Effects of Thickening Agents on the Mucociliary Transport Function: Comparison by the Type of Thickening Agents and the Viscosity of Thickened Water.

Thickening agents effectively prevent liquid aspiration, but their impact on the ease of discharging aspirated liquids from the trachea remains unclear due to alterations in the physical properties of liquids. This study clarifies the effects of thickening agents, comprising various raw materials, on mucociliary transport function, focusing on the viscosities of thickened waters. The subjects were 23 healthy adults. Five types of saccharin solution were prepared: a solution without a thickening agent, a starch-based nectar-like solution, a starch-based honey-like solution, a xanthan-gum-based nectar-like solution, and a xanthan-gum-based honey-like solution. Using these five types of saccharin solutions randomly, each subject underwent five trials of the saccharine dye test to evaluate the mucociliary transport function of the respiratory tract. The saccharin time was defined as the time from the placement of the saccharin solution on the nasal vestibule of the subject to when the subject reported that they became aware of the sweetness. The saccharin transit times for all samples of thickened water were longer compared to those of water without a thickening agent (p < 0.01). A comparison between thickened water samples with different viscosities showed that the saccharin transit time was longer when thickened water samples with high viscosity were prepared using the same thickening agent (p < 0.01). This suggests that while thickening reduces aspiration, the use of thickening agents may increase the difficulty in discharging aspirated fluids from the trachea.

Pharyngeal Residues Following Swallowing of Pureed Diets Thickened with a Gelling Agent or a Xanthan Gum-Based Thickener in Elderly Patients with Dysphagia.

The ideal texture of pureed diets to prevent aspiration pneumonia remains unclear. The aim of this study was to evaluate the effectiveness of a pureed diet with either a gelling agent or a xanthan gum-based thickener to prevent pharyngeal residues in patients with dysphagia. We retrospectively analyzed a randomized, crossover trial of pureed rice with either a gelling agent or a xanthan gum-based thickener in patients with dysphagia. The enrolled patients were classified into mild and moderate-to-severe dysphagia groups. The primary outcome measure was degree of need for cyclic ingestion using test jelly for pharyngeal residuals (cyclic ingestion score). The secondary outcome was the patient's sense of material remaining in the throat following swallowing. Sixty-two patients (58% men; mean age 83 ± 9 years) with dysphagia were included. They were classified into mild dysphagia (n = 26) and moderate-to-severe dysphagia (n = 36) groups. In the moderate-to-severe dysphagia group, pharyngeal residuals were significantly less likely with pureed diets using a gelling agent than with those using a xanthan gum-based thickener, with respective median cyclic ingestion scores (range) of 1 (0-4) vs. 2.5 (0-4) (p = 0.001). There was no significant difference in pharyngeal residuals between the pureed diets in the mild dysphagia group. The multivariate analysis identified gelling agent as an important factor significantly associated with less pharyngeal residual after swallowing of pureed diet in patients with moderate-to-severe dysphagia. Pureed diets thickened by a gelling agent decrease pharyngeal residues in patients with moderate-to-severe dysphagia and may reduce risk of aspiration pneumonia.

Investigation into pectin extraction and technological implementations in the food industry.

Pectin, a complex polysaccharide found abundantly in the cell walls of fruits and vegetables, plays a pivotal role in various food applications owing to its unique gelling, thickening and stabilizing properties. As consumer preferences lean towards natural and sustainable ingredients, the demand for pectin as a food additive has surged. This burgeoning interest has prompted a comprehensive exploration into both the extraction methods of pectin from its natural sources and its diverse technological applications in the food industry. The extraction process involves breaking down the plant cell wall to release the pectin. Traditional methods such as hot acid extraction have been widely used, but advances in technology have spurred the development of novel techniques like enzyme-assisted extraction and microwave-assisted extraction. These methods aim not only to enhance the yield and purity of extracted pectin but also to minimize environmental impact and energy consumption. Pectin's versatility has positioned it as a valuable ingredient in the food industry. Its ability to form gels under specific conditions makes it a key component in the production of jams, jellies and fruit preserves. Additionally, pectin acts as a stabilizer in dairy products, prevents syneresis in baked goods and improves the texture of confectionery items. The application of pectin goes beyond its role as a gelling agent; it is also employed in the encapsulation of bioactive compounds, enhancing the functional properties of various food products. © 2024 Society of Chemical Industry.

