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1.
Food Res Int ; 188: 114453, 2024 Jul.
Article En | MEDLINE | ID: mdl-38823833

In this study, whipped cream with blends of micellar casein (MCN) and whey protein (WPI) in different ratios were prepared to investigate the role of protein interfacial behavior in determining foam properties at multiple scales, using theoretical modeling, and microscopic and macroscopic analysis. Fluid force microscopy has been used for the first time as a more realistic and direct means of analyzing interfaces properties in multiphase systems. The adsorption kinetics showed that the interfacial permeability constant of WPI (4.24 × 10-4 s-1) was significantly higher than that of the MCN (2.97 × 10-4 s-1), and the WPI interfacial layer had a higher modulus of elasticity (71.38 mN/m) than that of the MCN (47.89 mN/m). This model was validated via the mechanical analysis of the fat globules in real emulsions. The WPI-stabilized fat globule was found to have a higher Young's modulus (219.67 Pa), which contributes to the integrity of its fat globule morphology. As the ratio of MCN was increased in the sample, however, both the interfacial modulus and Young's modulus decreased. Moreover, the rate of partial coalescence was found to increase, a phenomenon that decreased the stability of the emulsion and increased the rate of aeration. The mechanical analysis also revealed a higher level of adhesion between MCN-stabilized fat globule (25.16 nN), which increased fat globule aggregation and emulsion viscosity, while improving thixotropic recovery. The synergistic effect of the blended MCN and WPI provided the highest overrun, at 194.53 %. These studies elucidate the role of the interfacial behavior of proteins in determining the quality of whipped cream and provide ideas for the application of proteins in multiphase systems.


Caseins , Micelles , Whey Proteins , Whey Proteins/chemistry , Caseins/chemistry , Emulsions/chemistry , Dairy Products , Lipid Droplets/chemistry , Adsorption , Kinetics , Permeability , Food Handling/methods , Glycolipids/chemistry , Elastic Modulus , Viscosity , Glycoproteins
2.
Se Pu ; 42(6): 564-571, 2024 Jun.
Article Zh | MEDLINE | ID: mdl-38845517

Protein phosphorylation plays an important role in cellular signaling and disease development. Advances in mass spectrometry-based proteomics have enabled qualitative and quantitative phosphorylation studies as well as in-depth biological explorations for biomarker discovery and signaling pathway analysis. However, the dynamic changes that occur during phosphorylation and the low abundance of target analytes render direct analysis difficult because mass spectral detection offers no selectivity, unlike immunoassays such as Western blot and enzyme-linked immunosorbent assay (ELISA). The present study aimed to solve one of the key problems in the specific and efficient isolation of phosphorylated peptides. A method based on a magnetic carbon nitride composite coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was developed for the enrichment and analysis of phosphopeptides with low abundance in complex samples. Magnetic carbon nitride composite was synthesized and characterized by electron microscopy, infrared spectroscopy, and X-ray diffractometry. The composite showed a well-distributed two-dimensional layered structure and functional groups with excellent paramagnetic performance. Two classical phosphoproteins, namely, α- and ß-caseins, were selected as model phosphorylated samples to assess the performance of the proposed enrichment technique. The magnetic carbon nitride composite exhibited high selectivity and sensitivity for phosphopeptide enrichment. The limit of detection was determined by MALDI-TOF-MS analysis to be 0.1 fmol. The selectivity of the method was investigated using the digest mixtures of α-casein, ß-casein, and bovine serum albumin (BSA) with different mass ratios (1∶1∶1000, 1∶1∶2000, and 1∶1∶5000). Direct analysis of the samples revealed the dominance of spectral signals from the abundant peptides in BSA. After enrichment with the magnetic carbon nitride composite, the high concentration of background proteins was washed away and only the signals of the phosphopeptides were captured. The signals from the casein proteins were clearly observed with little background noise, indicating the high selectivity of the composite material. The robustness of the method was tested by assessing the reusability of the same batch of magnetic carbon nitride materials over 20 cycles of enrichment. The composite showed nearly the same enrichment ability even after several cycles of reuse, demonstrating its potential applicability for a large number of clinical samples. Finally, the method was applied to the analysis of phosphopeptides from several commonly used phosphoprotein-containing samples, including skimmed milk digest, human serum, and human saliva; these samples are significant in the analysis of food quality, disease biomarkers, and liquid biopsies for cancer. Without enrichment, no phosphopeptide was detected because of the high abundance of nonphosphopeptide materials dominating the spectral signals obtained. After pretreatment with the developed magnetic carbon nitride composite, most of the phosphosites were identified with high selectivity and sensitivity via MALDI-TOF-MS. These results revealed the practicality of the developed approach for clinical applications. In addition, our method may potentially be employed for phosphoproteomics with real complex biological samples.


