Pea Protein Research Articles

Development and characterization of fibrous high moisture extrudates based on pea protein isolate and whey protein.

Construction of meat analogs based on pea protein isolate (PPI) alone by high moisture extrusion (HME) is diffocult as a result of the lack of anisotropic structures. In the present study, 0%-15% of whey protein (WP) was introduced to PPI to make hybrid blends, which were used to construct HME extrudates. WP enhanced the hardness, adhesive, cohesiveness and gumminess of the extrudates and facilitated the formation of a distinct anisotropic structure of PPI. The fibrous degrees of the extrudates containing 10% and 15% WP were around 1.50. The addition of WP, which has more -SH groups, increased the disulfide bonds and hydrogen bonding in the extrudates, leading to a denser cross-linked structure. Particle size distribution and Fourier transform infrared analysis showed that WP induced more compact structured aggregates and more β-sheet structures in the extrudates. Furthermore, the higher hydration capacity of WP may also help form a dilute melt and generate a more pronounced plug flow, assisting the formation of fiber structures of PPI. The present study demonstrates that WP is a potential modifier, which could be used to improve the structure of PPI-based meat analogs. © 2024 Society of Chemical Industry.

Mechanism of sodium alginate synergistically improving foaming properties of pea protein isolate: Air/water interface microstructure and rheological properties

The synergistic effect of polysaccharides plays a crucial role in regulating the foaming properties of protein based aerated foods. In this study, the synergistic improvement mechanism of pea protein isolate (PPI)-sodium alginate (SA) composite on the foaming performance was determined through multi-component interaction, air/water interface adsorption behavior and foam properties. The results of interactions between PPI and SA indicated that SA and PPI could form smaller and more stable soluble composite through hydrogen bonding, hydrophobic interactions, and electrostatic interactions. The α-helix content of PPI significantly decreased, and PPI exhibited a more flexible secondary structure. In depth research on the air/water interfacial behavior and interfacial microstructure through adsorption kinetics, surface dilatational rheology and Lissajous plots indicated that the PPI-SA composite could accelerate the adsorption process, constructing a highly viscoelastic interface mainly based on elasticity. The results of foam properties showed soluble PPI-SA composite could prepare smaller and more dense foam with thicker and smoother interface film, which was beneficial to the foam stability. The results of small amplitude oscillatory shear and large amplitude oscillatory shear suggested that foam prepared by soluble PPI-SA composite showed stronger ability to resist deformation whether in linear or nonlinear viscoelastic region, revealing the good mechanical properties of these foam under extreme processing conditions and feasibility to improve the quality of aerated food. When the mass ratio of PPI/SA was 1:0.3, the foam properties was strongest. When the mass ratio of PPI/SA exceeded 1:0.3, insoluble substances appeared in the composite system, which was disadvantageous to foam properties and deformation resistance. Therefore, the complexation of PPI and SA was an effective way to improve the air/water interface and foaming properties of PPI, providing theoretical guidance for targeted regulation of the foaming properties of protein based aerated foods.

Construction of foam-templated Antarctic krill oil oleogel based on pea protein fibril and ι-carrageenan

Edible plant-based oleogels with zero trans-fat are promising solid fat substitutes. In this study, Antarctic krill oil (AKO) oleogels prepared from pea protein fibril (PPF) and ι-carrageenan (CG) by foam-templated method were developed for the first time. The modulation of the ratio of PPF and CG concentration on the structure and properties of foam, cryogel and oleogel was investigated and the potential formation mechanism of the foam-templated oleogel was explained. The results demonstrated that the addition of CG significantly decreased the foam size and enhanced the foam stability. The oil absorption and oil holding ability of the dense and reticular porous structure of the cryogel was demonstrated. Fourier infrared spectroscopy confirmed the interaction between PPF and CG involved in the formation of cryogels. With the addition of CG, the network structure and mechanical strength of the cryogel were reinforced, leading to more compact pores and higher capillary suction, which was appropriate for the establishment of good viscoelastic semi-solid oleogels. In addition, the oleogel was effective in masking the fishy odor of AKO. The significance of this study lies in its provision of a novel approach to the preparation of the foam-templated oleogel with PPF and CG as the oleogelators.

