Faba Bean Protein Research Articles

Effects of mono- and dual-frequency ultrasounds on structure and physicochemical properties of faba bean proteins

Faba bean proteins are currently viewed as promising animal protein alternatives. However, certain functional properties e.g. relatively low solubility compared to whey protein isolates, can limit the application of faba bean protein isolates (FPIs) in certain food products. Therefore, it may be desirable to use modification approaches such as the application of ultrasound to alter such limiting physicochemical properties. In this study, Faba Bean Protein Isolates (FPI) were treated by ultrasound with different frequencies (20 kHz, 40 kHz and 20 + 40 kHz) prior to hydration (1 %) at different pH levels (3, 7, and 9). Then the structure and physicochemical properties (i.e. particle size, ζ-potential, surface hydrophobicity, thermal behavior, and solubility) of control and untreated FPIs were investigated. Ultrasound treatment had no obvious effect on the molecular weight of FPIs, whereas it changed the secondary structure of FPIs from a more ordered structure to a more disordered structure. The applied treatment resulted in an increase in surface hydrophobicity across all treatment levels and pHs. It also decreased the particle size of FPI at pH 3, while it increased the particle size at pH 7 and 9, compared to the untreated FPI. In addition, the solubility and thermal properties of FPI were modified through the ultrasound treatment. The higher solubility of FPI could improve its potential to be used as a functional ingredient for many food applications. Ultrasound treatment at 20 kHz and 20 + 40 kHz had more effects on the physiochemical properties of FPI compared to that at 40 kHz. Overall, ultrasound treatment with different frequencies (20 kHz, 40 kHz, and 20 + 40 kHz) modified the structure and physiochemical properties of FPI to different degrees and may be beneficial for the development of FPI for certain food applications.

Faba bean nutrition: Macronutrients, antinutrients, and the effect of processing

AbstractBackground and ObjectivesFaba beans are emerging as highly nutritious ingredients that have the potential to contribute to the global demand for healthy and sustainable plant‐based proteins. The current review aims to provide a summarized overview of faba bean macronutrients, protein quality, and antinutritional factors (ANFs), as well as their reduction strategies through a variety of processing means.FindingsRelative to other pulses, faba beans are higher in protein content and similar in protein quality. However, without proper preparation and/or processing, the presence of minor amounts of ANFs can hinder their nutritional value. These nonnutritive, but biologically active, compounds can be diminished through mechanical, thermal, and nonthermal treatments.ConclusionsNonconventional processing techniques to retain or improve protein quality remain an area of future research for improving faba bean nutrition and expanding its utilization.Significance and NoveltyThis review will advance the science and utilization of faba bean ingredients while providing future research opportunities.

Optimization of ultrasound-assisted extraction of faba bean protein isolate: Structural, functional, and thermal properties. Part 2/2

Environmental concerns linked to animal-based protein production have intensified interest in sustainable alternatives, with a focus on underutilized plant proteins. Faba beans, primarily used for animal feed, offer a high-quality protein source with promising bioactive compounds for food applications. This study explores the efficacy of ultrasound-assisted extraction under optimal conditions (123 W power, 1:15 g/mL solute/solvent ratio, 41 min sonication, 623 mL total volume) to isolate faba bean protein (U-FBPI). The ultrasound-assisted method achieved a protein extraction yield of 19.75 % and a protein content of 92.87 %, outperforming the control method’s yield of 16.41 % and protein content of 89.88 %. Electrophoretic analysis confirmed no significant changes in the primary structure of U-FBPI compared to the control. However, Fourier-transform infrared spectroscopy revealed modifications in the secondary structure due to ultrasound treatment. The U-FBPI demonstrated superior water and oil holding capacities compared to the control protein isolate, although its foaming capacity was reduced by ultrasound. Thermal analysis indicated minimal impact on the protein’s thermal properties under the applied ultrasound conditions. This research highlights the potential of ultrasound-assisted extraction for improving the functional properties of faba bean protein isolates, presenting a viable approach for advancing plant-based food production and contributing to sustainable protein consumption.

