Decrease In Apparent Viscosity Research Articles

Effect of ethanol addition on the physicochemical, structural and in vitro digestive properties of Tartary buckwheat starch-quercetin/rutin complexes

The effects of ethanol on the physicochemical, structural and in vitro digestive properties of Tartary buckwheat starch-quercetin/rutin complexes (e-TBSQ and e-TBSR) were investigated. Ethanol restricted the gelatinization of Tartary buckwheat starch (TBS), which resulted an increase in ∆H, G' and G" as well as a decrease in apparent viscosity of e-TBSQ and e-TBSR. The particle size, scanning electron microscopy and X-ray diffraction results showed that ethanol influenced the morphological structure of TBS granules and the starch crystalline structure in e-TBSQ and e-TBSR changed from B-type to V-type when the ethanol concentration was 25%. Saturation transfer difference-nuclear magnetic resonance results revealed that ethanol weakened the binding ability of quercetin/rutin to TBS in e-TBSQ and e-TBSR, leading to a change in the binding site on the quercetin structural unit. The residual ungelatinized TBS granules in e-TBSQ and e-TBSR induced a high slowly digestible starch content, and thus displayed a “resistant-to-digestion”.

Development and characterization of sauces formulation based on tomato and garlic powders

Background: Consumers have increasingly high demands in terms of taste, color and texture; they expect foods to be safe, healthy and nutritious, more appealing in color, texture and taste, and ready-to-use products such as sauces. Aim: The aim of this study was to formulate sauces with tomato (TP) and garlic (GP) powders resulted from conventional and microwave dryings. Material and Methods: TP was used at 0, 5, 10 and 15% in the formulation of tomato sauce and GP at 0, 5, and 20% in the formulation of garlic sauce. For studying the effects of these powders on quality of sauces, some properties such as pH, Brix, apparent viscosity, mesophilic aerobic total flora (MATF), total coliforms,mold and yeast colony count and sensory evaluation were determined. Results: The results showed that the increase in the powders proportions increased pH from 5.32 to 5.72 for garlic sauces but decreased it from 5.42 to 5.04 for tomato sauces. However, the Brix values increased from 12.8 (5% tomato sauce) to 19.6% (15% tomato sauce), and from 15.5 (5% garlic sauce) to 18.8% (20% garlic sauce).On the other hand, it caused decrease in apparent viscosity from 7 to 3.5 cm for tomato sauces and from 5to 2.5 cm for garlic sauces. Similarly, MATF, mold and yeast colony count in sauce samples were diminished. Conclusion: The use of TP at 5% (estimated by 60% of the experts) is recommended for the formulation of the tomato sauce whereas for the garlic sauces, the two formulations used were equally appreciated by 100% of the experts. Keywords: Tomato sauce, garlic sauce, physicochemical analysis, microbiological analysis, sensory analysis.

Supplemental methionine selenium effects on egg yolk physicochemical, functional, and protein structure during storage.

To clarify the effect of the addition of methionine selenium on the physicochemical, functional, and protein structural properties of egg yolk during storage. We analyzed the changes in the main indicators of egg yolks stored at 4°C and 25°C for 28 days. The results showed that the increase in water content and pH, and the decrease in absolute zeta potential and apparent viscosity of the selenium-rich egg yolks (Se-group) during storage were smaller than those of the control group egg yolks (C-group). In addition, the antioxidant capacity and emulsifying ability of the Se-group during storage were better than those of the C-group. Simultaneously, the hardness and chewiness of the Se-group gel during storage were lower than those of the C-group. The protein structure results showed that selenium rich treatment did not affect the secondary structure of egg yolk protein during storage but could improve the fluorescence intensity of the egg yolk protein. Therefore, the addition of methionine selenium can reduce the degree of deterioration in the physicochemical properties of egg yolk during storage and extend its shelf life.