Optimization of the Encapsulation of Vitamin D3 in Oil in Water Nanoemulsions: Preliminary Application in a Functional Meat Model System.

Meat products containing Vitamin D3 (VD3) are an innovative option that could contribute to reducing deficiencies in this micronutrient. Designing nanoemulsions that carry VD3 is the first step in developing functional meat products. Thereby, this study investigated the impact of food components on the nanoemulsion properties. A central composite design was used to study the effects of pea protein (PP, 0.5-2.5%), safflower oil (SO, 5-15%), and salt (0-0.5%) on the nanoemulsion stability (ζ-potential and particle size) and the VD3 retention. Also, the optimized nanoemulsion carrying VD3 was incorporated into a meat matrix to study its retention after cooking. The combination of food components in the optimized nanoemulsion were SO = 9.12%, PP = 1.54%, and salt content = 0.4%, resulting in the predicted values of ζ-potential, particle size, and VD3 retention of -37.76 mV, 485 nm, and 55.1%, respectively. The VD3 that was nanoencapsulated and included in a meat product remained more stable after cooking than the VD3 that was not encapsulated. If a meat product is formulated with 5 or 10% safflower oil, the stability of the nanoencapsulated VD3 is reduced. This research contributes to developing functional meat products carrying nanoencapsulated vitamin D3 in natural food-grade components.

Isolation of Bioactive Compounds (Carotenoids, Tocopherols, and Tocotrienols) from Calendula Officinalis L., and Their Interaction with Proteins and Oils in Nanoemulsion Formulation.

Calendula officinalis L. has numerous health-promoting properties due to the presence of a large number of lipophilic compounds. Their effective delivery to the body requires the use of an appropriate technique such as emulsification. So, the main purpose of this study was to understand how the profile of lipophilic compounds from pot marigold and the pro-health potential are shaped by different types of protein, oil, and drying techniques in o/w nanoemulsion. To obtain this, the profiles of carotenoid compounds and tocols were measured. Additionally, antioxidant potential and the ability to inhibit α-amylase and α-glucosidase were measured. Pea protein emulsion exhibited a higher final content of carotenoid compounds (23.72-39.74 mg/100 g), whereas those with whey protein had stronger α-amylase inhibition (487.70 mg/mL). The predominant compounds in the studied nanoemulsions were β-carotene (between 19% and 40%), followed by α-tocopherol/γ-tocopherol. The type of proteins shaped the health-promoting properties and determined the content of health-promoting compounds.

Enhancing emulsion, texture, rheological and sensory properties of plant-based meat analogs with green tea extracts

Plant-based meat analogs require improvements in taste and texture to better replicate traditional meat. L-theanine and tannin, abundant in green tea, influence food taste and physicochemical properties. This study evaluated the quality characteristics of green tea extract (GE)-supplemented plant-based patties (PP) and the mechanisms affecting taste and texture. Green tea was extracted with water (GWE) or 70 % ethanol (GEE). GEE contained higher tannin and lower L-theanine levels than GWE. Both GWE and GEE reduced protein deterioration and lipid oxidation in PP throughout the 28-day storage period. PP with 1.0 % GEE (PP-GEE1.0) showed improved emulsion stability and texture due to non-covalent interactions including hydrophobic interaction and hydrogen bonds, and increased β-sheet structures between tannin and pea protein. PP-GEE1.0 also had superior sensory characteristics due to an optimal balance of L-theanine and tannin. Overall, the incorporation of GE, particularly GEE significantly improved physicochemical properties, sensory quality, and storage stability of PP.