Nitriles , Phosphopeptides , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Phosphopeptides/analysis , Phosphopeptides/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Nitriles/chemistry , Caseins/chemistry , Caseins/analysis , Phosphorylation , Proteomics/methods , Magnetics
3.
Food Res Int ; 186: 114161, 2024 Jun.
Article En | MEDLINE | ID: mdl-38729685

In this article, the synthesis of antioxidant peptides in the enzymatic hydrolysis of caprine casein was analyzed at three different time points (60 min, 90 min, and 120 min) using immobilized pepsin on activated and modified carbon (AC, ACF, ACG 50, ACG 100). The immobilization assays revealed a reduction in the biocatalysts' activity compared to the free enzyme. Among the modified ones, ACG 50 exhibited greater activity and better efficiency for reuse cycles, with superior values after 60 min and 90 min. Peptide synthesis was observed under all studied conditions. Analyses (DPPH, ß-carotene/linoleic acid, FRAP) confirmed the antioxidant potential of the peptides generated by the immobilized enzyme. However, the immobilized enzyme in ACG 50 and ACG 100, combined with longer hydrolysis times, allowed the formation of peptides with an antioxidant capacity greater than or equivalent to those generated by the free enzyme, despite reduced enzymatic activity.


Antioxidants , Caseins , Enzymes, Immobilized , Glutaral , Goats , Iridoids , Pepsin A , Peptides , Antioxidants/chemistry , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/metabolism , Caseins/chemistry , Animals , Pepsin A/metabolism , Pepsin A/chemistry , Glutaral/chemistry , Peptides/chemistry , Iridoids/chemistry , Hydrolysis , Charcoal/chemistry
4.
Molecules ; 29(9)2024 May 06.
Article En | MEDLINE | ID: mdl-38731652

Bovine milk is an essential supplement due to its rich energy- and nutrient-rich qualities. Caseins constitute the vast majority of the proteins in milk. Among these, ß-casein comprises around 37% of all caseins, and it is an important type of casein with several different variants. The A1 and A2 variants of ß-casein are the most researched genotypes due to the changes in their composition. It is accepted that the A2 variant is ancestral, while a point mutation in the 67th amino acid created the A1 variant. The digestion derived of both A1 and A2 milk is BCM-7. Digestion of A2 milk in the human intestine also forms BCM-9 peptide molecule. The opioid-like characteristics of BCM-7 are highlighted for their potential triggering effect on several diseases. Most research has been focused on gastrointestinal-related diseases; however other metabolic and nervous system-based diseases are also potentially triggered. By manipulating the mechanisms of these diseases, BCM-7 can induce certain situations, such as conformational changes, reduction in protein activity, and the creation of undesired activity in the biological system. Furthermore, the genotype of casein can also play a role in bone health, such as altering fracture rates, and calcium contents can change the characteristics of dietary products. The context between opioid molecules and BCM-7 points to a potential triggering mechanism for the central nervous system and other metabolic diseases discussed.


Caseins , Endorphins , Humans , Animals , Caseins/chemistry , Caseins/metabolism , Caseins/genetics , Endorphins/chemistry , Endorphins/metabolism , Milk/chemistry , Milk/metabolism , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Peptide Fragments/genetics , Opioid Peptides/chemistry , Opioid Peptides/metabolism , Cattle
5.
Food Chem ; 452: 139473, 2024 Sep 15.
Article En | MEDLINE | ID: mdl-38723564

We had previously observed that adding pectin into milk before fermentation inhibited gelation of yogurt but did not affect the pH. Thus, this work aimed to prepare such liquid yogurt and clarify its formation mechanism. It was found that liquid yogurt was obtained in the presence of 0.10%-0.20% pectin. However, at lower or higher pectin concentrations, yogurt was gelled. Confocal laser scanning microscopy analysis demonstrated that 0.10%-0.20% pectin induced milk protein aggregating into separated particles rather than a continuous network, which explained why liquid yogurt was formed. Moreover, adding 0.10%-0.20% pectin into the casein micelle suspension induced aggregation of casein micelles at pH 6.8. After pH decreased to 4.3, casein micelles showed more aggregation but they were still separated particles, which was the same in the corresponding yogurt samples. These results suggested that pectin changed the aggregation mode of casein micelles and induced formation of liquid yogurt.


