Critical pH Value Research Articles

Safety of epidural analgesia in an orthotopic liver transplantation

In the literature devoted to the problems of liver transplantation, there is no clearly indicated attitude of the authors to intraoperative epidural blocks, although theoretically the benefits of a sympathetic block are considered. Some sources recommend prophylactic sodium bicarbonate infusion to alleviate post-reperfusion syndrome, but its effectiveness is questionable.Purpose: to present the physiological, biochemical and hematological characteristics of recipients at the stages of orthotopic liver transplantation with an assessment of the feasibility of using sodium bicarbonate for the prevention of reperfusion complications.Materials and methods. An observational study, contains an analysis of data from 39 participants operated on in 2020 in the volume of: hepatectomy, an orthotopic liver transplantation, with an initial assessment on the Child- Turcott- Pugh scale of 11 points. All participants were operated on under general inhalation anesthesia with sevoflurane and thoracic epidural three- component anesthesia according to the Breivik- Niemi method. There are 3 stages of data registration: the beginning of the anhepatic stage; the beginning of the neohepatic stage; the end of the operation.Results and discussion. Significant fluctuations in hemodynamics, violations of the acid-base state and energy metabolism were not revealed; a decrease in hepatic protein synthesis, a shift of the P50 point to the left, and moderate metabolic acidosis did not exceed the levels described in the literature. The dynamics of acidosis, РСО2 and natremia did not depend on the infusion of soda. There was no close correlation between arterial blood pH and lactate concentration.Conclusion. The benefits and safety of epidural anesthesia in orthotopic liver transplants are obvious and make it possible to recommend this component as a routine element of anesthesia during these operations. The indications for sodium bicarbonate infusion should be narrowed and consensus is needed to determine the critical pH value for sodium bicarbonate infusion.

Binary Graft of Poly(N-vinylcaprolactam) and Poly(acrylic acid) onto Chitosan Hydrogels Using Ionizing Radiation for the Retention and Controlled Release of Therapeutic Compounds.

In this study, we carried out the synthesis of a thermo- and pH-sensitive binary graft, based on N-vinylcaprolactam (NVCL) and pH sensitive acrylic acid (AAc) monomers, onto chitosan gels (net-CS) by ionizing radiation. Pre-oxidative irradiation and direct methods were examined, and materials obtained were characterized by FTIR-ATR, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and swelling tests (equilibrium swelling time, critical pH, and temperature). The best synthesis radiation method was the direct method, which resulted in the maximum grafting percentages (~40%) at low doses (10–12 kGy). The main goal of this study was the comparison of the swelling behavior and physicochemical properties of net-CS with those of the binary system (net-CS)-g-NVCL/AAc with the optimum grafting percentage (~30%). This produced a material that showed an upper critical solution temperature (UCST) of 33.5 °C and a critical pH value of 3.8, indicating the system is more hydrophilic at higher temperatures and low pH values. Load and release studies were carried out using diclofenac. The grafted system (32%) was able to load 19.3 mg g−1 of diclofenac and release about 95% within 200 min, in comparison to net-CS, which only released 80% during the same period. When the grafted system was protonated before diclofenac loading, it loaded 27.6 mg g−1. However, the drug was strongly retained in the material by electrostatic interactions and only released about 20%.

Security-Enhanced 3D Data Encryption Using a Degradable pH-Responsive Hydrogel.

Based on degradable pH-responsive hydrogel, we report on an enhanced three-dimensional data encryption security technique in which a pH value is used for information manipulation. Featuring three types of states upon the pH value variation, namely, shrinkage, expansion and degradation, the hydrogel renders a limited pH value window as the “key” for information decryption. The pH-dependent shrinkage-to-expansion conversion of the hydrogel leads to a threshold pH value for retrieving the recorded data, whilst the degradability of the hydrogel, which can be tuned by adjusting the composition ratio of PEGDA/AAc, gives rise to a second threshold pH value for irreversibly sabotaging the retrieved data. Pre-doping silver ions in the hydrogel facilitates explicit recording and reading of binary data in forms of three-dimensional silver patterns through photoreduction and scattering, respectively, with a femtosecond laser. By accurately matching the vertical spacing of the encoded silver nanopatterns with the diffraction-limited focal depth of the decryption microscope, we can tune the pH value to encrypt and retrieve information recorded in layers and set a critical pH value to smash encoded information, which proves a highly secured 3D data encoding protocol. This strategy can effectively enrich data encryption techniques, vastly enhancing data security within unattained chemical dimensions.