Effects of Pre-Fermentative Treatments with Non-Synthetic Ternary Component Fining Agents Based on Pea Protein on the Volatile Profiles of Aromatic Wines of Tămâioasă Românească

To remove oxidizable polyphenolic compounds from wines, fining treatments with products of various origins are applied before or after fermentation. Seeking alternatives to the treatments with animal proteins or synthetic materials such as polyvinylpolypyrrolidone (PVPP), vegetal and mineral products are tested. One of these alternative agents is pea protein (P), which can be combined with chitosan (K), yeast cell walls (Y), active carbon (C), and/or Ca-bentonite (B). Aside from the proven polyphenol removal effect, these products can also have an impact on aroma. This research evaluates the effect of P and ternary combinations with P on the volatile compounds of aromatic wines from the Tămâioasă românească variety. Several variants of treatments with P and with ternary mixtures involving P were prepared in triplicate with a total dose of 20 g/hL of fining agent applied during the pre-fermentative phase. Volatile profiles were determined using a flash gas chromatograph with two short columns of different polarities. The chromatographic peak areas for the identified ethylic esters, acetates and terpenes were used to compare the fining treatment effects. To test the significant differences between experimental variants, the Analysis of Similarity (ANOSIM) was used. The influences of P used alone and PVPP used alone were both significantly different compared to control (untreated), but based on the dissimilarity index R, PVPP affected the volatile profile about twice as much as P, showing that pea protein is a good alternative for PVPP. The ethyl esters were especially reduced by PVPP, while P especially reduced the terpenes. From all the tested pea protein ternary agents, those containing bentonite (PCB and PYB) showed a significant reducing effect on all classes of compounds and therefore are not recommended. The combinations containing yeast cell walls, PCY and PKY, are the most interesting alternatives to both PVPP and P used independently, PCY being the least aggressive of all treatments on overall aroma, preserving well the aroma compounds of all determined classes, including terpenes.

Impact of Calcium Chloride Addition on the Microstructural and Physicochemical Properties of Pea Protein Isolate-Based Films Plasticized with Glycerol and Sorbitol

Ca2+ can boost protein-protein interactions and, if present at an appropriate level, can potentially improve some physicochemical properties of protein-based gels and films. This study aimed to determine the effects of CaCl2 (0%–0.05% w/w) on the microstructural, optical, water affinity, and mechanical characteristics of glycerol (Gly)- and sorbitol (Sor)-plasticized pea protein isolate (PPI)-based films. CaCl2 caused darkening and a color shift of the films from yellow to yellow-green. Additionally, decreased light transmission, particularly in the UV range, acidification, and reduced moisture content were observed. CaCl2 decreased the water vapor permeability of the Gly plasticized film by an average of 20% with no effect on the Sor-plasticized film. All films were completely soluble in water. CaCl2 negatively impacted the mechanical integrity of the films, reducing the tensile strength of the Gly- and Sor-plasticized films by ~16% and 14%–37%, respectively. Further increases in CaCl2 content (0.1% and 0.2% w/w) led to concentration-dependent microvoids resulting from protein over-crosslinking and/or coagulation. In summary, the incorporation of CaCl2 into PPI-based films did not provide significant benefits and actually worsened key properties, such as transparency and mechanical strength. The type of plasticizer influenced how CaCl2 affected some properties of the PPI-based film.

Acid gelation of high-concentrated casein micelles and pea proteins mixed systems

The increased demand for plant-based products brings a new challenge to the food industry. Especially, proteins from soy, chickpea, and pea are being highly demanded as food ingredients. However, they still present some drawbacks such as poor techno-functional properties and remarkable beany flavor that hamper their wider application. Contrarily, milk products such as yogurt and cheeses are highly consumed and accepted worldwide. Therefore, the association of plant proteins, such as pea with milk proteins is an interesting strategy to incorporate more plant-based proteins into people’s diet. However, this strategy can largely impact gel formation and final structure. This study aims to develop mixed casein micelles (CMs) and pea proteins gel at high concentrations in four protein ratios, 80:20, 60:40, 40:60, and 20:80 by acidification. The effect of a thermal treatment before gelation was also evaluated. The replacement of CMs for pea proteins disturbed the gel formation at the beginning of acidification, demand more time to increase the G*, being this effect more pronounced as more casein is replaced in the system. Despite of this effect, the final gel elasticity was higher in the presence of pea proteins for the ratios 80:20 and 60:40, probably due to the formation of pea network. It is hypothesized that pea proteins can form a network when surrounded by CMs, however, CMs restrict pea proteins aggregation. This study describes that the final characteristics of mixed gels can be tailored by changing protein ratios and applying thermal treatment before acidification, opening the possibility for the development of innovative food products.

