This work aimed to investigate the combined effect of ultrasound (US) treatment and κ-carrageenan (KC) addition on the gelling properties and rheological behaviors of myofibrillar protein (MP). Without US treatment, the KC incorporation promoted the gel strength and water-holding capacity (WHC) of MP gels. These properties were further improved by 20 min US treatment with gel strength of 98.61 g and WHC of 79.87 %, which was mainly attributed to changes associated with hydrophobic interactions and disulfide bonds and the transformation from α-helix to β-sheet in MP gels. In addition, US treatment for 20 min effectively resulted in a more homogeneous polymer distribution of the MP-KC mixed system, leading to lower particle size and the largest G\' and G″ values of the MP-KC mixed gels. However, longer US treatment times (30, 40 and 50 min) rendered lower gel strength, WHC, storage modulus and loss modulus of MP-KC mixed gels, which was mainly due to the formation of loose and disordered gel structures. Our present results indicated that the application of US to MP for an intermediate treatment time (20 min) combined with KC provides a potential and novel strategy to promote the gel qualities of heat-induced MP gels.

Functional properties and ability to stabilize Pickering emulsions of amaranth starch with the novel nonenyl succinic anhydride (NSA) modification and the widely used octenyl succinic anhydride (OSA) modification were compared. The NSA modification was more effective in altering the rheological properties of amaranth starches. NSA-modified amaranth starch showed significantly higher peak viscosity (7.13 Pa·s at DS of 0.02209) than the OSA-modified amaranth starch (6.10 Pa·s at DS of 0.03042). The gelatinization temperature, gelatinization enthalpy, and relative crystallinity of amaranth starch were more affected by the OSA than the NSA. The Pickering emulsions stabilized with NSA-modified starches had higher stability than those with the OSA-modified starches as characterized by particle size distribution, morphological, and rheological approaches. A lower degree of substitution by NSA than by OSA is needed to achieve a similar emulsification capacity. Thus, the NSA modification could be an efficient alternative to OSA modification in tailoring physicochemical and rheological functions, as well as stabilizing Pickering emulsions.

Eco-friendly waterborne polyurethanes (WPU) find wide application in agriculture as pesticide carriers, which enhances their efficiency. To provide better control of the retention time and capacity of pesticides, WPU can be modified by cyclodextrin derivatives able to form supramolecular assemblies with bioactive substances. Synthesis of WPU containing up to 15 wt.% of covalently bound β-cyclodextrin partial nitrate (CDPN) is reported in this work. Covalent bonding of CDPN to a polyurethane matrix has been proved by IR spectroscopy and size exclusion chromatography. The particle size and viscosity of the WPU dispersion have been determined. The introduction of CDPN affects molecular weight and thermal properties of WPU films. The presence of CDPN in WPU is shown to provide higher average molecular weight, wider molecular weight distribution, and larger average size of dispersed particles, compared with WPU reference samples containing 1,4-butanediol. The analysis of the rheological behavior of the obtained WPU dispersions shows that they can be classified as pseudoplastic liquids. The analysis of the thermal parameters of WPU films indicates that the introduction of 15.0 wt.% CDPN shifts the value of the glass transition temperature from -63 °C to -48 °C compared with reference samples. We believe that the results of the present study are sufficiently encouraging in terms of using CDPN-modified eco-friendly WPU as potential systems for developing the delivering agents of bioactive compounds. The application of such systems will allow the long-term contact of pesticides with the plant surface and minimize the possibility of their release into the environment.

With increasing consumer demand for \"clean label\" products, the use of natural ingredients is required in the food industry. Protein/polysaccharide complexes are considered good alternatives to synthetic emulsifiers and stabilizers for formulating stable emulsion-based foods. Milk protein and carrageenan are widely used to improve the physical properties and stability of dairy food products. In a previous study, milk protein isolate (MPI) was conjugated with κ-carrageenan (κ-Car) in a wet-heating system through the Maillard reaction, and the Maillard conjugates (MC) derived from MPI and κ-Car effectively improved the stability of oil-in-water emulsions. Therefore, MPI/κ-Car conjugates were used in whipping cream as natural emulsifiers in this study, and the physical and rheological properties of whipping creams stabilized using MPI/κ-Car MC and MPI/κ-Car electrostatic complexes (EC) were investigated. The whipping creams stabilized with MPI/κ-Car MC have lower rheological parameters (ηa,50, K, G\', and G″) than those of whipping creams stabilized with MPI/κ-Car EC. Although the overrun value was slightly reduced owing to the addition of MPI/κ-Car MC, the stability of the whipped creams with MC was effectively improved due to enhanced water-holding ability by conjugation.

