Effect of protein–polysaccharide mixtures on the continuous manufacturing of foamed food products

Understanding the foam stability mechanisms of complex formed by soy protein isolate and different charged polysaccharides: Air/water interfacial behavior and rheological characteristics

This study evaluated the foaming properties, the dynamic adsorption behavior at the air/water (A/W) interface and the foam rheological characteristics of complexes formed by soy protein isolate (SPI) and different charged polysaccharides, including chitosan (CS), guar gum (GUG) and gellan gum (GEG). The results showed that the SPI/CS10 had the highest initial foam volume (26.67 mL), which were 3.89 %, 100.08 % and 70.19 % higher than that of single SPI, SPI/GUG and SPI/GEG complexes, respectively. Moreover, three charged polysaccharides could all significantly improve the foam stability of complexes. Among them, foams stabilized by SPI/GEG10 were the most stable that the foam volume slightly changed (approximately 1 mL) and no drainage occurred throughout the whole recording process. The interfacial behavior analysis showed that SPI/CS10 had higher diffusion (Kdiff) and rearrangement rate (KR) but lower penetration rate (KP) at the A/W interface compared with single SPI, while SPI/GUG10 and all SPI/GEG complexes showed higher KR and KP but lower Kdiff. In addition, SPI/CS10 was beneficial to concurrently enhance the elastic strength and solid-like behavior of foam system, while all SPI/GEG complexes could improve the elastic strength of foam system but was not conducive to the solid-like behavior.

Assessing the effect of Maillard reaction products on the functionality and antioxidant properties of Amaranth-red seaweed blends

Plant-based proteins, represented by amaranth in our study, embrace a potential as an ingredient for the functional-food formulation. However, their efficacy is hindered by inherent limitations in solubility, emulsification, and antioxidant traits. The Maillard reaction, a complex chemical-process resulting in a diverse array of products, including Maillard conjugates and Maillard reaction products (MRPs), can employ variable effects on these specific attributes. To elucidate the influence of this reaction and the MRPs on the aforementioned properties, we used a complex blend of dehydrated seaweed Gracilaria and amaranth protein to create a conjugate-MRP blend. Our investigations revealed that the resultant incorporation enhanced solubility, emulsification, and antioxidant properties, while the intermediates formed did not progress to advanced glycation stages. This change is likely attributed to the dual effect of conjugates that altered the secondary protein structure, while the generation and/or preservation of MRPs post ultrasonication and spray drying enhanced its antioxidant potential.

Structure and rheological properties of extruded whey protein isolate: Impact of inulin

Impacts of inulin addition (0, 5, 10, 15 %) on structure, functional and rheological properties of whey protein isolate (WPI) after extrusion pretreatment (E-WPI) were investigated. The results proved that after adding 15 % inulin, water holding capacity of gels, emulsifying activity, emulsion stability, foaming ability and foaming stability of E-WPI were the best and increased by 24.38 %, 7.43 %, 12.35 %, 162.97 % and 41.31 %, compared with those of unextruded WPI, respectively. Rheology analysis showed that apparent viscosity and consistency index of all the samples after inulin addition were enhanced and exhibited pseudoplastic fluids. FTIR spectroscopy indicated that E-WPI/WPI and inulin was linked together due to hydrogen bonds and addition of inulin increased the proportion of their β-turn structure. These findings demonstrated that the addition of inulin in combination with extrusion pretreatment could jointly improve the functional properties of WPI. Therefore, E-WPI with the addition of inulin shows potential commercial applications in the production of novel food foaming agents and emulsifiers.

Experimental Study of the Influence of Inorganic Salts on Foam Stability

The aqueous film-forming foam (AFFF) extinguishing agent is suitable for fighting various hydrocarbon fuel fires due to its dual fire-fighting effect of foam and liquid film. Because the action law and microscopic mechanism of inorganic salts on the stabilization process of surfactant-generated AFFF are not perfect, this paper employs an experimental approach to investigate the effects of inorganic salt types and concentrations on sodium dodecyl sulfate-containing foam systems (SDS). Prior to critical micelle concentration (CMC), increasing inorganic salt concentration decreased solution surface tension, but the opposite was true after CMC. The CMC value of an SDS solution decreases as inorganic salt concentration increases, and the "salting effect" of inorganic salt cations also has an effect on the CMC value. Based on the resistance of the liquid film at the gas-liquid interface affecting gas transport, the foam evolution was divided into three stages: foam generation, liquid drainage, and gas transfer. The effect of inorganic salts on these three stages was studied at the molecular level, and it was discovered that the addition of NH₄Cl and MgCl₂ could improve the saturation adsorption at the gas-liquid interface, reduce the surface tension of the surfactant solution, and improve foam stability. Meanwhile, inorganic salts can change the force of gas molecules, so the equilibrium force of gas across the liquid membrane increases as inorganic salt concentration increases. Additionally, the addition of inorganic salts raises the diffusive drainage coefficient, but the gravity drainage coefficient still reigns supreme in the predecay period.

