Insights into the fabrication and antibacterial effect of fibrinogen hydrolysate-carrageenan loading apigenin and quercetin composite hydrogels.

Escherichia coli and Staphylococcus aureus are the most prevalent pathogenic bacteria, often resulting in the foodborne disease outbreaks through food spoilage and foodborne infections. To prevent and control food spoilage and foodborne infections induced by Escherichia coli and Staphylococcus aureus, the antibacterial hydrogels were fabricated using fibrinogen hydrolysate-carrageenan (AHs-C) and flavonoids (apigenin and quercetin), and the antibacterial effect of the composite hydrogels against Escherichia coli and Staphylococcus aureus was further investigated. The results of mechanical property exhibited that the composite hydrogels with 0.2 % of apigenin and quercetin (AHs-C-Ap/Que) showed the highest hardness and swelling property compared with the separate addition of apigenin or quercetin. Scanning electron microscopy and atomic force microscopy showed that the dense networks were formed in the hydrogels of AHs-C-Ap/Que., and the average roughness of AHs-C-Ap/Que. significantly increased to 30.70 nm compared with AHs-C. 1H NMR and FTIR spectra demonstrated that apigenin and quercetin were bound to AHs-C by hydrogen bond, hydrophobic interaction and Schiff base, where the interactions between Ap/Que. and AHs-C was stronger compared with the separate addition of apigenin or quercetin. The hydrogels of AHs-C-Ap/Que. showed the highest antibacterial capacity and antibacterial adhesion against Escherichia coli and Staphylococcus aureus. The antibacterial adhesion assay showed that 99 % removal ratios for E. coli and S. aureus were observed in AHs-C-Ap/Que. hydrogels, which showed a great potential to prevent food spoilage and foodborne infections.

Contribution of ultrasound-assisted protein structural changes in marinated beef to the improved binding ability of spices and flavor enhancement.

BACKGROUND: Marination is an important part of air-dried beef processing, and traditional methods are inefficient and produce inconsistent results. Ultrasound, as a novel technology, can be combined with traditional marination methods. The study aimed to investigate the improvement of beef flavor by ultrasound-assisted marination. At the same time, the potential relationship between the alteration of meat protein and flavor quality by ultrasound-assisted marinating was further investigated to enable better flavor modulation and research. RESULTS: Headspace solid-phase microextraction-gas chromatography-mass spectrometry revealed that the spice flavor of beef was significantly enhanced by 500 W ultrasound-assisted marination. Meanwhile, the experimental results demonstrated that the ultrasound-assisted marination promoted the unfolding of beef myofibrillar protein structure, which increased the number of hydrophobic and hydrogen bonding sites, enhanced the electrostatic effect and improved the functional properties of the protein. Ultrasound-assisted marination significantly enhanced the binding ability of beef myofibrillar proteins to flavor compounds compared with conventional marination. An electronic nose confirmed that this resulted in a significant increase in the flavor of the marinated meat. CONCLUSION: Ultrasound-assisted marination effectively enhanced the flavor of marinated meat, which was closely related to the development of protein conformation. The results of this study have important implications for the food industry and the role of protein unfolding processes in flavor modulation. In particular, the findings can be practically applied to improving meat flavor under ultrasound-assisted marination. © 2024 Society of Chemical Industry.

Goose liver protein emulsion with enhanced interfacial stabilization by facile core-shell curcumin complexation.

The role of facile curcumin dispersion and its hydrophobic complexation onto GLP, in the form of shell (GLPC-E), core (GLPE-C) and with synergy (GLP-ECE), on the protein interfacial and emulsion stabilization was investigated. Turbiscan instability index, microrheological elasticity, viscosity and solid-liquid balance values showed that the O/W emulsion stability was in the order of GLP-E < GLPC-E < GLPE-C < GLP-ECE. GLP-ECE also gave the most reduced D [4, 3] (8.11 ± 0.14 µm) with lowest indexes of flocculation (2.80 ± 0.05 %) and coalescence (2.83 ± 0.10 %) at day 5. Interfacial shear rheology suggested the GLP-curcumin complexation fortified the GLP interfacial gelling and then the efficiency as steric stabilizer, especially of core-shell complexation (14.2 mN/m) that showed the most sufficient in-plane protein interaction against strain. Dilatational elasticity and desorption observation revealed the synergistic curcumin complexation facilitated GLP unfolding and macromolecular association at O/W interface, as was also verified from SEM image and surface hydrophobicity (from 36.23 to 76.04). Overall, this study firstly reported the facile curcumin bi-physic dispersion and GLP complexation in improving the emulsion stabilizing efficiency of the protein by advancing its interfacial stabilization.

