolism and inflammatory environment. Especially in macrophage-derived foam cells, which has become a potential strategy for the treatment of AS. In this study, we prepared the conjugate (DB) of dextran (DEX) and bovine serum albumin (BSA). The DB was used as the emulsifier to prepare nanoemulsion loaded with upconversion nanoparticles (UCNPs) and chlorin e6 (Ce6) (UCNPs-Ce6@DB). The DEX modified on the surface of the nanoemulsion can recognise and bind to the scavenger receptor class A (SR-A) highly expressed on macrophages and promote the uptake of macrophage-derived foam cells in AS plates through SR-A-mediated endocytosis. In addition, UCNPs-Ce6@DB-mediated PDT enhanced ROS generation and induced autophagy in macrophage-derived foam cells, enhanced the expression of ABCA1, a protein closely related to cholesterol efflux, and inhibited the secretion of pro-inflammatory cytokines. Ultimately, UCNPs-Ce6@DB was shown to inhibit plaque formation in mouse models of AS. In conclusion, UCNPs-Ce6@DB offers a promising treatment for AS.

From Nature to Innovation: The Uncharted Potential of Natural Deep Eutectic Solvents

This review discusses the significance of natural deep eutectic solvents (NaDESs) as a promising green extraction technology. It employs the consolidated meta-analytic approach theory methodology, using the Web of Science and Scopus databases to analyze 2091 articles as the basis of the review. This review explores NaDESs by examining their properties, challenges, and limitations. It underscores the broad applications of NaDESs, some of which remain unexplored, with a focus on their roles as solvents and preservatives. NaDESs' connections with nanocarriers and their use in the food, cosmetics, and pharmaceutical sectors are highlighted. This article suggests that biomimicry could inspire researchers to develop technologies that are less harmful to the human body by emulating natural processes. This approach challenges the notion that green science is inferior. This review presents numerous successful studies and applications of NaDESs, concluding that they represent a viable and promising avenue for research in the field of green chemistry.

Structural characterization and stability of glycated bovine serum albumin-kaempferol nanocomplexes

Kaempferol (Kae), a flavonoid is endowed with various functions. However, due to its poor water solubility and stability, its application in the food and pharmaceutical fields remains elusive. Emerging reports have emphasized the importance of bovine serum albumin (BSA), and glycosylated BSA (GBSA) prepared in the nature deep eutectic solvent system as drug delivery system carriers. In our study, ultraviolet and fluorescence spectra revealed the higher interactions of BSA and GBSA with Kae. Through analysis of Z-average diameter, zeta-potential, polydispersity index (PDI), encapsulation efficiency (EE), loading capacity (LC) of BSA-Kae nanocomplexes (NPs) and GBSA-Kae NPs, GBSA-Kae NPs showed a higher absolute value of zeta-potential and lower PDI, while its EE and LC were also higher. Structural characterization and stability analysis revealed that GBSA-Kae NPs had more stable properties. This study laid the theoretical foundation for improving the solubility and stability of Kae during its delivery and transport.

Fabrication of glycated yeast cell protein via Maillard reaction for delivery of curcumin: improved environmental stability, antioxidant activity, and bioaccessibility

BACKGROUND

The application of curcumin (CUR) in the food industry is limited by its instability, hydrophobicity and low bioavailability. Yeast cell protein (YCP) is a by-product of spent brewer's yeast, which has the potential to deliver bioactive substances. However, the environmental stresses such as pH, salt and heat treatment has restricted its application in the food industry. Maillard reaction as a non-enzymatic browning reaction can improve protein stability under environmental stress.

RESULTS

The CUR was successfully encapsulated into the hydrophobic core of YCP/glycated YCP (GYCP) and enhanced by hydrogen bonding, resulting in static fluorescence quenching of YCP/GYCP. The average diameter and dispersibility of GYPC-CUR nanocomplex were significantly improved after glucose glycation (121.40 nm versus 139.70 nm). Moreover, the encapsulation capacity of CUR was not influenced by glucose glycation. The oxidative stability and bioaccessibility of CUR in nanocomplexes were increased compared with free CUR, especially complexed with GYCP conjugates.

CONCLUSION

Steric hindrance provided by glucose conjugation improved the enviriomental stability, oxidative activity and bioaccessibility of CUR in nanocomplexes. Thus, glucose-glycated YCP has potential application as a delivery carrier for hydrophobic compounds in functional foods. © 2022 Society of Chemical Industry.