Pectins , Yogurt , Yogurt/analysis , Pectins/chemistry , Hydrogen-Ion Concentration , Milk/chemistry , Animals , Micelles , Caseins/chemistry , Fermentation , Milk Proteins/chemistry , Food Handling
6.
Compr Rev Food Sci Food Saf ; 23(3): e13370, 2024 May.
Article En | MEDLINE | ID: mdl-38783570

Glycomacropeptide (GMP) is a bioactive peptide derived from whey protein, consisting of 64 amino acids. It is a phenylalanine-free peptide, making it a beneficial dietary option for individuals dealing with phenylketonuria (PKU). PKU is an inherited metabolic disorder characterized by high levels of phenylalanine in the bloodstream, resulting from a deficiency of phenylalanine dehydrogenase in affected individuals. Consequently, patients with PKU require lifelong adherence to a low-phenylalanine diet, wherein a significant portion of their protein intake is typically sourced from a phenylalanine-free amino acid formula. GMP has several nutritional values, numerous bioactivity properties, and therapeutic effects in various inflammatory disorders. Despite all these features, the purification of GMP is an imperative requirement; however, there are no unique methods for achieving this goal. Traditionally, several methods have been used for GMP purification, such as thermal or acid treatment, alcoholic precipitation, ultrafiltration (UF), gel filtration, and membrane separation techniques. However, these methods have poor specificity, and the presence of large amounts of impurities can interfere with the analysis of GMP. More efficient and highly specific GMP purification methods need to be developed. In this review, we have highlighted and summarized the current research progress on the major biological features and purification methodologies associated with GMP, as well as providing an extensive overview of the recent developments in using charged UF membranes for GMP purification and the influential factors.


Caseins , Caseins/chemistry , Peptide Fragments/analysis , Peptide Fragments/chemistry , Humans , Phenylketonurias
7.
J Phys Chem Lett ; 15(20): 5543-5548, 2024 May 23.
Article En | MEDLINE | ID: mdl-38752860

Protein dynamics display distinct traits that are linked to their specific biological function. However, the interplay between intrinsic dynamics and the molecular environment on protein stability remains poorly understood. In this study, we investigate, by incoherent neutron scattering, the subnanosecond time scale dynamics of three model proteins: the mesophilic lysozyme, the thermophilic thermolysin, and the intrinsically disordered ß-casein. Moreover, we address the influence of water, glycerol, and glucose, which create progressively more viscous matrices around the protein surface. By comparing the protein thermal fluctuations, we find that the internal dynamics of thermolysin are less affected by the environment compared to lysozyme and ß-casein. We ascribe this behavior to the protein dynamic personality, i.e., to the stiffer dynamics of the thermophilic protein that contrasts the influence of the environment. Remarkably, lysozyme and thermolysin in all molecular environments reach a critical common flexibility when approaching the calorimetric melting temperature.


Caseins , Muramidase , Thermolysin , Muramidase/chemistry , Muramidase/metabolism , Thermolysin/chemistry , Thermolysin/metabolism , Caseins/chemistry , Glycerol/chemistry , Water/chemistry , Glucose/chemistry , Neutron Diffraction , Molecular Dynamics Simulation
8.
J Agric Food Chem ; 72(20): 11515-11530, 2024 May 22.
Article En | MEDLINE | ID: mdl-38726599

Chronic stress is a major inducer of anxiety and insomnia. Milk casein has been studied for its stress-relieving effects. We previously prepared a casein hydrolysate (CP) rich in the sleep-enhancing peptide YPVEPF, and this study aims to systemically investigate the different protective effects of CP and casein on dysfunction and anxiety/insomnia behavior and its underlying mechanisms in chronically stressed mice. Behavioral results showed that CP ameliorated stress-induced insomnia and anxiety more effectively than milk casein, and this difference in amelioration was highly correlated with an increase in GABA, 5-HT, GABAA, 5-HT1A receptors, and BDNF and a decrease in IL-6 and NMDA receptors in stressed mice. Furthermore, CP restored these dysfunctions in the brain and colon by activating the HPA response, modulating the ERK/CREB-BDNF-TrκB signaling pathway, and alleviating inflammation. The abundant YPVEPF (1.20 ± 0.04%) and Tyr-based/Trp-containing peptides of CP may be the key reasons for its different effects compared to casein. Thus, this work revealed the main active structures of CP and provided a novel dietary intervention strategy for the prevention and treatment of chronic-stress-induced dysfunction and anxiety/insomnia behaviors.