Methodology to Quantify and Screen the Demineralization of Teeth by Immersing Them in Acidic Drinks (Orange Juice, Coca-Cola™, and Grape Juice): Evaluation by ICP OES.

Oral health problems may occur as a result of the ingestion of acid drinks. The objective of this in vitro study was to quantify and screen the concentration of potassium (K), phosphorus (P), calcium (Ca), magnesium (Mg), manganese (Mn), zinc (Zn), iron (Fe), copper (Cu), barium (Ba), lead (Pb), arsenic (As), cadmium (Cd), aluminum (Al), cobalt (Co), chromium (Cr), molybdenum (Mo), sodium (Na), nickel (Ni), selenium (Se), and vanadium (V) released from bovine incisors during an erosive challenge at different times of exposure when immersed in Coca-Cola™, orange juice, and grape juice. A total of 240 samples of bovine incisor teeth were used for the erosive challenge and allocated in groups. Digestion of drinks was performed using microwave-assisted digestion. The content in acidic drinks was monitored before and after the erosive challenge at exposure times of 1, 5, and 60 min using inductively coupled plasma optical emission spectrometry (ICP OES). The drinks’ pH varied slightly during the erosive challenge but remained below the critical value of pH 5 to cause tooth demineralization. The concentrations of elements released from the bovine incisors during the in vitro erosive challenge depend on exposure times when immersed in acidic beverages. For some elements such as Ca, Mn, Zn, Fe, Cu, Ba, Pb, As, and Cd, quantified in acidic drinks, grape juice had greater erosive potential than Coca-Cola™ and orange juice. Quantification and monitoring of chemical elements in bovine teeth can be performed considering a longer erosive time and other types of acidic drinks. Further analysis using human teeth is still not available and must be conducted. The demineralization of teeth not only occurs in acidic beverages; physical and chemical factors play other roles and should be investigated.

Finite Element Modeling of Chemical and Electrochemical Protection Mechanisms Offered by Mg-Based Organic Coatings to AA2024-T351

A finite element model of the protection mechanisms offered by Mg-based organic coatings was developed. The model predicted the change in the corrosion potential of AA2024-T351 as a function of pH, water layer thickness, and the inhibition of oxygen reduction reaction. The pH in the solution was calculated taking into account Mg dissolution, precipitation of Mg(OH)2, Al dissolution, and hydrolysis of Al3+ ions. The predicted critical pH value at which the corrosion potential of AA2024-T351 sharply decreases to values below pitting and pit repassivation potentials under full immersion conditions was in accordance with experimental observations. A limiting water layer thickness below which the pH-induced pit repassivation mechanism is not predicted to occur was calculated. If the inhibition of oxygen reduction reaction by Mg(OH)2 is considered, the pH-induced repassivation mechanism becomes feasible at thinner water layers. Cathodic protection offered by Mg-rich primers was modeled as a function of coating resistance, water layer thickness, and electrolyte chemistry. The magnitude of the resistance of the film in which Mg pigments are embedded mitigates the extent of the cathodic protection. The change in local pH due to corrosion reactions affected the galvanic potentials obtained. The framework developed can be used to help identify chemical inhibitors that can operate by the chemical protection mode described in this work.