This study aims to develop and evaluate fracturing nanofluids from the laboratory to the field trial with the dual purpose of increasing heavy crude oil mobility and reducing formation damage caused by the remaining fracturing fluid (FF). Two fumed silica nanoparticles of different sizes, and alumina nanoparticles were modified on the surface through basic and acidic treatments. The nanoparticles were characterized by transmission electron microscopy, dynamic light scattering, zeta potential and total acidity. The rheological behavior of the linear gel and the heavy crude oil after adding different chemical nature nanoparticles were measured at two concentrations of 100 and 1000 mg/L. Also, the contact angle assessed the alteration of the rock wettability. The nanoparticle with better performance was the raw fumed silica of 7 nm at 1000 mg/L. These were employed to prepare a fracturing nanofluid from a commercial FF. Both fluids were evaluated through their rheological behavior as a function of time at high pressure following the API RP39 test, and spontaneous imbibition tests were carried out to assess the FF\'s capacity to modify the wettability of the porous media. It was possible to conclude that the inclusion of 7 nm commercial silica nanoparticles allowed obtaining a reduction of 10 and 20% in the two breakers used in the commercial fracture fluid formulation without altering the rheological properties of the system. Displacement tests were also performed on proppant and rock samples at reservoir conditions of overburden and pore pressures of 3200 and 1200 psi, respectively, while the temperature was set at 77 °C and the flow rate at 0.3 cm3/min. According to the effective oil permeability, a decrease of 31% in the damage was obtained. Based on these results, the fracturing nanofluid was selected and used in the first worldwide field application in a Colombian oil field with a basic sediment and water (BSW%) of 100 and without oil production. After two weeks of the hydraulic fracture operation, crude oil was produced. Finally, one year after this work, crude oil viscosity and BSW% kept showing reductions near 75% and 33%, respectively; and having passed two years, the cumulative incremental oil production is around 120,000 barrels.

Pomegranate peel pectin is an important acidic anionic plant polysaccharide which can be used as a natural emulsifier. In order to study its emulsifying properties, this paper systematically analyses pomegranate peel pectin samples from Chinese Xinjiang, Sichuan and Yunnan provinces, through rheometer, interfacial rheometer, Zetasizer Nano-ZS and mastersizer. It is shown that pomegranate peel pectin can effectively reduce the oil-water interfacial tension, reaching an emulsion droplet size of only 0.507 μm, 0.669 μm and 0.569 μm, respectively, while the pectin concentration is 1.5% and the oil phase (MCT) is 10%. It has also shown that the extreme conditions of pH and ion strength can not significantly change its emulsion stability. However, freeze-thaw cycles can cause the pomegranate peel pectin emulsion to become less stable. Furthermore, the effects of decolourization, protein removal and dialysis on the emulsifying properties of pomegranate peel pectin are investigated using mastersizer rheometer and interfacial rheometer. It is found that the protein and pigment in pomegranate peel pectin have little effect on its emulsifying properties, while the results from dialyzed pectin show that the small molecule substances can reduce the emulsion particle size and increase the emulsion stability. The research outcomes of this study provide technical support for the further application of pomegranate peel pectin in the food industry.

Polysaccharides are broadly used as plasticizing, emulsifying, stabilizing, thickening, gelling, binding and coating agents. The optimum extraction point based on highest yield and total carbohydrate content and lowest amount of protein was extraction temperature of 68.75 °C, pH = 10 and water to seed ratio of 36:1. Lallemantia ibrica seed gum (LISG) is a high molecular weight polysaccharide (5.74 × 106 g/mol) containing, on average, 89.60% carbohydrate, 2.98% protein, 8.95% ash, 0.2% fat and 6.52% moisture. FTIR and 1H NMR analysis revealed the presence of galactose, mannose, rhamnose, uronic acid and O-acetyl functional groups. The intrinsic viscosity of LISG (at 25 °C) was estimated to be 1.96 dL/g. The gum solutions had a shear-thinning behavior at all tested concentrations, and the Power-law model satisfactory described their rheological behavior. It was found that deionized water (pH = 7 at 25 °C) is a good solvent for LISG macromolecules. The shear thinning behavior of LISG and its high viscosity at low concentration make it a good stabilizer and thickener in the food industry.

The influence of the addition of tunicate cellulose nanowhiskers on the structural and rheological properties of an agarose hydrogel matrix has been studied, with the objective to design innovative green material, with good mechanical properties. The cellulose nanowhiskers were characterized using transmission electron microscopy, and their charge surface density was determined by a titration method. Oscillatory shear and stress relaxation tests were performed in order to characterize the rheological properties of the agarose matrix, and of the agarose hydrogels filled by nanowhiskers at volume fractions below 0.2%. The results show a significant reinforcement effect due to the addition of nanowhiskers, and suggest changes in the matrix network structure induced by the cellulose nanoparticles.