Anxiety , Brain , Caseins , Sleep Initiation and Maintenance Disorders , Animals , Caseins/chemistry , Caseins/administration & dosage , Mice , Anxiety/prevention & control , Male , Brain/metabolism , Brain/drug effects , Sleep Initiation and Maintenance Disorders/drug therapy , Sleep Initiation and Maintenance Disorders/metabolism , Sleep Initiation and Maintenance Disorders/physiopathology , Sleep Initiation and Maintenance Disorders/prevention & control , Humans , Behavior, Animal/drug effects , Brain-Derived Neurotrophic Factor/metabolism , Brain-Derived Neurotrophic Factor/genetics , Stress, Psychological , Protective Agents/administration & dosage , Protective Agents/pharmacology , Protective Agents/chemistry
9.
Int J Biol Macromol ; 269(Pt 1): 132047, 2024 Jun.
Article En | MEDLINE | ID: mdl-38702008

In our study, we developed a novel nanobiocomposite using graphene oxide (GO), casein (Cas), ZnAl layered double hydroxide (LDH), sodium alginate (Alg), and Fe3O4 magnetic nanoparticles. To synthesize the GO, we used a modified Hummer's method and then covalently functionalized its surface with Cas protein. The functionalized GO was combined with as-synthesized ZnAl LDH, and the composite was conjugated with alginate hydrogel through the gelation process. Finally, we magnetized the nanobiocomposite using in-situ magnetization. The nanobiocomposite was comprehensively characterized using FT-IR, FE-SEM, EDX, and XRD. Its biological potential was assessed through cell viability, hemolysis, and anti-biofilm assays, as well as its application in hyperthermia. The MTT assay showed high cell viability percentages for Hu02 cells after 24, 48, and 72 h of incubation. The nanobiocomposite had a hemolytic effect lower than 3.84 %, and the measured bacterial growth inhibition percentages of E. coli and S. aureus bacteria in the presence of the nanobiocomposite were 52.18 % and 55.72 %, respectively. At a concentration of 1 mg.mL-1 and a frequency of 400 kHz, the nanocomposite exhibits a remarkable specific absorption rate (SAR) of 67.04 W.g-1, showcasing its promising prospects in hyperthermia applications.


Alginates , Caseins , Graphite , Hydrogels , Hydroxides , Magnetite Nanoparticles , Graphite/chemistry , Graphite/pharmacology , Alginates/chemistry , Caseins/chemistry , Hydrogels/chemistry , Hydrogels/pharmacology , Hydroxides/chemistry , Magnetite Nanoparticles/chemistry , Humans , Nanocomposites/chemistry , Cell Survival/drug effects , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Escherichia coli/drug effects , Escherichia coli/growth & development , Hemolysis/drug effects , Staphylococcus aureus/drug effects , Zinc/chemistry , Zinc/pharmacology , Biofilms/drug effects
10.
Int J Biol Macromol ; 269(Pt 1): 132107, 2024 Jun.
Article En | MEDLINE | ID: mdl-38710246

Soft assembly of peptide and curcumin (Cur) molecules enables functional integration by finding dynamic equilibrium states through non-covalent interactions. Herein, we developed two soft assembly systems, curcumin-egg white peptides (Cur-EWP) aggregations (AGs) and Cur-EWP-casein-quaternary chitosan (Cur-EWP-CA-QC) nanoparticles (NPs) to comparatively investigate their therapeutic effects on ulcerative colitis in mice and elucidate their underlying mechanism. Results revealed that Cur-EWP AGs, despite gastrointestinal tract instability, exhibited a propensity for swift accumulation within the colorectal region, enriching mucus-associated and short-chain fatty acid (SCAF)-producing bacteria, restoring the intestinal barrier damage. Whereas, Cur-EWP-CA-QC NPs, benefiting from their remarkable stability and exceptional mucosal adsorption properties, not only enhanced permeability of Cur and EWP in the small intestine to activate the immune response and boost tight junction protein expression but also, in their unabsorbed state, regulated the intestinal flora, exerting potent anti-inflammatory activity. Soft assembly of peptides and hydrophobic nutraceuticals could synergize biological activities to modulate chronic diseases.