Clinical Study of the Change of pH Level in the Supragingival Plaque in Children after Taking Homeopathic Remedies

Abstract Objective: There are numerous publications on the parameters of conventional medications, which contribute to their cariogenic and erosive potential. Little is known about the homeopathic remedies (HR) and the changes in the oral cavity they lead to, especially during childhood. Material and methods: The study involved 25 children (5-9 years of age). It monitored the change in plaque pH level after intake of three frequently used homeopathic remedies in five consecutive weeks. The pH level values were measured after the administration of the remedies, without HR intake, and after rinsing with 10% sucrose solution. Five groups were formed – two controls and three groups with results from the tested HR. Results: A drop in the plaque pH level was observed after intake of all HR and in all tested individuals. The biggest decrease was observed at the 15th minute for all HR. At the 30th minute the greatest decrease was observed with the second remedy, and at 60th minute – with the first and second. Conclusions: A dramatic decrease in the plaque pH level was observed after intake of each studied remedy. In many cases the drop was below the critical value of pH = 5.5. The low plaque pH values were maintained even at the 60th minute after the start of the study.

Phase behavior, thermodynamic and rheological properties of ovalbumin/dextran sulfate: Effect of biopolymer ratio and salt concentration

The complexation between ovalbumin (OVA) and highly charged dextran sulfate (DS) was investigated employing phase behavior, zeta potential, confocal laser scanning microscope (CLSM), isothermal titration calorimetry (ITC) measurement, and dynamic rheometer analysis. The critical boundary pH values (pHc, pHϕ1, pHmax) were strongly dependent on the biopolymer ratio and salt concentration. Results of the phase diagram and zeta potential showed that the formation of complexes was mainly driven by strong electrostatic interactions. As the increase of the OVA/DS ratio, the critical pH values shifted to higher values. However, the addition of NaCl has a diverse effect, lower salt concentration (CNaCl <100 mM) promoted the formation of OVA/DS coacervates, while higher salt concentration (CNaCl≥ 100 mM) suppress the formation of coacervates due to the shielding effect. The ITC results revealed that DS does bind to native form of OVA at pH 7.0 through the electrostatic forces and it was a spontaneous exothermic process (△G < 0, △H < 0). Additionally, much higher viscoelasticity (G'&G″) for all OVA/DS coacervates indicates that the formation of a highly interconnected gel-like structure. The maximum viscoelasticity was shown at an OVA/DS ratio of 10:1 with 50 mM NaCl. On the other hand, the addition of salt decreased the gel transition temperature of OVA thus promote its aggregation in the mixing system. Our work provides important insight for understanding the interaction between sulfated polysaccharide with egg white protein.

Quenched or alive quantum dots: The leading roles of ligand adsorption and photoinduced protonation

The fluorescence emission of water-soluble CdTe quantum dots (QDs) capped with mercaptocarboxylic acids (MCAs) is known to be pH-dependent. However, this behaviour is quite different from a study to another, so that literature suffers from a lack of coherence. Here we assume that the QD fluorescence efficiency is actually driven by the acid-base equilibrium of MCA thiol groups, and that light-excited QDs open a non-radiative relaxation path through photoinduced protonation. We address this issue by examining colloidal CdTe QDs with (time-resolved) fluorescence spectroscopy under various conditions of acidity and light excitation. It appears that the emission of QDs is quenched below a critical pH value of 6.87, and that light excitation power strengthens this quenching. We thus demonstrate the existence of an additional photochemical process and developed a mathematical modeling accounting for all our experimental results. With only three parameters, it is possible to accurately predict the fluorescence decay of QDs over time, at any pH. Further, we also related the critical pH value of 6.87 to QD surface properties, explaining why observations may differ from a study to another and making the literature much more coherent.

Complex Coacervation of Α-Lactalbumin with Gum Arabic: Effect of Environmental Condition, Mass Ratio, and Biopolymer Concentration

The coacervate formation and interaction between α-lactalbumin (ALA) and gum arabic (GA) was investigated with turbidimetric analysis, fluorescence spectroscopy, atom force microscopy (AFM), and isothermal titration calorimetry (ITC). Critical pH values (pHc, pHφ1, pH opt and pHφ2) of phase transitions for ALA-GA complexes (1:1, 0.1%, w/v) without NaCl, representing the formation of soluble and insoluble complexes, were 4.95, 3.85, 3.70, and 2.30, respectively. pH and NaCl concentrations are dominant in influencing the formation of ALA-GA complexes. AFM graphs evidently indicated the formation, association, and dissociation of ALA-GA complex. ITC results confirmed that the formation of soluble ALA/GA complex was a spontaneous exothermic process, and the electrostatic interaction between ALA and GA was stronger at pH 3.0 than that at pH 4.9 and 5.6. The obtained information of this study provided insights into the interaction between ALA and GA and expand the application of ALA-based formulation in food system with desirable functionality.