Fe2O3/Ni Nanocomposite Electrocatalyst on Cellulose for Hydrogen Evolution Reaction and Oxygen Evolution Reaction.

A key challenge in the development of sustainable water-splitting (WS) systems is the formulation of electrodes by efficient combinations of electrocatalyst and binder materials. Cellulose, a biopolymer, can be considered an excellent dispersing agent and binder that can replace high-cost synthetic polymers to construct low-cost electrodes. Herein, a novel electrocatalyst was fabricated by combining Fe2O3 and Ni on microcrystalline cellulose (MCC) without the use of any additional binder. Structural characterization techniques confirmed the formation of the Fe2O3-Ni nanocomposite. Microstructural studies confirmed the homogeneity of the ~50 nm-sized Fe2O3-Ni on MCC. The WS performance, which involves the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), was evaluated using a 1 M KOH electrolyte solution. The Fe2O3-Ni nanocomposite on MCC displayed an efficient performance toward lowering the overpotential in both the HER (163 mV @ 10 mA cm-2) and OER (360 mV @ 10 mA cm-2). These results demonstrate that MCC facilitated the cohesive binding of electrocatalyst materials and attachment to the substrate surface. In the future, modified cellulose-based structures (such as functionalized gels and those dissolved in various media) can be used as efficient binder materials and alternative options for preparing electrodes for WS applications.

Effects of polymerized goat milk whey protein on physicochemical properties and microstructure of recombined goat milk yogurt.

Goat milk whey protein concentrates were manufactured by microfiltration (MF) and ultrafiltration (UF). When MF retentate blended with cream, which could be used as a starting material in yogurt making. The objective of this study was to prepare goat milk whey protein concentrates by membrane separation technology and to investigate the effects of polymerized goat milk whey protein (PGWP) on the physicochemical properties and microstructure of recombined goat milk yogurt. A 3-stage MF study was conducted to separate whey protein from casein in skim milk with 0.1-µm ceramic membrane. The MF permeate was ultrafiltered using a 10 kDa cut-off membrane to 10-fold, followed by 3 step diafiltration. The ultrafiltration-diafiltration-treated whey was electrodialyzed to remove 85% of salt, and to obtain goat milk whey protein concentrates with 80.99% protein content (wt/wt, dry basis). Recombined goat milk yogurt was prepared by mixing cream and MF retentate, and PGWP was used as main thickening agent. Compared with the recombined goat milk yogurt without PGWP, the yogurt with 0.50% PGWP had desirable viscosity and low level of syneresis. There was no significant difference in chemical composition and pH between the recombined goat milk yogurt with PGWP and control (without PGWP). Viscosity of all the yogurt samples decreased during the study. There was a slight but not significant decrease in pH during storage. Bifidobacterium and Lactobacillus acidophilus in yogurt samples remained above 106 cfu/g during 8-wk storage. Scanning electron microscopy of the recombined goat milk yogurt with PGWP displayed a compact protein network. Results indicated that PGWP prepared directly from raw milk may be a novel protein-based thickening agent for authentic goat milk yogurt making.

Simple Advanced Preparation Method for Improving the Thickness Stability of Powder Thickening Agents in Dysphagia Management.

Texture modification of foods by using thickening agents is a routine practice for assessing and treating dysphagic patients. However, a powder-thickened fluid's viscosity might change over time, and little has been proposed to overcome this inconsistency. This study aimed to evaluate variations in the thickness of a fluid thickened with a common xanthan gum-based powder and to explore the feasibility of a simple advanced preparation method for thickened liquids to improve thickness stability. Thickened fluids with concentrations of 1.0 g/100 mL, 0.7 g/100 mL, and 0.5 g/100 mL were prepared from both freshly opened and previously opened thickening powders. Fluid thickness was measured every 10 min in a series of International Dysphagia Diet Standardization Initiative flow tests. A significant time-dependent decline in thickness was observed for all three concentrations in both groups, namely those prepared with freshly opened and previously opened thickening powders, and the shortest periods to achieve a stable viscosity after liquid preparation for the two groups were 80 and 70 min, respectively. On diluting the thickened liquids from the base liquid, which was prepared at a concentration of 1.0 g/100 mL and stored at room temperature for 90 min, no significant time-dependent thickness changes were observed over the following 60 min. The simple protocol of preparing the thickest "base" liquid in advance and then diluting it to the desired thickness resulted in a consistent liquid thickness, with the prepared liquids ready to be clinically applied and consumed, with high stability within 60 min.