Mixing oat proteins with lentil or faba bean proteins: How is the techno-functional behavior of the different protein systems affected by heat treatments?

Despite the growing market for plant-based products, rarely a single plant protein source manages to provide all the essential amino acids in a balanced way. Mixed protein systems combining proteins from more than one plant source may be useful to overcome this drawback. However, the mixture of proteins from different plant sources may impact the technological performance of the system. In this context, the influence of heat treatments of 75 and 95 °C for 15 min at neutral pH on the colloidal and the techno-functional properties of mixtures of protein isolates from lentil and oat (LO) and from faba bean and oat (FO) were investigated. The applied heat treatments induced subtle changes in the colloidal properties of the different systems. It was evidenced by size exclusion chromatography that oat proteins were more prone to heat induced changes than lentil or faba bean proteins. Regarding the techno-functional properties, mixing the proteins from the different sources had an antagonistic effect on foamability. On the other hand, an additive effect was observed for emulsifying capacities, with legume proteins displaying values between 93 and 100%, oat proteins close to 65%, and mixed systems between 78 and 93 %. Vicilin (7S) and β-basic subunits of legumin (11S) from lentil and faba bean, and oat 12S globulin were the main protein fractions stabilizing the interface of the obtained emulsions. The proteins from both sources coexisted at the interface of the emulsions stabilized by the mixed systems. The microstructure of the thermo-induced gels was dictated by oat proteins. However, the different legumes played a determining role in the critical gelling concentration measured (8 % w/w and 11.5 % w/w respectively for LO and FO). Mixing oat proteins with lentil or faba bean proteins allows modulating the techno-functional performance of the systems, thus represents an opportunity for innovative applications.

Whipped cream stabilized by faba bean protein isolate microgel particles substituted for sodium caseinate: Whipping performance and foam stabilization analysis

In this study, faba bean protein isolate microgel particles (FPIMPs) were used as substitutes for sodium caseinate in whipped cream ingredients, the effect of FPIMPs on properties of emulsion system before whipping and foam system after whipping was investigated, and the stabilization mechanisms of whipped cream systems stabilized by FPIMPs and sodium caseinate, respectively, were analyzed and compared. Elevated levels of FPIMPs facilitated the cross-linking and flocculation of oil droplets in the emulsions, which further promoted the formation of gel-like networks, leading to a larger average particle size and higher viscoelasticity. Meanwhile, the firmness, shaping ability, and shape retention ability of whipped creams were gradually enhanced with the increase of FPIMPs content. The quality of whipped creams with FPIMPs concentrations of 0.8% and above was comparable to that of commercial whipped cream. Tribological results showed that the coefficient of friction of whipped creams was roughly negatively correlated with the concentration of FPIMPs, and the lubricating properties of whipped creams with high FPIMPs concentrations (>0.8%) were better than those of commercial whipped cream. The oil-water interface film with high mechanical strength formed by FPIMPs made the FPIMPs-stabilized whipped creams more resistant to whipping than sodium caseinate-stabilized whipped cream, delaying the occurrence of excessive whipping phenomenon. This work has important implications for expanding the application of faba bean protein isolate in food systems, as well as provides new strategies for the development of healthier plant-based whipped creams.

The effect of heat treatment and high‐pressure homogenization on the dispersibility and interfacial behavior of faba bean protein isolate and concentrate

AbstractThe effect of hydrothermal treatments, high‐pressure homogenization (HPH) and their combined effects on faba bean protein isolate (FBI) and concentrate (FBC) dispersions was investigated. With HPH, a significant reduction in particle size was observed for FBI but not for FBC. For FBI, dispersion stability under accelerated gravitation was significantly improved by both hydrothermal and HPH. For FBC, hydrothermal treatment had a negative effect on dispersion stability unless it was combined with HPH. The protein dispersibility of FBI increased, and FBC decreased with increasing temperature. Upon HPH, the protein dispersibility of FBI dramatically improved, making it almost completely soluble. All FBI dispersions had a higher surface charge compared to FBC. SDS PAGE profile showed strong protein crosslinking in the original FBI, leading to a loss of legumin and vicilin bands, which were visible in a more native state of FBC. Physical modifications did not significantly affect the viscosities except for a significant increase in FBC heated at 75°C due to starch gelatinization. The equilibrium interfacial tension of the modified FBI was significantly lower than the FBC. Analysis of dynamic interfacial adsorption showed that FBI had a much faster initial diffusion (beyond detection limit) towards the interface than FBC. Physical modifications improved the surface hydrophobicity of the proteins, leading to faster interfacial adsorption. Overall, FBI dispersions had improved functional properties compared to FBC, and HPH had a more significant effect than hydrothermal treatments. Physically modified FBI could be a promising emulsifier in various food applications.

