Functional characterization of commercial plant proteins and their application on stabilization of emulsions

Recent progress in fabrication, characterization and application of functional protein aggregates derived from plant proteins

This review highlights recent advancements in fabrication, characterization, and applications of functional plant protein aggregates, emphasizing their growing importance in the food industry because of their sustainability as well as cost-effectiveness compared to animal proteins. While native plant proteins often exhibit limited technofunctional properties, the formation of protein aggregates offers a promising solution. This review explores various aggregation methods, including physical methods (e.g., heat treatment, ultrasonication), chemical modifications (e.g., glycation, acylation), and biological processes (e.g., enzymatic hydrolysis, fermentation), and structural and functional properties changes after these treatments. Advanced characterization techniques such as spectroscopy, microscopy, and rheological methods, are discussed to assess microstructures and key properties like emulsification, gelation, and foaming. Applications of these aggregates in products like beverages, mayonnaise, and whipped cream are highlighted. The review concludes with future research directions to enhance industrial applications and nutritional benefits, providing insights into the potential of plant protein aggregates for developing innovative and sustainable plant-based food and non-food products.

Non-spherical microparticles from complex coacervation of rice or pea proteins and chia mucilage

Complex coacervation is a microencapsulation technique recognized by its low cost, high efficiency, and reproducibility. It involves interactions between oppositely charged biopolymers, such as proteins and polysaccharides. The present study evaluated the formation of non-spherical microparticles through the interactions of rice protein (RP) or pea protein (PP) with chia mucilage (CM) to encapsulate hydrophobic compounds. Gum Arabic (GA) and type B gelatin (GE) were used as model materials. Optimal ratio and pH values for the mixtures were determined through macroscopic, turbidity and zeta potential analyses. The microparticles containing gum Arabic were smaller and more spherical, with mean diameters ranging from 22.03 to 35.20 μm, whereas those containing chia mucilage exhibited an irregular shape and diameters ranging from 33.49 to 53.10 μm. The yields (74.0 %-84.5 %) and encapsulation efficiency (around 99 %) for the microparticles containing chia mucilage were significantly higher than those of the formulations containing gum Arabic (yields of 18.4 %-40.1 %, and encapsulation efficiencies of 8.7 %-71.0 %). Based on the results, the most effective encapsulation system was identified PP:CM. All microparticles formed by chia mucilage and proteins have non-spherical characteristics and some roughness which can be interesting for applications in food or biological systems.

Plant protein-based Pickering emulsion for the encapsulation and delivery of fat-soluble vitamins: A systematic review

Vitamin deficiencies pose a significant global health challenge, leading to various health issues and economic burdens. These challenges arise with the delivery of fat-soluble vitamin (FSV) due to its poor stability against the environmental stimuli. The commercial fortification methods such as Pickering emulsion (PE), hydrogel and others offer a potential solution over the limitations of conventional vitamin delivery methods (degradation and poor bioavailability). PE stabilized by solid plant protein particles, have emerged as a promising approach for encapsulation and delivery of oil-soluble vitamins (A, D, E, and K). Plant proteins, with their amphiphilic nature and nutritional benefits, are particularly well-suited as a stabilizer for PE. Plant protein-based PE enhances protection of vitamins against the environmental stimuli and enhances the delivery efficiency of oil-soluble vitamins. Factors such as particle size, concentration, and oil type also influence the stability, encapsulation efficiency, and bio-accessibility of fat-soluble vitamins in PE. Hence, the present review explores the impact of various factors on the stability and bio-accessibility of fat-soluble vitamins (A, D and E) and also emphasizing the role of particle size and concentration of stabilizer in controlling release rates of vitamin encapsulated PE. The review also highlights the application of plant protein-based PEs in various food products including nutrient fortification, functional foods, and 3D food printing.