Flow test by the International Dysphagia Diet Standardization Initiative reveals distinct viscosity parameters of three thickening agents.

The International Dysphagia Diet Standardization Initiative (IDDSI) flow test is useful for the global standardization of food consistencies of dysphagia patients. In clinical practice, different compositions of food thickeners are commonly used, directly influencing viscosity parameters and swallowing physiology. We aimed to compare the IDDSI thickness levels, remaining volume in the syringe (RVS), and viscosity parameters of three different food thickeners. As a secondary objective, we compared the cost of preparing 100 mL of thickened drinks using the studied thickeners. Thickeners A (xanthan gum), B (corn starch, tara gum, xanthan gum, and guar gum), and C (corn starch) were prepared in increasing concentrations from 1 to 7 g/100 mL and were assayed in quintuplicate using the IDDSI flow test. Thickeners A, B, and C presented statistically different results for the IDDSI levels, RVS, and viscosity parameters at all concentrations. Thickener A reached higher levels in the IDDSI framework, RVS, and viscosity parameters compared with thickeners B and C. A large range of RVS was observed at different concentrations for thickener B compared with C. Regarding viscosity, thickeners B and C, with corn starch in their composition, showed exponential behavior as concentrations increased, while thickener A presented a linear trend. The thickener composition was significantly influenced by IDDSI classification, RVS, and viscosity parameters. The study shows that xanthan gum thickeners present less variability in IDDSI, RVS, and viscosity compared with starch-based thickeners.

Physicochemical, texture properties, and microstructure of yogurt using polymerized whey protein directly prepared from cheese whey as a thickening agent.

The aim of this study was to investigate suitability of polymerized whey protein prepared directly from cheese whey on the physicochemical, texture properties, and microstructure of the yogurt. The results indicated that addition of polymerized whey protein obtained by heating the liquid whey protein concentrate at 75°C for 10 min had no significant differences in pH, titratable acidity, total solids, protein content, viscosity, texture, and syneresis between the yogurt with polymerized liquid whey protein (YWPS) and the yogurt with polymerized whey protein concentrate. However, the YWPS had significant differences in viscosity, texture, and syneresis compared with the control yogurt. Scanning electron micrographs of YWPS displayed a compact and homogeneous protein network for polymerized whey protein solution (PWPS) samples. The 4 yogurt samples were evaluated by the quantitative descriptive analysis method, and 14 sensory attributes were analyzed by principal component analysis. All 3 principal components had significant effects on the sensory profiles, accounting for 52.3, 24.32, and 10.8% of the variability in the results, respectively. Polymerized whey protein prepared directly from cheese whey may be a good protein base as a thickening agent for yogurt making.

Influence of Carboxymethyl Cellulose as a Thickening Agent for Glauber's Salt-Based Low Temperature PCM.

