Arginine as a regulator of antioxidant and gel formation in yak Myofibrillar proteins: Efficacy and mechanistic insights.

Arginine (Arg), a safe basic amino acid, modulates interprotein interactions and impacts the processing characteristics of myofibrillar proteins (MP) in meat products, as numerous studies have demonstrated. This study aimed to explore the effects of varying concentrations of Arg (0.025, 0.050, 0.100, 0.200 %) on the physicochemical properties and gel behavior of yak MP. Utilizing yak MP as the substrate, we assessed and analyzed the physicochemical attributes and gel performance of the MP-Arg composite system. The findings revealed that Arg facilitates MP unfolding and internal group exposure, effectively mitigating oxidative tertiary structure alterations. Arg exerts potent antioxidant activity on MP, augmenting their water-holding capacity, which ameliorates gel properties. In this experiment, 0.05 % Arg maximally inhibited oxidative damage to MP, with protection being concentration-dependent. Collectively, these findings suggest that Arg effectively inhibits the oxidative degradation of MP structure and promotes the formation of enhanced gel characteristics.

Synthesis and characterization of thermosensitive 2-hydroxypropyl-trimethylammonium chitin and its antibacterial sponge for noncompressible hemostasis and tissue regeneration.

Noncompressible hemorrhage is a leading cause of preventable death in battlefield/civilian trauma. The development of novel injectable and biodegradable hemostatic sponges, with rapid shape recovery and excellent antibacterial activity that can control hemorrhage in noncompressible bleeding sites and promote in situ tissue regeneration is still urgently needed. In this study, thermo/pH sensitive 2-hydroxypropyl-trimethylammonium chitins (QCHs) with low degree of quaternization substitution (DS: 0.07-0.23) and high degree of acetylation (DA: 0.91-0.94) were synthesized homogeneously for the first time. Their chemical compositions including DS and DA were characterized accurately by proton NMR for the first time. High strength QCH based sponges with good water/blood absorbency, rapid shape recovery and good antibacterial activity were prepared without using any crosslinkers but only due to their thermosensitive property, since they are soluble at low temperature but insoluble at high temperature. Compared with commercial products, the QCH sponges with cationic groups had the stronger pro-coagulant ability, better hemostatic effect in normal/heparinized liver perforation and femoral artery models in rats and porcine subclavian arteriovenous resection model. Moreover, the porous structure and biodegradability of the QCH sponges could promote in situ tissue regeneration. Overall, the QCH sponges show great clinical translational potential for noncompressible hemorrhage and tissue regeneration.

Water soluble AIEgen-based thermosensitive and antibacterial hydroxypropyl chitin hydrogels for non-invasive visualization and wound healing.

Antimicrobial hydrogels containing antibacterial agents have been extensively studied for postoperative infections, wound repair and tissue engineering. However, the abuse of antibiotics has led to the enhancement of bacterial resistance and traditional antibacterial agents are losing their effect. Therefore, fabricating novel and efficient antibacterial hydrogels with enhanced photodynamic antimicrobial activity, good biocompatibility, biodegradability and injectability are highly desirable for clinical application. Herein, a fluorescent and sunlight-triggered synergetic antibacterial thermosensitive hydrogel (red fluorescent hydroxypropyl chitin, redFHPCH) is constructed based on a new water-soluble AIEgen (aggregation-induced emission fluorogen) covalently introduced in hydroxypropyl chitin for non-invasive visualization and wound healing. The thermosensitive redFHPCH solution showing good injectability with fluidity at low temperature was completely transformed into hydrogel under body temperature. The in vitro and in vivo visualization and reactive oxygen species (ROS) generation of the redFHPCH hydrogel are demonstrated clearly because of its excellent AIE fluorescence imaging quality in the red/near-infrared region and superefficient ROS production by sunlight. Moreover, the redFHPCH hydrogel with positively charged quaternary ammonium groups displays a strong synergistic antibacterial effect for healing of infected wound under sunlight irradiation. We believe that this novel strategy can open a new door to explore diversified and multifunctional hydrogels for clinical application.