Caseins , Chitosan , Colitis, Ulcerative , Curcumin , Curcumin/pharmacology , Curcumin/chemistry , Chitosan/chemistry , Chitosan/pharmacology , Colitis, Ulcerative/drug therapy , Colitis, Ulcerative/metabolism , Animals , Mice , Caseins/chemistry , Caseins/pharmacology , Nanoparticles/chemistry , Peptides/pharmacology , Peptides/chemistry , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/chemistry , Male , Gastrointestinal Microbiome/drug effects , Egg White/chemistry , Intestinal Mucosa/metabolism , Intestinal Mucosa/drug effects
11.
J Agric Food Chem ; 72(22): 12719-12724, 2024 Jun 05.
Article En | MEDLINE | ID: mdl-38789103

Lactononadecapeptide (LNDP; NIPPLTQTPVVVPPFLQPE), a casein-derived peptide comprising 19 residues, is known for its capacity to enhance cognitive function. This study aimed to explore the transepithelial transport and stability of LNDP. Results showed that LNDP retained over 90% stability after 2 h of treatment with gastrointestinal enzymes. The stability of LNDP on Caco-2 cell monolayers ranged from 93.4% ± 0.9% to 101.1% ± 1.2% over a period of 15-60 min, with no significant differences at each time point. The permeability of LNDP across an artificial lipid membrane was very low with the effective permeability of 3.6 × 10-11 cm/s. The Caco-2 assay demonstrated that LNDP could traverse the intestinal epithelium, with an apparent permeability of 1.22 × 10-6 cm/s. Its transport was significantly inhibited to 67.9% ± 5.0% of the control by Gly-Pro, a competitor of peptide transporter 1 (PEPT1). Furthermore, PEPT1 knockdown using siRNA significantly inhibited LNDP transport by 77.6% ± 1.9% in Caco-2 cell monolayers. The LNDP uptake in PEPT1-expressing HEK293 cells was significantly higher (54.5% ± 14.6%) than that in mock cells. These findings suggest that PEPT1 plays a crucial role in LNDP transport, and LNDP exhibits good resistance to gastrointestinal enzymes.


Caseins , Humans , Caco-2 Cells , Biological Transport , Caseins/metabolism , Caseins/chemistry , Caseins/genetics , Peptide Transporter 1/genetics , Peptide Transporter 1/metabolism , Intestinal Mucosa/metabolism , Enzyme Stability , Peptides/chemistry , Peptides/metabolism
12.
Langmuir ; 40(22): 11516-11525, 2024 Jun 04.
Article En | MEDLINE | ID: mdl-38778622

Using the surface characterization techniques of quartz crystal microbalance with dissipation, atomic force microscopy, and scanning electron microscopy, the structure of the salivary pellicle was investigated before and after it was exposed to dairy proteins, including micellar casein, skim milk, whey protein isolate (WPI), and a mixture of skim milk and WPI. We have shown that the hydration, viscoelasticity, and adsorbed proteinaceous mass of a preadsorbed salivary pellicle on a PDMS surface are greatly affected by the type of dairy protein. After interaction with whey protein, the preadsorbed saliva pellicle becomes softer. However, exposure of the saliva pellicle to micellar casein causes the pellicle to partially collapse, which results in a thinner and more rigid surface layer. This structure change correlates with the measured lubrication behavior when the saliva pellicle is exposed to dairy proteins. While previous studies suggest that whey protein is the main component in milk to interact with salivary proteins, our study indicates interactions with casein are more important. The knowledge gained here provides insights into the mechanisms by which different components of dairy foods and beverages contribute to mouthfeel and texture perception, as well as influence oral hygiene.