Unlocking the molecular modifications of plasma-activated water-induced oxidation through redox proteomics: In the case of duck myofibrillar protein (Anas platyrhynchos).

Plasma-activated water (PAW) contains multiple active species that alter the structure of myofibrillar protein (MP) to enhance their gel properties. This work investigated the impact of PAW on the oxidation of cysteine in MP by label-free quantitative proteomics. PAW treatment caused the oxidation of 8241 cysteine sites on 2815 proteins, and structural proteins such as nebulin, myosin XVIIIB, myosin XVIIIA, and myosin heavy chain were susceptible to oxidation by PAW. Bioinformatics analysis, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, subcellular localization, and STRING analysis, indicated that these proteins with differential oxidation sites were mainly derived from the cytoplasm and membrane, and were involved in multiple GO terms and KEGG pathways. This is one of the first reports of the redox proteomic changes induced by PAW treatment, and the results are useful for understanding the possible mechanism of PAW-induced oxidation of MP.

Novel aptasensor based on polyaniline functionalized carboxylated dobby carbon nanotubes and molybdenum disulfide for endotoxin detection.

Endotoxins, also known as lipopolysaccharides (LPS), are present within the cell walls of Gram-negative bacteria and are released upon cellular death, which can pose a significant risk to human and animal health. Due to the minimal amount of endotoxin required to trigger an inflammatory response in human body, the demand for sensitive methods with low endotoxin detection limits is essential necessary. This paper presents a straightforward aptamer sensor which can enhance the conductivity and specific surface area of molybdenum disulfide (MoS2) by incorporating carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) and polyaniline (PANI). Doping with gold nanoparticles (AuNPs) improves biocompatibility and sensitivity while providing binding sites for thiolated endotoxin-binding aptamers (LBA). This biosensor achieved a remarkable detection limit as low as 0.5 fg mL-1, enabling trace-level identification of LPS. It also exhibits excellent repeatability, selectivity, and stability, facilitating rapid and accurate LPS detection. Moreover, this method demonstrates high recovery rates and specificity for LPS analysis in food samples, showcasing its promising application prospects in trace-level LPS detection within the food industry.

Solanum aculeatissimum and Solanum torvum chloroplast genome sequences: a comparative analysis with other Solanum chloroplast genomes.

BACKGROUND: Solanum aculeatissimum and Solanum torvum belong to the Solanum species, and they are essential plants known for their high resistance to diseases and adverse conditions. They are frequently used as rootstocks for grafting and are often crossbred with other Solanum species to leverage their resistance traits. However, the phylogenetic relationship between S. aculeatissimum and S. torvum within the Solanum genus remains unclear. Therefore, this paper aims to sequence the complete chloroplast genomes of S. aculeatissimum and S. torvum and analyze them in comparison with 29 other previously published chloroplast genomes of Solanum species. RESULTS: We observed that the chloroplast genomes of S. aculeatissimum and S. torvum possess typical tetrameric structures, consisting of one Large Single Copy (LSC) region, two reverse-symmetric Inverted Repeats (IRs), and one Small Single Copy (SSC) region. The total length of these chloroplast genomes ranged from 154,942 to 156,004 bp, with minimal variation. The highest GC content was found in the IR region, while the lowest was in the SSC region. Regarding gene content, the total number of chloroplast genes and CDS genes remained relatively consistent, ranging from 128 to 134 and 83 to 91, respectively. Nevertheless, there was notable variability in the number of tRNA genes and rRNAs. Relative synonymous codon usage (RSCU) analysis revealed that both S. aculeatissimum and S. torvum preferred codons that utilized A and U bases. Analysis of the IR boundary regions indicated that contraction and expansion primarily occurred at the junction between SSC and IR regions. Nucleotide polymorphism analysis and structural variation analysis demonstrated that chloroplast variation in Solanum species mainly occurred in the LSC and SSC regions. Repeat sequence analysis revealed that A/T was the most frequent base pair in simple repeat sequences (SSR), while Palindromic and Forward repeats were more common in long sequence repeats (LSR), with Reverse and Complement repeats being less frequent. Phylogenetic analysis indicated that S. aculeatissimum and S. torvum belonged to the same meristem and were more closely related to Cultivated Eggplant. CONCLUSION: These findings enhance our comprehension of chloroplast genomes within the Solanum genus, offering valuable insights for plant classification, evolutionary studies, and potential molecular markers for species identification.