Mild extraction of faba bean (Vicia faba L.) proteins against conventional methods: Impact on physicochemical and thermal characteristics

Faba bean (high- and low-tannin) protein isolates were water extracted followed by dialysis or micellization in comparison to concentrates from conventional alkali extraction + acid precipitation, and salt-based extraction (1% NaCl) + dialysis. Protein fractions were characterised for secondary structure conformational changes, crystalline structure, particle size distribution in aqueous suspension and thermal properties. Mild water or salt extraction did not influence particle size distribution. Based on XRD, FTIR and CD, β-sheet structures were the most abundant secondary structures and water extraction + dialysis had minimal impact on their native conformation. DSC results showed an association between protein purity, glass transition temperature and endothermic enthalpy. High melting temperature above glass transition confirms the suitability of faba bean proteins for thermal/extrusion processing. Fractionation method was a more significant determinant of physicochemical characteristics compared to the cultivar. Further exploration of the techno-functional characteristics of faba bean proteins is essential for value-added food applications.

Effect of solid-state fermentation on the functionality, digestibility, and volatile profiles of pulse protein isolates

Fermentation, as a clean processing technique, induces structural and compositional modifications to plant proteins, improving their functionality and nutrition. However, the effect varies depending on the level of hydrolysis, the fermenting strain, and the specific substrate used. The present work examined the effect of solid-state fermentation (SSF) by Lactobacillus plantarum, Aspergillus niger and Aspergillus oryzae of several niche market pulse (chickpea, green lentil, and faba bean) protein isolates on their functional and nutritional properties. The pulse proteins were moderately hydrolyzed to different extents (degree of hydrolysis of 9%–15%) after 48 h of fermentation, enhancing surface charge and solubility while decreasing water holding capacity and emulsion stability. Protein digestibility was reduced for all pulses which was hypothesized to be due to an increase in phenolic content caused by fermentation. Among the strains, only A. niger outgrew the natural microbiota for all pulses. Variations relating to the property changes were observed among the inocula and pulses; however, no general trend could be concluded. Fermentation produced a large variety of favourable new volatile compounds in the protein isolates.

3D printing of prawn mimics with faba proteins: The effects of transglutaminase and curdlan gum on texture

With its capability for automated production of high-resolution structures, 3D printing can develop plant-based seafood mimics with comparable protein content. However, the challenge lies in solidifying 3D printed products to achieve the firmness of seafood. Targeting prawn, texturisation of its 3D printed mimic by curdlan gum was compared against incubation with a protein cross-linking enzyme, microbial transglutaminase. Faba bean protein extract (FBP) was selected for its lightest colour. To confer structural stability to the FBP-based ink without hindering extrudability, adding 1 % xanthan gum was optimal. Printed curdlan-containing mimics were steamed for 9 min, while printed transglutaminase-containing mimics were incubated at 55 °C before steaming. Either adding 0.0625 % or 0.125 % w/w curdlan or, incubating the transglutaminase-containing mimics for an hour achieved chewiness of 818.8–940.6 g, comparable to that of steamed prawn (953.13 g). Curdlan hydrogel penetrated and reinforced the FBP network as observed under confocal imaging. Whereas incubation of transglutaminase-containing mimics enhanced microstructural connectivity, attributable to transglutaminase-catalysed isopeptide cross-linkages, and the consequent increase in disulfide bonding and β-sheet. Ultimately, transglutaminase treatment appeared more suitable than curdlan, as it yielded mimics with cutting strength comparable to steamed prawn. Both demonstrated promising potential to broaden the variety of 3D printed seafood mimics.