What makes oil-in-water emulsions with pea protein stable? The role of excess protein in network formation and yield stress development

Emulsions stabilized with pea protein exhibit enhanced stability only if excess protein is present in the continuous aqueous phase. We hypothesize that the additional protein, beyond the interfacial layer surrounding the oil droplets, is important for the emergence of a yield stress as well as for the overall stability and properties. Stable emulsions with oil concentrations of 40-60% v/v were prepared and compared to layers from various separated emulsions. Confocal microscopy visualized both the oil droplets and the protein distribution. Rheological measurements were used to assess mechanical properties and network formation. Small angle X-ray scattering provided quantitative structural information. Results identified that stable emulsions have a protein layer encapsulating the oil droplets and that excess protein forms irregular aggregates in the aqueous phase. Rheological analysis indicated that the protein aggregates contribute to network formation and give rise to a yield stress which enhances stability. Only for sufficiently high protein concentrations were the emulsions stable. Other samples separated and the upper phases were always similar in emulsion composition regardless of the initial component fractions. This study highlights the dual role of pea protein in emulsions as a dispersed protein network and as interfacial material. Determination of the most favourable emulsion composition provides insight into design of stable emulsions for applications.

Interfacial and Bulk Properties of Potato and Faba Protein in Connection with Physical Emulsion Stability at Various pH Values and High Salt Concentrations

The protein transition motivates the use of plant proteins, but their application in food emulsions is challenging, especially when high concentrations of oil and salt are needed for formulation and sensory properties. In the present work, we connect the iso-electric point of two potato protein isolates (patatin-rich, POPI-200; protease inhibitor-rich, POPI-300) and a faba protein isolate (FPI) to the behavior in the bulk phase and at the interface, and relate this to the physical stability of 45 wt% oil-in-water (O/W) emulsions in the presence of NaCl at pH 4.0-7.0. In the absence of NaCl, a higher bulk viscosity was found at the iso-electric point (IEP), especially for the FPI. In the presence of NaCl, the viscosity of the POPI-200 solutions was highest, followed by POPI-300, and that of the FPI was lowest, irrespective of the pH. Both POPIs showed faster initial adsorption at the O/W interface in the absence of NaCl, and formed a more elastic layer compared to the FPI. For all proteins, salt addition leads to less elastic films. Interestingly, the interfaces were more elastic at a pH close to the IEP of the protein in the presence of NaCl. Both POPI-stabilized emulsions showed higher stability (smaller size and less oiling off) than the FPI-stabilized emulsions, which makes potato proteins relevant for food emulsion product formulation, even under high salt conditions.

Almond protein as Pickering emulsion stabilizer: Impact of microgel fabrication method and pH on emulsion stability

We evaluated the ability of almond proteins to produce Pickering emulsions (EM) stabilized by microgels (MG) fabricated by three different methods (heat treatment-HT, crosslinking with transglutaminase-TG or calcium-CA), at two pH levels (pH 3 or 7). Compared to pH 7, acidic pH significantly denatured almond proteins (ellipticity ∼0 mdeg), decreased absolute zeta potential values (10.5 to 18.6 mV at pH 3 and - 24.6 to -32.6 mV at pH 7), and free thiol content (114.64-131.60 μmol SH/g protein at pH 3 and 129.46-148.17 μmol SH/g protein at pH 7 - except in CA-crosslinked microgels, p > 0.05). These changes led to larger microgel sizes (D3,2pH3: 26.3-39.5 μm vs. D3,2pH7: 5.9-9.0 μm) with lower polydispersity (SpanpH3: ∼ 1.94 vs. SpanpH7: 2.32, excluding CA-based samples). Consequently, the Turbiscan Stability Index (TSI) was higher in acidic conditions for all emulsions, except for the calcium-containing formulation (EM_CApH3), emphasizing the critical role of calcium binding in maintaining emulsion stability in acidic environments. Microgels prepared via the traditional heat treatment method produced emulsions with intermediate stability (TSI ranging from 3.4 % to 5.1 % at 28 days of storage). Conversely, TG-crosslinked microgels led to unstable emulsions at pH 3, likely due to the lowest zeta potential (+4.2 mV), whereas at pH 7, the greatest stability was attributed to bridging flocculation that created a stable gel-like structure. Indeed, emulsions with lower TSI (EM_CApH3 = 1.8 %, EM_CApH7 = 2.3 % and EM_TGpH7 = 1.0 %, at 28 days of storage) also exhibited higher elastic modulus (G') over frequency sweep, indicating that the strong elastic network was relevant for emulsion stability (up to 28 days). This study, for the first time, demonstrated the production of stable almond-based Pickering emulsions, with properties modulated by the pH and method used to fabricate the microgels.