Characterization of the Effects of Low-Sodium Salt Substitution on Sensory Quality, Protein Oxidation, and Hydrolysis of Air-Dried Chicken Meat and Its Molecular Mechanisms Based on Tandem Mass Tagging-Labeled Quantitative Proteomics.

The effects of low-sodium salt mixture substitution on the sensory quality, protein oxidation, and hydrolysis of air-dried chicken and its molecular mechanisms were investigated based on tandem mass tagging (TMT) quantitative proteomics. The composite salt formulated with 1.6% KCl, 0.8% MgCl2, and 5.6% NaCl was found to improve the freshness and texture quality scores. Low-sodium salt mixture substitution significantly decreased the carbonyl content (1.52 nmol/mg), surface hydrophobicity (102.58 µg), and dimeric tyrosine content (2.69 A.U.), and significantly increased the sulfhydryl content (74.46 nmol/mg) and tryptophan fluorescence intensity, suggesting that protein oxidation was inhibited. Furthermore, low-sodium salt mixture substitution significantly increased the protein hydrolysis index (0.067), and cathepsin B and L activities (102.13 U/g and 349.25 U/g), suggesting that protein hydrolysis was facilitated. The correlation results showed that changes in the degree of protein hydrolysis and protein oxidation were closely related to sensory quality. TMT quantitative proteomics indicated that the degradation of myosin and titin as well as changes in the activities of the enzymes, CNDP2, DPP7, ABHD12B, FADH2A, and AASS, were responsible for the changes in the taste quality. In addition, CNDP2, ALDH1A1, and NMNAT1 are key enzymes that reduce protein oxidation. Overall, KCl and MgCl2 composite salt substitution is an effective method for producing low-sodium air-dried chicken.

Binary probiotic fermentation promotes signal (cyclic AMP) exchange to increases the number of viable probiotics, anthocyanins and polyphenol content, and the odor scores of wolfberry fermented beverages.

The effects and underlying molecular mechanisms of binary probiotics (Lactiplantibacillus plantarum subsp. plantarum CGMCC 1.5953 and Lacticaseibacillus casei CGMCC 1.5956) on the quality of wolfberry fermented beverages (WFB) were investigated. The results indicated that binary probiotics increased the number of probiotics, anthocyanin (89.92 ± 1.64 mg/L), polyphenol content (283.04 ± 3.81 µg/mL), and odor score (24.19) in WFB. Metabolomics found that they could enhance signal exchange (cyclic AMP) between binary probiotics and improve the utilization of citrulline, d-proline, d-glucose, and d-galactose through galactose metabolism and amino acid biosynthesis pathway to promote probiotics growth. Furthermore, HS-SPME-GC-MS and GS-IMS revealed that the improvement in flavor was mainly due to an increase in the content of the aromatic flavor substances 3-heptanol, glutaraldehyde, and 2-heptanone, and a decrease in the content of the off-flavor substances methyl isobutyl ketone-D and 2-undecanone. This is strategically important for the development of WFB with high probiotic content and unique flavor.

Living alone increases the risk of developing type 2 diabetes mellitus: A systematic review and meta-analysis based on longitudinal studies.