Effect of single and two-stage fermentation on the antioxidative activity of soybean meal, and the structural and interfacial characteristics of its protein

The efficiency of single and two-stage solid-state fermentation (SSF) of soybean meal (SBM) by thermophilc Bacillus licheniformis YYC4 was examined. Crude and soluble protein contents were significantly increased after SSF, especially two-stage SSF (TS-SSF), however, substantial reduction in trypsin inhibitor was observed. Additionally, TS-SSF significantly enhanced the reducing power and scavenging DPPH, hydroxyl and ABTS radical activities of SBM. On the other hand, TS-SSF significantly reduced the α-helix, fluorescence intensity and caused a red-shifted in the maximum absorption wavelength (λmax), but increased the surface hydrophobicity, β-sheet, and sulfhydryl group and disulfide bond content of SBM protein (SBMP). Again, SSF, particularly TS-SSF, reduced the particle size of SBMP, leading to a corresponding decrease in apparent viscosity. Compared to the single-stage SSF (SS-SSF), TS-SSF caused significant improvement in the interfacial properties of SBMP. Likewise, SBM fermented by TS-SSF had higher nutritional value, better antioxidative activity and interfacial properties than the SS-SSF sample.

Chemical and Pasting Properties of Potato Flour (Solanum tuberosum L.) in relation to Different Processing Techniques

Processing potato tubers into flour can be done using various methods, which can impact the flour’s nutritional and pasting properties. This study evaluated the effects of five different processing methods, namely, low-temperature blanching, followed by oven drying (LTB_OD), high-temperature blanching followed by oven drying (HTB_OD), boiling followed by oven drying (Boiling_OD), freeze drying (FD), and oven drying (OD), on the nutritional and pasting properties of potato flour derived from Shangi potato variety. The relationships between the nutritional and pasting properties were determined using Pearson’s correlation and principal component analyses (PCA). The results indicated that freeze-dried flour exhibited higher protein content (10.17%), sucrose (88.87 mg/100 g), and magnesium (44.90 mg/100 g) content, while Boiling_OD flour showed the lowest protein (6.41%), sucrose (15.34 mg/100 g), and magnesium (35.55 mg/100 g) content. All potato flour types demonstrated a decrease in apparent viscosity with increasing shear rate, with freeze-dried flour having the highest apparent viscosity. Freeze-dried flour showed the highest peak viscosity (7098.33 cP) and breakdown viscosity (2672.00 cP). The highest final viscosity (7989.00 cP) was recorded in HTB_OD flour. Protein ( r = − 0.92 ), fiber ( r = − 0.81 ), and fat ( r = − 0.83 ) negatively correlated with the peak viscosity, while sugars (glucose ( r = 0.95 ), fructose ( r = 0.93 ), and sucrose ( r = 0.87 )) and phosphorus ( r = 0.86 ) positively correlated with pasting properties. The first two principal components explained 90.2% of the total variance. Oven drying and freeze drying were in close proximity in the PCA score plot, indicating that these two flour types have similar chemical and pasting properties. In conclusion, the different processing methods altered the chemical and pasting properties of the flour, therefore influencing their potential use in the food industry. Considering the correlations established in this study, it is likely that chemical properties could be used to predict the pasting properties of potato flour.

Preparation of Polymer Solution for Profile Control and Displacement Using Wastewater with High Ca2+/Mg2+ and Fe2+ Concentrations