Isolation and characterization of nettle (Urtica dioica L.) seed proteins: Conversion of underutilized by-products of the edible oil industry into food emulsifiers

This study aimed to upcycle a byproduct of the edible oil industry, cold-pressed nettle seed meal (CPNSM), into a plant-based emulsifier, thereby increasing the sustainability of the food system. The protein content of the nettle seed protein (NSP) powder was 48.3% with glutamic acid (16.6%), asparagine (10.7%), and arginine (9.7%) being the major amino acids. NSPs had a denaturation temperature of 66.6 °C and an isoelectric point of pH 4.3. They could be used as emulsifiers to form highly viscous coarse corn oil-in-water emulsions (10% oil, 4% NSP). Nevertheless, 10-fold diluted emulsions exhibited rapid creaming under different pH (2-9), salt (0-500 mM NaCl) and temperature (>40 °C) conditions, but they were relatively stable to aggregation. Our findings suggest that NSPs could be used as emulsifiers in highly viscous or gelled foods, like dressings, sauces, egg, cheese, or meat analogs.

Incorporation of amylose improves rheological and textural properties of Moringa oleifera seed salt-soluble protein

The interactions between corn amylose (CA) and Moringa oleifera seed salt-soluble protein (MOSP) were explored to improve the gel properties of MOSP. With increasing CA content, the MOSP-CA gel network structure was improved but the size of the gel porosity decreased firstly and then increased; the water holding retention (WHR) of MOSP-CA was decreased from approximately 94 % to 85.43 ± 2.54 %. The MOSP-CA-2.5 gel exhibited the best water holding stability (WHS), with a value of 37.1 ± 0.33 %. The MOSP-CA gel hardness increased with CA concentration, and MOSP-CA-2.5 showed relatively optimal cohesiveness, elasticity, adhesiveness, and chewiness. Meanwhile, MOSP-CA-2.5 exhibited gel strength. Incorporation of CA significantly increased the exposure of hydrophobic residues and the concentration-dependent increase in disulfide bonds in MOSP-CA gel. Thus, hydrophobic interactions, hydrogen bonds, and disulfide bonds collectively stabilized the structure of MOSP-CA gel. The findings would broaden the application of MOSP and improve the utilization value of MOSP in various industries.

Toward Diverse Plant Proteins for Food Innovation

This review highlights the development of plant proteins from a wide variety of sources, as most of the research and development efforts to date have been limited to a few sources including soy, chickpea, wheat, and pea. The native structure of plant proteins during production and their impact on food colloids including emulsions, foams, and gels are considered in relation to their fundamental properties, while highlighting the recent developments in the production and processing technologies with regard to their impacts on the molecular properties and aggregation of the proteins. The ability to quantify structural, morphological, and rheological properties can provide a better understanding of the roles of plant proteins in food systems. The applications of plant proteins as dairy and meat alternatives are discussed from the perspective of food structure formation. Future directions on the processing of plant proteins and potential applications are outlined to encourage the generation of more diverse plant-based products.

The emulsifying capacity and stability of potato proteins and peptides: A comprehensive review

The potato has recently attracted more attention as a promising protein source. Potato proteins are commonly extracted from potato fruit juice, a byproduct of starch production. Potato proteins are characterized by superior techno-functional properties, such as water solubility, gel-forming, emulsifying, and foaming properties. However, commercially isolated potato proteins are often denatured, leading to a loss of these functionalities. Extensive research has explored the influence of different conditions and techniques on the emulsifying capacity and stability of potato proteins. However, there has been no comprehensive review of this topic yet. This paper aims to provide an in-depth overview of current research progress on the emulsifying capacity and stability of potato proteins and peptides, discussing research challenges and future perspectives. This paper discusses genetic diversity in potato proteins and various methods for extracting proteins from potatoes, including thermal and acid precipitation, salt precipitation, organic solvent precipitation, carboxymethyl cellulose complexation, chromatography, and membrane technology. It also covers enzymatic hydrolysis for producing potato-derived peptides and methods for identifying potato protein-derived emulsifying peptides. Furthermore, it reviews the influence of factors, such as physicochemical properties, environmental conditions, and food-processing techniques on the emulsifying capacity and stability of potato proteins and their derived peptides. Finally, it highlights chemical modifications, such as acylation, succinylation, phosphorylation, and glycation to enhance emulsifying capacity and stability. This review provides insight into future research directions for utilizing potato proteins as sustainable protein sources and high-value food emulsifiers, thereby contributing to adding value to the potato processing industry.