BACKGROUND: Living alone is a prevalent psychological issue that has been found to have significant implications for lifestyle and health status. While considerable research has been conducted to explore the relationship between living alone and the risk of developing type 2 diabetes mellitus (T2DM), the majority of studies have been cross-sectional, leaving direct correlations elusive. Therefore, this study aims to analyze data from longitudinal studies to determine whether living alone increases the risk of T2DM. METHODS: A comprehensive search was conducted in the PubMed, Cochrane, and Embase databases to identify studies examining the association between living alone and T2DM risk. The search encompassed studies published until September 2023. Pooled analysis utilized the random-effects model with inverse variance and included adjusted hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs). RESULTS: The meta-analysis comprised a total of 8 studies, which consisted of 5 prospective cohort studies and 3 retrospective cohort studies. The total population under consideration included 11,686,677 individuals without T2DM, of whom 54.3% were female. Among this population, 396,368 individuals developed T2DM. To account for heterogeneity, a random-effects model was employed. Overall, the pooled data demonstrated a significant association between living alone and an increased risk of T2DM when compared to living with others (HR 1.24, 95% CI 1.06-1.46). Subgroup analysis revealed that this risk was not statistically significant for either males (HR 1.28, 95% CI 0.93-1.76) or females (HR 1.06, 95% CI 0.84-1.33), nor in prospective cohort studies (HR 1.26, 95% CI 0.91-1.74) or retrospective cohort studies (HR 1.26, 95% CI 0.91-1.74). CONCLUSION: Individuals living alone faced a significantly higher risk of developing diabetes compared to those who did not live alone. However, no significant difference in this risk was observed between genders and study types. Further high-quality studies are necessary in the future to elucidate this causal association.

Insights into the mechanism of extracellular proteases from Penicillium on myofibrillar protein hydrolysis and volatile compound evolutions.

To investigate the mechanism of Penicillium proteases on the hydrolysis of myofibrillar protein (MP) and volatile compound evolutions, enzymatic characteristics of Penicillium proteases, hydrolysis capacities for MP, interactions between Penicillium proteases and MP, and profile changes of volatile compounds were investigated. P. aethiopicum (PA) and P. chrysogenum (PC) proteases showed the largest hydrolysis activities at pH 9.0 and 7.0, and were identified as alkaline serine protease and serine protease by LC-MS/MS, respectively. The proteases of PA and PC significantly degraded myosin and actin, and PA protease showed higher hydrolysis capacity for myosin than that of PC protease, which was confirmed by higher proteolysis index (56.06 %) and lower roughness (3.99 nm) of MP after PA treatment. Molecular docking revealed that hydrogen bond and hydrophobic interaction were the major interaction forces of Penicillium proteases with myosin and actin, and PA protease showed more binding sites with myosin compared with PC protease. The total content of free amino acids increased to 6.02-fold for PA treatment and to 5.51-fold for PC treatment after 4 h hydrolysis of MP, respectively. GC-MS showed that aromatic aldehydes and pyrazines in PA showed the largest increase compared with the control and PC during the hydrolysis of MP. Correlation analysis demonstrated that Phe, Leu and Ile were positively related with the accumulation of benzaldehyde, benzeneacetaldehyde, 2,4-dimethyl benzaldehyde and 2,5-dimethyl pyrazine.

Soy protein isolate-guar gum-goose liver oil O/W Pickering emulsions that remain stable under accelerated oxidation at high temperatures.

BACKGROUND: Goose liver oil (GLO) is a solid-liquid mixture, rich in polyunsaturated fatty acids and high in nutritional value, but poor in fluidity and easily oxidized. Therefore, oil-in-water (O/W) Pickering emulsions of three polysaccharides and soy protein isolate (SPI) with GLO were prepared to improve the stability of it. RESULTS: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier-transform infrared spectroscopy, and zeta potential revealed that the SPI and complexes with konjac glucomannan, pectin, and guar gum (GG) ranged from 17 to 75 kDa, with the site of action being the -OH stretch and the amide group, and bound by hydrogen bonding. Adding konjac glucomannan and GG significantly increased the water contact angle of the SPI to 74.1° and 59.0°, respectively. Therefore, the protein-polysaccharide complexes could enhance the emulsion stability. In addition, the O/W Pickering emulsions with GLO had near-Newtonian fluid rheological properties with a significant increase in apparent viscosity and viscoelasticity, forming a dual network structure consisting of a ductile and flexible protein network and a rigid and brittle polysaccharide network. The microstructure observation indicated that the O/W emulsions were spherical and homogeneous. The highest emulsification activity was observed for the SPI-GG-GLO emulsions, without significant delamination or flocculation and high oxidative stability after 7 days in storage. CONCLUSION: These results demonstrate that the construction of SPI-GG-GLO O/W Pickering emulsions can stabilize GLO even at high temperatures that promote oxidation. © 2023 Society of Chemical Industry.

