Protein Isolate Research Articles

Isolation and functional characterization of a pathogenesis-related protein 4 gene from Panax notoginseng

Isolation and functional characterization of a pathogenesis-related protein 4 gene from Panax notoginseng

Amino Acid Composition of Dried Bovine Dairy Powders from a Range of Product Streams

The amino acid (AA) content of multiple samples of various dairy powders was determined, providing a comprehensive evaluation of the differences in AA profiles attributable to distinct manufacturing processes. Products examined included whole milk powder (WMP), skim milk powder (SMP), cheese whey protein concentrate (WPC-C), lactic acid casein whey protein concentrate (WPC-L), high-fat whey protein concentrate (WPC-HF), hydrolyzed whey protein concentrate (WPH), whey protein isolate (WPI), and demineralized whey protein (D90). WMP and SMP exhibited broadly similar AA profiles, with minor differences likely due to the minimal milk fat protein content, which is nearly absent from SMP. Comparative analysis of WPC-C and WPC-L indicated higher levels of threonine, serine, glutamic acid, and proline in WPC-C but lower levels of tyrosine, phenylalanine, and tryptophan, attributed to the different methods of separation from casein proteins. WPI and WPC-HF originate from similar sweet whey streams but follow divergent processing methods; consequent on this were variations in the levels of all AAs except histidine. The nanofiltration step in D90 production retains its non-protein nitrogen content and affects its AA profile; consequently, D90 consistently exhibited lower AA levels than WPC-C. These findings underscore the significant impact of manufacturing processes on dairy powder AA composition.

Opportunities and challenges of plant proteins as functional ingredients for food production

Consumer interest in meat and dairy alternatives drives demand for plant-based protein ingredients. While soy and gluten dominate the market, there is a trend to explore alternative crops for functional ingredient production. The multitude of ingredients poses challenges for food manufacturers in selecting the right protein. We investigated 61 commercially available protein ingredients from various sources, categorizing them based on their protein content into protein-rich flours (protein content less than 50%), protein concentrates (protein content between 50% and 80%), and protein isolates (protein content higher than 80%). Methionine, cysteine, and lysine were decisive for the amino acid score, which even varied between ingredients produced from the same raw material. Such differences were also observed in the protein solubility profiles, characterized by their raw material-specific protein pattern. By focusing on soy, pea, and fava bean ingredients, the broad spectra of emulsifying and foaming properties were illustrated. These ranged from non-emulsifying and non-foaming to high emulsifying capacities of 737 mL/g ingredient and foaming activities of 2,278%, accompanied by a foam stability of 100%. Additionally, we demonstrated that the functionality of ingredients obtained from different batches could vary by up to 24% relative SD. Protein solubility, powder wettability, color, and particle size were determined as key properties for the differentiation of soy, pea, and fava bean protein ingredients by principal component analysis. In our study conclusion, we propose essential measures for overcoming challenges in protein ingredient production and utilization to realize their full potential in fostering sustainable and innovative plant-based food production.

A perspective on the environmental impact of plant-based protein concentrates and isolates

Plant-based proteins are promoted as nutritious, environmentally safe, and a key element for food security. Numerous studies using environmental life cycle assessments confirmed plant-based meat alternatives are more environmentally favorable than animal-derived meat. However, most missed other factors from protein extraction and concentration that contribute to environmental impact (both positive and negative). Furthermore, few studies examined the entire environmental impact because they overlooked social and nutritional life cycle assessments. Many publications assumed most environmental impact occurred in crop cultivation before high protein products are manufactured. However, industrial plant-based protein extraction, concentration, and purification require large amounts of natural resources, energy, chemicals, and highly specialized equipment seldom accurately assessed from an environmental, social, and nutritional perspective. This paper presents opinions and perspectives on additional information to consider to fully realize environmental benefits of highly proteinaceous plant-based food ingredients. Elements are also discussed we perceive as “hot spots” for future assessments in presenting a complete picture for minimizing environmental impact and how the numerous actors in this supply chain can transform our food system and secure protein availability for future generations.

Optimization of a green tea seed oil-loaded double-layer emulsion and its preventive effects on dextran sulfate sodium-induced colitis in mice.