Hemostasis-osteogenesis integrated Janus carboxymethyl chitin/hydroxyapatite porous membrane for bone defect repair.

Barrier membranes with osteogenesis are desirable for promoting bone repair. Janus membrane, which has a bilayered structure with different properties on each side, could meet the osteogenesis/barrier dual functions of guided bone regeneration. In this work, new biodegradable Janus carboxymethyl chitin membrane with asymmetric pore structure was prepared based on thermosensitive carboxymethyl chitin without using any crosslinkers. Nano-hydroxyapatites were cast on single-sided membrane. The obtained carboxymethyl chitin/nano-hydroxyapatite Janus membrane showed dual biofunctions: the dense layer of the Janus membrane could act as a barrier to prevent connective tissue cells from invading the bone defects, while the porous layer (with pore size 100-200 µm) containing nano-hydroxyapatite could guide bone regeneration. After implanted on the rat critical-sized calvarial defect 8 weeks, carboxymethyl chitin/nano-hydroxyapatite membrane showed the most newly formed bone tissue with the highest bone volume/total volume ratio (10.03 ± 1.81 %, analyzed by micro CT), which was significantly better than the commercial collagen membrane GTR® (5.05 ± 0.76 %). Meanwhile, this Janus membrane possessed good hemostatic ability. These results suggest a facile strategy to construct hemostasis-osteogenesis integrated Janus carboxymethyl chitin/hydroxyapatite membrane for guided bone regeneration.

Synthesis of controlled-size starch nanoparticles and superparamagnetic starch nanocomposites by microemulsion method.

In this study, a synthesis process based on the microemulsion method (ME) was developed with the aim to produce controlled-size starch nanoparticles (SNPs). Several formulations were tested for the preparation of the W/O microemulsions varying the organic/aqueous phase ratios and co-stabilizers concentrations. SNPs were characterized in terms of size, morphology, monodispersity and crystallinity. Spherical shape particles with mean sizes 30-40 nm were prepared. The method was then used to simultaneously synthesize SNPs and iron oxide nanoparticles with superparamagnetic properties. Starch-based nanocomposites with superparamagnetic properties and controlled size were obtained. Therefore, the microemulsion method developed could be considered an innovative technology for the design and development of novel functional nanomaterials. The starch-based nanocomposites were evaluated in terms of morphology and magnetic properties, and they are being considered as promising sustainable nanomaterials for different biomedical applications.

Effects of tetrasodium pyrophosphate coupled with soy protein isolate on the emulsion gel properties of oxidative myofibrillar protein.

The effects of protein oxidation on the emulsion gel properties of myofibrillar protein (MP) in the presence of tetrasodium pyrophosphate (TSPP) and soybean protein isolate (SPI) were investigated from the perspective of interfacial protein interactions. The results showed that the emulsifying activity and emulsion stability of MP increased by 35.2 %-181.6 % with elevated H2O2 concentrations (1-20 mM), while the gel strength and water holding capacity of MP emulsions first increased to a maximum at 5 mM H2O2 and then decreased. TSPP and SPI further reinforced the effects caused by oxidation. The emulsifying properties of MP and its emulsion gel properties were closely related to surface hydrophobicity/hydrogen bonds/hydrophobic interactions and disulfide bonds among interfacial proteins, respectively. However, these correlations became difficult to define when TSPP and SPI were introduced. The study provides a theoretical basis for the strategy development to reduce protein oxidation damage on meat product quality.

Visualization of degradation of injectable thermosensitive hydroxypropyl chitin modified by aggregation-induced emission.

