Investigation into potential allergenicity of DBD plasma-treated casein digestion products based on immunoglobulin E linear epitopes and the sensitized-cell model.

The study aimed to investigate the allergenicity change in casein treated with dielectric barrier discharge (DBD) plasma during in vitro simulated digestion, focusing on the immunoglobulin E (IgE) linear epitopes and utilizing a sensitized-cell model. Results indicated that prior treatment with DBD plasma treatment (4 min) before simulated digestion led to a 10.5% reduction in the IgE-binding capacity of casein digestion products. Moreover, the release of biologically active substances induced from KU812 cells, including ß-HEX release rate, human histamine, IL-4, IL-6, and TNF-α, decreased by 2.1, 28.1, 20.6, 11.6, and 17.3%, respectively. Through a combined analysis of LC-MS/MS and immunoinformatics tools, it was revealed that DBD plasma treatment promoted the degradation of the IgE linear epitopes of casein during digestion, particularly those located in the α-helix region of αs1-CN and αs2-CN. These findings suggest that DBD plasma treatment prior to digestion may alleviate casein allergic reactions.

Fabrication and stability of W/O/W emulsions stabilized by gum arabic and polyglycerol polyricinoleate.

BACKGROUND: In order to study the effect of adsorption of surfactant at the two interfacial layers on emulsion stability, the kinetically stable water-in-oil-in-water (W/O/W) emulsion carriers were prepared using polyglycerol polyricinoleate (PGPR) and gum arabic (GA) as emulsifiers. The relationship between the adsorption of the surfactant and the stability mechanism of the emulsions was elucidated. RESULTS: When the contents of PGPR and GA were low, the interfaces between oil and the inner and outer water phases, respectively, could not be completely covered. However, when the concentration of PGPR was higher than 60 g kg-1 , the excess PGPR was adsorbed on the interface between the oil phase and the outer water phase. When the concentration of GA reached 80 g kg-1 , more GA was adsorbed to the oil-in-water interface. Moreover, the presence of PGPR on the interface could reduce the adsorption capacity of GA. Two types of kinetically stable emulsions were obtained by optimizing the interface composition (60 g kg-1 GA/80 g kg-1 PGPR and 60 g kg-1 PGPR/80 g kg-1 GA). The kinetically stable W/O/W emulsions prepared in this study were successfully used to encapsulate a hydrophilic vitamin (vitamin B12) with an encapsulation efficiency (EE) of 80% and release efficiency (RE) of 95%. The interfacial adsorption GA can accelerate the hydrolysis of fat. CONCLUSION: Overall, this study provides a new strategy for the preparation of W/O/W emulsions, which might be beneficial for application in food, cosmetic, chemical, and pharmaceutical industries. © 2023 Society of Chemical Industry.

Interaction between potassium iodide and bovine serum albumin, ovalbumin and lysozyme under different temperature induction.

In this study, the interaction between potassium iodide and protein molecules under different temperature induction was studied, taking potassium iodide (KI) and protein molecules as a model system. The effects of KI on protein conformation, size, surface charge, binding constant, and binding site were analyzed by fluorescence spectrum, infrared spectrum, and diffusing wave spectroscopy. The results revealed that bovine serum albumin (BSA)/ovalbumin (OVA) and I-1 formed the 1: 1 complex and significantly affected the hydrodynamic radius and spatial structure. This could be attributed to the exposure of tyrosine residues inside the proteins to the polar conditions under increased temperature. The unfolding of protein structures induced the interaction between KI/KCl and proteins. As for BSA and OVA, the particle size and surface charge of the complex increased significantly in the presence of KI/KCl. KI had a strong static quenching effect on the fluorescence of BSA and OVA. Overall, these results provide insights into the physiological effects of iodine ions.

Aggregation and Growth Mechanism of Ovalbumin and Sodium Carboxymethylcellulose Colloidal Particles under Thermal Induction.