Green tea seed oil (GTSO; Camellia sinensis) is rich in bioactive compounds and has great potential for preventing intestinal inflammation. Conversely, high-fat diets have been shown to promote or aggravate gastrointestinal inflammation, and the bioactive ingredients of GTSO face difficulty passing through the gastrointestinal tract while remaining intact. This study employed whey protein isolate (WPI) and sodium carboxymethyl cellulose (CMC-Na) to prepare a GTSO-loaded double-layer emulsion. The optimal parameters were as follows: WPI (2% w/w) and 35% oil phase for the primary emulsion preparation, CMC-Na (0.8% w/w) for the final emulsion, and 450W of ultrasonic power for homogenization. No significant changes in particle size or coalescence in the emulsions were observed after 30days of storage at 4°C. In addition, in a simulated gastrointestinal digestion system, more than 60% of the encapsulated GTSO was able to remain intact while passing through the gastric and small intestinal environment. In mice with dextran sulfate sodium-induced colitis, pretreatment with the GTSO emulsion significantly prevented the further development of colitis, whereas an empty-carrier-plus-free-GTSO treatment had no such protective effects and even tended to aggravate the disease. The results of the present study suggest that encapsulated GTSO is a reliable alternative approach for colitis prevention. PRACTICAL APPLICATION: The green tea seed oil-loaded double-layer emulsion demonstrates good storage stability when kept at 4°C, exhibits excellent slow-release performance, and achieves superior outcomes in the prevention of colitis. Our current study provides a reliable alternative approach for the prevention of colitis.

Physicochemical and structural properties of novel cornmeal, pea protein isolate and wheat gluten meat analogues prepared by high moisture extrusion

Physicochemical and structural properties of novel cornmeal, pea protein isolate and wheat gluten meat analogues prepared by high moisture extrusion

Examining osteoprotective properties of gluten-free bread made with a combination of amaranth and tigernut flours

AbstractGluten-free bread (GFB) consisting of amaranth flour, tigernut (chufa tuber) flour, apple powder, carrot powder, and soy protein isolate can have osteoprotective effects. Glucocorticoid-induced osteoporosis (GIO) was chosen as a model of experimental osteoporosis. Experimental studies were carried out on white male Wistar rats (n = 150): Group 1 – healthy animals receiving standard diet (StD); Group 2 – GIO rats receiving StD; Group 3 – GIO animals receiving zoledronic acid (ZA) and StD; Group 4 – GIO rats receiving ZA and GFB; Group 5 – GIO animals receiving GFB. We evaluated the general condition of animals and carried out morphological and biochemical studies. Destructive changes in the spatial structure of the bone tissue in GIO, observed in Group 2, led to the inability of the bone to withstand the functional load. At the same time, isolated treatment with ZA had virtually no effect on the final morphological picture. Including GFB in the diet of experimental animals both alone and with ZA had a noticeable protective effect on conditions triggering GIO.

The formation of protein coronas and the interaction of soy protein isolate and whey protein isolate with starch nanoparticles

The influence of food components on the physicochemical properties and biological responses of nanoparticles is pivotal. Since soy protein isolate (SPI) and whey protein isolate (WPI) are commonly used as plant and animal proteins in food, it is imperative to gain comprehensive knowledge of the interaction between SPI/WPI and nanoparticles. Accordingly, we examined the adsorption of SPI and WPI onto starch nanoparticles (SNPs) and their associated interactions. SNP aggregation was observed in the SPI/WPI, and coronas formed around the surfaces of the SNPs. The binding of the protein isolates reduced the zeta potential of the SNPs from −10.34 to −26.5 mV for the SPI and to −21.37 mV for the WPI. However, mixing the SNPs with the protein isolates did not alter the microenvironment of aromatic amino acids and had no substantial impact on the secondary structure of the proteins. Thermogravimetric analysis revealed that the formation of SPI/WPI coronas enhanced the thermal stability of the SNPs. Isothermal titration calorimetry indicated that the adsorption of the SPI and WPI onto the SNPs was driven primarily by weak van der Waals forces and hydrogen bonds. This study facilitates the predicting of organic nanoparticle behaviours in complex food matrix and human gastrointestinal environments.