In the present study, we used Kalamkas, which is a typical Kazakhstani oilfield, which produces wastewater with high Ca2+/Mg2+ and Fe2+ concentrations, as a case study. We investigated a method for preparing Fe2+ polymer solutions without oxygen isolation under the conditions of salinity >110 × 103 mg/L, Ca2+/Mg2+ concentration >7000 mg/L, and Fe2+ concentration >30 mg/L. Fe2+-resistant groups were grafted onto the molecular chains of a hydrophobically associating polymer prepared using existing synthesis technology to overcome the decrease in apparent viscosity of the polymer solution due to the oxidation of Fe2+ during solution preparation. The experiments showed that PAM-IR with iron-resistant groups can be completely dissolved in the wastewater within 180 min, and can tolerate an NaCl concentration of up to 0.23 × 106 mg/L, a Ca2+ concentration of up to 10 × 103 mg/L, an Mg2+ concentration of up to 9 × 103 mg/L, and a Fe2+ concentration of up to 90 mg/L, with favorable thickening performance and resistances to NaCl, Ca2+, Mg2+, and Fe2+. PAM-IR has good injection performance and can establish a high resistance factor (FR) and residual resistance factor (FRR) to increase the sweep efficiency. Therefore, it is potentially useful for enhancing oil recovery.

Effect of bulk nanobubbles on ultrafiltration membrane performance: Physiochemical, rheological, and microstructural properties of the resulting skim milk concentrate dispersions

The objective of this study was to evaluate the influence of bulk nanobubble (BNB) incorporation during ultrafiltration (UF) process. Both lab and pilot-scale UF experiments were conducted to evaluate effect of BNB incorporation on UF process by evaluating permeate flux, membrane microstructure, fouling resistance, and energy consumption. Additionally, control and BNB incorporated skim milk concentrate (SMC) dispersions were characterized in terms of physicochemical properties, rheology, and microstructure. Operating UF with BNB incorporation gave better membrane performance, evidenced by better permeation flux. The permeation flux of control SMC was 9.27, and 6.89 kg/h∙m 2 and with BNB incorporation permeate flux significantly increased (P < 0.05) to 14.57 and 9.59 kg/h∙m 2 for lab and pilot-scale UF runs, respectively. BNB incorporation also resulted in a significant decrease (P < 0.05) in apparent viscosity and showed marked changes in microstructure of resultant skim milk concentrate dispersions. In conclusion, BNB incorporation helped to improve UF membrane performance, and therefore this study suggests the potential of using BNB incorporation for a more efficient UF processing. • Bulk nanobubbles (BNB) generated by acoustic and hydrodynamic cavitation improved ultrafiltration membrane performance. • Higher permeate flux can be achieved with BNB incorporation. • The apparent viscosity of resultant skim milk concentrate dispersions reduced with BNB incorporation. • Less membrane depositions with the BNB incorporation. • Permeate flux enhancement of ⁓50% can be achieved with the BNB incorporation. • BNB incorporation influenced the rheological and microstructural properties of skim milk concentrate dispersions.

Insight into Effects of high Intensity Ultrasound Treatment on Foamability and Physicochemical Properties of Frozen egg White Protein

Frozen storage can greatly improve the shelf life of fresh egg white protein (EWP), but it will also lead to the reduction of protein foaming and can not meet the application needs. Herein, high-intensity ultrasound (HIUS) was used to improve the foam characteristics of EWP in different frozen storage periods. The results showed that compared with fresh egg white, the foaming ability of EWP with different freezing times (0, 3, 7, 14, 21 days) after HIUS treatment (20 kHz, 60% amplitude, 5 min) was significantly improved, especially the EWP after 21 days of frozen storage was doubled by HIUS induction. Furthermore, it was found that the improvement of EWP foamability was mainly due to the enhancement of surface hydrophobicity (H0, the value from 263 to 456) and the decrease of apparent viscosity (from 0.506 Pa.s to 0.007 Pa.s), which increased the diffusion rate of protein to the interface (from 0.19 mNm− 1s− 0.5 to 0.26 mNm− 1s− 0.5) and its adsorption amount (from 35.8 to 43.3%) at the interface. These results showed that HIUS was a simple, efficient and residue free way to improve the foam characteristics of frozen EWP, which has strong promotion and application value.

