The effect of various pH values on foaming properties of whey protein preparations

Effect of whey protein isolate addition on set-type camel milk yogurt: Rheological properties and biological activities of the bioaccessible fraction

The manufacture of camel milk (CM) yogurt has been associated with several challenges, such as the weak structure and watery texture, thereby decreasing its acceptability. Therefore, this study aimed to investigate the effect of whey protein isolate (WPI) addition on the health-promoting benefits, texture profile, and rheological properties of CM yogurt after 1 and 15 d of storage. Yogurt was prepared from CM supplemented with 0, 3, and 5% of WPI and compared with bovine milk yogurt. The results show that the water holding capacity was affected by WPI addition representing 31.3%, 56.8%, 64.7%, and 45.1% for yogurt from CM containing 0, 3 or 5% WPI, and bovine milk yogurt, respectively, after 15 d. The addition of WPI increased yogurt hardness, adhesiveness, and decreased the resilience. CM yogurt without WPI showed lower apparent viscosity, storage modulus, and loss modulus values compared with other samples. The supplementation of CM with WPI improved the rheological properties of the obtained yogurt. Furthermore, the antioxidant activities of yogurt before and after in vitro digestion varied among yogurt treatments, which significantly increased after digestion except the superoxide anion scavenging and lipid oxidation inhibition. After in vitro digestion at d 1, the superoxide anion scavenging of the 4 yogurt treatments respectively decreased from 83.7%, 83.0%, 79.1%, and 87.4% to 36.7%, 38.3%, 44.6%, and 41.3%. The inhibition of α-amylase and α-glucosidase, angiotensin-converting enzyme inhibition, cholesterol removal, and degree of hydrolysis exhibited different values before and after in vitro digestion.

Observation of curcumin-encapsulated Pickering emulsion stabilized by cellulose nanocrystals-whey protein isolate (CNCs-WPI) complex under in vitro lipid digestion through INFOGEST model

Curcumin-encapsulated Pickering emulsion (Cur-PE) was successfully prepared using cellulose nanocrystals (CNCs)-whey protein isolate (WPI) complex as a stabilizer to control the size and stability of the Cur-PE. Firstly, needle-like CNCs were prepared by acid hydrolysis, and the mean particle size, polydispersity index (PDI), zeta potential, and aspect ratio of the CNCs were 100.7 nm, 0.32, -43.6 mV, and 20.8, respectively. The Cur-PE-C_0.5W_0.1, prepared with 0.5 wt% CNCs and 0.1 wt% WPI at pH 2, had a mean droplet size of 230.0 nm, PDI of 0.275, and zeta potential of +53.5 mV. The Cur-PE-C_0.5W_0.1 prepared at pH 2 exhibited the highest stability during storage for 14 days. FE-SEM revealed that the droplets of the Cur-PE-C_0.5W_0.1 prepared at pH 2 were spherical and fully covered by CNCs. The adsorption of CNCs at the oil-water interface increases the encapsulation efficiency (89.4 %) of curcumin in the Cur-PE-C_0.5W_0.1 and protects curcumin from pepsin digestion in the gastric phase. However, the Cur-PE-C_0.5W_0.1 was sensitive to release curcumin in the intestine phase. The CNCs-WPI complex developed in this study could serve as a promising stabilizer to make Pickering emulsions stable at pH 2 for the encapsulation and delivery of curcumin to the expected target area.