Offsetting pb induced oxidative stress in Vicia faba plants by foliar spray of chitosan through adjustment of morpho-biochemical and molecular indices

In the course of their life, plants face a multitude of environmental anomaly that affects their growth and production. In recent decades, lead (Pb) gained an increasing attention as it is among the most significant contaminants in the environment. Therefore, in this study the effects of Pb concentrations (0, 50 and 100 ppm) on Vicia faba plants and attempts to alleviate this stress using chitosan (Chs; 0 and 0.1%) were performed. The results validated that with increasing Pb concentrations, a decline in growth, pigments and protein contents was observed. In the same time, a significant upsurge in the stress markers, both malondialdehyde (MDA) and H2O2, was observed under Pb stress. Nonetheless, foliar spraying with Chs improves the faba bean growth, pigment fractions, protein, carbohydrates, reduces MDA and H2O2 contents and decreases Pb concentrations under Pb stress. Pb mitigation effects by Chs are probably related with the activity of antioxidant enzymes, phenylalanine ammonia lyase (PAL) and proline. The application of Chs enhanced the activities of peroxidase, catalase and PAL by 25.77, 17.71 and 20.07%, respectively at 100 ppm Pb compared to their control. Plant genomic material exhibits significant molecular polymorphism, with an average polymorphism of 91.66% across all primers. To assess the genetic distance created among treatments, the dendrogram was constructed and the results of the similarity index ranged from 0.75 to 0.95, indicating genetic divergence. Our research offers a thorough comprehension of the role of Chs in lessening the oxidative stress, which will encourage the use of Chs in agricultural plant protection.

Molecular, interfacial and foaming properties of pulse proteins

Pulses are important protein sources in the current protein transition, but much of the behavior of pulse proteins in food systems (e.g. foam) is still unknown. This study compared the similarities and differences of the proteins from three common pulses: lentil, faba bean, and chickpea, at the molecular, mesoscopic and functionality levels. For each source, the proteins were extracted with a simple one-pot alkaline extraction, resulting in protein extracts with high protein content (67–85%) rich in globulins (68–81%) and albumins (19–32%). All pulse protein fractions were predominantly in a native state with high solubilities (83–91%), high denaturation enthalpies (8.9–10.1 J/(g protein)) and low aggregation levels. Lentil protein showed higher absolute value of the ζ-potential (−18.5 ± 1.2 mV) than faba bean (−13.2 ± 0.8 mV) and chickpea protein (−12.4 ± 1.2 mV). The behavior of all pulse proteins at the air-water interface including adsorption kinetics, interfacial dilatational rheology and interfacial microstructure was investigated and linked to their foaming properties. The pulse protein with the highest vicilin and convicilin content (39.5% in lentil protein) showed the shortest adsorption lag time (300 ms), and demonstrated the highest foam overrun (290 ± 17%). All three pulse protein fractions formed interfaces with disordered solid-like behavior and consisted of heterogeneous network structures. These structures were mostly comprised of intact globulin proteins for lentil and faba bean proteins, while mixtures of intact globulins and unfolded proteins/albumins were observed for chickpea protein. The interfacial stiffness, interfacial density and ζ-potential of these pulse proteins showed a high positive correlation with their foam stabilization properties. Lentil protein has the highest values of those parameters and showed the longest foam half-life time of 115 (± 22) min, while faba bean and chickpea proteins showed comparably lower values of those parameters and shared similarly shorter foam half-life times of 46 (± 19) min and 38 (± 6) min, respectively. These findings can aid to provide clearer directions in screening pulse proteins for desirable performance in aerated food products.