This work is focused on a novel, promising low temperature phase change material (PCM), based on the eutectic Glauber's salt composition. To allow phase transition within the refrigeration range of temperatures of +5 °C to +12 °C, combined with a high repeatability of melting-freezing processes, and minimized subcooling, the application of three variants of sodium carboxymethyl cellulose (Na-CMC) with distinct molecular weights (700,000, 250,000, and 90,000) is considered. The primary objective is to optimize the stabilization of this eutectic PCM formulation, while maintaining the desired enthalpy level. Preparation methods are refined to ensure repeatability in mixing components, thereby optimizing performance and stability. Additionally, the influence of Na-CMC molecular weight on stabilization is examined through differential scanning calorimetry (DSC), T-history, and rheology tests. The PCM formulation of interest builds upon prior research in which borax, ammonium chloride, and potassium chloride were used as additives to sodium sulfate decahydrate (Glauber's salt), prioritizing environmentally responsible materials. The results reveal that CMC with molecular weights of 250 kg/mol and 90 kg/mol effectively stabilize the PCM without phase separation issues, slowing crystallization kinetics. Conversely, CMC of 700 kg/mol proved ineffective due to the disruption of gel formation at its low gel point, hindering higher concentrations. Calculations of ionic concentration indicate higher Na ion content in PCM stabilized with 90 kg/mol CMC, suggesting increased ionic interactions and gel strength. A tradeoff is discovered between the faster crystallization in lower molecular weight CMC and the higher concentration required, which increases the amount of inert material that does not participate in the phase transition. After thermal cycling, the best formulation had a latent heat of 130 J/g with no supercooling, demonstrating excellent performance. This work advances PCM's reliability as a thermal energy storage solution for diverse applications and highlights the complex relationship between Na-CMC molecular weight and PCM stabilization.

Green banana biomass (Musa spp.) as a natural food additive in artisanal tomato sauce.

This study aimed to prepare artisanal tomato sauce (TSC, control) containing 10% (TS10) or 20% (TS20) of whole green banana biomass (GBB). Tomato sauce formulations were evaluated for storage stability, sensory acceptability, and color and sensory parameters correlations. Data were subjected to Analysis of Variance, followed by the comparison of means by Tukey's test (p < 0.05 and p < 0.01). Correspondence analysis was used to assess the responses to a Check-All-That-Apply questionnaire. A significant effect was observed (p > 0.05) for the interaction between storage time and GBB addition on all physicochemical parameters. GBB reduced titratable acidity and total soluble solids (p < 0.05), possibly because of its high content of complex carbohydrates. All tomato sauce formulations had adequate microbiological quality for human consumption after preparation. Sauce consistency increased with increasing GBB concentrations, improving the sensory acceptance of this attribute. All formulations achieved the minimum threshold for overall acceptability (70%). A thickening effect was observed with the addition of 20% GBB, resulting in significantly (p < 0.05) higher body, higher consistency, and reduced syneresis. TS20 was described as firm, very consistent, light orange in color, and very smooth. The results support the potential of whole GBB as a natural food additive.

Influence of the thickening agent contained in a phosphoric acid etchant on bonding between feldspar porcelain and resin cement with a silane coupling agent.

Phosphoric acid (PA) etchants are widely used for the bonding pretreatment of teeth; however, their influences on the bonding between glass-ceramics and resin cement have not been clarified yet. This study investigated the effect of a thickening agent on the bonding strength between feldspar porcelain treated with a PA etchant and resin cement with a silane coupling agent. The experiments were performed using two PA etchants: commercial one and prepared one consisting a PA aqueous solution and poly(ethylene glycol) thickening agent. The samples were evaluated by shear bond strength testing, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The obtained results revealed that the thickening agent adhered to the porcelain surface and inhibited cement bonding. Meanwhile, PA remained on the surface due to the presence of the thickening agent and activated the silane coupling agent. Overall, the PA etchant did not improve the bond durability.

Effects of polysaccharide thickening agent on the preparation of walnut oil oleogels based on methylcellulose: Characterization and delivery of curcumin.

Walnut oil-based oleogels were prepared by the emulsion-templated method using methylcellulose at different concentrations and viscosities as the oleogelators and polysaccharides (sodium alginate, xanthan gum and κ-carrageenan) as the thickening agents. The microscopic properties, rheological properties and oil binding capacity (OBC) of the oleogels were evaluated. The intermolecular and intramolecular hydrogen bonding of polysaccharide stabilized the network structure of the oleogel. The increasing methylcellulose concentration contributed to forming a more stable interfacial layer and providing oleogel with a compact structure. κ-Carrageenan resulted in a better OBC (97.37 %) and rheological properties of the methylcellulose-based oleogel. When served as a delivery system of curcumin, the highest encapsulation rate of curcumin (38.06 %) was achieved by the κ-carrageenan oleogel. The structure of oleogels slowed down the release rate of free fatty acids and curcumin during the early stage of in vitro digestion and the κ-carrageenan oleogel exhibited the highest inhibiting effect. This finding suggests that the polysaccharide-based walnut oil oleogels had a firmer structure and could be a promising approach to deliver curcumin.