Ovalbumin (OVA)/sodium carboxymethylcellulose (CMC) colloidal particles were prepared with different compactness and morphologies by regulating the interaction between proteins and polysaccharides during heating. Electrostatic interactions between the amine groups of OVA (-NH3+) and carboxyl groups of CMC (-COO-) enhanced complex formation. The protein conformation change benefited the hydrophobic interaction between the particles. Proteins in colloidal particles were unfolded/folded under thermal induction to form aggregates having more ß-sheet structures. When the OVA/CMC ratio was 1:2, the initially loosely connected OVA/CMC aggregation changed into a uniform sphere between 25 and 90 °C. The mass ratio of OVA to CMC within the final colloidal particle (90 °C) was about 1:1.4. The OVA/CMC particle stability was maintained with hydrogen bonding, hydrophobicity, and disulfide bond. When OVA levels were predominant, OVA and CMC developed an approximately hollow sphere. Moreover, the final colloidal particle composition showed the OVA-to-CMC ratio as 3:1 (w/w). OVA bound into colloidal particle pores to increase compactness. Moreover, OVA and CMC bound to the colloidal particle while the particle shrank, thereby increasing the compactness of colloidal particles. There was a significant decrease in ABTS•+ scavenging activity of curcumin compared with that of the particles with a ratio of 1:2. Thus, the rational adjustment of the structure of colloidal particles could effectively enhance their functional characteristics, providing a new way for the controlled release of the active ingredients.

Highly biologically active and pH-sensitive collagen hydrolysate-chitosan film loaded with red cabbage extracts realizing dynamic visualization and preservation of shrimp freshness.

Accurate and efficient detection of food freshness is of great significance to guarantee food safety. Herein, pH sensitive colorimetric films with considerable biological activities have been prepared by combining red cabbage anthocyanin extracts (RCE) with collagen hydrolysate-chitosan (CH-CS) matrix film. The formation mechanism of CH-CS-RCE films was discussed by SEM, FT-IR and XRD, which showed that RCE was successfully fixed in CH-CS film through hydrogen bonding and electrostatic interaction. The CH-CS-RCE films exhibited good mechanical properties, high barrier ability, excellent thermal stability, significant antioxidant and antimicrobial activity, and especially sensitive response to pH and ammonia. Fickian diffusion was the main mechanism for the release of RCE from CH-CS-RCE films and such release mechanism facilitated the maintenance of functional features of films. During the storage of shrimps at 4 °C, CH-CS-RCE2% showed a remarkable preservation effect on shrimps, and their shelf life was prolonged from 2 d to 5 d. Furthermore, CH-CS-RCE2% provided a dynamic visual color switching to detect the freshness of shrimp, realizing real-time monitoring of freshness. Color information (RGB) extracted via smartphone APP was used to enhance the accuracy and universality of freshness indication. Thus, this multifunctional film has great potential in food preservation and freshness monitoring.

Preparation, characterization and antibacterial activity of new ionized chitosan.

In order to improve the solubility and antibacterial activity of chitosan and expand its application range, ionized chitosan (ICS) was successfully synthesized from chitosan through methylation and sulfonation reactions in this study. The chemical structures of the polymers were verified by Fourier transform infrared spectroscopy (FTIR) and 1H NMR, and a series of characterizations of the polymer were carried out by analytical methods such as element analysis (EA), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The results showed that the water solubility of the modified ICS was significantly improved. The introduction of propyl sulfonic acid groups with particle size decreasing and potential increasing greatly improved the antibacterial activity of chitosan, indicating that the ICS had the potential as a water-soluble antibacterial agent.

Effect of microcrystalline cellulose under different hydrolysis durations on the stability of thyme oil emulsion.