Preparation of oil-in-water emulsions stabilized by faba bean protein-grape leaf polyphenol conjugates: pH-, salt-, heat-, and freeze-thaw-stability

BACKGROUND

Plant proteins are being increasingly utilized as functional ingredients in foods because of their potential health, sustainability, and environmental benefits. However, their functionality is often worse than the synthetic or animal-derived ingredients they are meant to replace. The functional performance of plant proteins can be improved by conjugating them with polyphenols. In this study, the formation and stability of oil-in-water emulsions prepared using faba bean protein-grape leaf polyphenol (FP-GLP) conjugates as emulsifiers. Initially, FP-GLP conjugates were formed using an ultrasound-assisted alkali treatment. Then, corn oil-in-water emulsions were prepared using high-intensity sonication (60% amplitude, 10 min) and the impacts of conjugate concentration, pH, ionic strength, freezing-thawing, and heating on their physicochemical properties and stability were determined.

RESULTS

Microscopy and light scattering analysis showed that oil-in-water emulsions containing small oil droplets could be formed at conjugate concentrations of 2% and higher. The addition of salt reduced the electrostatic repulsion between the droplets, which increased their susceptibility to aggregation. Indeed, appreciable droplet aggregation was observed at ≥ 50 mmol/L sodium chloride. The freeze-thaw stability of emulsions prepared with protein-polyphenol conjugates was better than those prepared using the proteins alone. In addition, the emulsions stabilized by the conjugates had a higher viscosity than those prepared by proteins alone.

CONCLUSION

This study showed that FP-GLP conjugates are effective plant-based emulsifiers for forming and stabilizing oil-in-water emulsions. Indeed, emulsions formed using these conjugates showed improved resistance to pH changes, heating, freezing, and salt addition. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The role of fiber in modulating plant protein-induced metabolic responses

The rising consumption of plant protein foods and the emergence of meat alternatives have prompted interest in the health benefits of such products, which contain fiber in addition to protein. This review investigates the effect of fiber on plant-based protein metabolism and evaluates its contribution to gut-derived health impacts. Plant proteins, which often come with added fiber, can have varying health outcomes. Factors such as processing and the presence of fiber and starch influence the digestibility of plant proteins, potentially leading to increased proteolytic fermentation in the gut and the production of harmful metabolites. However, fermentable fiber can counteract this effect by serving as a primary substrate for gut microbes, decreasing proteolytic activity. The increased amount of fiber, rather than the protein source itself, plays a significant role in the observed health benefits of plant-based diets in human studies. Differences between extrinsic and intrinsic fiber in the food matrix further impact protein fermentation and digestibility. Thus, in novel protein products without naturally occurring fiber, the health impact may differ from conventional plant protein sources. The influence of various fibers on plant-based protein metabolism throughout the gastrointestinal tract is not fully understood, necessitating further research.

Pea protein [Pisum sativum] as stabilizer for oil/water emulsions

A map of stability for various water/oil/pea protein compositions has been plotted from the numerous reported results. Two clear regions of stability were identified. High internal oil phase emulsions with 70-80%, v/v oil content stabilized by total pea protein concentration <2.5%, w/v showed stability. Low oil content of 10-30%, v/v for a range of total pea protein concentrations >0.5%, w/v have also been identified as stable. Intermediate oil content and pea protein concentrations >4% w/v are unexplored regions and are likely to be areas of fruitful future research. The wide range of stability suggests that different stabilization mechanisms could be important for different compositions and careful consideration has to be taken to avoid oversimplification. Both stabilization with particles, i.e. Pickering emulsions, and protein unfolding have been suggested as mechanisms. The diverse way of describing stability makes it difficult to intercompare results in different studies. A summary of different oil types used have been presented and several properties such as dynamic viscosity, density, the dielectric constant and interfacial tension have been summarized for common vegetable oils. The type of vegetable oil and emulsion preparation techniques were seen to have rather little effect on emulsion stability. However, the different extraction methods and processing of the pea material had more effect, which could be attributed to changing composition of different proteins and to the states of aggregation and denaturing. Careful consideration has to be taken in the choice of extraction method and an increased understanding of what contributes to the stability is desirable for further progress in research and eventual product formulation.