Shear-Viscosity-Dependent Effect of a Gum-Based Thickening Product on the Safety of Swallowing in Older Patients with Severe Oropharyngeal Dysphagia.

Fluid thickening is a valid therapeutic strategy for patients with oropharyngeal dysphagia (OD). The main aim of this study was to determine the therapeutic effect of the xanthan-gum-based thickener Tsururinko Quickly (TQ, Morinaga Milk Co., Tokyo, Japan) in older patients with severe OD. A total of 85 patients (83.32 ± 6.75 y) with OD and a penetration-aspiration score (PAS) of n ≥ 3 were studied by videofluoroscopy while swallowing duplicate 10 mL boluses at <50 mPa·s, 100, 200, 400, 800, and 1600 mPa·s, to assess the safety and efficacy of swallowing and the biomechanics of a swallowing response at each viscosity level. At <50 mPa·s, only 16.25% patients swallowed safely, 45% had penetrations (PAS 3-5), and 38.75% had aspirations (PAS 6-8). Fluid thickening with TQ greatly increased the prevalence of patients with safe swallowing from 62.90% at 100 mPa·s to 95.24% at 1600 mPa·s in a shear-viscosity-dependent manner. The penetrations and aspirations were significantly reduced to 3.60% and 1.19%, respectively, at 1600 mPa·s. The threshold viscosity was 100 mPa·s and the increasing viscosity above 800 mPa·s did not further improve the therapeutic effect significantly. Increasing the shear viscosity significantly reduced the time to laryngeal vestibule closure (-16.70%), increased the time to upper oesophageal sphincter opening (+26.88%), and reduced the pharyngeal bolus velocity (-31.62%) without affecting the pharyngeal residue. TQ has a strong shear-viscosity-dependent effect on the safety of swallowing in older patients with severe OD without increasing the pharyngeal residue. The therapeutic range for TQ is 100-800 mPa·s, with 200 and 800 mPa·s being the optimal doses to cover the needs of older patients with OD.

Effect of Different Drying Treatments and Sieving on Royal Gala Apple Pomace, a Thickening Agent with Antioxidant Properties.

Currently, there is an increasing interest in the search of natural derived materials as valuable substitutes for microplastics. One of the categories investigated, represented by thickening agents deriving from agri-food waste and apple pomace (AP), was considered of interest. In this study AP was submitted to three different treatments and drying conditions (oven drying at 55 °C for 12 h; homogenization and oven drying at 55 °C for 12 h; homogenization and freeze-drying), and then grinded and sieved obtaining three different dimensional fractions (>400 µm, 250-400 µm and <250 µm). The hydroalcoholic extracts of these fractions, obtained by ultrasound-assisted extraction, were analyzed to compare their total phenol content (TPC), antioxidant properties, and phenol profile. Correlation studies between the above-indicated parameters were also carried out. The highest values of TPC, antioxidant capacity, and phenol content (determined by liquid chromatography) were found for oven dried AP (250-400 µm) or homogenized and freeze-dried (>400 µm) samples. Both samples were most suitable to form stable hydrogels and the sample obtained after drying at 55 °C showed the best performances in terms of ability to form a stable hydrogel. Among the studied treatments and drying conditions, the oven dried AP was demonstrated to be an interesting stabilizing material with potential applications in many fields (such as food, cosmetics, and nutraceuticals) showing both antioxidant activity and thickening capacity.

Pharmaceutical Incompatibility of Lubricating Gel Formulation Reduces Antibacterial Activity of Chlorhexidine Gluconate: In Vitro Study in Northern Thailand.