Plant-based fish analogues vs. fish: Assessment of consumer perception, acceptance, and attitudes

Plant-based fish is developed to mimic the taste, texture, and appearance of fish. Despite being the fastest-growing segment in plant-based analogues sales, it remains a niche product due to several hindrances, including sensory and nutritional issues. This study assessed consumer perception, attitudes and acceptance drivers of plant-based canned tuna involving 165 consumers who evaluated for liking and described through the Check-All-That-Apply method five plant-based and three animal-based samples. Consumers’ food neophobia level, food related lifestyles and food frequency consumption of a series of plant-based and animal-based products were investigated as potential explanatory variables in drivers of acceptance. Generalised linear models showed that plant-based samples scored very low (<40 VAS score), while animal-based products were well accepted (63.6 – 75.2). Principal Coordinate Analysis revealed that pink colour, tuna/fish flavour, and dryness characterised tuna samples and contributed positively to liking, while unappealing appearance, off-flavour, legume/vegetable flavour, bitterness, gelatinous and gumminess, characterised plant-based samples and contributed negatively to liking. Agglomerative hierarchical analysis identified two consumer clusters differing in liking for plant-based fish analogues. One cluster (27 % of consumers) showed significantly higher liking scores for all plant-based samples, a higher consumption of plant-based analogues and seemed more careful when buying food, both regarding its nutritional composition and its naturalness than the other cluster. This study suggests that the exploitation of plant-based ingredients (textured soy, pea and wheat proteins) affect all sensory dimensions of plant-based canned tuna and highlights the importance of sensory optimisation in the development of plant-based alternatives to meet consumer preferences.

Pig True Ileal Digestible Amino Acid Contents of Individual Ingredients are Additive in Mixed Meals and Allow Accurate Predictions of Digestible Indispensable Amino Acid Score Values

BackgroundAlthough not every food protein contributes sufficient quantities of all of the indispensable amino acids (AAs) required for human health, the human diet is a mixture of foods. It is therefore important to evaluate protein quality in mixed meals. ObjectivesThe hypothesis was that the true ileal digestible AA content of mixed meals can be predicted from the amounts of digestible AA determined for individual food ingredients, allowing further prediction of the digestible indispensable amino acid score (DIAAS) for meals. MethodsFour diets contained either pea protein isolate (PPI), whey protein concentrate (WPC), or mixtures of PPI:WPC at a ratio of 25:75 (PP25) or 75:25 (PP75). Six ileal cannulated pigs were allocated to a 4 × 6 Latin Square design. Experimental diets at 10% protein and a protein-free diet were fed for 7 d with ileal digesta collection on days 6 and 7. True ileal digestibility (TID) of AA, amount of digestible AA, and DIAAS were calculated for each diet and predicted for the 2 mixed meals. ResultsPredicted and determined digestible AA contents of the mixed diets were not different. The predicted values fell within the confidence interval (95%) of the determined values. DIAAS for PPI was 61% and for WPC it was 96%. DIAAS calculated based on the predicted amounts of digestible AA for PP25 was 104% and for PP75 83%. These values were nearly identical to the determined values of 104% and 84% for PP25 and PP75, respectively. ConclusionsThe amount of digestible AA and DIAAS can be accurately predicted in mixtures of PP and WPC from the AA digestibility values for the individual ingredients.