Physicochemical stability and in vitro digestibility of goat milk affected by freeze-thaw cycles

Freezing and thawing are widely used in dairy processing to ensure the continuous supply of raw milk. In virtue of this, the influences of freeze-thaw cycles on physicochemical stability and in vitro digestibility of goat milk were evaluated. Experimental results showed that repeated freeze-thaw cycles led to the increase of acidity and medium-short chain free fatty acids of goat milk, and the significant decrease of fat and apparent viscosity. Furthermore, the degree of protein oxidation was enhanced, and the secondary structure changed to random coil. The particle size distribution and microstructure all showed the aggregation of goat milk droplets, resulting in the decrease of physical stability. Nevertheless, repeated freeze-thaw cycles could enhance the simulated in vitro digestibility and antioxidant capacity of digested products. These results are helpful to evaluate the quality characteristics of raw goat milk and provide theoretical reference for the industrial production of goat milk products.

Magneto‐hydrodynamic mixing: A new technique for preparing carbomer hydrogels

AbstractMagnetohydrodynamic mixing was evaluated as an alternative to conventional high shear mixing (HSM) in the preparation of carbomer hydrogels containing 1.22 wt% Carbopol® 980 NF. Neutralization of the carbomer dispersion (pH = 2.74) with triethanolamine (TEA) enabled to adjust the pH of the mixture and tune the viscosity of the hydrogel. Using HSM, this approach was limited to 0.2 wt% TEA (pH = 3.83) as the gel became too viscous and the recirculation flow dropped from 12 to 0.3 m3/h. Magnetohydrodynamic mixing enabled to reach TEA concentrations up to 1.0 wt% (pH = 5.31). Apparent viscosity measurements on samples having 0.2 wt% TEA revealed lower viscosities for carbomer hydrogels prepared with HSM, that is, 6800 mPa s versus 8800 mPa for magneto‐hydrodynamic mixing. Based on 1H NMR evidence, this decrease in apparent viscosity was attributed to structural damage to the carbomer backbone in combination with mechanochemical degradation of the added TEA.

Low-cholesterol-low-fat mayonnaise prepared from soybean oil body as a substitute for egg yolk: The effect of substitution ratio on physicochemical properties and sensory evaluation

Due to the higher fat and cholesterol content in egg yolks, it is urgent to explore egg yolk substitutes in mayonnaise. Soybean oil body (SOB) has the potential to be a substitute for egg yolk due to its stable natural emulsifying properties. Therefore, this study investigated the effects of different ratios of SOB (10%–50%) substitution for egg yolk on the physicochemical, texture, flavor, sensory and digestive properties of mayonnaise. It was found that when SOB substituted for 50% of egg yolk, the cholesterol content per 100 g of mayonnaise sample was decreased from (124.10 ± 3.81) mg to (48.25 ± 1.44) mg, and the fat content decreased from (53.15 ± 0.24)% to (44.09 ± 0.38)%. Although, the higher moisture content in SOB resulted in a decrease in apparent viscosity and stability of the mayonnaise samples, the sensory score of mayonnaise with SOB substituted for 20% of egg yolk was not significantly different from that of the mayonnaise without SOB substitution (p > 0.05). Furthermore, SOB-substituted mayonnaise has health benefits by releasing more antioxidant active components during digestion, compared to whole egg yolk mayonnaise. Therefore, SOB has potential as an egg yolk substitute for the development of functional low-fat mayonnaise.

Influence of molecular structure and interface behavior on foam properties of rice bran protein nano-particles

According to our previous research, thermal-acidic treatment was an effective way to improve foaming properties, especially foam stability, of rice bran protein (RBP) samples. In this article, the molecular structure and interface behavior of native RBP and rice bran protein nano-particles (RBPNs) were characterized to illustrate the relevant mechanisms affecting foaming properties. The circular dichroism (CD) and intrinsic fluorescence measurements suggested that thermal-acidic treatment could increase the flexible conformation of RBPNs corresponding to a higher surface activity at the interface. The decrease in apparent viscosity of RBPNs also illustrated the improvement in foam capacity of RBPNs. Moreover, the studies of air-water interfacial behavior demonstrated that the interfacial interaction of RBPNs-1 behaved stronger resulting in forming a stronger and more stretchable interfacial viscoelastic film compared to native RBP, which was mainly related to the different intermolecular interactions at the interface between the RBPNs-1 and native RBP. Further, combined with the analysis of the foam microstructure, it could indicate that in addition to the effects of the interface film on foam stability, the RBPNs trapped in Plateau borders provided the jamming effect by impeding the flow and reducing the rate of drainage. These findings are helpful to understand the relationship between molecular structure, interface behavior, and foaming properties.