On the Question of the Method for Determining the Critical pH Value during the Formation of Complexes between Nonionic Polymers and Polyacid in Aqueous Solutions

A new method is proposed for the quantitative determination of critical pH values during the formation of complexes between nonionic polymers and polyacids in aqueous solutions. As an indicator reflecting the pH value, where there is a transition from a solution containing noninteracting macromolecules to a solution in which the formation of an interpolymer complex occurs, the pH value should be taken with a yield of the complex formation reaction 1/2 of the maximum. The expediency of using just such an indicator is due to the fact that there is a fairly extended pH boundary region with the coexistence of noninteracting macromolecules and the reaction product between them. It is shown that the indicator determined in this way can be conveniently to calculated using the phase portrait method. This technique was tested by analyzing families of experimentally obtained curves describing the effect of potassium chloride additives on the complexation process between a copolymer of 2-hydroxyethyl acrylate and butyl acrylate and poly(acrylic acid) in an aqueous solution. It was found that for this system, the nature of the dependence of the effect of ionic strength on the formation of the polycomplex significantly depends on the composition of the copolymer, while the increase of only 4.9 mol % in the content of hydrophobic butyl acrylate units in the copolymer is accompanied by the transition of this system from a weak complex to strong complex.

Fine Migration Control in Sandstones: Surface Force Analysis and Application of DLVO Theory.

Formation damage caused by fine migration and straining is a well-documented phenomenon in sandstone reservoirs. Fine migration and the associated permeability decline have been observed in various experimental studies, and this phenomenon has been broadly explained by the analysis of surface forces between fines and sand grains. The Derjaguin–Landau–Verwey–Overbeek (DLVO) theory is a useful tool to help understand and model the fine release, migration, and control phenomena within porous media by quantifying the total interaction energy of the fine–brine–rock (FBR) system. Fine migration is mainly caused by changes in the attractive and repulsive surface forces, which are triggered by mud invasion during drilling activity, the utilization of completion fluid, acidizing treatment, and water injection into the reservoir during secondary and tertiary recovery operations. Increasing pH and decreasing water salinity collectively affect the attractive and repulsive forces and, at a specific value of pH, and critical salt concentration (CSC), the total interaction energy of the FBR system (VT) shifts from negative to positive, indicating the initiation of fine release. Maintaining the system pH, setting the salinity above the CSC, tuning the ionic composition of injected water, and using nanoparticles (NPs) are practical options to control fine migration. DLVO modeling elucidates the total interaction energy between fines and sand grains based on the calculation of surface forces of the system. In this context, zeta potential is an important indicator of an increase or decrease in repulsive forces. Using available data, two correlations have been developed to calculate the zeta potential for sandstone reservoirs in high- and low-salinity environments and validated with experimental values. Based on surface force analysis, the CSC is predicted by the DLVO model; it is in close agreement with the experimental value from the literature. The critical pH value is also estimated for alkaline flooding. Model results confirm that the application of NPs and the presence of divalent ions increase the attractive force and help to mitigate the fine migration problem. Hence, a new insight into the analysis of quantified surface forces is presented in current research work by the practical application of the DLVO theory to model fine migration initiation under the influence of injection water chemistry.

Complexation and coacervation of whey protein isolate with quince seed mucilage

In this study, the electrostatic interactions between quince seed mucilage (QSM) and whey protein isolate (WPI) were investigated by analysis of ζ-potential, turbidity, coacervation yield, and phase diagram. The maximum values of turbidity (2200 NTU) and coacervation yield (80.7%) were observed at the optimum values of WPI to QSM ratio (70:30) and pH (4). The soluble and insoluble complexes formed at the critical pH values of 5.5 and 5, respectively, while the biopolymers complexes decomposed at pH 2.5. SEM analysis revealed the coacervates as semi-spherical particles smaller than 200 nm, which aggregated without detectable porosity. The FTIR spectra showed that both electrostatic interactions and hydrogen bonds are important in the formation of WPI–QSM coacervates. The peaks in the DSC thermogram of coacervates were similar to those in WPI's but shifted and became smaller. These coacervates may be useful for the encapsulation of active substances.