Structural and functional properties of a high moisture extruded mixture of pea proteins (Pisum sativum), amaranth flour (Amaranthus hypochondriacus), and oat flour (Avena sativa)

Textured vegetable proteins (TVP) are an alternative to meet the increasing demand for non-animal food. This study aimed to develop a TVP from mixtures with 45 % pea protein isolate (PPI) enriched with amaranth (AF) and oat (OF) flours using high-moisture extrusion technology (HME) varying the moisture (50–70 %) and the temperature in the second heating zone of the extruder (110–140 °C). After extrusion, all samples demonstrated higher values of water absorption capacity (WAC) than non-extruded mixtures. Mixture of AF:OF:PPI (40:15:45 %) extruded at 60 % moisture and 135 °C showed promising functional properties with WAC and WSI values of 3.2 ± 0.2 g H2O/g and 24.89 ± 2.31 %, respectively, and oil absorption capacity (OAC) of 1.3 g oil/g. The extrusion process altered the thermal and structural properties of proteins promoting a desirable fibrous structure. This confirms the feasibility of using HME to develop TVP based on PPI, AF, and OF.

Valorization of berry pomace for extraction of polyphenol compounds and its co-encapsulation with probiotic bacteria

Saskatoon berry pomace, an antioxidant rich byproduct, may be suitable for nutraceuticals and functional foods. The present study aimed to co-encapsulate polyphenol-rich berry extract with probiotics to utilize the polyphenolic compounds present in berry pomace. The major benefit of co-encapsulation is that polyphenolic compounds increase the survival characteristics of probiotic bacteria in gastrointestinal tract. To make the process cost-effective, a conventional solvent extraction method was used for extraction of polyphenolic compounds from berry pomace. Spray drying was used to co-encapsulate polyphenols and probiotics by using plant-based carrier materials (pea protein isolate with gum Arabic). Spray dried powder was evaluated for encapsulation efficiency, gastrointestinal stability, bio-accessibility index, along with functional, structural and thermal characteristics. Berry pomace was found to be a good source of TPC, DPPH and ABTS with 2.49 mg GAE/1 g, 4.48 mg QE/1 g and 2.96 mg QE/1 g, respectively. The encapsulation efficiency (retention of polyphenolics and bacteria in capsules) of polyphenolic compounds and probiotics was 72.6% and 94.4%, respectively. Probiotic cells encapsulated with polyphenolic compounds showed improved survival (9.08 log CFU/mL) during in vitro gastrointestinal digestion. The bio-accessibility of TPC was 63.6% after intestinal digestion. The spray dried powder was observed to possess good thermal stability but poor functional properties, thus limiting applications to products such as bakery goods, sports bars, cereals and other foods where dispersibility is not imperative. Therefore, co-encapsulation by spray drying method offers an efficient and cost-effective method for simultaneous delivery of bioactive compounds and probiotics to the gut, extending their benefits by this combination.

Textural improvement of pea protein-based high-moisture extrudates with corn zein and rice starch

High moisture extrusion allows the production of plant protein-based products, including meat analogues. Building upon our previous findings showing that zein mixed with rice starch provides the necessary textural properties to formulations, different pea protein-based formulations with varying amounts of zein and rice starch or wheat gluten (as control) were produced using high moisture extrusion and the rheological, textural, and microstructural characteristics were evaluated and associated with the secondary structure of proteins. Samples containing wheat gluten presented desirable rheological and mechanical properties in terms of texturization, which was evidenced by the generation of a layered and three-dimensional viscoelastic network. The addition of rice starch to zein significantly increased the viscoelasticity of the samples due to enhanced development of non-covalent interactions that led to higher and more stable β-sheets content and to the formation of a fibrous and layered microstructure and a 3D network nearly like those obtained with gluten. The sole replacement of pea protein by zein was not enough to develop these desired characteristics, demonstrating the importance of the non-covalent interactions between rice starch and zein for the generation of these properties. Overall, zein and rice starch improved texturization of pea protein-based gluten-free analogues made by high moisture extrusion.