Combined application of high-throughput sequencing and LC-MS-based lipidomics in the evaluation of microorganisms and lipidomics of restructured ham of different salted substitution.

The optimization of processed meats through salt replacement using KCl and k-lactate may reduce the risk of chronic diseases through reduction in dietary sodium. The objective of this study was to investigate the changes and relationships between microbial and lipid metabolism during the fermentation of restructured duck ham with different salt substitutions. Lactobacillus and Staphylococcus were found to be the dominant bacterial species in the 30 % KCl + 70 % NaCl (w/w) and 25 % k-lactate + 75 % NaCl (w/w). The LefSe analysis showed that different biomarkers were present in different ham groups, and the PLS-DA showed that triglycerides (GL) and glycerophospholipids (GP) were the two classes with the highest abundance. Besides, the KEGG pathway analysis revealed that glycerophospholipid metabolism and triglyceride metabolism were also the main metabolic pathways. According to the correlation study, Staphylococcus, Halomonas, and Lactobacillus were mostly linked to the important metabolic pathways in restructured ham. Our findings serve as a foundation for quality assurance and product enhancement for low-salt restructured ham.

Influence of atmospheric pressure plasma jet on the structural, functional and digestive properties of chickpea protein isolate.

Chickpea protein (CPI) is a promising dietary protein and potential substitute for soy protein in food product development due to its high protein content and low allergenicity. However, CPI possesses denser tertiary and quaternary structures and contains certain amount of anti-nutritional factors, both of which constrain its functional properties and digestibility. The objective of this study was to assess the effectiveness of atmospheric pressure plasma jets (APPJ) as a non-thermal method for enhancing the functional characteristics and digestibility of CPI. In this study, the reactive oxygen and nitrogen species generated by the APPJ treatment led to protein oxidation and increased carbonyl and di-tyrosine contents. At the same time, the secondary, tertiary and microstructural structures of CPI were changed. The solubility, water holding capacity, fat absorption capacity, emulsifying capacity and foaming capacity of CPI were significantly improved after 30 s APPJ treatment, and a higher storage modulus in rheology was observed. Additionally, it was observed that the in vitro protein digestibility (IVPD) of APPJ-treated CPI increased significantly from 44.85 ± 0.6 % to 50.2 ± 0.59 % following in vitro simulated gastric and intestinal digestion, marking a noteworthy improvement of 11.93 %. These findings indicate that APPJ processing can enhance the functional and digestive properties of CPI through structural modification and expand its potential applications within the food industry.

Genome-Wide Exploration and Expression Analysis of the CNGC Gene Family in Eggplant (Solanum melongena L.) under Cold Stress, with Functional Characterization of SmCNGC1a.

Eggplant (Solanum melongena L.) is an important economic crop, and to date, there has been no genome-wide identification and analysis of the cyclic nucleotide-gated channel (CNGC) gene family in eggplant. In this study, we identified the CNGC gene family in eggplant, and the results showed that 29 SmCNGC genes were classified into five groups, unevenly distributed across the 12 chromosomes of eggplant. The gene structure and motif analysis indicated that the SmCNGC family proteins may exhibit apparent preferences during evolution. Furthermore, our study revealed the presence of numerous light-responsive elements, hormone-responsive elements, and transcription factor binding sites in the promoter regions of SmCNGC genes, suggesting their significant role in environmental adaptability regulation. Finally, we analyzed the expression patterns of all SmCNGC genes under cold stress and found that SmCNGC1a was significantly upregulated under cold stress. Subcellular localization experiments indicated that this gene is located on the plasma membrane. Subsequently, its importance in the low-temperature response of eggplant was validated through virus-induced gene silencing (VIGS), and its protein interactome was predicted. In summary, our study provides a comprehensive understanding of the function and regulatory mechanisms of the CNGC gene family in eggplant, laying an important foundation for further research on cold adaptation in eggplant.

Phenolic structure dependent interaction onto modified goose liver protein enhanced by pH shifting: Modulations on protein interfacial and emulsifying properties.