The reversible thermosensitive hydroxypropyl chitin (HPCH) has been widely investigated for drug delivery, tissue engineering, wound repair and antibacterial hemostasis. To achieve non-invasive and real-time visualization of in vivo degradation of HPCH, aggregation-induced emission fluorogen (AIEgen) was introduced covalently in HPCH in water to obtain thermosensitive fluorescent hydroxypropyl chitin (FHPCH) avoiding using any organic solvent. The obtained fluorescent FHPCH hydrogel showed strong yellow-green fluorescence feature under UV irradiation, enabling visualization of the hydrogel with reversible thermosensitivity and reliable injectability. The in vitro enzymatic degradation study of FHPCH hydrogel showed that the attenuation of fluorescence intensity well matched with hydrogel weight loss. The injection through a 26-gauge needle for real-time fluorescence imaging in mice indeed indicated that AIE modified injectable thermosensitive FHPCH can be used for non-invasive, continuous and real-time visualization and quantitative analysis of in vivo degradation. This provides a new method for non-invasive real-time monitoring of similar implantable materials.

Chitosan nanomaterials: A prelim of next-generation fertilizers; existing and future prospects.

Global agriculture is urgently seeking ways to mitigate the detrimental effects of conventional chemical fertilizers on the environment. Biodegradable, eco-friendly, renewable energy-sourced next-generation fertilizers could be an answer, allowing for improved nutrient use efficiency and a lower environmental footprint. During the last decade, agricultural research on chitosan nanomaterials (NMs) has expanded, demonstrating their usefulness in enhancing agricultural output not only as plant immune boosters but also via slow, controlled and target delivery of nutrients to plants. Chitosan NMs natively act as an abundant nutrient source of C (54.4-47.9 wt%), O (42.3-30.19 wt%), N (7.6-5.8 wt%), and P (6.1-3.4 wt%) to plants. Moreover, chitosan NMs can further functionalized by more nutrients payloads through its functional groups. The current review investigates the technical features of chitosan NMs as prospective next-generation fertilizers based on rationales. The review offers crucial insights into future directions, sources, production capacity of chitosan-based next-generation nanofertilizers for industrial-scale manufacturing.

Biodegradable carboxymethyl chitin-based hemostatic sponges with high strength and shape memory for non-compressible hemorrhage.

Uncontrolled hemorrhage of deep, narrow and non-compressible perforating wounds is responsible for many trauma deaths. In this work, a novel biodegradable hemostatic sponge based on thermosensitive carboxymethyl chitin was prepared via simple cryo-regeneration process without using any crosslinkers. The collagen and polydopamine were added to further enhance mechanical and hemostatic properties of the sponge. All the carboxymethyl chitin based sponges showed high strength with excellent water/blood-triggered shape memory property, and the highest compressive fracture wet-strength could reach about 291.2 kPa, which was almost higher than those of many reported biodegradable hemostatic sponges pre-swelled in water. More importantly, the carboxymethyl chitin-collagen-polydopamine sponges displayed much better blood-clotting capacity and superior hemostasis performance than gauze and clinically used collagen sponge iRegene@ in vitro and in the rat liver perforating wound model. This study revealed a facile strategy to construct the effective carboxymethyl chitin based hemostatic sponges for the deep and non-compressible perforating wound.

Water based-deep eutectic solvent for ultrasound-assisted liquid-liquid microextraction of parabens in edible oil.

A novel water-based deep eutectic solvent was synthesized and used for the ultrasound-assisted liquid-liquid microextraction of parabens in edible oil and for their determination by high performance liquid chromatography. Herein, the water-based deep eutectic solvent was formulated at room temperature by tetrabutylammonium chloride as hydrogen bond acceptor and water as hydrogen bond donor at the molar ratio of 1:5. As component, water has the effect on tailoring the physicochemical properties of water-based deep eutectic solvent and assisting tetrabutylammonium chloride (hydrogen bond acceptor) capturing parabens (hydrogen bond donor) through in-situ deep eutectic solvent formation. The developed method has satisfactory linearity (1.5-500 µg/L), limits of detections (0.2-0.4 µg/L), precisions (RSDs ≤ 5.8%), and was fruitfully applied to detect parabens in edible oil with excellent recoveries (85.1-106.8%). The feature of the procedure lies in simplicity, low cost and high sensitivity, and this can be extended for the efficient separation of other hydrophobic compounds.