Interactions between pea protein and gellan gum for the development of plant-based structures

Plant-based analogs have been developed to mimic foods from animal sources by using ingredients from vegetable sources. Among the strategies to produce plant-based structures is the gelation of mixtures between plant proteins and polysaccharides. In this study, our aim was to investigate gels of pea proteins and gellan gum with high protein concentration and the addition of salt (potassium and sodium chloride). In the first step, a qualitative mapping was performed to select pea protein and gellan gum concentrations to produce self-sustainable gels. After that, the effect of salt addition was investigated for the formulations containing 10-15 % (wt) pea protein and 0.5-1 % (wt) gellan gum. The results showed that the gels containing potassium ions were more rigid and less deformable, with lesser water loss by syneresis. The morphological analysis showed a spatial exclusion of pea protein from the gel network mainly structured by the gellan gum. While potassium ions led to a more compact network, calcium ions promoted higher pores in the structure. Depending on the composition, the mechanical properties of gels were similar to some products from animal sources. So, the information obtained from these gels can be applied to the structuring of formulations in the development of plant-based analogs.

Applications of Plant Bioactive Compounds as Replacers of Synthetic Additives in the Food Industry

According to the Codex Alimentarius, a food additive is any substance that is incorporated into a food solely for technological or organoleptic purposes during the production of that food. Food additives can be of synthetic or natural origin. Several scientific evidence (in vitro studies and epidemiological studies like the controversial Southampton study published in 2007) have pointed out that several synthetic additives may lead to health issues for consumers. In that sense, the actual consumer searches for "Clean Label" foods with ingredient lists clean of coded additives, which are rejected by the actual consumer, highlighting the need to distinguish synthetic and natural codded additives from the ingredient lists. However, this natural approach must focus on an integrated vision of the replacement of chemical substances from the food ingredients, food contact materials (packaging), and their application on the final product. Hence, natural plant alternatives are hereby presented, analyzing their potential success in replacing common synthetic emulsifiers, colorants, flavorings, inhibitors of quality-degrading enzymes, antimicrobials, and antioxidants. In addition, the need for a complete absence of chemical additive migration to the food is approached through the use of plant-origin bioactive compounds (e.g., plant essential oils) incorporated in active packaging.

Effect of Pea Legumin-to-Vicilin Ratio on the Protein Emulsifying Properties: Explanation in Terms of Protein Molecular and Interfacial Properties

In isolates from different pea cultivars, the legumin-to-vicilin (L:V) ratio is known to vary from 66:33 to 10:90 (w/w). In this study, the effect of variations in the L:V ratio on the pea protein emulsifying properties (emulsion droplet size (d3,2) vs protein concentration (Cp)) at pH 7.0 was investigated using a purified pea legumin (PLFsol) and pea vicilin fraction (PVFsol). Despite a different Γmax,theo, the interfacial properties at the oil-water interface and the emulsifying properties were similar for PLFsol and PVFsol. Hence, the L:V ratio did not affect the pea protein emulsifying properties. Further, PLFsol and PVFsol were less efficient than whey protein isolate (WPIsol) in stabilizing the emulsion droplets against coalescence. This was explained by their larger radius and thus slower diffusion. For this reason, the difference in diffusion rate was added as a parameter to the surface coverage model. With this addition, the surface coverage model described the d3,2 versus Cp of the pea protein samples well.