The thyme oil emulsion was prepared using a novel type of nanocellulose obtained under different hydrolysis durations. The effect of different cellulose structures on interfacial adsorption properties of emulsion and loading efficiency of thyme oil were analyzed. The results showed that the cellulose particles became more homogeneous and hydrophilic after hydrolysis duration for 10 h. The loading efficiency of thyme oil for all emulsions reached about 80%. The retention rate of thyme oil decreased during the storage period, and rising temperatures will exacerbate the loss of thyme oil. Compared to Hd2, emulsions stabilized by Hd10 exhibited better stability and higher retention at all storage conditions. Cellulose emulsion can increase the dispersion and improve the stability of thyme oil. A smaller cellulose particle could make the emulsion become more stable. The experimental results confirmed that cellulose can be used as a stabilizer to encapsulate and transport hydrophobic active ingredient. PRACTICAL APPLICATION: The study results demonstrated that the emulsion transport system was developed using cellulose nanoparticles prepared by hydrolysis. The system can be used to load hydrophobic active substances (active peptides, curcumin, ß-carotene, essential oils, etc.). It can protect the active substance from environmental damage, enhance water solubility and stability, and improve the bioavailability of the active substance.

The role of glycerol on the thermal gelation of myofibrillar protein from giant squid (Dosidicus gigas) mince.

This work studies the effect of glycerol on the chemical physics of the thermal gelatin of protein from giant squid minced meat. The presence of glycerol induced changes in the nano protein particles (NPP) self-assembled structures. These nanoscale events resulted in dramatic changes on the interactions between proteins when forming gels, with the contribution of ionic interactions increasing by 17% upon gelation, that of hydrogen bonds reducing by 50%, that of hydrophobic interactions decreasing by 45%, and that of disulphide bonding increasing by 18%. Glycerol also induced cluster formation in myofibrillar solutions. As a result, incorporation of glycerol increased springiness, resilience, and adhesiveness of the formed gels by 13%, 25%, and 370% respectively. The heating gelation of myofibrillar proteins was monitored at various temperatures via recording the elastic and storage moduli. Rheology and micro-rheology studies revealed that the presence of glycerol increased G' and G″ of thermally-gelled giant squid meat.

Ovalbumin/carboxymethylcellulose colloids: Particle compactness and interfacial stability.

A protein/polysaccharide colloidal particle was prepared via combined complex coacervation and heat-induction. When the ratio of ovalbumin (OVA) to carboxymethylcellulose (CMC) was at 1:2, loose flexible particles (low Df) with low surface hydrophobicity were obtained. Conversely, dense and compact particles (high Df) were easily formed at a higher OVA/CMC ratio. Only in the appropriate OVA/CMC ratio, pH will have a greater impact on the colloidal particles. At the pH value of 4.4, the OVA/CMC ratio had a greater impact on the colloidal particles compared to pH. The emulsion stabilized by loose particles had a mean particle size of 3888 nm and was easily flocculated and creamed. On the other hand, compact particles formed a stable emulsion, which had a higher exponent of Δr2 (0.867) and could resist flocculation during the 7 days storage. As such, the results showed that stable emulsion could be realized by utilizing compact particles as emulsifiers.

The influence of KCl concentration on the gelation of myofibrillar protein giant squid (Dosidicus gigas) due to molecular conformation change.

Introduction: Protein gelation process is of importance in food industry. The objective of this study is to investigate the influence of salt concentration variation, which induced protein conformation change, on protein's intermolecular interactions and its gelation process. Methods: Paramyosin has been separated and purified from myofibrillar protein extracted from giant squid. Then Giant squid's paramyosin molecular mass and intermolecular interactions were quantified by means of light scattering techniques. Finally, the micro-rheology study via diffusing wave spectroscopy (DWS) technique revealed that this conformation change dramatically affected myofibrillar protein gelation process. Results: The obtained apparent molecular weight (ca 2 × 105 g/mol) suggested that protein molecules existed as dimers, while the second virial coefficient A2 significantly reduced from -3.98456 × 10-5 to -5.07575 × 10-4 ml mol/g2 when KCl concentrated from 0.15 to 1 mol/L. Light scattering data also suggest that paramyosin dimers are stiff, with a persistence length of 120 nm, almost the length of a molecule and independent of salt concentration. Mean-square displacement (MSD) of tracer particles at 5 temperatures with 4 salt concentrations displayed that this conformation change had dramatic effect. Therefore, G' and G" were remarkably altered with at least one order of magnitude difference owing to this event occurrence. Conclusions: Paramyosin conformation change due to KCl concentrated enhances attractive interactions with apparent molecular mass increase, which resulted in majority paramyosin molecules (> 99%) in dimeric form and promoted aggregates formation. DWS technique revealed that the conformation change dramatic affected this process characterized by the correlation functions, MSD, and G' and G". This study brings forward data on understanding the effect of a major salt supplement, KCl, on the chemical physics of a major muscle protein.