Theabrownin/whey protein isolate complex coacervate strengthens C2C12 cell proliferation via modulation of energy metabolism and mitochondrial apoptosis.

Theabrownin (TB)-whey protein isolate (WPI) complex coacervates (TW) were firstly prepared to investigate the regulatory effects on skeletal muscle. The binding of TB to WPI reached saturation with the strongest electrostatic interaction at the ratio of 10:1. The formation of TW was driven by electrostatic interactions with the aid of hydrogen bonding and hydrophobic interactions, and the digestion behavior of TW was investigated based on in vitro gastrointestinal and CaCO2 cell models. The regulatory effect of TW on muscle cells was investigated by C2C12 cell assay. Cell cycle analysis showed that TW promoted the transition of skeletal muscle cells from proliferative state to differentiated state. Immunofluorescence and gene expression revealed that TW positively regulated myogenic regulatory factors, contributing to myofiber formation. Moreover, TW activated the intracellular TCA cycling and oxidative phosphorylation, providing energy for skeletal muscle regeneration and repair. Mechanistically, TW inhibited the release of cytochrome C from mitochondria to cytoplasm through the Bcl-2/Cytochrome C/Cleaved-Caspase-3 pathway, exhibiting a protective effect on skeletal muscle cells. In the future, the molecular mechanism of TW enhancing skeletal muscle function should be validated through aging animal models and clinical trials and expand its therapeutic application for muscle health in functional food and dietary supplements.

Development and Characterization of an Environmentally Friendly Soy Protein-Modified Phenol–Formaldehyde Resin for Plywood Manufacturing

Most wood-based panels were currently prepared using aldehyde-based adhesives, making the development of natural, renewable, and eco-friendly biomass-based adhesives a prominent area of research. Herein, the phenolic resin was modified using a soybean protein isolate (SPI) treated with a NaOH/urea solution through a copolymerization method. The physicochemical properties, chemical structure, bonding properties, and thermal properties of the soybean protein-modified phenolic resin (SPF-U) were analyzed using Fourier transform infrared spectroscopy, thermogravimetric analysis, and formaldehyde emission tests. The results indicated that the molecular structure of the soy protein isolate degraded after NaOH/urea solution treatment, while the gel time was gradually shortened with increasing NaOH/urea solution-treated soy protein isolate (SPI-U) dosages. Although the thermal stability of the soy protein isolate was lower than that of the phenolic resin, the 20% SPF-U resin demonstrated better thermal stability than other modified resins. The PF modified with 30% SPI-U (SPF-U-3) exhibited the lowest curing peak temperature of 139.69 °C than that of the control PF resin. In addition, all modified PF resins exhibited formaldehyde emissions ranging from 0.18 to 0.38 mg/L when the SPI-U dosage varied between 20% and 50%, thereby meeting the E0 plywood grade standard (≤0.5 mg/L).

Effect of screw pressing temperature on apricot (Prunus armeniaca L.) kernels oil quality properties and apricot kernels protein isolate functional properties

This study evaluated the effects of screw pressing temperature (40°C to 200°C) on the yields, physicochemical properties, oxidation stabilities, and antioxidant activities of apricot kernels oil (AO). Additionally, this study comparatively analyzed the functional properties of different apricot kernels protein isolates (APIs). The oil yield ranged from 30.06% to 49.07% with AO-200 showing the highest yield. Compared with cold pressing, high-temperature pressing significantly increased the trace components (such as total phenols, tocopherols, and phytosterols), oxidation stabilities, and antioxidant activities of AOs. High-temperature pressing also increased the functional properties of API. Multivariate analysis revealed that spiral pressing at 120°C may be an optimal strategy for obtaining high-quality oil and protein isolate from apricot kernels. These findings provide a theoretical basis for the extraction and application of AO and API.