Chlorhexidine gluconate (CHG) is a cationic disinfectant. The positive charge of CHG molecules binds to phospholipid's negative charge in bacterial cell walls, causing membrane disruption. The in vitro kinetic physical, chemical and biological incompatibilities of nine lubricating gels with 1% w/v CHG were investigated. Five containing anionic thickener, two containing nonionic thickener, and two containing cationic thickener were collected from hospitals in northern Thailand. All the anionic and nonionic lubricating gels significantly reduced (p < 0.05) the CHG amount after 5 min of exposure time from 12.54% to 54.99%, respectively. In contrast, the amount of CHG exposed with cationic lubricating gels was maintained. Antibacterial activity was significantly reduced to a 1.17-4.33 log10 reduction for Staphylococcus aureus ATCC25923 and a 1.07-3.52 log10 reduction for Escherichia coli ATCC25922 after 5 min exposure to all anionic and nonionic lubricating gels. In contrast, the two cationic lubricating gels maintained the antibacterial activity of the CHG solution (5.69 ± 0.14 and 5.45 ± 0.17 log10 reduction). The results suggest that anionic and nonionic thickeners in lubricating gel formulations may neutralize the positive charge and reduce the antibacterial activity of CHG, reducing its effectiveness as a disinfectant.

Rheological Properties and Early-Age Microstructure of Cement Pastes with Limestone Powder, Redispersible Polymer Powder and Cellulose Ether.

In order to study the synergistic effects of organic and inorganic thickening agents on the rheological properties of cement paste, the rheological parameters, thixotropy cement-paste containing limestone powder (LP), re-dispersible polymer powder (RPP), and hydroxypropyl methylcellulose ether (HPMC) were investigated using the Anton Paar MCR 102 rheometer at different resting times. The early-age hydration process, hydration products, and microstructure were also analyzed with scanning electron microscopy (SEM) and thermogravimetry analyses (TGA). The results showed that the addition of LP, RPP, and HPMC affected the rheological properties of cement paste, but the thickening mechanism between organic and inorganic thickening agents was different. The small amount of LP increased the plastic viscosity but decreased the yield stress of cement paste due to its dense filling effect. Adding 1% of RPP improved the thixotropic property of cement paste by 50%; prolonging the standing time could improve the thixotropic performance by as much as two times. Only 0.035% HPMC added to the cement paste increased the plastic viscosity by 20%, while the yield stress increased nearly twice. The more HPMC added, the more significant effect it showed. Cement paste compounds with LP, RPP, and HPMC balanced the yield stress and plastic viscosity and improved the thixotropy. The C-L6-R1.0-H0.035 paste presented as a pseudoplastic, its rheological indexes were close to one, and it was hardly affected by the resting time. The composite superposition effect of organic and inorganic thickening agents reduced the impact of resting time for all pastes. As the organic thickening component inhibited the hydration more than the LP promoted the hydration of the cement paste, indicating that the C-L6-R1.0-H0.035 paste remained in the particle fusion stage after curing for three days, as shown by the SEM images.

Effects of yogurt as a deglutition aid on disintegration and dissolution of oral tablets.

Patients with dysphagia have difficulty swallowing oral medications. Swallowing aid foods, such as deglutition aid jellies and food thickeners, are often used to help such patients take oral medications. Yogurt is occasionally used to help swallow medications. It is also advantageous as it is nutritious and easy to swallow. However, the influence of yogurt on the pharmacokinetics of oral medications is poorly understood. In this study, we aimed to evaluate yogurt as a potential swallowing aid for the intake of oral tablets, by comparing the physical properties and effects of yogurt on disintegration and dissolution profiles of various oral tablets with deglutition aid jelly and xanthan gum-based food thickener. Yogurt and the food thickener were found to extend the disintegration time of several tablets; however, this increase was unremarkable. Although dissolution of magnesium oxide tablets decreased by 6%, 14%, and 25% after immersion in deglutition aid jelly, food thickener, and yogurt, respectively, at 15 min, this impact on dissolution reduced over time (dissolution rates of all samples at 120 min were over 90%). Rheological measurements showed that yogurt and food thickeners have a weak gel structure and therefore have better fluidity than deglutition aid jelly. The adhesiveness and dynamic viscosity of yogurt were higher than those of the food thickener, which delayed tablet disintegration and reduced the dissolution rate. However, these effects were not substantial. We can thus conclude that yogurt may be a useful swallowing aid for patients with deglutition disorders who take oral medications.