Effect of cellulose-rich fibres on faba bean protein gels is determined by the gel microstructure

Increased consumption of plant-based foods and better utilisation of side-streams can reduce the environmental impact of food consumption. A promising crop for production of protein-rich plant-based foods is faba bean, which can serve as a local alternative to soy in cold-climate regions. This study investigated faba bean protein gelation at multiple pH values and the effect of adding a fibre-rich side-stream from protein extraction. Two different sources were used to extract the fibre (cotyledon and hull). The gels were characterised in terms of textural properties, microstructure and water mobility. Gels produced at pH 4 and 5 showed reduced fracture stress, fracture strain and water-holding capacity, but higher Young's modulus, than gels produced at pH 7. The effect of adding fibre (at fixed solids content) varied with pH. Differences observed were attributed to the gel microstructure, as light and scanning electron micrographs showed coarse, aggregated microstructure at pH 4 and 5 and a fine-stranded protein network at pH 7. Irrespective of fibre source (cotyledon/hull), addition of fibre had comparable effects on textural properties. Low-field NMR revealed differences in water mobility between gels at pH 4–5 versus pH 7, and between gels with/without added fibre, likely related to contrasting microstructures and the water-binding properties of the fibre fractions.

The chemical and microbiological safety of emerging alternative protein sources and derived analogues: A review.

Climate change and changing consumer demand are the main factors driving the protein transition. This shift toward more sustainable protein sources as alternatives to animal proteins is also reflected in the rapid upscaling of meat and dairy food analogues. Such changes could challenge food safety, as new food sources could result in new and unexpected food safety risks for consumers. This review analyzed the current knowledge on chemical and microbiological contamination of emerging alternative protein sources of plant origin, including soil-based (faba bean, mung bean, lentils, black gram, cowpea, quinoa, hemp, and leaf proteins) and aquatic-based (microalgae and duckweeds) proteins. Moreover, findings on commercial analogues from known alternative protein sources were included. Overall, the main focus of the investigations is on the European context. The review aimed to enable foresight approaches to food safety concerning the protein transition. The results indicated the occurrence of multiple chemical and microbiological hazards either in the raw materials that are the protein sources and eventually in the analogues. Moreover, current European legislation on maximum limits does not address most of the "contaminant-food" pairs identified, and no legislative framework has been developed for analogues. Results of this study provide stakeholders with a more comprehensive understanding of the chemical and microbiological safety of alternative protein sources and derived analogues to enable a holistic and safe approach to the protein transition.

Effect of Dry and Wet Fractionation on Nutritional and Physicochemical Properties of Faba Bean and Yellow Pea Protein

ABSTRACTPlant‐based proteins continue to gain popularity as a sustainable alternative to animal proteins due to their nutritional, functional and health benefits. Dry and wet fractionation methods are increasingly being used for the production of value‐added pulse protein ingredients. The objective of this study was to compare the nutritional properties, protein quality, physicochemical properties and secondary structure of Australian faba bean and yellow pea protein concentrates and protein isolates obtained by dry and wet fractionation. Amino acid scores highlighted that faba bean and yellow pea protein isolates and concentrates were deficient in the sulphur‐containing amino acids, methionine and cysteine and tryptophan. Faba bean (63.7%) and yellow pea protein (63.0%) isolates had higher in vitro protein digestibility‐corrected amino acid scores compared to the protein concentrates, being 50.7% and 54.4%, respectively. Fourier‐transform infrared spectroscopy revealed different secondary structures between protein concentrates and isolates, especially for the amide I region. Faba bean and yellow pea protein concentrates had higher protein solubility (46.2% and 50.1%, respectively) and higher foaming capacity (65% and 59%, respectively) compared to the protein isolates. Water‐holding capacity was higher for faba bean and yellow pea protein isolates, being 4.3% and 4.0 g/g, respectively. These findings demonstrate that faba bean and yellow pea protein concentrates and isolates have unique functional properties that can be exploited for use in a diverse range of new and existing food applications.