Asymmetric barrier membranes based on polysaccharide micro-nanocomposite hydrogel: Synthesis, characterization, and their antibacterial and osteogenic activities.

Guided tissue regeneration (GTR) strategies enable periodontal tissue regeneration, generally by providing barrier membranes. However, currently available membranes have limited osteoconductive and antibacterial potential. To address these challenges, we fabricated a new asymmetric barrier membrane. Agarose hydrogel functions as the main body of the barrier membrane. Hollow carbonated hydroxyapatite (CHA) prepared by hydrothermal method, was sedimented in agarose to exhibit an asymmetrical structure. And ε-poly-lysine (ε-PLL) was chosen as an antimicrobial agent to equip the membrane with long-lasting antibacterial activity. With the increased dose of CHA addition, the barrier membrane shows better biocompatibility, and higher mechanical properties. We demonstrated the osteoconductivity and antibacterial properties of the membrane in vitro and in vivo. In summary, our findings suggest that the barrier membrane has good osteoconductive and antibacterial properties, indicating its potential for periodontal tissue engineering.

A phosphoproteomics study reveals a defined genetic program for neural lineage commitment of neural stem cells induced by olfactory ensheathing cell-conditioned medium.

Since both Olfactory ensheathing cells (OECs) and neural stem cells (NSCs) have shown certain efficacy in the cellular therapy of nerve injury and disease, there have been a series of investigations in recent years looking at the co-culture of NSCs and OECs. Protein phosphorylation forms the basis for identifying a variety of cellular signaling pathways responsible for regulating the self-renewal and differentiation of NSCs induced by OECs. To better understand the signaling cascades in the early phases of OEC-induced NSC differentiation, changes in the NSC proteome and phosphoproteome during the first 24 h were determined using dimethyl labeling and TiO2 phosphorylation enrichment coupled with Liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 565 proteins and 2511 phosphorylation sites were identified. According to quantitative phosphoproteomics analyses of NSC differentiation induced by OECs during the first 12 and 24 h, it was speculated that there were at least two different signal waves: one peaking within 12 h after stimulation and the second upsurge after 24 h. In addition to understanding the dynamics of the proteome and phosphoproteome in the early stages of NSC differentiation, our analyses identified a key role of the TGF-ß3 protein secreted by OECs, which may be an initiating factor that promotes differentiation of NSCs into neurons induced by OECs. These findings not only redemonstrated a OECs-based therapeutic strategy in cell therapy, but also added a node to the regulatory network for the neural lineage commitment of NSCs induced by OECs.

Functionalization of cellulosic fibers with a kaolinite-TiO2 nano-hybrid composite via a solvothermal process for flame retardant applications.

Eco-responsible flame retardant treatments with some resistance to washing are of considerable interest in the sale and applications of technical garments and home textiles. Thus, in the present study, a nano-hybrid composite based on kaolinite-TiO2 was prepared and incorporated into the fibers of cotton fabric through a more sustainable route compared to existing commercial processes. SEM analyses revealed a mineral covering of the treated cotton fibers, which do not propagate flames when exposed to fire and have a self-extinguishing behavior after the heat source removal. The method proved to be efficient in obtaining a cotton product with high fireproof performance. It was observed that after functionalization, the fabric showed a thermal degradation 41% less at 800 °C, an increase in the residue formation, and a reduction of about 85% in peak heat release measured by PCFC. Some resistance to washing was noticed, and the mechanical resistance of fibers was preserved.

Exogenic production of bioactive filamentous biopolymer by monogonant rotifers.