Characteristics and antioxidant properties of Harpadon nehereus protein hydrolysate-xylose conjugates obtained from the Maillard reaction by ultrasound-assisted wet heating in a natural deep eutectic solvents system

BACKGROUND

Harpadon nehereus is a high-protein marine fish. A valuable way to add value to H. nehereus is to convert it into protein hydrolysate. The Maillard reaction is an effective way to improve the functional properties of peptides and proteins, which are affected by many factors such as reactant concentration, water activity, pH, temperature, and heating time. However, the traditional Maillard reaction method is inefficient. The purpose of this study was therefore to explore the effect of the ultrasound-assisted wet heating method on the Maillard reaction of H. nehereus protein hydrolysate (HNPH) in a new-type green solvent - a natural hypereutectic solvent (NADES).

RESULTS

Harpadon nehereus protein hydrolysate-xylose (Xy) conjugates were prepared via a Maillard reaction in a NADES system using an ultrasound-assisted wet heating method. The effects of different treatment conditions on the Maillard reaction were studied. The optimized glycation degree (DG) of HNPH-Xy conjugates was obtained with a water content of 10%, a reaction temperature of 80 °C, a reaction time of 35 min, and an ultrasonic power level of 300 W. Compared with HNPH, the structure of HNPH-Xy conjugates were significantly changed. Moreover, the functional properties and antioxidant activity of HNPH-Xy were all superior to the HNPH.

CONCLUSIONS

An ultrasound-assisted wet-heating Maillard reaction between HNPH and Xy in the NADES system could be a promising way to improve the functional properties of HNPH. © 2023 Society of Chemical Industry.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2019-2020

This review is the tenth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2020. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. The review is basically divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of arrays. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other areas such as medicine, industrial processes and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. The reported work shows increasing use of incorporation of new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented nearly 40 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show little sign of diminishing.

An Overview on the Recent Advances in Alternative Solvents as Stabilizers of Proteins and Enzymes

Currently, the use of alternative solvents is increasing, namely ionic liquids (ILs) and deep eutectic solvents (DESs) in diverse fields of knowledge, such as biochemistry, chemistry, chemical engineering, biotechnology and biomedicine. Particularly, when compared to traditional solvents, these alternative solvents have great importance for biomolecules due to the enhanced solubility, structure stability and the biological activity of biomolecules, such as protein and enzymes. Thus, in this review article, the recent developments and efforts on the technological developments carried out with ILs and DESs for the stabilization and activation of proteins and enzymes are provided. The most studied IL- and DES-based formulations for proteins and enzymes are discussed and the molecular mechanisms and interactions related to the increased stability promoted by these alternative solvents are disclosed, while emphasizing their main advantages.

Comparison of globular albumin methacryloyl and random-coil gelatin methacryloyl: Preparation, hydrogel properties, cell behaviors, and mineralization

Bovine serum albumin methacryloyl (BSAMA) is a newly emerging photocurable globular protein-based material whereas gelatin methacryloyl (GelMA) is one of the most popular photocurable fibrous protein-based materials. So far, the influence of their different structural conformations as building blocks on hydrogel properties and mineral deposition has not been investigated. Here, we compared their differences in structures, gelation kinetics, hydrogel properties, mineralization, and cell behaviors. BSAMA maintained a stable globular structure while GelMA exhibited temperature-sensitive conformations (4 - 37 °C). BSAMA displayed slower gelation kinetics and much more retarded enzymatic degradation compared to GelMA. Photocurable BSAMA (6.41 - 390.95 kPa) and GelMA hydrogels (36.09 - 199.70 kPa) exhibited tunable mechanical properties depending on their concentrations (10 - 20%). Interestingly, BSAMA hydrogels mineralized needle-like apatite (Ca/P: 1.409) with higher crystallinity compared to GelMA hydrogels (Ca/P: 1.344). BSAMA and GelMA supported satisfactory cell (MC3T3-L1) viability of 99.43 ± 0.57% and 97.14 ± 0.69%, respectively. However, BSAMA gels were less favorable to cell proliferation and migration than GelMA gels. In serum-free environments, cells on GelMA displayed a higher amount of attachment, a more elongated shape, and a longer protrusion compared to those on BSAMA (p < 0.01) during the early adhesion.

Effects of Baicalein and Chrysin on the Structure and Functional Properties of β-Lactoglobulin

Two flavonoids with similar structures, baicalein (Bai) and chrysin (Chr), were selected to investigate the interactions with β-lactoglobulin (BLG) and the influences on the structure and functional properties of BLG by multispectral methods combined with molecular docking and dynamic (MD) simulation techniques. The results of fluorescence quenching suggested that both Bai and Chr interacted with BLG to form complexes with the binding constant of the magnitude of 10⁵ L·mol⁻¹. The binding affinity between BLG and Bai was stronger than that of Chr due to more hydrogen bond formation in Bai–BLG binding. The existence of Bai or Chr induced a looser conformation of BLG, but Chr had a greater effect on the secondary structure of BLG. The surface hydrophobicity and free sulfhydryl group content of BLG lessened due to the presence of the two flavonoids. Molecular docking was performed at the binding site of Bai or Chr located in the surface of BLG, and hydrophobic interaction and hydrogen bond actuated the formation of the Bai/Chr–BLG complex. Molecular dynamics simulation verified that the combination of Chr and BLG decreased the stability of BLG, while Bai had little effect on it. Moreover, the foaming properties of BLG got better in the presence of the two flavonoids compounds and Bai improved its emulsification stability of the protein, but Chr had the opposite effect. This work provides a new idea for the development of novel dietary supplements using functional proteins as flavonoid delivery vectors.