The Effect of Erythritol on the Physicochemical Properties of Reformulated, High-Protein, and Sugar-Free Macarons Produced from Whey Protein Isolate Intended for Diabetics, Athletes, and Physically Active People

This study reports the possibility of obtaining sugar-free WPI-based macarons with erythritol addition. The whey protein isolate (WPI) solution (20%, w/v) was whipped, and erythritol was added to the foam at concentrations of 20, 40, and 60 g, with 125 g of almond flour. The rheological properties (τ, G', G″, and tan (δ)) and stability of the macaron batters before baking were evaluated. In order to produce the macarons, the batters were solidified at 147 °C for 12 min. The textural and surface properties (roughness and color), as well as the microstructures and water activities, were determined for the macarons. It was feasible to produce macarons over the entire range of the tested erythritol content. Even the smallest amount of erythritol (20 g) facilitated the preservation of the macaron structure. The medium erythritol concentration (40 g) improved the stability of the batters and their rheology and was the most effective for air pocket stabilization during baking; however, its largest addition (60 g) resulted in an increase in the final macaron volume. The increased erythritol addition improved mechanical properties and shelf life, producing a smoothing effect on the macaron surfaces and having a significant effect on their color co-ordinates.

Impact of Electric Arcs and Pulsed Electric Fields on the Functional Properties of Beta-Lactoglobulin

Beta-lactoglobulin (β-lg) is a major whey protein with various techno-functional properties that can be improved by several treatments. Therefore, the objective of this study was to explore the impact of green high-voltage electrical treatments (HVETs)—namely, pulsed electric fields and electric arcs—on the functional properties of β-lg. Both emulsifying and foaming stability and capacity, as well as the hygroscopicity of non-treated and pretreated β-lg, were explored. The results demonstrated that the emulsifying capacity and stability of pretreated samples increased by 43% and 22% when compared to native β-lg, respectively. Likewise, the pretreated β-lg displayed better foaming stability compared to native β-lg. In addition, the HVETs significantly decreased the hygroscopicity of β-lg (by 48% on average), making it a good ingredient with reduced hygroscopicity for the food industry.

Soy Protein Isolate/Sodium Alginate Microparticles under Different pH Conditions: Formation Mechanism and Physicochemical Properties

The effects of sodium alginate (SA) and pH value on the formation, structural properties, microscopic morphology, and physicochemical properties of soybean protein isolate (SPI)/SA microparticles were investigated. The results of ζ-potential and free sulfhydryl (SH) content showed electrostatic interactions between SPI and SA, which promoted the conversion of free SH into disulfide bonds within the protein. The surface hydrophobicity, fluorescence spectra, and Fourier transform infrared spectroscopy data suggested that the secondary structure and microenvironment of the internal hydrophobic groups of the protein in the SPI/SA microparticles were changed. Compared with SPI microparticles, the surface of SPI/SA microparticles was smoother, the degree of collapse was reduced, and the thermal stability was improved. In addition, under the condition of pH 9.0, the average particle size of SPI/SA microparticles was only 15.92 ± 0.66 μm, and the distribution was uniform. Rheological tests indicated that SA significantly increased the apparent viscosity of SPI/SA microparticles at pH 9.0. The maximum protein solubility (67.32%), foaming ability (91.53 ± 1.12%), and emulsion activity (200.29 ± 3.38 m²/g) of SPI/SA microparticles occurred at pH 9.0. The application of SPI/SA microparticles as ingredients in high-protein foods is expected to be of great significance in the food industry.

Immune-enhancing effects of β-lactoglobulin glycated with lactose following in vitro digestion on cyclophosphamide-induced immunosuppressed mice

β-Lactoglobulin (β-LG) is a major milk protein, making up more than 53% of the total whey proteins, and is seen as a valuable ingredient in food processing because of its high essential amino acid content and diverse functional applications. The Maillard reaction can occur during the storage and processing of food and generate various beneficial effects, including anti-allergenicity, antioxidant, and immunomodulatory effects. The addition of an β-LG-lactose conjugate (LGL) produced by the Maillard reaction was shown to have a strong immune-enhancing effect, increasing both nitric oxide generation and cytokine expression through activation of RAW 264.7 cells, even after in vitro digestion. Furthermore, daily LGL administration resulted in the upregulation of several immune markers in a cyclophosphamide-induced immunosuppressive mouse model, indicating that this treatment stimulates multiple immune cells, including macrophages, natural killer cells, and lymphocytes, enhancing the proliferation and activation of both the innate and adaptive immune responses. Taken together, these findings indicate that consuming LGL on a regular basis can improve immunity by increasing the natural production of various immune cells.