Fast-dissolving antioxidant nanofibers based on Spirulina protein concentrate and gelatin developed using needleless electrospinning

Spirulina is a microalga that is well-known for its high protein content and biological activities directly related to its antioxidant capacity. The objective of this study was to produce fast-dissolving antioxidant nanofibers based on Spirulina protein concentrate (SPC) and gelatin using needleless electrospinning technique. The effect of mixing ratios of SPC (10% w/w) and gelatin (20% w/w) on the viscosity, electrical conductivity and surface tension of electrospinning solutions as well as diameter and morphology of resulting nanofibers was investigated. Increasing the SPC level in the solution blends resulted in a decrease in apparent viscosity and electrical conductivity and an almost stable trend in surface tension (29.25–32.19 mN/m) that led to diminish of diameter of the nanofibers. Scanning electron microscopy images showed that SPC/gelatin ratio of 40:60 led to the production of uniform and bead-free nanofibers with a relatively smaller average diameter (208.7 ± 46.5 nm). Atomic force microscopy images indicated mesh-like, fibrillary, and bead-free structures. Fourier transform infrared spectroscopy verified the formation of composite nanofibers and intermolecular interactions between both proteins. X-ray diffraction and thermal analysis showed higher amorphous structure and stability of produced SPC/gelatin nanofibers in comparison to pure materials which was favorable for formation of stable fast-dissolving fibers. Results of DPPH and ABTS radical scavenging activities showed that the antioxidant activity of composite nanofibers significantly improved with increasing SPC mixing ratio (p < 0.05). The dissolution test demonstrated that SPC/gelatin nanofibers can be rapidly dissolved in aqueous medium within 2 s. Finally, the results indicated that the electrospun SPC/gelatin nanofibers could be potentially used for nutraceutical delivery in food and packaging applications under high humidity.

Study on the preparation of coal wastewater slurry from salt/alkali wastewater

Combining experimental research and simulation calculation, the effect of high-concentration salt/alkali wastewater on the preparation of coal wastewater slurry (CWWS) was studied. The research on the slurry-ability of CWWS shows that Na+ in NaCl will be electrically neutralized with the negative charge on the coal, the electrostatic repulsion of particles will decrease, and the viscosity will increase. In the presence of HCO3c, negative charge increases on coal particles, the apparent viscosity decreases by 42 mPa·s compared with the absence of HCO3−. In the CO32− systems, the pH is 8.25. Higher pH indicates that there are more OH−. Because CO32− is easy to combine with water to form a stable structure, and the strong polar effect of OH− is also easy to bind water molecules, forming a stable water molecule layer configuration on the coal, which hinders the adsorption of sodium lignosulfonate (SL), resulting in a decrease in steric hindrance effect, which is not conducive to the dispersion of particles. The molecular dynamics (MD) simulation results confirmed the existence of the neutralization of Na+ and the negative charge on coal in the NaCl system. The adsorption energies (Eadsorption) of each system were negative, indicating that the dispersant was easily adsorbed on the coal. However, in the CO32− system, the absolute value of Eadsorption was lower than that the pure water system, indicating that the presence of CO32− is not conducive to the adsorption of SL. The self-diffusion coefficient(D) of Na2CO3 system is lower than that of coal/water/SL system, NaCl system, and NaHCO3 system. It shows that the presence of CO32− can significantly reduce the migration rate of water molecules and is easy to bind water molecules. The presence of HCO3− is also easy to bind water molecules, but it is weaker than CO32−. The migration and diffusion rate of water molecules in the saline-alkali mixed system decrease. This may be mainly affected by CO32−, which easily binds water molecules on the coal surface and hinders the adsorption of SL.