Hybrid meat batter system: effects of plant proteins (pea, brown rice, faba bean) and concentrations (3–12%) on texture, microstructure, rheology, water binding, and color

A lean meat batter system was mixed with four plant proteins at 3, 6, 9, and 12% (w/w): pea protein A (PA), pea protein B (PB), brown rice protein (BR) and faba bean protein (FB). Texture profile analysis (TPA) revealed that increasing plant protein levels hardened the hybrid meat batters, with PA and PB leading to the hardest gels. TPA results were supported by micrographs, demonstrating that the two pea proteins formed large aggregates, contributing to a firmer hybrid meat gel. Dynamic rheology showed that the incorporation of plant proteins lowered the storage modulus (G') during the heating stage (20 to 72°C), yet the 6% PA treatment produced a final G' (after cooling) closest to the control (CL). Nuclear Magnetic Resonance (NMR) T2 relaxometry also demonstrated that plant proteins reduced the water mobility in hybrid meat batters. Results were in line with the cooking loss, except for a higher cooking loss in the BR formulation compared to the CL. Color measurement showed that increasing plant protein levels led to darker and yellower meat batters; however, the effect on redness varied among treatments. Overall, the findings suggest that pea proteins have superior functionality and compatibility within a lean poultry meat protein system, compared to BR and FB tested here.

Effect of Faba Bean Isolate and Microbial Transglutaminase on Rheological Properties of Pork Myofibrillar Protein Gel and Physicochemical and Textural Properties of Reduced-Salt, Low-Fat Pork Model Sausages.

The study was performed to determine the effect of faba bean protein isolate (FBPI) alone or in combination with microbial transglutaminase (MTG) on the rheological properties of pork myofibrillar protein gel (MPG), and physiochemical and textural properties of reduced-salt, low-fat pork model sausages (LFMSs). The cooking yields of MPGs with MTG or FBPI alone decreased and increased, respectively. However, the combination of FBPI and MTG was similar to the control (CTL) without FBPI or MTG. Gel strength values of MPG added with both FBPI and MTG were higher than treatments with FBPI or MTG alone. The hydrophobicity values of CTL were lower than those of MPG with FBPI alone, whereas the addition of MTG decreased the hydrophobicity of MPGs. The incorporation of FBPI alone or in combination with MTG decreased sulfhydryl groups (p<0.05). Shear stress values of MPGs with MTG tended to be higher than those of non-MTG treatments at all shear rates, and the addition of FBPI into MPGs increased shear stress values. Reduced-salt (1.0%) LFMSs with FBPI alone or combined with MTG had both lower cooking loss and expressible moisture values than those of CTL and similar values to the reference sample (REF, 1.5% salt). Textural properties of reduced-salt LFMSs with FBPI or MTG were similar to those of REF. These results demonstrated that the combination of FBPI and MTG could improve the water binding capacity and textural properties of pork MPGs and LFMSs and might be suitable for application in the development of healthier meat products.

Impact of thermosonication at neutral pH on the structural characteristics of faba bean protein isolate dispersions and their physicochemical and techno-functional properties

The effect of thermosonication (TS) (90 °C, 10–30 min) on faba bean protein isolate (FPI) at pH 7 was investigated. The microstructural and techno-functional properties of TS-treated FPI were compared with native FPI or FPI treated with conventional prolonged heating (CH, up to 8 h) at 90 °C. TS treatment effectively converted FPI to amorphous aggregates containing predominant β-sheet secondary structures, as determined by Thioflavin T (ThT) fluorescence and circular dichroism (CD). According to sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), these amorphous aggregates could be formed by disulfide bonds. Additionally, TS treatment is efficient in disrupting large protein aggregates of FPI, thus improving their solubility. Both TS and CH treatments induced formation of viscoelastic FPI hydrogels, whose gel strength depends on the type and time of treatment. Hydrogels formation is likely to arise from the entanglement and interaction of protein aggregates as revealed by small angle neutron scattering (SANS) and scanning electron microscopy (SEM). TS-treated FPI was also used to prepare O/W emulsions and whose structural and physical properties were compared with those stabilised by untreated FPI. At all oil volume fractions (φ = 0.2, 0.5, and 0.7) and FPI concentrations (1, 3, and 5 wt %), emulsions stabilised by TS-treated FPI exhibited smaller oil droplet size, greater mechanical strength and superior stability compared to those stabilised by untreated FPI. The study suggests that TS treatment is promising in improving techno-functional properties of FPI; further studies are needed to exploit TS-treated plant proteins as a novel food ingredient in food product development.