Scalable Advanced Li(Ni0.8Co0.1Mn0.1)O2 Cathode Materials from a Slug Flow Continuous Process

Li[Ni_0.8Co_0.1Mn_0.1]O₂ (LNCMO811) is the most studied cathode material for next-generation lithium-ion batteries with high energy density. However, available synthesis methods are time-consuming and complex, restricting their mass production. A scalable manufacturing process for producing NCM811 hydroxide precursors is vital for commercialization of the material. In this work, a three-phase slug flow reactor, which has been demonstrated for its ease of scale-up, better synthetic control, and excellent uniform mixing, was developed to control the initial stage of the coprecipitation of NCM811 hydroxide. Furthermore, an equilibrium model was established to predict the yield and composition of the final product. The homogeneous slurry from the slug flow system was obtained and then transferred into a ripening vessel for the necessary ripening process. Finally, the lithium-nickel-cobalt-manganese oxide was obtained through the calcination of the slug flow-derived precursor with lithium hydroxide, having a tap density of 1.3 g cm^-3 with a well-layered structure. As-synthesized LNCMO811 shows a high specific capacity of 169.5 mAh g^-1 at a current rate of 0.1C and a long cycling stability of 1000 cycling with good capacity retention. This demonstration provides a pathway toward scaling up the cathode synthesis process for large-scale battery applications.

Mapping Bubble Formation and Coalescence in a Tubular Cross-Flow Membrane Foaming System

Membrane foaming is a promising alternative to conventional foaming methods to produce uniform bubbles. In this study, we provide a fundamental study of a cross-flow membrane foaming (CFMF) system to understand and control bubble formation for various process conditions and fluid properties. Observations with high spatial and temporal resolution allowed us to study bubble formation and bubble coalescence processes simultaneously. Bubble formation time and the snap-off bubble size (D0) were primarily controlled by the continuous phase flow rate (Qc); they decreased as Qc increased, from 1.64 to 0.13 ms and from 125 to 49 µm. Coalescence resulted in an increase in bubble size (Dcoal>D0), which can be strongly reduced by increasing either continuous phase viscosity or protein concentration-factors that only slightly influence D0. Particularly, in a 2.5 wt % whey protein system, coalescence could be suppressed with a coefficient of variation below 20%. The stabilizing effect is ascribed to the convective transport of proteins and the intersection of timescales (i.e., μs to ms) of bubble formation and protein adsorption. Our study provides insights into the membrane foaming process at relevant (micro-) length and time scales and paves the way for its further development and application.

Utilization of pulse protein-xanthan gum complexes for foam stabilization: The effect of protein concentrate and isolate at various pH

The present study examines the foaming behavior of pea and faba bean protein concentrates and isolates and explores the impact of pH and protein-polysaccharide complexation on overrun and foam stability. Foams were prepared with 5 wt% proteins with and without 0.25 wt% xanthan gum (XG) at pH 3, 5, 7 and 9. Most foams were unstable without XG. With XG foaming properties of protein concentrates were better than isolates. Irrespective of protein type and content, all protein-XG foams at pH 3 destabilized due to large insoluble complexes, however, at pH 5 foams were stable due to smaller size of insoluble complexes. Both the protein concentrate-XG foams were stable at pH 7 and 9 due to optimum viscosity and surface tension of the soluble complexes. Overall, the study revealed that the overrun and stability of pulse protein foams can be significantly improved by adding XG and controlling their intermolecular interactions as a function of pH.

Ferulic acid-ovalbumin protein nanoparticles: Structure and foaming behavior

Egg white was known for its excellent foaming properties, and some reports had studied the effect of polyphenol such as green tea on the foaming properties. However, ovalbumin, as the most abundant component of egg white protein, few literatures have reported the effects of polyphenols on its structure and foam property. In this study, ferulic acid (FA) was selected to explore the influence of polyphenol on the structure and foaming properties of ovalbumin (OVA). Results showed that hydrophobic interaction and hydrogen chemical bonds were the main driving force. FA could induce a significant decrease of free-SH content (12.76-3.72 μmol/g), a slight decline of surface hydrophobicity (716.39-577.65). Meanwhile, combined with the results of fluorescence spectroscopy and circular dichroism spectroscopy, we conclude that FA changed the structures and molecular flexibility of OVA. The increase of particle size and absolute zeta-potential showed there was a little aggregation between OVA molecules, proved FA could act as a cross-linker between OVA proteins. This behavior makes the adjacent films more firm and stable, therefore improved the foaming properties. This study suggested that FA could be a potential foaming agent to modify the foaming properties of OVA in the foam-related food industry.