Preparation of ultra-long stable ovalbumin/sodium carboxymethylcellulose nanoparticle and loading properties of curcumin.

OVA (ovalbumin)/CMC (sodium carboxymethylcellulose) nanoparticles are prepared by combining complex coacervation and thermal induction. The effect of different parameters on stability of OVA/CMC nanoparticles (different ratios, pH, temperature, salt concentration and storage time) is investigated. And then the loading and stabilizing mechanism of particles on curcumin are further analyzed. After heating, OVA and CMC in particle could further cross-linking and a highly salt-tolerant and ultra-long stable nanoparticle can be formed. OVA/CMC nanoparticle with the loose structure of wool ball could effectively load curcumin with the loading content and loading efficiency of 36.40 and 95.40%, 36.30 and 92.82%, 36.0 and 94.48% for the ratios of 1:2, 1:1 and 2:1, respectively. Curcumin-loaded of OVA/CMC nanoparticles show good DPPH· scavenging activity, Ferric-reducing ability and ABTS+ scavenging activity compared with curcumin/water. The results can be useful for designing food and beverage particle with improving bioactive substances functional properties.

Properties of nano protein particle in solutions of myofibrillar protein extracted from giant squid (Dosidicusgigas).

This work studied the quantitation of myofibrillar protein isolated from giant squid by three methods (Bradford, biuret, and direct ultraviolet absorbance). The results were examined in relation to compositional size exclusion chromatography, static light scattering, zeta-potential and thermal analysis; comparisons between the apparent vs. the true protein concentration revealed the existence of disk-like nano protein particles (NPP) with a height of 2-3 nm, diameters ranging from several tens nm to 140 nm, and fractal dimensions df of less than 1.3. In order to probe the heterogeneity of NPP particles, their properties were studied under consecutive dilutions: the df decreased from 1.265 to 1.087, the zeta-potential increased from -4.55 mV to -1.83 mV, the denaturation temperature reduced from 63.9 °C to 58.6 °C, and the endothermic enthalpy reduced from 0.529 J s-1 to 0.362 J s-1. In addition, ca. 90% protein molecules in solution were aggregated to form NPP.

Structural characteristics and digestibility of bovine skin protein and corn starch extruded blend complexes.

The interaction mechanism and digestibility of bovine skin protein (BSP)/corn starch (CS) blend complexes prepared by single screw extrusion were investigated. The effects of temperature and BSP/CS ratios on the physicochemical properties of BSP/CS blend complexes were analyzed. The results showed that the BSP/CS blend complexes extruded at a ratio of 3:7 had higher bulk density, texture and RVA viscosity compared with that of 7:3 and 5:5. It was mainly because the CS improved the formation of BSP/CS gel network structure through the screw extrusion. BSP and CS achieved an optimal entanglement at this ratio, potentially making pets play longer. The interaction between the -COOH of CS and the -NH3 of BSP during the process of extrusion was detected. The micrograph of blend system at ratio of 5:5 showed looser and special mosaic structure compared with other ratios, and further led to greater digestion rate. So we can design products with digestibility or longer play time by adjusting different proportions.

Effects of environmental stresses on physiochemical stability of ß-carotene in zein-carboxymethyl chitosan-tea polyphenols ternary delivery system.