The chemical ecology of rotifers has been little studied. A yet unknown property is presented within some monogonant rotifers, namely the ability to produce an exogenic filamentous biopolymer, named 'Rotimer'. This rotifer-specific viscoelastic fiber was observed in six different freshwater monogonants (Euchlanis dilatata, Lecane bulla, Lepadella patella, Itura aurita, Colurella adriatica and Trichocerca iernis) in exception of four species. Induction of Rotimer secretion can only be achieved by mechanically irritating rotifer ciliate with administering different types (yeast cell skeleton, denatured BSA, epoxy, Carmine or urea crystals and micro-cellulose) and sizes (approx. from 2.5 to 50 µm diameter) of inert particles, as inductors or visualization by adhering particles. The thickness of this Rotimer is 33 ± 3 nm, detected by scanning electron microscope. This material has two structural formations (fiber or gluelike) in nano dimension. The existence of the novel adherent natural product becomes visible by forming a 'Rotimer-Inductor Conglomerate' (RIC) web structure within a few minutes. The RIC-producing capacity of animals, depends on viability, is significantly modified according to physiological- (depletion), drug- (toxin or stimulator) and environmental (temperature, salt content and pH) effects. The E. dilatata-produced RIC is affected by protein disruptors but is resistant to several chemical influences and its Rotimer component has an overwhelming cell (algae, yeast and human neuroblastoma) motility inhibitory effect, associated with low toxicity. This biopolymer-secretion-capacity is protective of rotifers against human-type beta-amyloid aggregates.

Development of a liquid chromatography-tandem mass spectrometry method for simultaneous quantification of hen's egg white allergens Gal d 1-4 in fresh and processed eggs.

Hen's egg white allergens, namely Gal d 1-4, cause food allergies worldwide and their intake must be strictly controlled by allergic individuals. However, an efficient method for quantifying these allergens is currently unavailable. We aimed to develop an LC-MS/MS method for simultaneous Gal d 1-4 quantification. Purified Gal d 1-4 proteins were trypsin-digested and the resulting peptides used in LC-MS/MS analysis. The limits of quantification were 9.77-39.1 ng/mL. The Gal d 1-4 recovery in fresh and processed eggs was 68.3-121.3%, and intra- and interassay coefficients of variation were 1.5-15.7% and 2.4-38.1%, respectively, indicating high sensitivity, accuracy, and reproducibility. In addition, the high specificity of this method was confirmed by testing 27 other foods. This newly developed method could provide reliable information to the industrial food and clinical fields, facilitating improved quality of life for individuals with egg allergies.

Properties and kinetics of the in vitro release of anthocyanin-rich microcapsules produced through spray and freeze-drying complex coacervated double emulsions.

This study aimed to prepare anthocyanin-rich microcapsules by spray and freeze-drying complex coacervated double emulsion using gelatin-acacia gum (GE-AG) and chitosan-carboxymethylcellulose (CS-CMC) and to investigate their properties and in vitro release kinetics. Microencapsulation efficiency (MEE) of the microcapsules varied from 84.9% to 94.7%. CS-CMS microcapsules showed significantly higher MEEs than those of GE-AG microcapsules. A significant higher MEE and lower moisture content and hygroscopicity was observed in spray-dried double emulsion (SDE) microcapsules. Freeze-dried double emulsion (FDE) microcapsules possessed higher total anthocyanin and total phenolic contents. The best fit for release kinetics was achieved using first-order and Higuchi models for SDE and FDE microcapsules, respectively. Diffusion-controlled release in the simulated gastric fluid was found for SDE microcapsules, while erosion-controlled release in simulated gastric and intestinal fluids predominated for FDE microcapsules. These findings suggest that the microcapsules can be applied for loading anthocyanins as a nutraceutical with controllable release requirement.

Synthesis of controlled size starch nanoparticles (SNPs).