Gel Stability of Calcium Bentonite Suspension in Brine and Its Application in Water-Based Drilling Fluids.

With the development of the oil industry and the increasingly complex drilling environment, the performance of drilling fluids has to be constantly improved. In order to solve the problem of bentonite dispersion and hydration in a saline medium, a drilling fluid additive with good performance and acceptable cost was sought. The effects of several water-soluble polymers, such as cellulose polymers, synthetic polymers and natural polymers, on the rheology and gel suspension stability of calcium-based bentonite were compared in this study. Among the examined polymers, the xanthan gum biopolymer (XC) was the least negatively affected in the saline medium used. However, its high price limits its industrial application in oil and gas drilling fluids. In this study, a salt-tolerant polymer, modified vegetable gum (MVG), was prepared by a cross-linking modification of a natural plant gum, which is abundant and cheap. Then, a salt-tolerant polymer mixture called SNV was prepared, composed of the salt-resistant natural polymer MVG and the biopolymer XC. The salt tolerance and slurry ability of SNV and common water-soluble polymers were evaluated and compared. We then selected the most suitable Herschel-Bulkley model to fit the rheological curve of the SNV-bentonite aqueous suspension system. SNV improved the rheological properties of the calcium-based bentonite slurry and the dispersion stability of bentonite. In an SNV concentration of 0.35%, the apparent viscosity (AV) of the base slurry increased from 2 mPa·s to 32 mPa·s, and the low shear reading value at 3 rpm increased from 0 dia to 5 dia. This could greatly improve the viscosity and cutting carrying capacity of the bentonite drilling fluid. The bentonite drilling fluid prepared with SNV could be directly slurried with brine and even seawater; this means that when drilling in ocean, coastal saline water and high-salinity-surface saline water areas, the slurry preparation cost and preparation time can be conveniently reduced.

Impact of polymerized whey protein/pectin thickening (PP) system on physical properties and volatile compounds of goat milk kefir mild and kefir.

Polymerized whey protein and low-methoxyl pectin were used as thickening agents in fermented dairy food formulations. Effects of polymerized whey protein and pectin (PP) system on particle size distributions, rheological properties, molecular weight distributions of polysaccharides, microstructures, and volatile compounds of goat milk kefir mild and kefir were investigated. Clustering analysis indicated that the PP system addition could increase the particle size distributions and rheological properties of both kefir products. Molecular weight distributions of polysaccharides shown that an intermolecular aggregation occurred between pectin and exopolysaccharides (produced by microorganisms from starter cultures). Micrographs suggested that polymerized whey protein interacted with casein network to form a dense structure. Meanwhile, PP system did not change the characteristics flavor of goat milk kefir mild and kefir. Results indicated that the PP system may be a good combination to improve the physical properties of kefir products. PRACTICAL APPLICATION: Goat milk kefir has gained more and more attention due to its specific flavor and functional properties. However, poor texture of milk curd limits the consumption of fermented goat milk. As a new combination of thickening agents, PP system could specifically improve the particle size distributions and rheological properties of fermented goat milk. And the characteristic flavor of goat milk kefir was not changed. Results indicated that PP system can be used as thickening agents for formulations of different fermented goat milk products.

Ovalbumin and guar gum foam and its surface properties as influenced by sucrose and sorbitol.

The surface properties and foaming of ovalbumin and guar gum aqueous solutions was investigated in the presence of sucrose or sorbitol. All solutions had a broad particle size distribution (395.60 at 1137.50 nm). Higher ovalbumin concentrations had lower equilibrium surface tension and higher absolute values of the zeta potential, regardless the presence of sucrose or sorbitol. Mixtures containing ovalbumin and guar gum resulted in a predominantly elastic character of the air-water interface probably due to the formation of a complex (hydrogen bonding and/or hydrophobic interactions) between ovalbumin and guar gum. Besides, the increase in guar gum concentration enhanced the elasticity of the surface film. Higher concentrations of both polymers were required to provide higher kinetic stability to the system, although the increase in guar gum concentration reduced foam capacity due to the increase in the apparent viscosity. Foams formed in the presence of sucrose or sorbitol showed similar half-lives.