ß-Carotene is a natural nutrient that serves as a natural food colorant. However, the weak physical stability restricts its development in food industrial production. Here, the influences of a variety of external environmental conditions on the stability of ß-carotene enriched zein-carboxymethyl chitosan (CMCS)-tea polyphenols (TP) ternary composite nanoparticles were investigated. Compared with zein unitary and zein-CMCS binary complexes, it was interesting to note that ternary complexes had the best stability against color fading and there was little impact on its nanoparticle size during storage with change in temperature. Besides excellent antioxidant properties, ternary complexes were extremely effective in inhibiting ß-carotene color degradation when exposed to ultraviolet light. Based on our results, the novel zein-CMCS-TP nanoparticles are expected to be an effective delivery system to encapsulate hydrophobic bioactive compounds, which is a promising approach to improve their storage stability against external environmental stresses.

One-step assembly of zein/caseinate/alginate nanoparticles for encapsulation and improved bioaccessibility of propolis.

The design of zein-based nanoparticles to encapsulate bioactive molecules has gained great attention in recent years. However, the use of ethanol to dissolve zein presents flammability concerns and the scale-up production of zein-based nanoparticles is also a concern. In our study, propolis loaded zein/caseinate/alginate nanoparticles were fabricated using a facile one-step procedure: a well-blended solution was prepared containing deprotonated propolis, soluble zein, dissociated sodium caseinate micelles (NaCas) and alginate at alkaline pH, and then this alkaline solution was added to 0.1 M citrate buffer (pH 3.8) to fabricate composite nanoparticles without using organic solvents and sophisticated equipment. During acidification, the alginate molecules adsorbed on the zein/NaCas surfaces by electrostatic complexation, which improved the stability towards aggregation of zein/NaCas nanoparticles under gastrointestinal (GI) or acidic pH. The nanoparticles prepared under the optimized method (method 3 sample) were of spherical morphology with a particle size around 208 nm and a negative zeta potential around -27 mV. The encapsulation efficiency (EE) and loading capacity (LC) of propolis reached 86.5% and 59.6 µg mg-1 by zein/NaCas/alginate nanoparticles, respectively. These nanoparticles were shown to be stable towards aggregation over a wide range of pH values (2-8) and salt concentrations (0-300 mM NaCl). Compared to free propolis, the bioaccessibility of propolis encapsulated with nanoparticles was increased to 80%. Our results showed a promising clean and scalability strategy to encapsulate hydrophobic nutraceuticals for applications in foods, supplements, and pharmaceuticals.

Investigation of the AQP Family in Soybean and the Promoter Activity of TIP2;6 in Heat Stress and Hormone Responses.

Aquaporins (AQPs) are one diverse family of membrane channel proteins that play crucial regulatory roles in plant stress physiology. However, the heat stress responsiveness of AQP genes in soybean remains poorly understood. In this study, 75 non-redundant AQP encoding genes were identified in soybean. Multiple sequence alignments showed that all GmAQP proteins possessed the conserved regions, which contained 6 trans-membrane domains (TM1 to TM6). Different GmAQP members consisted of distinct Asn-Pro-Ala (NPA) motifs, aromatic/arginine (ar/R) selectivity filters and Froger's positions (FPs). Phylogenetic analyses distinguished five sub-families within these GmAQPs: 24 GmPIPs, 24 GmTIPs, 17 GmNIPs, 8 GmSIPs, and 2 GmXIPs. Promoter cis-acting elements analyses revealed that distinct number and composition of heat stress and hormone responsive elements existed in different promoter regions of GmAQPs. QRT-PCR assays demonstrated that 12 candidate GmAQPs with relatively extensive expression in various tissues or high expression levels in root or leaf exhibited different expression changes under heat stress and hormone cues (abscisic acid (ABA), l-aminocyclopropane-l-carboxylic acid (ACC), salicylic acid (SA) and methyl jasmonate (MeJA)). Furthermore, the promoter activity of one previously functionally unknown AQP gene-GmTIP2;6 was investigated in transgenic Arabidopsis plants. The beta-glucuronidase (GUS) activity driven by the promoter of GmTIP2;6 was strongly induced in the heat- and ACC-treated transgenic plants and tended to be accumulated in the hypocotyls, vascular bundles, and leaf trichomes. These results will contribute to uncovering the potential functions and molecular mechanisms of soybean GmAQPs in mediating heat stress and hormone signal responses.