Dental Pellicle , Salivary Proteins and Peptides , Dental Pellicle/chemistry , Dental Pellicle/metabolism , Salivary Proteins and Peptides/chemistry , Salivary Proteins and Peptides/metabolism , Adsorption , Caseins/chemistry , Caseins/metabolism , Surface Properties , Whey Proteins/chemistry , Humans , Animals , Microscopy, Atomic Force , Saliva/chemistry , Saliva/metabolism , Quartz Crystal Microbalance Techniques
13.
Food Res Int ; 187: 114432, 2024 Jul.
Article En | MEDLINE | ID: mdl-38763680

Probiotics are subjected to various edible coatings, especially proteins and polysaccharides, which serve as the predominant wall materials, with ultrasound, a sustainable green technology. Herein, sodium caseinate, inulin, and soy protein isolate composites were produced using multi-frequency ultrasound and utilized to encapsulateLactiplantibacillus plantarumto enhance its storage, thermal, and gastrointestinal viability. The physicochemical analyses revealed that the composites with 5 % soy protein isolate treated with ultrasound at 50 kHz exhibited enough repulsion forces to maintain stability, pH resistance, and the ability to encapsulate larger particles and possessed the highest encapsulation efficiency (95.95 %). The structural analyses showed changes in the composite structure at CC, CH, CO, and amino acid residual levels. Rheology, texture, and water-holding capacity demonstrated the production of soft hydrogels with mild chewing and gummy properties, carried the microcapsules without coagulation or sedimentation. Moreover, the viability attributes ofL. plantarumevinced superior encapsulation, protecting them for at least eight weeks and against heat (63 °C), reactive oxidative species (H2O2), and GI conditions.


Carboxymethylcellulose Sodium , Caseins , Hydrogels , Inulin , Probiotics , Soybean Proteins , Soybean Proteins/chemistry , Hydrogels/chemistry , Caseins/chemistry , Carboxymethylcellulose Sodium/chemistry , Inulin/chemistry , Inulin/pharmacology , Lactobacillus plantarum/metabolism , Rheology , Hydrogen-Ion Concentration , Microbial Viability , Capsules
14.
Int J Biol Macromol ; 269(Pt 2): 132212, 2024 Jun.
Article En | MEDLINE | ID: mdl-38729495

Polyphenols, polysaccharides, and proteins are essential nutrients and functional substances present in food, and when present together these components often interact with each other to influence their structure and function. Proteins and polysaccharides are also excellent carrier materials for polyphenols. In this context, this study investigated the non-covalent interactions between taxifolin (TAX), Lentinus edodes mycelia polysaccharide (LMP), and ß-casein (ß-CN). ß-CN and LMP spontaneously formed nanocomplexes by hydrogen bonds and van der Waals forces. The quenching constant and binding constant were (1.94 ± 0.02) × 1013 L mol-1 s-1 and (3.22 ± 0.17) × 105 L mol-1 at 298 K, respectively. The altered conformation of ß-CN, resulting from the binding to LMP, affected the interaction with TAX. LMP significantly enhanced the binding affinity of TAX and ß-CN, but did not change the static quenching binding mode. The binding constant for ß-CN-TAX was (3.96 ± 0.09) × 1013 L mol-1, and that for the interaction between TAX and ß-CN-LMP was (32.06 ± 0.05) × 1013 L mol-1. In summary, ß-CN-LMP nanocomplexes have great potential as a nanocarrier for polyphenols, and this study provides a theoretical foundation for the rational design of non-covalent complexes involving LMP and ß-CN, both in binary and ternary configurations.


Caseins , Quercetin , Shiitake Mushrooms , Caseins/chemistry , Quercetin/chemistry , Quercetin/analogs & derivatives , Shiitake Mushrooms/chemistry , Hydrogen Bonding , Fungal Polysaccharides/chemistry , Protein Binding
15.
Int J Biol Macromol ; 267(Pt 2): 131613, 2024 May.
Article En | MEDLINE | ID: mdl-38642686