Silkworm cocoon-like nanocoatings for single-cell encapsulation of probiotics: Construction, mechanism and characterization

Single-cell encapsulation technology is an advanced method to protect probiotics from adverse environmental conditions by forming coating on the surface of individual probiotics. In this study, Lactiplantibacillus plantarum (L. plantarum) was used as model probiotic. Four polysaccharides, namely carboxymethyl chitosan (CMCS), chitooligosaccharide (COS), amylopectin (AP) and pectin (PE), as well as four proteins, namely gelatin (GE), whey protein isolate (WPI), ovalbumin (OVA) and soy protein isolate (SPI), were selected as the initial coating materials. The coated probiotics were prepared by single-cell encapsulation under pH 3.0–6.0 for the first time. The feasibility, mechanism and effect of these coatings were then explored. Results indicated that the positively charged materials were conducive to the formation of coating, and the optimal pH was 4.0. Silkworm cocoon-like coatings with a thickness of 100–150 nm on the surface of L. plantarum were observed. Subsequently, fourier transform infrared spectroscopy (FTIR) analysis showed that electrostatic interaction, hydrogen bonding and hydrophobic interaction were the main driving forces between coatings and L. plantarum. In addition, COS coating fostered the growth and reproduction of L. plantarum, while CMCS and OVA inhibited it. Finally, COS, WPI and GE coatings as barriers all improved the survival rate of L. plantarum under pasteurization, freeze-thaw cycle and storage conditions. Among them, COS as a marine oligosaccharide had the best protective effect on L. plantarum due to its excellent properties and the dense coating it formed. The results may provide more support for further development of nanocoated probiotics.

Purification and Characterization of Kyasanur Forest Disease Virus EDIII domain of major Envelope Glycoprotein

Current research efforts are underway to create novel approaches for the efficient diagnosis, monitoring, and mitigation of Kyasanur Forest Disease Virus (KFDV) infections. Flavivirus subunit-based vaccines based on envelope glycoprotein EDIII are now in preclinical and clinical research stages. Efficient purification and isolation methods for surface immunogenic viral antigens, including the recombinant envelope immunoglobulin-like domain III (rEDIII) protein, are crucial for the production and manufacturing of promising vaccine candidates that have been extensively assessed in previous literature. Here, we describe a method for high-yield expression, purification, and refolding of a KFDV rEDIII protein from a bacterial expression system. The KFDV rEDIII protein is extracted from the inclusion bodies in urea denaturing buffer followed by nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography. The purified, denatured KFDV rEDIII protein was subsequently refolded using a step-wise gradient urea dilution via the dialysis method. The circular dichroism and Fourier transform infrared spectroscopy analysis confirms that the refolded KFDV rEDIII maintains the native secondary conformation majorly containing β-strands. Our study provides valuable insights into the design and expression strategies of rEDIII as a novel subunit vaccine candidate against KFDV.

Preparation and characterization of lutein functional salt by microemulsion stabilized by whey protein isolate and maltodextrin: Exploration of a novel dietary nutritional supplement

Excessive salt intake has become one of the leading causes of various non-communicable diseases such as hypertension and cardiovascular diseases. Researchers have been looking for alternative ways to reduce sodium intake without compromising the sensory properties of food. One promising approach is to develop hollow salts, which can provide the same salty taste while significantly reducing sodium consumption. Hollow salts were developed using microemulsion stabilized by whey protein isolate (WPI) and maltodextrin (MD) via spray drying in this study. The Maillard reaction between WPI and MD was confirmed through grafting and browning degree measurements. Optical microscopy revealed that the WPI-MD emulsion had more uniform droplet sizes, producing hollow salt particles with a size about 5 to 15 μm. Scanning electron microscopy images confirmed the successful formation of the hollow structure, while energy dispersive spectroscopy results showed that the surface of the salt microspheres was mainly composed of sodium and chlorine elements. The use of MD improved the stability and prevented agglomeration of hollow salt. Lutein functional salt was successfully prepared with a high encapsulation efficiency about 77.57 %, excellent antioxidant activity, and stability. In conclusion, this study demonstrated that stable lutein functional salt can be prepared using WPI and MD spray drying methods.