Field pea protein isolate/chitosan complex coacervates: Formation and characterization

Influence of chitosan (Ch) with low, medium, and high molecular weight (LMW, MMW, and HMW) on the formation of field pea protein isolate (FPPI)/Ch complex coacervates was investigated. An increase in maximum turbidity and a gradual shift of critical pH values towards the isoelectronic point of FPPI were observed as the FPPI/Ch ratio increased. Formation of FPPI/Ch complex coacervates was dominated by the electrostatic and hydrophobic interactions. FPPI/Ch complex coacervates exhibited a porous network microstructure and relatively uniform-sized and even-distributed pores were found in FPPI/Ch-HMW coacervates. Different thermodynamic profiles were observed during complex coacervation between FPPI and Ch with varying MWs and the largest binding stoichiometry was observed in the Ch-MMW at pH 6.6. In summary, the Ch-HMW was demonstrated to be most suitable for the formation of FPPI/Ch complex coacervates with homogenous microstructure but caused less changes in the tertiary conformation of FPPI compared to the Ch-LWM and Ch-MMW.

Effects of iron oxide nanoparticles on the mineral composition and growth of soybean (Glycine max L.) plants

Nano-fertilization of agricultural systems is emerging as an innovative and unique strategy for agronomic fortification. In this study, a laboratory experiment was conducted to evaluate the physiological performance of soybean (Glycine max L.) exposed to either foliar or soil amendments of Fe2O3 nanoparticles (nFe2O3; 15, 30, and 60 mg/pot), fulvic acid-coated nFe2O3 (nFe2O3-FA; 60 mg nFe2O3/pot), and Fe-EDTA during an eight-week growing period. The experimental results demonstrated that none of the treatments produced toxicity stress or growth disorders. Amendments of nFe2O3 and nFe2O3-FA remarkably enhanced chlorophyll content, plant biomass, and root developmental indices. Fe-EDTA, a conventional fertilizer, did not provide satisfactory results compared with the other treatments. Regarding the supply of iron (Fe), foliar amendment provided 2–4 times higher shoot Fe concentration than soil application. Foliar amendments of nFe2O3-FA exclusively stimulated biological nitrogen fixation, which was primarily reflected in the formation of root nodules. This finding might be associated with the binary effect of the fulvic-Fe supply as well as enhanced potassium and zinc absorption in the plant than that of selective Fe penetration via negatively charged complexes. Further analysis of soil pH showed no evidence for facilitated Fe uptake via rhizosphere acidification. Conclusively, soybean responded better to the foliar amendment of nFe2O3-FA than nFe2O3 alone. This result suggests a novel perspective on the potential application of natural nanomaterial coating agents for nano-fertilization. From a practical perspective, it is necessary to consider the phosphorus (P) interaction and availability in the soil under nFe2O3 amendment, since the treatments substantially decreased P concentration in the soybean shoots, and thus a possible deficiency in plants under the critical pH value (below 6 and between 8–8.5) would be expected.