Effect of carbohydrate type on the structural and functional properties of Maillard-reacted black bean protein

Protein from black beans (Phaseolus vulgaris L.) has good solubility, emulsification, and antioxidant properties, with significant potential applications in the food industry. Maillard-reaction-mediated dry-heat glycosylation is a relatively safe modification method to improve the functional properties of black bean protein (BBP). Here, Maillard-reacted conjugates were prepared by applying 24-h dry-heating to induce a reaction between BBP and one of three carbohydrates (dextran, chitosan, and sodium alginate) at 70°C and 79% relative humidity. The resulting Maillard conjugates were designated as BBP-Dex, BBP-Ch, and BBP-SA, respectively. The formation of each Maillard conjugate was characterized by analyzing the grafting degree, free sulfhydryl (SH) groups content, and surface hydrophobicity, as well as the results of Fourier-transform infrared (FTIR) spectroscopy and fluorescence spectroscopy. The FTIR and fluorescence spectroscopy results provided information on the formation of the Maillard conjugates. The BBP-SA conjugate had a higher grafting degree and SH group content than the other two conjugates. The solubility, emulsifying properties, and antioxidant properties of the BBP were significantly improved after the Maillard reaction (p < 0.05). Moreover, the physicochemical and functional properties of the conjugates were superior to those of the BBP-carbohydrate mixtures, indicating that covalent interactions may be stronger than noncovalent interactions. This study provides theoretical guidance for future research on protein-carbohydrate conjugates. PRACTICAL APPLICATION: This study has great potential applications in the development of new multi-functional food ingredients and the realization of functional factor homeostasis, and provides scientific and theoretical bases for the application of protein-carbohydrate conjugate in the field of functional food.

Surface functionalized inorganic phosphor by grafting organic antenna for long term preservation of latent fingerprints and data-security applications

Creative advancements are enormously sought for the advanced forensic and data security in modern era. Herein, fabrication of Bovine Serum Albumin (BSA) functionalized Gd₂O₃:Eu³⁺ (5 mol %) nanopowders dispersed in a poly(vinyl alcohol) (PVA) matrix for long term preservation and visualization of latent fingerprints, as well as printing. Efficient intramolecular energy transfers from coordinated ligand to the doped Eu³⁺ ions, called the antenna effect was precisely organized by grafting organic molecule, resultant to an enhanced photoluminescence emission. On this basis, the masking of PVA/Gd₂O₃:Eu³⁺ (5 mol %)@BSA solution on a latent fingerprints results a flexible transparent film; a highly stable fingerprint images with well-defined ridge characteristics was developed on the film, which enabling personal individualization. Interestingly, the followed latent fingerprints development technique was non-destructive and stored long duration up to 1 year on filtrating and non-filtrating surfaces. The same mechanism was also validated by utilized for application of PVA/Gd₂O₃:Eu³⁺ (5 mol %)@BSA nanocomposites in dip pen and intaglio printing. Hence, the prepared nanocomposites signify an competent method towards long preservative fingerprints as well as great performance for data security operations. This work endorses a prospective paradigm for luminescence enhancement and its applications in advanced forensic science.

Nanocomplexes of curcumin and glycated bovine serum albumin: The formation mechanism and effect of glycation on their physicochemical properties

Bovine serum albumin (BSA) and BSA-glucose conjugates (GBSAⅠ and GBSAⅠI) with different extent of glycation were complexed with curcumin (CUR). The formation mechanism of BSA/GBSA-CUR complexes and the effect of glycation on their physicochemical properties were investigated. Fluorescence quenching and FTIR analysis indicated that the BSA/GBSA-CUR nanocomplexes were formed mainly by hydrophobic interactions. XRD analysis demonstrated that CUR was present in an amorphous state in the nanocomplexes. BSA with a greater extent of glycation (BSA < GBSAⅠ<GBSAⅠI) displayed a higher binding affinity for CUR. The highest CUR encapsulation efficiency (86.77%) and loading capacity (7.81 mg/g) were obtained in the GBSAⅠI-CUR nanocomplex. The zeta-potential varied from -17.45 to -27.65 mV, depending on the extent of glycation. Furthermore, the physicochemical stability of BSA/GBSA-CUR nanocomplexes increased with the increasing extent of glycation of BSA. Thus, the obtained GBSAⅠI have the potential to become new delivery carriers for encapsulating hydrophobic food components.