Microencapsulation of Essential Oils Using Faba Bean Protein and Chia Seed Polysaccharides via Complex Coacervation Method.

The aim of this study was to develop microcapsules containing juniper or black pepper essential oils, using a combination of faba bean protein and chia seed polysaccharides (in ratios of 1:1, 1:2, 2:1). By synergizing these two polymers, our goal was to enhance the efficiency of essential oil microencapsulation, opening up various applications in the food industry. Additionally, we aimed to investigate the influence of different polymer mixing ratios on the properties of the resulting microcapsules and the course of the complex coacervation process. To dissolve the essential oils and limit their evaporation, soybean and rapeseed oils were used. The powders resulting from the freeze-drying of coacervates underwent testing to assess microencapsulation efficiency (65.64-87.85%), density, flowability, water content, solubility, and hygroscopicity. Additionally, FT-IR and DSC analyses were conducted. FT-IR analysis confirmed the interactions between the components of the microcapsules, and these interactions were reflected in their high thermal resistance, especially at a protein-to-polysaccharide ratio of 2:1 (177.2 °C). The water content in the obtained powders was low (3.72-7.65%), but it contributed to their hygroscopicity (40.40-76.98%).

Fibrillisation of faba bean protein isolate by thermosonication for process efficacy: Microstructural characteristics, assembly behaviour, and physicochemical properties

The effect of thermosonication (TS) (90 °C, 10–30 min) on the fibrillisation of faba bean protein isolate (FPI) was studied. The self-assembly behaviour, microstructural characteristics and techno-functional (gelation and emulsification) properties of FPI fibrils obtained from TS treatment were compared with those obtained from conventional prolonged heating (CH) at 90 °C up to 8 h. Compared to CH treatment, TS treatment was shown to significantly accelerate the formation of FPI fibrils with prominent β-sheet structures as revealed by Thioflavin T (ThT) fluorescence, Fourier-transform infrared spectroscopy (FTIR) and circular dichroism (CD). The characteristics of fibril building blocks were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography linked to tandem mass spectrometry (LC-MS/MS) to obtain the differences between TS and CH induced fibrillisation of FPI. Transmission electron microscopy (TEM) and small-angle neutron scattering (SANS) showed that 4 h CH and 10 min TS treatments resulted in the fibrils with similar radius (from 5 to 10 nm). Furthermore, SANS indicated that TS treatment induced the formation of an entangled FPI fibrillar network, which could lead to the observed viscoelastic properties of FPI at a high concentration (10 wt%). Finally, high internal phase O/W emulsions (HIPE, φ = 0.75) stabilised by 30 min TS induced FPI fibrils (3 wt%) demonstrated a stronger gel strength and smaller oil droplet size compared to those prepared with untreated FPI, suggesting a superior emulsification capability of FPI fibrils. This finding demonstrates that TS treatment is a promising and efficient method for fibrillisation of plant proteins with the resultant fibrils generating excellent gelation and emulsification properties.

Structural, thermal, and physicochemical properties of ultrasound-assisted extraction of faba bean protein isolate (FPI)

This study aimed to understand the impact of ultrasonication (24 kHz) at a fixed power (100 W) and duration (5–60 min) on the physicochemical, structural, and thermal properties of faba bean protein isolates. Ultrasound-relevant parameters such as acoustic density, intensity, and yield conversion were estimated. The average protein purity (∼85% protein) and yield (up to 22 %) of the ultrasound-assisted protein isolate were higher than those of the control protein isolate. Compared to the original flour, the isolate had significantly lower levels of vicine and convicine. Electrophoresis revealed no substantial alterations in the primary structure of the native and sonicated faba bean isolates. SDS-PAGE and SE-HPLC showed that sonicated samples had profiles similar to those of the native protein isolate. FTIR spectra and X-ray diffraction (XRD) patterns were used to measure structural changes in all faba bean protein isolates (FBPI). XRD study revealed two distinct diffraction peaks at 2 θ = 10° and 2 θ = 20° for protein isolates, indicating that alteration in native conformational crystallite size was altered after the ultrasound application.