Pickering Emulsion Stabilized by Tea Seed Cake Protein Nanoparticles as Lutein Carrier

To effectively deliver lutein, hydrothermally prepared tea seed cake protein nanoparticles (TSCPN) were used to fabricate Pickering emulsion, and the bioaccessibility of lutein encapsulated by Pickering emulsion and the conventional emulsion was evaluated in vitro. The results indicated that the average size and absolute value of zeta potential of TSCPN increased along with the increase in the protein concentration, and 2% protein concentration was adopted to prepare TSCPN. With the increase in the concentration of TSCPN, the size of Pickering emulsion decreased from 337.02 μm to 89.36 μm, and when the TSCPN concentration was greater than 0.6%, all emulsions exhibited good stability during the 14 days storage. Combined with the microstructure result, 1.2% TSCPN was used to stabilize Pickering emulsion. With the increase in ionic concentration (0-400 mM), the particle size of the emulsions increased while the absolute value of zeta potential decreased. TSCPN-based Pickering emulsion was superior to the conventional emulsion for both lutein encapsulation (96.6 ± 1.0% vs. 82.1 ± 1.4%) and bioaccessibility (56.0 ± 1.1% vs. 35.2 ± 1.2%). Thus, TSCPN-based Pickering emulsion in this study have the potential as an effective carrier for lutein.

Effects of pH and Ionic Salts on the Emulsifying and Rheological Properties of Acorn Protein Isolate

This study was designed to evaluate the emulsifying and rheological properties of acorn protein isolate (API) in different pH mediums (pH 3, 7 and 9) and in the presence of ionic salts (1 M NaCl and 1 M CaCl2). API shows higher solubility in distilled water at pH 7, while at the same pH, a decrease in solubility was observed for API in the presence of CaCl2 (61.30%). A lower emulsifying activity index (EAI), lower stability index (ESI), larger droplet sizes and slight flocculation were observed for API in the presence of salts at different pHs. Importantly, CaCl2 treated samples showed relevantly higher EAI (252.67 m2/g) and ESI (152.67 min) values at all pH as compared to NaCl (221.76 m2/g), (111.82 min), respectively. A significant increase in interfacial protein concentration (4.61 mg/m2) was observed for emulsion at pH 9 with CaCl2, while the major fractions of API were observed in an interfacial layer after SDS-PAGE analysis. All of the emulsion shows shear thinning behavior (τc > 0 and n < 1), while the highest viscosity was observed for emulsion prepared with CaCl2 at pH 3 (11.03 ± 1.62). In conclusion, API, in the presence of ionic salts at acidic, neutral and basic pH, can produce natural emulsions, which could be substitutes for synthetic surfactants for such formulations.

Effect of Fibril Entanglement on Pickering Emulsions Stabilized by Whey Protein Fibrils for Nobiletin Delivery

The aim of the study was to investigate the effects of whey protein isolate (WPI) fibrils entanglement on the stability and loading capacity of WPI fibrils-stabilized Pickering emulsion. The results of rheology and small-angle X-ray scattering (SAXS) showed the overlap concentration (C*) of WPI fibrils was around 0.5 wt.%. When the concentration was higher than C*, the fibrils became compact and entangled in solution due to a small cross-sectional radius of gyration value (1.18 nm). The interfacial behavior was evaluated by interfacial adsorption and confocal laser scanning microscopy (CLSM). As the fibril concentration increased from 0.1 wt.% to 1.25 wt.%, faster adsorption kinetics (from 0.13 to 0.21) and lower interfacial tension (from 11.85 mN/m to 10.34 mN/m) were achieved. CLSM results showed that WPI fibrils can effectively absorb on the surface of oil droplets. Finally, the microstructure and in vitro lipolysis were used to evaluate the effect of fibrils entanglement on the stability of emulsion and bioaccessibility of nobiletin. At C* concentration, WPI fibrils-stabilized Pickering emulsions exhibited excellent long-term stability and were also stable at various pHs (2.0–7.0) and ionic strengths (0–200 mM). WPI fibrils-stabilized Pickering emulsions after loading nobiletin remained stable, and in vitro digestion showed that these Pickering emulsions could significantly improve the extent of lipolysis (from 36% to 49%) and nobiletin bioaccessibility (21.9% to 62.5%). This study could provide new insight into the fabrication of food-grade Pickering emulsion with good nutraceutical protection.