Starch nanoparticles (SNPs) are a promising choice for the strategic development of new renewable and biodegradable nanomaterials for novel biomedical and pharmaceutical applications when loaded with antibiotics or with anticancer agents as target drug delivery systems. The final properties of the SNPs are strongly influenced by the synthesis method and conditions being a controlled and monodispersed size crucial for these applications. The aim of this work was to synthesize controlled size SNPs through nanoprecipitation and microemulsion methods by modifying main operating parameters regarding the effect of amylose and amylopectin ratio in maize starches. SNPs were characterized by size and shape. SNPs from 59 to 118 nm were obtained by the nanoprecipitation method, registering the higer values when surfactant was added to the aqueous phase. Microemulsion method led to 35-147 nm sizes observing a higher particle formation capacity. The composition of the maize used influenced the final particle size and shape.

Opportunities for fraudsters: When would profitable milk adulterations go unnoticed by common, standardized FTIR measurements?

Milk is regarded as one of the top food products susceptible to adulteration where its valuable components are specifically identified as high-risk indicators for milk fraud. The current study explores the impact of common milk adulterants on the apparent compositional parameters of milk from the Dutch market as measured by standardized Fourier transform infrared (FTIR) spectroscopy. More precisely, it examines the detectability of these adulterants at various concentration levels using the compositional parameters individually, in a univariate manner, and together in a multivariate approach. In this study we used measured boundaries but also more practical variance-adjusted boundaries to set thresholds for detection of adulteration. The potential economic impact of these adulterations under a milk payment scheme is also evaluated. Twenty-four substances were used to produce various categories of milk adulterations, each at four concentration levels. These substances comprised five protein-rich adulterants, five nitrogen-based adulterants, seven carbohydrate-based adulterants, six preservatives and water, resulting in a set of 360 samples to be analysed. The results showed that the addition of protein-rich adulterants, as well as dicyandiamide and melamine, increased the apparent protein content, while the addition of carbohydrate-based adulterants, whey protein isolate, and skimmed milk powder, increased the apparent lactose content. When considering the compositional parameters univariately, especially protein- and nitrogen-based adulterants did not raise a flag of unusual apparent concentrations at lower concentration levels. Addition of preservatives also went unnoticed. The multivariate approach did not improve the level of detection. Regarding the potential profit of milk adulteration, whey protein and corn starch seem particularly interesting. Combining the artificial inflation of valuable components, the resulting potential profit, and the gaps in detection, it appears that the whey protein isolates deserve particular attention when thinking like a criminal.

LC-HRMS/MS for the simultaneous determination of four allergens in fish and swine food products.

The inclusion on the label of packed foods of any ingredient or technological adjuvant causing allergies is required by EU food legislation. In this study a targeted proteomics method for detecting four allergens in animal-derived food matrices was developed. Liquid chromatography coupled with high-resolution tandem mass spectrometry (LC-HRMS/MS) was used to select marker peptides from four allergens and develop a quantitative method able to simultaneously detect the presence of milk, egg, crustaceans and soy. The method was validated on fish or swine processed food products contaminated at 5 µg g-1 for milk and egg and 10 µg g-1 for soy and crustaceans. The method was tested by analyzing commercial food products with high protein content and was compared to the ELISA technique. Our results indicated the presence of soy not reported on the food label of some products, pointing out the need for efficient controls to protect allergic consumers.

An improved LC-MS method to profile molecular diversity and quantify the six main bovine milk proteins, including genetic and splicing variants as well as post-translationally modified isoforms.

Here we describe a method based on Liquid Chromatography coupled with Mass Spectrometry (LC-MS) that provides an accurate determination of the six main bovine milk proteins, including allelic and splicing variants, as well as isoforms resulting from post-translational modifications, with an unprecedented level of resolution. Proteins are identified from observed molecular masses in comparison with theoretical masses of intact proteins indexed in an "in-house" database that includes nearly 3000 entries. Quantification was performed either from UV (214 nm) or mass signals. Thus, up to one hundred molecules, derived from the six major milk proteins, can be identified and quantified from an individual milk sample. This powerful and reliable method, initially developed as an anchoring method to estimate the composition of the six main bovine milk proteins from MIR spectra, is transferable to several mammalian species, including small ruminants, camels, equines, rabbits, etc., for which specific mass databases are available.