The appropriateness of animal by-product proteins as emulsifiers is barely explored compared to their meat counterparts. This paper focused on improving interfacial and emulsifying properties of modified goose liver protein using three structurally relevant polyphenols either enhanced by pH shifting (P-catechin, P-quercetin and P-rutin) or not (catechin, quercetin and rutin). Due to its high hydrophobicity and limited steric hindrance, quercetin was more sufficient to hydrophobically interact (ΔH > 0, ΔS > 0) with MGLP than catechin and rutin. Results showed that polyphenol interactive affinity was positively correlated to surface hydrophobicity but negatively to size and aggregation extent of MGLP. Interfacial pressure and dilatational elastic modulus implied that synergistic polyphenol interaction and pH shifting favored the interfacial adsorption and macromolecular association of MGLP, particularly for P-quercetin with the values reached to 19.9 ± 2.0 mN/m and 22.9 ± 1.2 mN/m, respectively. Emulsion stabilized by P-quercetin also maintained highest physical and oxidative stabilities regarding the lowest D [4,3] (3.78 ± 0.27 µm) and creaming index (8.38 ± 0.43 %), together with highest mono- (19.51 %) and polyunsaturated fatty acid content (29.39 %) during storage. Overall, chemical structure of polyphenols may be determining in fabricating MGLP-polyphenol complexes with improved emulsion stabilization efficiency.

Genome-Wide Identification and Expression Analysis of Respiratory Burst Oxidase Homolog (RBOH) Gene Family in Eggplant (Solanum melongena L.) under Abiotic and Biotic Stress.

Respiratory burst oxidase homologs (RBOHs) are important proteins that catalyze the production of reactive oxygen species (ROS), which play important roles in growth and stress response. For a comprehensive analysis of SmRBOH genes, we conducted genome-wide identification of the SmRBOH gene family in eggplant (Solanum melongena L.) and analyzed the expression of SmRBOHs under abiotic (salt, high-temperature, and low-temperature) and biotic stress (Verticillium dahliae inoculation) by quantitative real-time PCR (qRT-PCR). The result showed that a total of eight SmRBOH members were identified from the genome database of eggplant, and they were relatively evenly distributed across seven chromosomes. The analysis of Motif and the conserved domain showed that SmRBOHs have high similarity in protein sequences and functions. Based on phylogenetics, SmRBOHs were classified into three distinct clades. Furthermore, the promoter regions of SmRBOHs were found to contain different cis-elements. Additionally, the results of the qRT-PCR demonstrated differential expression patterns of SmRBOHs in different tissues (the roots, stems, and leaves) and stress conditions. SmRBOHB, SmRBOHD, SmRBOHH1, and SmRBOHH2 showed significant upregulation (>20-fold) under at least one stress condition. Subcellular localization analysis of the above four members further confirmed that they localized on the plasma membrane. This study provides a theoretical foundation for understanding the functions of SmRBOHs in eggplant.

Characterisation, slow-release, and antibacterial properties of carboxymethyl chitosan/inulin hydrogel film loaded with novel antilisterial durancin GL.

This paper reports the development of a hydrogel film with antibacterial activity and controlled release characteristics. Carboxymethyl chitosan (CMCS) is grafted onto durancin GL and inulin via a mediated reaction between N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. Rheology tests, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy, and lap shear tests confirmed the formation of a stable chemical cross-linking and excellent adhesion hydrogel with 4 % CMCS and 8 % inulin. The CMCS/inulin hydrogel film loaded with durancin GL appears transparent and uniform. FTIR spectroscopy results reveal the interaction mode among CMCS, inulin, durancin GL, and the hydrogel film structure. Cross-linking improved thermal stability and water-vapour barrier performance. The hydrophobicity of CMCS/inulin @Durancin GL increased under a durancin GL concentration of 0.036 g/30 mL, and the release of active substances is prolonged. In-vitro antibacterial capacity and salmon preservation experiments show that the addition of durancin GL enhanced the antibacterial activity of the hydrogel film. Therefore, CMCS/inulin@Durancin GL hydrogel films can be used as fresh-keeping packaging materials in practical applications.

A Comparative Study of Binding Interactions between Proteins and Flavonoids in Angelica Keiskei: Stability, α-Glucosidase Inhibition and Interaction Mechanisms.