Interfacial characteristics and in vitro digestion of emulsion coated by single or mixed natural emulsifiers: lecithin and/or rice glutelin hydrolysates

BACKGROUND

The interfacial characteristics and in vitro digestion of emulsion were related to emulsifier type. The mean droplet diameter, ζ-potential, microstructure, interfacial tension, Quartz crystal microbalance with dissipation (QCM-D) and in vitro gastrointestinal fate of emulsions stabilized by soybean lecithin, hydrolyzed rice glutelin (HRG) and their mixture were researched.

RESULTS

The value of interfacial tension was much more dramatically declined for the sample containing 20 g kg^-1 of HRG. For QCM-D, a rigid layer was formed for all the samples after rinsing. The layer thickness was 0.87 ± 0.20, 2.11 ± 0.31 and 2.63 ± 0.22 nm, and adsorbed mass was 87.17 ± 10.31, 210.56 ± 20.12 and 263.09 ± 23.23 ng cm^-2 , for HRG, lecithin and HRG/lecithin, respectively, indicating both HRG and lecithin were adsorbed at the oil-water interface. Structural rearrangements at the interface occurred for HRG/lecithin. The kinetics and final amount of lipid digestion depended on emulsifier type: lecithin > HRG/lecithin > HRG. These differences in digestion rate were primarily due to differences in the aggregation state of the emulsifiers.

CONCLUSION

The incorporation of lecithin into HRG emulsions had better interfacial properties comparing with HRG emulsion and facilitated lipid digestibility. These results provide important information for the rational design of plant-based functional food. © 2021 Society of Chemical Industry.

Multifunctionality of Rapeseed Meal Protein Isolates Prepared by Sequential Isoelectric Precipitation

Rapeseed meal is a by-product of the oil-producing industry with a currently underestimated application. Two protein isolates, PI_2.5–8.5 or PI_10.5–2.5, were obtained from industrial rapeseed meal after treatment with an aqueous ethanol solution. The alkaline-extracted proteins were sequentially precipitated by two different modes, from pH 10.5 to 2.5, and vice versa, from 2.5 to 8.5, with a step of 1 pH unit. The preparation approach influenced both the functional and antioxidant properties of the isolates. The PI_10.5–2.5 exhibited higher water and oil absorption capacities than PI_2.5–8.5, reaching 2.68 g H₂O/g sample and 2.36 g oil/g sample, respectively. The emulsion stability of the PI_2.5–8.5, evaluated after heating at 80 °C, was either 100% or close to 100% for all pH values studied (from 2 to 10), except for pH 6 where it reached 93.87%. For the PI_10.5–2.5, decreases in the emulsion stability were observed at pH 8 (85.71%) and pH 10 (53.15%). In the entire concentration range, the PI_10.5–2.5 exhibited a higher scavenging ability on 2,2-diphenyl-1-picryl hydrazyl (DPPH) and hydroxyl radicals than PI_2.5–8.5 as evaluated by DPPH and 2-deoxyribose assays, respectively. At the highest concentration studied, 1.0%, the neutralization of DPPH radicals by PI_10.5–2 reached half of that exhibited by synthetic antioxidant butylhydroxytoluene (82.65%). At the same concentration, the inhibition of hydroxyl radicals by PI_10.5–2 (71.25%) was close to that achieved by mannitol (75.62%), which was used as a positive control. Established antioxidant capacities add value to the protein isolates that can thus be used as both emulsifiers and antioxidants.

Potato protein: current review of structure, technological properties, and potential application on spray drying microencapsulation

Studies regarding spray drying microencapsulation are aplenty available; especially focusing on processing parameters, microparticle characteristics and encapsulation efficiency. Hence, there is a rising interest in tailoring wall materials aiming to improve the process's effectiveness. Reflecting a market trend in the food industry, plant-based proteins are emerging as alternative protein sources, and their application adaptability is an increasing research of interest related to consumers' demand for healthy food, product innovation, and sustainability. This review presents a perspective on the investigation of potato protein as a technological ingredient, considering it a nonconventional source obtained as by-product from starch industry. Furthermore, this piece emphasizes the potential application of potato protein as wall material in spray drying encapsulation, considering that this purpose is still limited for this ingredient. The literature reports that vegetal-based proteins might present compromised functionality due to processing conditions, impairing its technological application. Structural modification can offer a potential approach to modify potato protein configuration aiming to improve its utilization. Studies reported that modified proteins can perform as better emulsifiers and antioxidant agents compared to intact proteins. Hence, it is expected that their use in microencapsulation would improve process efficiency and protection of the core material, consequently delivering superior encapsulation performance.