Effects of mild thermal pre-treatment combined with H2O2 addition on waste activated sludge digestibility

The pre-treatment of waste activated sludge (WAS) has become more common since it often results in improved bioconversion to methane, in both rate and extent. However, thorough insights on the possible effects and mechanisms of mild pre-treatment techniques, such as temperatures <100 °C combined with the addition of H2O2, are still limited. This study reports the effects of the addition of 5–30 mgH2O2/g TS and its interaction with thermal pre-treatment at 70 °C on methane production, using WAS as the substrate. It was found that the addition of H2O2 increased the methane production rate, coinciding with a decrease in apparent viscosity of WAS, which probably improved mass transfer under non-ideal mixing conditions. While H2O2 solubilized proteins and carbohydrates and mineralized a small fraction of the humic substances in WAS, these biochemical transformations did not suffice to explain the observed extent and rate of methane production. A decreased particle size, the presence of Fenton’s reagent, and the presence of cationic polymers in the WAS were discarded as the reasons for the observed decrease in apparent viscosity. It was concluded that the pre-treatment conditions applied in the present study might be a strategy to enhance mixing conditions in full-scale anaerobic digesters.

Shape recovery of deformed biomolecular droplets: Dependence on condensate viscoelasticity.

A theoretical study on the shape dynamics of phase-separated biomolecular droplets is presented, highlighting the importance of condensate viscoelasticity. Previous studies on shape dynamics have modeled biomolecular condensates as purely viscous, but recent data have shown them to be viscoelastic. Here, we present an exact analytical solution for the shape recovery dynamics of deformed biomolecular droplets. The shape recovery of viscous droplets has an exponential time dependence, with the time constant given by the "viscocapillary" ratio, i.e., viscosity over interfacial tension. In contrast, the shape recovery dynamics of viscoelastic droplets is multi-exponential, with shear relaxation yielding additional time constants. During shape recovery, viscoelastic droplets exhibit shear thickening (increase in apparent viscosity) at fast shear relaxation rates but shear thinning (decrease in apparent viscosity) at slow shear relaxation rates. These results highlight the importance of viscoelasticity and expand our understanding of how material properties affect condensate dynamics in general, including aging.

Preparation and properties of electrospun peanut protein isolate/poly-l-lactic acid nanofibers

Peanut protein isolate (PPI) is bio-friendly, degradable, and may be obtained from a wide range of sources. In this study, hexafluoroisopropanol solutions of PPI and poly-l-lactic acid (PLLA) were electrospun to prepare nanofibers. The effects of the surface tension, conductivity, and viscosity of the PPI/PLLA solution on nanofiber morphology were investigated. Furthermore, the PPI/PLLA nanofibers were thoroughly characterized using a range of techniques. The results revealed that as the PPI content of the solution increases, its apparent viscosity decreases, its conductivity increases, and the diameter of the nanofibers is reduced from 339 nm to 164 nm. At a PPI/PLLA mass ratio of 50:50, the fiber morphology is good, no beading is observed, and the fiber diameter is uniform. In mechanistic terms, our results indicated that PPI and PLLA molecules interact by forces such as hydrogen bonding, and that PPI disrupts the ordered molecular arrangement of the PLLA, thereby reducing the crystallinity of the nanofibers while improving their thermal stability. Furthermore, as the mass fraction of PPI increases, the tensile strength of the nanofibers decreases while their hydrophobicity increases. Overall, this study has successfully realized the preparation of PPI nanofibers, providing a basis for their application in biomedicine, catalysis, and other fields.