Flavonoids are easily destroyed and their activity lost during gastrointestinal digestion. Protein-based nanocomplexes, a delivery system that promotes nutrient stability and bioactivity, have received increasing attention in recent years. This study investigated the stability, inhibitory activity against α-glucosidase and interaction mechanisms of protein-based nanocomplexes combining whey protein isolate (WPI), soybean protein isolate (SPI) and bovine serum albumin (BSA) with flavonoids (F) from A. keiskei using spectrophotometry, fluorescence spectra and molecular docking approaches. The results show that the flavonoid content of WPI-F (23.17 ± 0.86 mg/g) was higher than those of SPI-F (19.41 ± 0.56 mg/g) and BSA-F (20.15 ± 0.62 mg/g) after simulated digestion in vitro. Furthermore, the inhibition rate of WPI-F (23.63 ± 0.02%) against α-glucosidase was also better than those of SPI-F (18.56 ± 0.02%) and BSA-F (21.62 ± 0.02%). The inhibition rate of WPI-F increased to nearly double that of F alone (12.43 ± 0.02%) (p < 0.05). Molecular docking results indicated that the protein-flavonoids (P-F) binding occurs primarily through hydrophobic forces, hydrogen bonds and ionic bonds. Thermodynamic analysis (ΔH > 0, ΔS > 0) indicated that the P-F interactions are predominantly hydrophobic forces. In addition, the absolute value of ΔG for WPI-F is greater (-30.22 ± 2.69 kJ mol-1), indicating that WPI-F releases more heat energy when synthesized and is more conducive to combination. This paper serves as a valuable reference for the stability and bioactivity of flavonoids from A. keiskei.

Effect of lentinan on gelling properties and structural changes of goose myofibrillar protein under oxidative stress.

BACKGROUND: The reduction of protein oxidation is important for maintaining the product quality of reconstituted meat. In this study, the dose-dependent effects of lentinan (LNT) on gelling properties and chemical changes in oxidatively stressed goose myofibrillar protein were investigated. RESULTS: Myofibrillar protein (MP) with 200 µmol g-1 protein LNT increased gel strength by 87.90 ± 9.26% in comparison with LNT-free myofibrillar protein after oxidation. Scanning electron microscopy analysis revealed that the gel network containing LNT was compact, with small pores and uniform distribution. The absolute value of the zeta potential reduced significantly following oxidation of LNT with 200 µmol g-1 protein at 4 °C for 12 h compared with the zeta potential without LNT, according to the laser particle size analyzer. The incorporation of LNT increased protein solubility and -SH content, inhibited carbonyl formation, enhanced α-helix content and tryptophan intrinsic fluorescence intensity, and reduced exposure of hydrophobic groups and protein aggregation. CONCLUSION: The results indicated that adding LNT to myofibrillar protein could improve gel. This is related to its protective effect on conformational changes in the oxidation system. Lentinan is therefore recommended for oxidatively stressed goose meat processing to enhance the MP gelling potential. © 2023 Society of Chemical Industry.

Enhanced Gel Properties of Duck Myofibrillar Protein by Plasma-Activated Water: Through Mild Structure Modifications.

This study assessed the gel properties and conformational changes of duck myofibrillar protein (DMP) affected by plasma-activated water (PAW) generated at various discharge times (0 s, 10 s, 20 s, 30 s, and 40 s). With the treatment of PAW-20 s, the gel strength and water-holding capacity (WHC) of DMP gels were significantly increased when compared to the control group. Throughout the heating process, dynamic rheology revealed that the PAW-treated DMP had a higher storage modulus than the control. The hydrophobic interactions between protein molecules were significantly improved by PAW, resulting in a more ordered and homogeneous gel microstructure. The increased sulfhydryl and carbonyl content in DMP indicated a higher degree of protein oxidation with PAW treatment. Additionally, the circular dichroism spectroscopy demonstrated that PAW induced α-helix and ß-turn transformed to ß-sheet in DMP. Surface hydrophobicity, fluorescence spectroscopy, and UV absorption spectroscopy suggested that PAW altered DMP's tertiary structure, although the electrophoretic pattern indicated that the primary structure of DMP was mostly unaffected. These results suggest that PAW can improve the gel properties of DMP through mild alteration in its conformation.