Effects of mixing ratio on physicochemical, structural properties and application in lycopene-loaded emulsions of blends of whey protein and pea protein

Physicochemical, structural properties and application in lycopene-loaded emulsions of blends of whey protein isolate (WPI) and pea protein isolate (PPI) at varying mass ratios (100/0, 75/25, 50/50, 25/75, 0/100) were investigated. Data indicated that the mass ratios affected the physical, chemical and storage stability of the emulsion by influencing the particle size, zeta-potential, surface hydrophobicity, free sulfhydryl content, and secondary structure of the blends. Particularly, emulsion with a mixing ratio of 75/25 exhibited superior physical stability against salt concentrations (200 and 500 mM), better chemical stability against UV light and heat, and maintained stability over a 30-day storage period. Emulsions stabilized by blends of different ratios exhibited similar digestion behavior, with no significant differences observed in lycopene's transformation stability and bio-accessibility. Data indicated that substitution of whey protein by pea protein is effective in term of emulsifier application and replacement ratio is an important factor need to be considered.

Determining the influence of plant-based proteins on the characteristics of dairy ice cream

This paper investigates the functional and technological properties of proteins in the composition of dairy ice cream. The object of the research was the technology of ice cream with plant-based proteins. The problem to be solved was the improvement of physical-chemical and rheological characteristics of mixtures and ice cream with a low fat content by using moisture-binding structuring proteins of plant origin. It was established that pea protein concentrate has the highest foaming properties. Oat protein concentrate shows a moderate ability to form and stabilize foams, while soy protein isolate does not reveal this function at all. The presence of plant-based proteins in all ice cream mixtures increases their nominal viscosity, but the highest thixotropy is observed for the concentrate of pea (56.5–61.0 %) and oat (54.8–57.2 %) proteins. They form food systems with a pronounced coagulation structure, which are capable of self-repair of bonds during the maturation of mixtures for 8 hours. Soy protein isolate reduces the thixotropic ability of ice cream mixtures, which limits the expediency of its use. The defined physical-chemical indicators of ice cream make it possible to justify the rational content of proteins in the composition of ice cream, which is 1–2 % for pea protein concentrate and 1 % for oat protein concentrate. Data on the rheological behavior of ice cream mixtures do not always coincide with previously established patterns, which is due to the difference in chemical composition between the studied food systems, as well as methods of their preparation and use. The results of this work could be used in the technology of low-fat ice cream, as well as in compositions for new types of ice cream enriched with protein

The impact of κ-carrageenan on the pea protein gelation by high pressure processing and the gelling mechanisms study

The transition toward sustainable and health-conscious diets has intensified plant-based proteins, particularly pea protein. This research explored the gelation mechanisms of pea protein with κ-carrageenan by high-pressure processing (HPP) as an alternative to traditional thermal methods. Suspensions containing 15% pea protein with 0.1–1% κ-carrageenan were subjected to HPP at 100–600 MPa for 5–30 min. Increasing κ-carrageenan concentration reduced the pressure required to obtain good gels, rendering HPP more energy efficient. Pea protein gels with 1% κ-carrageenan at 600 MPa demonstrated a 27-fold increase in compressive strength compared to 15% pea protein alone by HPP and over 5 times the strength of heat-induced counterparts. Gel textures could be tailored by modulating HPP conditions and κ-carrageenan concentrations. Fourier transform infrared spectroscopy, confocal laser scanning microscopy, and scanning electron microscopy characterized protein unfolding, phase separation, and network formation to study the gelation mechanisms. Results revealed that HPP induced protein tertiary structure unfolding, facilitating phase separation and uniform submicron κ-carrageenan particle distribution in the protein matrix. This, along with a more compact protein network induced by HPP, enhanced gel strength, compensating for limited cysteine in pea protein for disulfide bonds. Higher pressures intensified protein unfolding and aggregation, with κ-carrageenan particles evenly distributing into smaller particles, further strengthening gel structures. Conversely, heating-induced gelation caused more random protein aggregation, leading to coarser and weaker gel networks. This research highlights HPP's effectiveness over traditional heating methods in preparing strong pea protein gels with minimal κ-carrageenan and provides preliminary insights into tailoring HPP and κ-carrageenan for desirable gel textures.