Characterization of structure and stability of emulsions stabilized with cellulose macro/nano particles.

The characterization of emulsions covered with cellulose particles prepared under varying hydrolysis durations investigated. The results showed that with the increasing hydrolysis durations, the particle size distribution profiles of emulsion stabilized cellulose particles shifted to a lower particle size. This was primarily because at longer hydrolysis durations, a larger number of particles per interfacial area were expected to be adsorbed at the interface of oil droplets. At hydrolysis durations of 6 and 10 h, the mean particle diameter of emulsion had an increase of 20-30 nm after 7 days and showed good stability with storage time, which can be attributed to a relatively thick interface layer. Emulsions stabilized by cellulose particles prepared at hydrolysis durations of 6 and 10 h showed good stability against changes in pH and NaCl concentration. These results can be useful for designing food and beverage Pickering emulsions with the improved bioavailability of functional nutrients.

Structural characteristics and rheological properties of ovalbumin-gum arabic complex coacervates.

After formation of the ovalbumin (OVA)-gum arabic (GA) complex coacervates, a more ordered crystal structure was obtained, and the protein denaturation temperature increased from 72 to 96 °C. GA can reduce the pH-induced conformational perturbations of ovalbumin. The presence of GA improved the stability of the α-helix and ß-turn regions against pH, but showed less influence on the random coil and ß-sheet domains. The complex coacervates showed the highest viscosity value at pH 3.7 compared with the other pH values tested (4.0, 3.4, 3.0, 2.7) due to the stronger interactions of OVA and GA. A large thixotropic loop was observed for the coacervate obtained at pH 3.7 compared with that obtained at pH 4.0. Moreover, the salt concentration and OVA:GA ratio influenced the rheological properties by affecting the structure and composition of the complexes. A stronger interaction between OVA and GA led to greater viscoelastic properties.

Adsorption activity of coconut (Cocos nucifera L.) cake dietary fibers: effect of acidic treatment, cellulase hydrolysis, particle size and pH.

The effects of acidic treatment, cellulase hydrolysis, particle size distribution and pH on the adsorption capacity of defatted coconut cake dietary fibers (DCCDF) were studied. The results demonstrated that cellulase hydrolysis could significantly improve the soluble dietary fiber content, water holding ability and adsorption ability of DCCDF on cholesterol, bile and nitrite ions. Acidic treatment enhanced the oil holding capacity and adsorption ability in cholesterol and nitrite ions. Moreover, the adsorption ability of DFs in cholesterol, nitrite and bile all increased with reduced particle size (250 to 167 µm), and DCCDF demonstrated a higher adsorption capacity at pH 2.0 than at pH 7.0. The change in adsorption capacity of DCCDF might be suitable for application in the food industry as a low-calorie and cholesterol lowering functional ingredient.

The characteristic and dispersion stability of nanocellulose produced by mixed acid hydrolysis and ultrasonic assistance.

Axiolitic shape nanocellulose particles were prepared using a combined mixed acid hydrolysis and ultrasonic treatment. The crystallinity, morphology and stability properties of cellulose were characterized to investigate the mechanism of nanocellulose formation and stability. It was found the hydrodynamic radius decreased from 205nm to 89nm, and the crystallinity index of the nanocellulose increased from 62.90% to 72.31% with an increase in hydrolysis time from 2 to 10h. Sulfate esters and sulfonate group were present in the nanocellulose, and released more COH groups after hydrolysis. The ζ-potential of cellulose decreased from -11.5 to -43.8mV after 10h of hydrolysis. These results illustrated the amorphous characteristic of cellulose was removed after acid hydrolysis and ultrasonic treatment. The higher ζ-potential and relatively small cellulose particles caused a more stable suspension, suggesting that electrostatic interactions played an important role in maintaining the stability and dispersibility of the nanocellulose particles.