Optimization and Development of Albumin-Biopolymer Bioconjugates with Solubility-Improving Properties

Bioconjugation is an emerging field in the food and pharmaceutical industry. Due to its biocompatibility and high ligand binding capacity, albumin is widely used in modern drug delivery systems. However, the protein is sensitive to environmental stresses; albumin conjugates, on the other hand, have improved functional properties. Biopolymers are gaining interest due to their biodegradability and safety, compared to synthetic polymers. In this study, albumin–biopolymer bioconjugates were prepared by nonenzymatic Maillard reaction at 60 °C and 80% relative humidity. This nonenzymatic conjugation takes place between reducing sugars and available amino groups of a protein in certain conditions. The optimal molar ratio and time for the conjugation were studied by several investigation methods, including circular dichroism and fluorescence spectroscopy, sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), and determination of available amino groups with ortho-phthaldialdehyde (OPA) assay. All of the measurements provided evidence for the covalent bonding of albumin and biopolymers, resulting in bioconjugates. Based on the results, a higher molar ratio and longer time are necessary to complete the reaction with the available amino groups. However, the optimal parameters are specific to each given biopolymer. The rheological behavior of the conjugates is characteristic of the initial biopolymer, which can be useful in drug development. Moreover, both the physical characteristics of albumin and the solubility-improving capacity were enhanced. Therefore, the potential use of albumin–biopolymer bioconjugates in the pharmaceutical industry could be considered.

Highly Efficient Deamidation of Wheat Gluten by Glucose-Citric Acid-Based Natural Deep Eutectic Solvent: A Potential Effective Reaction Media

An efficient technique using citric acid and glucose based natural deep eutectic solvent (G-C-NADES) was developed to obtain ultrahigh deamidated wheat gluten (UDWG) (deamidation degree (DD) > 90%). FTIR and ¹H NMR indicated intensive hydrogen bonds (HBs) in G-C-NADES supermolecules. Quantum chemical calculations and molecular dynamic simulations demonstrated that 10 wt % diluted G-C-NADES still had a myriad of HBs. Physicochemical results showed UDWG had DD up to 92.45% after G-C-NADES deamidation, that is, 22% higher than citric-acid-DWG with a weak degree of hydrolysis (1.75%). Conformational characterization demonstrated the obvious conversion from α-helix to β-sheet via FTIR, the least amount of disulfide bonds by Raman spectra, and more exposure of tryptophan residues by fluorescence measurement for UDWG. It is proven that enhanced accessible conformation of WG reached with HBs of G-C-NADESs could contribute to the improvement on nucleophilic attack of deamidation, declaring that G-C-NADES might be a potential solvent for obtaining an ultrahigh deamidation for WG to successfully guarantee the safety of wheat gluten based cereal food regarding to lowering its allergy.

Fucoxanthin activities motivate its nano/micro-encapsulation for food or nutraceutical application: a review

Fucoxanthin is a xanthophyll carotenoid abundant in marine brown algae. The potential therapeutic effects of fucoxanthin on tumor intervention have been well documented, which have aroused great interests in utilizing fucoxanthin in functional foods and nutraceuticals. However, the utilization of fucoxanthin as a nutraceutical in food and nutrient supplements is currently limited due to its low water solubility, poor stability, and limited bioaccessibility. Nano/micro-encapsulation is a technology that can overcome these challenges. A systematic review on the recent progresses in nano/micro-delivery systems to encapsulate fucoxanthin in foods or nutraceuticals is warranted. This article starts with a brief introduction of fucoxanthin and the challenges of oral delivery of fucoxanthin. Nano/micro-encapsulation technology is then covered, including materials and strategies for constructing the delivery system. Finally, future prospective has been discussed on properly designed oral delivery systems of fucoxanthin for managing cancer. Natural edible materials such as whey protein, casein, zein, gelatin, and starch have been successfully utilized to fabricate lipid-based, gel-based, or emulsion-based delivery systems, molecular nanocomplexes, and biopolymer nanoparticles with the aid of advanced processing techniques, such as freeze-drying, high pressure homogenization, sonication, anti-solvent precipitation, coacervation, ion crosslinking, ionic gelation, emulsification, and enzymatic conjugation. These formulated nano/micro-capsules have proven to be effective in stabilizing and enhancing the bioaccessibility of fucoxanthin. This review will inspire a surge of multidisciplinary research in a broader community of foods and motivate material scientists and researchers to focus on nano/micro-encapsulated fucoxanthin in order to facilitate the commercialization of orally-deliverable tumor intervention products.