Enhancing lipid digestion and absorption rate: The role of whey protein isolate short fibrils in emulsions

Lipid serve as a crucial energy source during prolonged endurance exercise, and whey protein isolate (WPI) is commonly applied in food emulsions to modulate lipid digestibility. Herein, we prepared WPI short fibrils, <400 nm in length, to stabilize emulsion and increase lipid digestion and absorption rates. Specifically, a 2 % (w/v) WPI solution was adjusted to pH 2 and heated at 90 °C for 6 h to produce long fibrils, followed by 168 h of shear force treatment to obtain short fibrils. Compared to native WPI and long fibrils, short fibrils exhibited smaller molecular weight and higher surface hydrophobicity. Both short and long fibrils showed no cytotoxic effects on BRL and HEK-293 cells. Emulsions stabilized by short fibrils displayed excellent emulsifying capacity and stability, along with favorable dispersion during in vitro digestion. Importantly, the short fibrils emulsion improved in vitro digestion rate of lipids and promoted the rapid lipid absorption in vivo. These findings suggest that modifying protein fibrils around oil droplets can modulate lipid digestibility, with short fibrils offering potential to improve lipid absorption in functional foods tailored for personalized nutrition in extreme endurance exercise.

Polysaccharide-potato protein coacervates for enhanced anthocyanin bioavailability and stability

Anthocyanins (ACNs) possess strong antioxidants, anti-cancer, anti-obesity, anti-diabetic, and anti-inflammatory properties but are limited use by their susceptibility to environmental factors. This study aims to overcome these limitations by developing and assessing a novel coacervate system, consisting of potato protein isolate (PPI) combined with various polysaccharides, to stabilize and encapsulate anthocyanins from black carrot concentrate The polysaccharides included in this system include inulin, gum Arabic, guar gum, pectin, and soluble fiber. The coacervate system's effectiveness in maintaining stability and increasing the bioavailability of anthocyanins was evaluated compared to conventional soybean protein-based systems. The results show that pH considerably influences potato protein solubility, with maximum solubility at strongly acidic (pH 2) conditions. Hygroscopicity and moisture content analysis of the coacervates showed significant variations, with potato protein-guar gum (PPIGG) microcapsules having the lowest moisture content and potato protein gum Arabic (PPIGA) microcapsules having the highest moisture content. SEM imaging illustrated distinct microcapsule morphologies, while FT-IR measurement verified the successful integration of proteins and polysaccharides. The significance of the research reflects its proof that potato protein isolate (PPI) based coacervate systems consists of potato protein with polysaccharides, particularly those containing gum Arabic and pectin, have significant potential for improving anthocyanin stability and bioavailability. These findings guide future studies to investigate other polysaccharides, improve coacervation processes, and explore applications in the food and nutraceutical sectors. It also offers valuable insights for creating efficient encapsulation techniques for bioactive substances.

Effect of dynamic high-pressure microfluidization on the structural, emulsifying properties, in vitro digestion and antioxidant activity of whey protein isolate.

The effects of dynamic high-pressure microfluidization (DHPM) on the structural, emulsifying properties, in vitro digestion and antioxidant activity of whey protein isolate (WPI) were investigated. The results demonstrated that WPI treated with 100MPa DHPM exhibited superior emulsification performance. This can be attributed to the conformational changes induced by 100MPa DHPM in WPI, leading to a transformation from disordered structures to ordered structures and an increased exposure of fluorophore such as tryptophan residues and hydrophobic groups, reduced aggregation state and particle size of WPI. These factors facilitated the migration of WPI towards the oil-water interface, resulting in the formation of a robust and compact adsorption layer which reduces interfacial tension and enhances emulsification stability. Furthermore, it was observed that while DHPM did not significantly affect the digestibility of WPI, it did enhance exposure to antioxidant amino acids in the digestive products thereby enhanced their antioxidant properties. In summary, structural modification induced by DHPM treatment enhanced both emulsification and antioxidant properties of WPI. These findings highlight the significant potential of DHPM treatment for enhancing the quality of meat products with an emulsion-type structure.