Plant Protein-Based Delivery Systems: An Emerging Approach for Increasing the Efficacy of Lipophilic Bioactive Compounds

The development of plant protein-based delivery systems to protect and control lipophilic bioactive compound delivery (such as vitamins, polyphenols, carotenoids, polyunsaturated fatty acids) has increased interest in food, nutraceutical, and pharmaceutical fields. The quite significant ascension of plant proteins from legumes, oil/edible seeds, nuts, tuber, and cereals is motivated by their eco-friendly, sustainable, and healthy profile compared with other sources. However, many challenges need to be overcome before their widespread use as raw material for carriers. Thus, modification approaches have been used to improve their techno-functionality and address their limitations, aiming to produce a new generation of plant-based carriers (hydrogels, emulsions, self-assembled structures, films). This paper addresses the advantages and challenges of using plant proteins and the effects of modification methods on their nutritional quality, bioactivity, and techno-functionalities. Furthermore, we review the recent progress in designing plant protein-based delivery systems, their main applications as carriers for lipophilic bioactive compounds, and the contribution of protein-bioactive compound interactions to the dynamics and structure of delivery systems. Expressive advances have been made in the plant protein area; however, new extraction/purification technologies and protein sources need to be found Their functional properties must also be deeply studied for the rational development of effective delivery platforms.

Formation by high power ultrasound of aggregated emulsions stabilised with milk protein concentrate (MPC70)

In this work, oil-in-water emulsions stabilised by milk protein concentrate (MPC70) were investigated. The MPC70 concentration was kept constant at 5% (close to the protein content found in skim milk) and the oil volume fraction was varied from 20 to 65%. Sonication was performed at 20 kHz and at a constant power of 14.4 W for a total emulsion volume of 10 mL. Under certain oil concentration (≥35%) and sonication times (≥3s) the emulsion aggregated and formed high-viscosity pseudo plastic materials. However, the viscosity behaviour of the emulsion made with 35% oil reverted to that of a liquid if sonicated for longer times (≥15 s). Confocal laser scanning microscopy showed clearly that the oil droplets are aggregated under the sonication conditions and oil concentrations indicated above. An attempt to explain this behaviour through a simple model based on the bridging of oil droplets by the MPC70 particles and, taking into account the oil droplet and MPC70 particle sizes as well as the oil volume fraction, was made. The model fails to describe in details the aggregation behaviour of these emulsions, likely due to the inhomogeneous protein layer, where both free caseins and casein micelles are adsorbed, and to the packing of the oil droplets at concentrations ≤55%. Nonetheless, this work demonstrates the potential of ultrasound processing for the formation of dairy emulsions with tailored textures.

Spirulina platensis Protein as Sustainable Ingredient for Nutritional Food Products Development

Spirulina platensis, microalgae, is emerging as a sustainable source for highly nutritional food ingredient production to cover the food demands of the global population. This study aimed to characterize food prototypes supplemented with microalgae protein isolate to develop health-promoting food products. The nutritional composition (proximate composition, fatty acids, and mineral content) of the spirulina biomass, the structural characterization of spirulina platensis protein (SPP) isolates, and the physicochemical properties of SPP- developed food products were evaluated. High protein (47%), ϒ-Linolenic acid (24.45 g/100 g of fat), iron (16.27 mg/100 g), calcium (207 mg/100 g), and potassium (1675 mg/100 g) content in the spirulina biomass was found. SPP (76% of purity) with sodium alginate produced stable emulsions (>90%) during storage (14 days). Amaranth + SPP pasta resulted in good appearance, texture, color, and high nutritional value in protein (above 30%) and minerals, mainly iron (9–10 mg/100 g) and magnesium (300 mg/100 g), meeting the daily intake recommendations. In addition, the amino acid profile of the pasta was in line with the amino acid pattern requirements for adults. SPP can be considered as potential additive for emulsions stability and provided nutritional and physicochemical desired in the elaborated pasta.