PH-Responsive Antibacterial Resin Adhesives for Secondary Caries Inhibition

Secondary caries caused by dental plaque is one of the major reasons for the high failure rate of resin composite restoration. Although antimicrobial agent–modified dental restoration systems have been researched for years, few reported intelligent anticaries materials could respond to the change of the oral environment and help keep oral eubiosis. Herein, we report tertiary amine (TA)–modified resin adhesives (TA@RAs) with pH-responsive antibacterial effect to reduce the occurrence of secondary caries. Two kinds of newly designed TA monomers were synthesized: DMAEM (dodecylmethylaminoethyl methacrylate) and HMAEM (hexadecylmethylaminoethyl methacrylate). In the minimum inhibitory concentration and minimum bactericidal concentration test against Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii, they exhibited antibacterial effect only in acidic medium, which preliminarily verified the acid-activated effect of TAs. Then DMAEM and HMAEM were incorporated into adhesive resin at the mass fraction of 5%, yielding TA@RAs. In vivo and in vitro tests showed that the mechanical properties and biocompatibility of the adhesive were not affected. A S. mutans biofilm model in acidic and neutral medium was used and confirmed that TA@RAs could respond to the critical pH value of de-/remineralization and acquire reversible antibiofilm effect via the protonation and deprotonation of TAs. Meanwhile, the stability of antibacterial effect was confirmed via a 5-d pH-cycling experiment and a saliva-derived biofilm aging model. Furthermore, 16S rRNA gene sequencing showed that TA@RAs could increase the diversity of the saliva-derived biofilms, which implied that the novel materials could help regulate the microbial community to a healthy one. Finally, an in vitro demineralization model and in vivo secondary caries model were applied and demonstrated that TA@RAs could prevent secondary dental caries effectively. In summary, the reversible pH-responsive and non–drug release antibacterial resin adhesives ingeniously overcome the defect of the present materials and hold great promise for clinical application.

Fabrication and characterization of Grass pea (Lathyrus sativus) protein isolate-Alyssum homolocarpum seed gum complex coacervate

The present work was carried out to fabricate Grass pea (Lathyrus sativus) protein isolate (GPPI) and Alyssum homolocarpum seed gum (AHSG) complex coacervate and investigate its morphological and structural properties. Formation of complex coacervates were studied by zeta potentiometry and turbidimetric analysis as function of different pHs (7.0–2.0) and GPPI to AHSG ratios (3:1 to 1:3). The critical pH values associated with the formation of soluble (pHc) and insoluble (pHφ1) complexes, and complete dissociation (pHφ2) at GPPI to AHSG ratio (1:1) were found to be 4.8, 4.0, and 2.5, respectively. Formation of insoluble complex coacervate was maximum at pH 3.2 and GPPI to AHSG ratio of 1:1, where the highest yield (69%) was observed. Scanning electron microscopic (SEM) demonstrated that GPPI-AHSG complex had a rough branched-like structure. Results also showed that the complexation between GPPI and AHSG were formed through the electrostatic interaction and hydrogen bonding. Circular dichroism spectroscopy (CD) indicated that the β-sheet and random coil content in GPPI increased when AHSG molecules were added to protein solution. The fading of pure peaks of GPPI and AHSG in X-Ray diffraction (XRD) patterns of GPPI-AHSG complexes confirmed the alterations in the physical state of mixture from crystalline to amorphous. GPPI-AHSG complex coacervates had lower weight loss compared to individual GPPI and AHSG.

Structure formation in pH-sensitive micro porous membrane from well-defined ethyl cellulose-g-PDEAEMA via non-solvent-induced phase separation process

To clarify the structure formation in pH-sensitive cellulose based micro porous membrane in non-solvent-induced phase separation process, first, a series of ethyl cellulose-graft-poly(2-(diethylamino)) ethyl methacrylate) (EC-g-PDEAEMA) with different graft density and graft length were synthesized via atom transfer radical polymerization (ATRP). The results of the micelles characterized by UV, Laser particle analysis and TEM indicated that the copolymer had pH responsive behavior and the increase of grafting density and grafting length led to the decrease of critical pH value. Furthermore, the morphology study of micro porous membrane via the NIPS process from mixture of THF and DMF indicated that the pores became smaller and more uniform with the increase of THF content and “open time”, and the most optimal preparation conditions was using EC0.2-g-PDEAEMA32 as the film-forming material and 75%THF/25%DMF (v/v) as solvent with the “open time” 1 min. What’s more, the membrane was responsive to pH stimulus in terms of water flux and demonstrated by scanning electron microscopy.