Applications of Plant Polymer-Based Solid Foams: Current Trends in the Food Industry

Foams are a type of material of great importance, having an extensive range of applications due to a combination of several characteristics, such as ultra-low density, tunable porous architecture, and outstanding mechanical properties. The production of polymer foams worldwide is dominated by those based on synthetic polymers, which might be biodegradable or non-biodegradable. The latter is a great environmental concern and has become a major waste management problem. Foams derived from renewable resources have aroused the interest of researchers, solid foams made from plant polymers in particular. This review focuses on the development of plant polymer-based solid foams and their applications in the food industry over the last fifteen years, highlighting the relationship between their material and structural properties. The applications of these foams fall mainly into two categories: edible foams and packaging materials. Most plant polymers utilized for edible applications are protein-based, while starch and cellulose are commonly used to produce food packaging materials because of their ready availability and low cost. However, plant polymer-based solid foams exhibit some drawbacks related to their high water absorbency and poor mechanical properties. Most research has concentrated on improving these two physical properties, though few studies give a solid understanding and comprehension of the micro- to macrostructural modifications that would allow for the proper handling and design of foaming processes. There are, therefore, several challenges to be faced, the control of solid foam structural properties being the main one.

Effect of Sucrose on Physicochemical Properties of High-Protein Meringues Obtained from Whey Protein Isolate

This study reports the possibility of obtaining the WPI-based meringues with the small sucrose content (0–15%). The whey protein isolate (WPI) solution (20%, w/v) was whipped and sucrose was added to foam at the concentrations of 5, 10 and 15%. The surface tension, viscosity, zeta potential of the pre-foam solutions, foam overrun, foam stability and their rheological properties (G′, G″ and tan (δ)) were evaluated. To produce meringues, liquid foams were solidified at 130 °C for 2 h. The surface properties (roughness, contact angles, apparent free surface energy) as well as microstructural ones were determined for the solid foams (meringues). The 15% sugar concentration was detrimental for overrun, stability and rheological properties of liquid foams. The meringue production without sugar was infeasible. The addition of the smallest amount of sucrose (5%) enabled preservation of the aerated structure of the liquid foam during solidification. The 10% sugar concentration increased the stability of liquid foam, its rheology and it was the most effective for air bubbles stabilization during the foam solidification, however, its largest addition (15%) resulted in an increase in the final meringue volume. Larger sucrose concentrations produced a smoothing effect on the meringue surfaces.

Improved Heat Stability of Whey Protein Isolate by Glycation with Inulin

Glycation between proteins and sugars via the Maillard reaction has been shown to improve the heat stability of proteins. In this study, inulin, a healthy dietary fiber, was glycated with whey protein isolate (WPI), and the effects of reaction conditions were investigated. Conjugates were prepared by freeze-drying mixed WPI and inulin solutions at 1:1 to 6:1 WPI-to-inulin weight ratios followed by dry heating at 70, 75, or 80 °C for 12 to 72 h under uncontrolled, 44%, or 80% relative humidity. Heat stability was evaluated by turbidity, particle size, and rheological measurements. Degree of glycation was assessed by quantifying the loss of amino groups and the formation of the Amadori compounds. Results showed that conjugation led to improved heat stability, as shown by decreased turbidity and particle size as well as the ability to maintain the viscosity compared to control samples. Based on the loss of amino groups, the optimum glycation conditions were achieved with WPI–inulin mixtures at 2:1, 4:1, and 6:1 weight ratios and 80 °C temperature for 12 to 72 h without controlling the relative humidity. The improved heat stability could be due to an increase in negative charge as well as increased structural stabilization of the proteins. Under a limited degree of glycation, glycated WPI–inulin conjugates have great potential to be utilized as food ingredients, especially in the beverage industry.