As glycosylations are difficult to analyze, their roles and effects are poorly understood. Glycosylations in human milk (HM) differ across lactation. Glycosylations can be involved in antimicrobial activities and may serve as food for beneficial microorganisms. This study aimed to identify and analyze O-linked glycans in HM by high-throughput mass spectrometry. 184 longitudinal HM samples from 66 donors from day 3 and months 1, 2, and 3 postpartum were subjected to a post-translational modification specific enrichment-based strategy using TiO2 and ZrO2 beads for O-linked glycopeptide enrichment. ß-CN was found to be a major O-linked glycoprotein, additionally, αS1-CN, κ-CN, lactotransferrin, and albumin also contained O-linked glycans. As glycosyltransferases and glycosidases are involved in assembling the glycans including O-linked glycosylations, these were further investigated. Some glycosyltransferases and glycosidases were found to be significantly decreasing through lactation, including two O-linked glycan initiator enzymes (GLNT1 and GLNT2). Despite their decrease, the overall level of O-linked glycans remained stable in HM over lactation. Three different motifs for O-linked glycosylation were enriched in HM proteins: Gly-Xxx-Xxx-Gly-Ser/Thr, Arg-Ser/Thr and Lys-Ser/Thr. Further O-linked glycan motifs on ß-CN were observed to differ between intact proteins and endogenous peptides in HM.


Caseins , Lactation , Milk, Human , Whey Proteins , Humans , Milk, Human/chemistry , Glycosylation , Female , Caseins/metabolism , Caseins/chemistry , Lactation/metabolism , Whey Proteins/chemistry , Whey Proteins/metabolism , Polysaccharides/chemistry , Polysaccharides/metabolism , Glycopeptides/metabolism , Glycopeptides/chemistry , Protein Processing, Post-Translational
16.
J Agric Food Chem ; 72(17): 10031-10045, 2024 May 01.
Article En | MEDLINE | ID: mdl-38629959

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.


Allergens , Caseins , Mice, Inbred BALB C , Th1 Cells , Th2 Cells , Animals , Humans , Mice , Th2 Cells/immunology , Caseins/immunology , Caseins/chemistry , Th1 Cells/immunology , Allergens/immunology , Allergens/chemistry , Caco-2 Cells , Female , Glycosylation , Cattle , Homeostasis , Food Hypersensitivity/immunology
17.
Int J Biol Macromol ; 267(Pt 2): 131501, 2024 May.
Article En | MEDLINE | ID: mdl-38614170

Developing novel antimicrobial wound dressings that have the potential to address the challenges associated with chronic wounds is highly imperative in providing effective infection control and wound healing support. Biocompatible electrospun nanofibers with their high porosity and surface area enabling efficient drug loading and delivery have been investigated in this regard as viable candidates for chronic wound care. Here, we design Casein/Polyvinyl alcohol (CAN/PVA) nanofibers reinforced with silver nanoparticles (Ag NPs) by the electrospinning technique to develop diabetic wound healing scaffolds. The prepared samples were characterized using spectroscopic and electron microscopic techniques. The biocompatibility of the polymer samples were assessed using 3 T3 fibroblast cell lines and the maximum cell viability was found to 95 % at a concentration of 50 µg/mL for the prepared nanofibers. Scratch assay tests were also performed to analyze the wound healing activity of the nanofibers wherein they demonstrated increased migration and proliferation of fibroblast 3 T3 cells. Moreover, these nanofibers also exhibit antibacterial efficiency against Gram-negative bacteria, Escherichia coli (E.coli). Therefore, the antimicrobial nature of the electrospun nanofibers coupled with their moisture absorption properties and wound healing ability render them as effective materials for wound dressing applications.


Anti-Bacterial Agents , Caseins , Metal Nanoparticles , Nanofibers , Polyvinyl Alcohol , Silver , Tissue Engineering , Tissue Scaffolds , Nanofibers/chemistry , Polyvinyl Alcohol/chemistry , Silver/chemistry , Silver/pharmacology , Metal Nanoparticles/chemistry , Tissue Scaffolds/chemistry , Tissue Engineering/methods , Caseins/chemistry , Caseins/pharmacology , Animals , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Mice , Escherichia coli/drug effects , Wound Healing/drug effects , Cell Line , Cell Survival/drug effects , Fibroblasts/drug effects , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Cell Proliferation/drug effects
18.
Int J Biol Macromol ; 267(Pt 2): 131585, 2024 May.
Article En | MEDLINE | ID: mdl-38621557

Casein forms diverse structures with functionalities tunable by complexation with surfactants, and shellac is an emerging surfactant. In the present work, molecular and mesoscopic structures of shellac and micellar casein and the underlying interactions after treatment with a pH-cycle were investigated. Dispersions with 0.5 % w/v shellac and various shellac:casein mass ratios were prepared at pH 12.0 to dissolve shellac and dissociate casein micelles, followed by neutralization to pH 7.0 to form complexes. Both covalent and non-covalent (hydrogen bonding, electrostatic, and hydrophobic) interactions contributed to the complex formation. The formed complexes had an average diameter of ~80 nm. The complexation of shellac and casein prevented the precipitation of protonated shellac during neutralization, and dispersions with casein:shellac mass ratios of 2:1 and above were absent of precipitates at pH 7.0. The formed nanocomplexes may have applications for preparing novel colloidal systems and loading lipophilic bioactive compounds.