Influence of phosphates and pH value on white efflorescence formation on dry fermented sausages

The effect of chelators added to the gel of the alginate casing of dry fermented sausages on the white efflorescence formation was investigated. For this purpose, the chelators were added in different concentrations (0.8–2.3%) to the alginate gel before the co-extrusion of the sausage. The applied chelators were the polyphosphate P69, citrate, citric acid, and the mixture of di- and polyphosphates TARI S78. The hypothesis of the study was that the application of the chelators to the alginate gel could inhibit the white efflorescence formation by complexing the efflorescence, causing the divalent cations magnesium and calcium. The application of only the polyphosphate P69 and citric acid reduced the white efflorescence formation (reduced by 17.82–22.75% by P69 and 18.38–82.30% by citric acid). Moreover, two different inhibition effects were identified: the polyphosphate P69 reduced the diffusion of the main efflorescence-causing substances to rise to the surface of the sausages (magnesium, calcium, lactate and creatine) by diffusion from the surface inside the sausages and complexing the divalent cations. Citric acid reduced the white efflorescence formation by decreasing the pH value on the surface (4.73 compared to 4.90); furthermore, a critical pH value of 4.80 was identified due to the increase in the pH on the surface (protein degradation) at which the efflorescence formation occurs. The reduction of the efflorescences could be due to solubility effects at pH values below 4.80. The finding indicates that efflorescence formation could be reduced by chelating the efflorescence-causing divalent cations or by pH reduction on the surface of the sausage.

Complex Coacervation Between Gelatin and Chia Mucilage as an Alternative of Encapsulating Agents.

Complex coacervation between gelatin type B (GE) and chia mucilage (ChM) was studied. GE-ChM were mixed at mass ratios of 1:1, 2:1, 3:1, 4:1, and 1:2 in a pH range of 1.50 to 5.00, maintaining a total solid concentration of 0.2% (w/w), using turbidity and viscosity tests to obtain the highest yield of complex coacervates. To characterize the complex coacervates, morphology and Fourier-transform infrared spectroscopy (FTIR) were determined. The optimum yield for complex coacervation was achieved with a GE-ChM mass ratio of 2:1 and pH value of 3.6. The critical pH values associated with the formation of soluble (pHc ) and insoluble (pHɸ1 ) complexes, and complete dissociation (pHɸ2 ) at the optimum GE-ChM ratio were found to be 4.50, 4.10, and 2.00, respectively. It was observed that increasing the mass ratio of GE or ChM, the yield of complex coacervates decreased; the higher yields were obtained with the proportions of 2:1 and 1:1 with values of 68.25 ± 0.05% and 61.04 ± 0.05%, respectively. Capsules formed at mass ratios of 1:1, 2:1, and 3:1, had the characteristic grape agglomerate shape for complex coacervates. Further characterization with scanning electron microscopy (SEM) showed a spherical shape for capsules. FTIR spectrum of complex coacervates at optimum conditions had a combination of bands corresponding to GE and ChM, suggesting an interaction between GE-ChM during the formation of complex coacervates. Therefore, complex coacervates between GE-ChM can be formed, and could be used as an alternative as encapsulating agents to be applied in the food industry. PRACTICAL APPLICATION: Complex coacervation is a technique that is being studied in several applications in the food industry. However, studies are still being made to explore different possibilities of natural sources to be used in complex coacervation. This study showed that the combination of gelatin and chia mucilage may be an alternative as encapsulating agents for complex coacervation to be applied in the food industry.

Comparison of structural and physicochemical properties of lysozyme/carboxymethylcellulose complexes and microgels.

Proteins and polysaccharides can be used to assemble colloidal delivery systems suitable for industrial applications, such as functional foods, supplements, pharmaceuticals, and personal care products. The purpose of this work was to compare the physicochemical and structural properties of colloidal delivery systems prepared from lysozyme and carboxymethyl cellulose (CMC) at different biopolymer ratios, pH values, and salt levels. Specifically, the performance of unheated ("complexes") and heated ("microgels") lysozyme-CMC systems were compared. Isothermal turbidity-pH titrations indicated that the critical pH value for complex formation was lower for microgels than for complexes. Complexes were prone to dissociation when the pH or ionic strength was altered due to weakening of electrostatic interactions between the CMC and lysozyme. Conversely, microgels remained intact when the pH or ionic strength was altered, exhibiting swelling or shrinkage rather than dissociation. These results have important implications for the selection of the most appropriate protein/polysaccharide systems to achieve specific functional requirements. Complexes may be more suitable for pH- or salt-based triggered release whereas microgels may be more suitable for sustained release.