Interactions between Pea Protein Isolate and Carboxymethylcellulose in Neutral and Acid Aqueous Systems

Pea protein isolate-soluble soybean polysaccharides electrostatic assembly: effect of pH, biopolymer mass ratio and heat treatment

BACKGROUND

In past years, thousands of protein-polysaccharide complexes have been investigated to modify protein characteristics and functionality in food systems. However, the interaction between pea protein isolate (PPI) and soluble soybean polysaccharide (SSPS) has not been thoroughly characterized yet.

RESULTS

In the present study, the phase behavior of PPI and SSPS mixtures was analyzed as a function of PPI:SSPS mixing ratio (1:1 to 1:0.10) and pH (7.0 to 2.0), showing that these biopolymers could be electrostatically assembled at 1:1 to 1:0.25 mixing ratios and 4.0 to 3.0 pH values. Then, the characteristics of the PPI-SSPS complexes were studied before and after heating (90 °C and 30 min) by ζ-potential, surface hydrophobicity, protein solubility, particle size distribution and physical stability for 56 days. By lowering the pH and PPI:SSPS mixing ratio, the complexes showed increased solubility, changed 𝜁-potential and higher physical stability. By heating, the complexes presented increased hydrophobicity and physical stability.

CONCLUSION

Overall, PPI-SSPS complexes increased the protein solubility, reduced the particle size, and changed both the ζ-potential and the surface hydrophobicity with respect to PPI control, allowing stabilization of the colloidal system and broadening the possible applications of these high-quality proteins in acidic food systems. © 2024 Society of Chemical Industry.

Effect of limited proteolysis and CaCl2 on the rheology, microstructure and in vitro digestibility of pea protein-carboxymethyl cellulose mixed gel

Limited proteolysis, CaCl2 and carboxymethyl cellulose (CMC) have individually demonstrated ability to increase the gel strength of laboratory-extracted plant proteins. However, the syneresis effects of their combination on the gelling capacity of commercial plant protein remains unclear. This was investigated by measuring the rheological property, microstructure and protein-protein interactions of gels formed from Alcalase hydrolyzed or intact pea proteins in the presence of 0.1 % CMC and 0-25 mM CaCl2. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed the molecular weight of pea protein in the mixture were < 15 kDa after hydrolysis. The hydrolysates showed higher intrinsic fluorescence intensity and lower surface hydrophobicity than the intact proteins. Rheology showed that the storage modulus (G') of hydrolyzed pea protein (PPH)-based gels sightly decreased compared to those of native proteins. 5-15 mM CaCl2 increased the G' for both PP and PPH-based gels and decreased the strain in the creep-recovery test. Scanning electron microscopy (SEM) showed the presence of smaller protein aggregates in the PPH-based gels compared to PP gels and the gel network became denser, and more compact and heterogenous in the presence of 15 and 25 mM CaCl2. The gel dissociation assay revealed that hydrophobic interactions and hydrogen bonds were the dominant forces to maintain the gel structure. In vitro digestion showed that the soluble protein content in PPH-based gels was 10 ∼ 30 % higher compared to those of the PP counterpart. CaCl2 addition reduced protein digestibility with a concentration dependent behavior. The results obtained show contrasting effects of limited proteolysis and CaCl2 on the gelling capacity and digestibility of commercial pea proteins. These findings offer practical guidelines for developing pea protein-based food products with a balanced texture and protein nutrition through formulation and enzymatic pre-treatment.

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.

Single-Piece Membrane Supercapacitor with Exceptional Areal/Volumetric Capacitance via Double-Face Print of Electrode/Electrolyte Active Ink

Single-piece flexible supercapacitors (FSCs) have light and ultrathin superiorities, thereby having great potential in portable/wearable electronics. However, all the available single-piece FSCs are fabricated by in situ growth routes, which are incompatible with large-scale technology. This work designs a carboxymethyl cellulose/phytic acid/polyaniline ink, incorporating electrode with electrolyte active compositions. Based on the electrode/electrolyte active ink, a double-face print technique on mixed cellulose ester and nylon membranes to fabricate single-piece membrane-FSCs, where both sides of membranes can be utilized well, is proposed. Consequently, one FSC is measured to be only ≈0.785 cm² in area, ≈0.021 g in weight, and ≈200 µm in thickness, while it has exceptional areal and volumetric capacitances up to 757 mF cm^-2 and 37.8 F cm^-3 , respectively, based on the entire device. It also exhibits high flexibility with a capacitance retention of 98% after 2000 bend cycles from 0° to 180°. The state-of-the-art FSCs are expected to have exciting prospects in portable/wearable electronics, smart reading, and flexible displays. The preparation strategy renders the massive production of large-area and mini-size arrayed FSCs, and also the "do-it-yourself" or homemade preparation, which adds more interest and designability for general users.

Scaffolds for Cultured Meat on the Basis of Polysaccharide Hydrogels Enriched with Plant-Based Proteins

The world population is growing and alternative ways of satisfying the increasing demand for meat are being explored, such as using animal cells for the fabrication of cultured meat. Edible biomaterials are required as supporting structures. Hence, we chose agarose, gellan and a xanthan-locust bean gum blend (XLB) as support materials with pea and soy protein additives and analyzed them regarding material properties and biocompatibility. We successfully built stable hydrogels containing up to 1% pea or soy protein. Higher amounts of protein resulted in poor handling properties and unstable gels. The gelation temperature range for agarose and gellan blends is between 23-30 °C, but for XLB blends it is above 55 °C. A change in viscosity and a decrease in the swelling behavior was observed in the polysaccharide-protein gels compared to the pure polysaccharide gels. None of the leachates of the investigated materials had cytotoxic effects on the myoblast cell line C2C12. All polysaccharide-protein blends evaluated turned out as potential candidates for cultured meat. For cell-laden gels, the gellan blends were the most suitable in terms of processing and uniform distribution of cells, followed by agarose blends, whereas no stable cell-laden gels could be formed with XLB blends.