A continuum mechanics model for the F\xe5hr\xe6us-Lindqvist effect

The decrease in apparent relative viscosity that occurs when blood is made to flow through a tube whose diameter is less than about 0.3 mm is a well-known and documented phenomenon in physiology, known as the Fåhræus-Lindqvist effect. However, since the historical work of Fåhræus and Lindqvist (Amer. J. Physiol. 96(3): pp. 562–568, 1931), the underlying physical mechanism has remained enigmatic. A widely accepted qualitative explanation was provided by Haynes (Amer. J. Physiol. 198, pp. 1193–1200, 1960) according to which blood flows in microvessels with a core-annulus structure, where the erythrocytes concentrate within a central core surrounded by a plasma layer. Although sustained by observations, this conjecture lacks a rigorous deduction from the basic principles of continuum dynamics. Moreover, relations aimed to reproduce the blood apparent relative viscosity, extensively used in micro-circulation, are all empirical and not derived from the analysis of the fluid mechanical phenomena involved. In this paper, we apply the recent results illustrated in Guadagni and Farina (Int. J. Nonlinear Mech. 126, p. 103587, 2020), with the purpose of showing that Haynes’ conjecture, slightly corrected to make it more realistic, can be proved and can be used to reach a sound explanation of the Fåhræus-Lindqvist effect based on continuum mechanics. We propose a theoretical model for the blood apparent relative viscosity which is validated by matching not only the original experimental data reported by Fåhræus and Lindqvist (Amer. J. Physiol. 96(3), pp. 562–568, 1931), but also those provided by several subsequent authors.

Plant protein-based antioxidant Pickering emulsions and high internal phase Pickering emulsions against broad pH range and high ionic strength: Effects of interfacial rheology and microstructure

The present work aimed to explore the stability mechanism of Pickering emulsions (PEs) and high internal phase PEs (HIPPEs) to resist environmental stresses (i.e., pH and ionic strength) via altering the interfacial rheology and microstructure. The storage, centrifugal, oxidative stabilities and interfacial properties of PEs and HIPPEs stabilized by pea protein isolate-high pectin-epigallocatechin gallate (PPI-HMP-EGCG) complex were investigated. The compact and dense viscoelastic interfacial layers, appropriate gel-like elastic network structure and apparent viscosity allowed PEs and HIPPEs to have excellent long-term storage stability, the best centrifugal and oxidative stabilities at pH 3.5 and 0 mmol/L NaCl. As PEs and HIPPEs at neutral and alkaline conditions, the centrifugal and oxidative stabilities of PEs and HIPPEs reduced, which was ascribed to the insufficient number of complexes, leading to the formation of the weak interfacial layer and the decrease of apparent viscosity and viscoelasticity. As NaCl concentration increased to 1000 mmol/L, the oil droplets were not completely surrounded by the interfacial layer with weak viscoelastic response, which resulted in the reduction of centrifugal and oxidative stabilities. These findings are useful to broaden the application of antioxidant PEs and HIPPEs in the food industry under a wide range of pH and ionic strengths.

Study on the Relationship between Emulsion Properties and Interfacial Rheology of Sugar Beet Pectin Modified by Different Enzymes.

The contribution of rheological properties and viscoelasticity of the interfacial adsorbed layer to the emulsification mechanism of enzymatic modified sugar beet pectin (SBP) was studied. The component content of each enzymatic modified pectin was lower than that of untreated SBP. Protein and ferulic acid decreased from 5.52% and 1.08% to 0.54% and 0.13%, respectively, resulting in a decrease in thermal stability, apparent viscosity, and molecular weight (Mw). The dynamic interfacial rheological properties showed that the interfacial pressure and modulus (E) decreased significantly with the decrease of functional groups (especially proteins), which also led to the bimodal distribution of particle size. These results indicated that the superior emulsification property of SBP is mainly determined by proteins, followed by ferulic acid, and the existence of other functional groups also promotes the emulsification property of SBP.