Circulating Amino Acid Concentration after the Consumption of Pea or Whey Proteins in Young and Older Adults Affects Protein Synthesis in C2C12 Myotubes.

As older adults tend to reduce their intake of animal-source proteins, plant-source proteins may offer valuable resources for better protein intake. The aim of this study was to assess whether the pea proteins can be used to achieve blood amino acid levels that stimulate muscle protein synthesis. We measured variations in plasma amino acid concentrations in young and older adults given pea (NUTRALYS® S85 Plus) or whey proteins either alone or in a standardized meal. The effect of amino acid concentrations on protein synthesis in C2C12 myotubes was determined. In terms of results, plasma amino acid concentrations reflected the difference between the amino acid contents of whey and pea proteins. Blood leucine showed a greater increase of 91 to 130% with whey protein compared to pea protein, while the opposite was observed for arginine (A greater increase of 147 to 210% with pea compared to whey). Culture media prepared with plasmas from the human study induced age-dependent but not protein-type-dependent changes in myotube protein synthesis. In conclusion, pea and whey proteins have the same qualities in terms of their properties to maintain muscle protein synthesis. Pea proteins can be recommended for older people who do not consume enough animal-source proteins.

Modulation of acid-induced pea protein gels by gellan gum and glucono-δ-lactone: Rheological and microstructural insights

This study investigated the effect of gellan gum (GG) and glucono-δ-lactone (GDL) on the acid-induced gel properties of pea protein isolate (PPI) pretreated with media milling. The inclusion of GG substantially enhanced the gel hardness of PPI gel from 18.69 g to 792.47 g though slightly reduced its water holding capacity (WHC). Rheological analysis showed that GG increased storage modulus (G’) and decreased damping factor of gels in the small amplitude oscillatory shear region and transformed its strain thinning behavior into weak strain overshoot behavior in the large amplitude oscillatory shear region. SEM revealed that GG transformed the microstructure of gel from a uniform particle aggregate structure to a chain-like architecture composed of filaments with small protein particles attached. Turbidity and zeta potential analysis showed that GG promoted the transformation of PPI from a soluble polymer system to an insoluble coagulant during acidification. When GG content was relatively high (0.2 %-0.3 %), high GDL content increased the electrostatic interaction between PPI and GG molecules, causing their rapid aggregation into a dense irregular aggregate structure, further enhancing gel strength and WHC. Overall, GG and GDL can offer the opportunity to modulate the microstructure and gel properties of acid-induced PPI gels, presenting potential for diversifying food gel design strategies through PPI-GG hybrid systems.

Comparison of Colorimetric Methods for Measuring the Solubility of Legume Proteins.

Increasing the use of plant proteins in foods requires improving their physical and chemical properties, such as emulsification, gelation capacity, and thermal stability. These properties determine the acceptability and functionality of food products. Higher protein solubility significantly impacts these properties by affecting denaturation and the stability of emulsifiers or gels. Therefore, developing plant-based protein ingredients requires accurately and conveniently measuring their solubility. Colorimetric solubility methods overcome many issues of more robust combustion and titration methods, but complicated chemical mechanisms limit their applicability for certain proteins. This study aims to compare the effectiveness of four common colorimetric solubility measurement methods for pulse and non-pulse legume proteins and hydrolysates. Pea, chickpea, lentil, and soy protein isolates were made from defatted flour and their solubility at a range of pHs was measured using the Bradford, Lowry, bicinchoninic acid (BCA), and biuret methods. Solubility was also measured for chickpea and soy protein hydrolysates made using Alcalase and Flavourzyme. A comparison of the methods for solubility quantification revealed that the Bradford and Lowry methods most closely match the expected results for the unhydrolyzed protein, with the BCA and biuret methods underestimating solubility by 30%. The Lowry method was the preferred method for hydrolysate solubility measurement, with the Bradford method measuring 0% solubility at the isoelectric point due to an inability to interact with peptides that are soluble at this pH. This study identifies reliable methods for measuring plant protein solubility that establish uniform outcomes and enable a better comparison across studies, giving a consensus for key functional properties in food applications.