Caseins , Micelles , Caseins/chemistry , Hydrogen-Ion Concentration , Hydrophobic and Hydrophilic Interactions , Surface-Active Agents/chemistry , Static Electricity , Hydrogen Bonding , Nanoparticles/chemistry
19.
Int J Biol Macromol ; 268(Pt 2): 131516, 2024 May.
Article En | MEDLINE | ID: mdl-38621556

Simvastatin (SV) is a statin drug that can effectively control cholesterol and prevent cardiovascular diseases. However, SV is water-insoluble, and poor oral bioavailability (<5 %). Solid self-emulsifying carrier system is more stable than liquid emulsions, facilitating to improve the solubility and bioavailability of poorly soluble drugs. In the present study, a solid self-emulsifying carrier stabilized by casein (Cas-SSE) was successfully used to load SV to improve its solubility in water, by formulation selection and emulsification process optimization. Compared with oral tablets, the release of SV from Cas-SSE was significantly enhanced in artificial intestinal fluid. Furthermore, everted gut sac experiments indicated some water-soluble dispersing agents such as hydroxyethyl starch (HES), were not conducive to drug absorption. Pharmacokinetic studies suggested Cas-SSE without dispersing agent has much higher relative bioavailability (184.1 % of SV and 284.5 % of simvastatin acid) than SV tablet. The present work suggests Cas-SSE is a promising drug delivery platform with good biocompatibility for improving oral bioavailability of poorly water-soluble drugs.


Biological Availability , Caseins , Drug Carriers , Emulsions , Simvastatin , Solubility , Simvastatin/pharmacokinetics , Simvastatin/chemistry , Simvastatin/administration & dosage , Caseins/chemistry , Caseins/pharmacokinetics , Administration, Oral , Animals , Drug Carriers/chemistry , Emulsions/chemistry , Rats , Male , Drug Liberation
20.
Biopolymers ; 115(3): e23579, 2024 May.
Article En | MEDLINE | ID: mdl-38578129

In this study, a new biomaterial with polyvinyl alcohol (PVA)/sodium caseinate (SodCa)/reduced graphene oxide (rGO) structure was developed. Antibacterial effective nanofibers were successfully produced by electrospinning method from 1%, 3%, 5%, and 7% rGO added PVA/SodCa (60:40, w:w) solution mixtures prepared for use as modern wound dressings. To create a usage area, especially in exuding wounds, hydrophilic PVA/SodCa/rGO electrospun mats were cross-linked by dipping them in a glutaraldehyde (GLA) bath. The surface micrographs of all nanofibers were homogeneous and smooth. rGO-doped biomaterials were obtained as thin nanofibers in the range of 301-348 nm. Nanofibers, which were completely soluble in water, after cross-linking preserved their existence in the range of 87%-81% at the end of the 24th hour in distilled water. It was reported that these biomaterials that persist in an aqueous environment show swelling behavior in the range of 275%-608%. The porosity of uncross-linked pure PVA/SodCa nanofibers increased by 46.75% after cross-linking. Moreover, the tensile strength of cross-linked PVA/SodCa electrospun mats increased in the presence of rGO. Provided that wound dressing is done every 24 h with 3% rGO-doped PVA/SodCa nanofiber and provided that wound dressing is done every 48 h with 5% rGO-doped PVA/SodCa nanofiber showed antibacterial activity against S. aureus as 99.38% and 99.55%, respectively.


Anti-Bacterial Agents , Bandages , Caseins , Graphite , Nanofibers , Polyvinyl Alcohol , Polyvinyl Alcohol/chemistry , Graphite/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Nanofibers/chemistry , Caseins/chemistry , Tensile Strength , Staphylococcus aureus/drug effects , Cross-Linking Reagents/chemistry , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology
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