Enhancement of extraction efficiency and functional properties of chickpea protein isolate using pulsed electric field combined with ultrasound treatment

Chickpea protein isolate (CPI) is a promising dietary protein with the advantages of low allergenicity, easy digestion and balanced composition of essential amino acids. However, due to the thick skin of chickpeas, the extraction of CPI is challenging, resulting in lower efficiency of the alkaline extraction-isoelectric precipitation (AE-IEP) method. Therefore, the present study investigated the effect of pulsed electric field combined with ultrasound (PEF-US) treatment on the extraction efficiency of CPI and the functional properties was characterized. Parameter optimization was carried out using response surface methodology (RSM), with the following optimized conditions: pulse duration of 87 s, electric field intensity of 0.9 kV/cm, ultrasonic time of 15 min, and ultrasonic power of 325 W. Under the optimized conditions, the yield of CPI after combined (PEF-US) treatment was 13.52 ± 0.13 %, which was a 47.28 % improvement over the AE-IEP method. This yield was better than that obtained with either individual PEF or US treatment. Additionally, the functional properties (solubility, emulsification, and foaming) of CPI were significantly enhanced compared to AE-IEP. However, the stability of emulsification and foaming did not show significant differences among the four methods. The PEF-US method efficiently extracts CPI with excellent functional properties, enabling the production of proteins as desired functional additives in the food industry.

Application of machine learning tools to study the synergistic impact of physicochemical properties of peptides and filtration membranes on peptide migration during electrodialysis with filtration membranes

The present study aimed to explore the application of machine learning-based tools to study the impact of physicochemical properties of peptides and filtration membranes (FM) on peptide migration during electrodialysis with filtration membranes (EDFM). A total of 14 membranes characterized in terms of 10 physicochemical properties were employed to evaluate the selective migration of cationic and anionic peptides from a tryptic hydrolysate of whey protein isolate well characterized by chemometric and bioinformatic methods. Two machine learning approaches were compared: Decision Tree (DT) and Binary Greedy Network (BGN). Based on the feature selection and model performance results, DT appeared to be the most appropriate approach to generate explanatory models of peptide migration. From the selected DT models, selective migration patterns associated with specific physicochemical properties of peptides and FMs were established for the first time. The migration of anionic peptides was positively affected by higher average peak-to-valley roughness (Rz) values and macropores distribution in the filtrating layer (Mp-FL), where S11N+ and PES300 were the FMs providing the highest recovery of this type of peptides, particularly for those with isoelectric point (pI) values lower than 4.407 (IDALNENK, KYLLFCMENSAEPEQSLACQCLVRTPEVD, SLAMAASDISLLDAQSAPL, SLAMAASDISLLDAQSAPLR, TDYKKYLLFCMENSAEPEQ, TPEVDDEALEK, TPEVDDEALEKFDK, VLVLDTDYK, and VYVEELKPTPEGDLEILLQK) which reached average recovery rates of 16.617 and 4.556%, respectively. Regarding the migration of cationic peptides, this was mainly affected by other membrane characteristics such as volumetric porosity (Vp) and zeta potential (ZP), as well as peptide parameters such as polar residue content, pI, and leucine content. S11, S11SO3-, PES100, and PES300 were the FMs with the highest selective recovery rate for 7 out of 11 cationic peptides (ALPHMIR, IPAVFK, PMHI, PMHIR, TKIPAVF, TKIPAVFK, and VGINYWLAHK) with average values between 2.149 to 4.328%. This novel DT-based approach represents a suitable tool for studying peptide migration, choosing the most appropriate FMs for selective bioactive peptide migration during EDFM, and understanding the phenomena involved in their migration process.

Facile preparation of soybean protein-based oil-resistant paper for food packaging

The use of plastic packaging is harmful to the environment. Due to the advantages of degradability, renewability, and safety of paper packaging materials, replacing plastic with paper has received much attention. However, the poor oil resistance of traditional paper constrains its application. In this research, oil-resistant agent is prepared using soy protein isolate and montmorillonite through physical blending. This oil-resistant agent has advantages of low cost and food safety. Subsequently, food packaging oil-proof paper is obtained by coating the above-mentioned coating on paper. This oil-proof paper has good heat resistance, oil resistance (kit rating is 8/12) and mechanical properties. In addition, it is found that the optimal storage environment for the oil-proof paper. This study provides a feasible method for producing, biodegradable, and eco-friendly food packaging oil-proof paper.