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The incorporation of fibre into pea protein matrices influences their microstructure, yet our understanding of their gut fermentability remains unexplored. In this study, dietary fibres and protein from yellow pea were investigated for their physico-chemical properties and impact on in vitro colonic fermentation using human inoculum. Pea fibre and pea protein blends were studied at different pH and after thermal treatment at 95 °C for 30 min with oscillatory rheology, static light scattering and confocal laser scanning microscopy. The effect on in vitro colonic fermentation was evaluated measuring gas production, ammonia, and short chain fatty acid (SCFA) production. Rheology indicated that during thermal treatment a firmer gel is formed close to the protein isoelectric point with a structure characterised by aggregation, but less particle swelling compared to other pH. Addition of fibre led to higher storage modulus (G′), with the fibre dominating the rheological properties. Fermentation of samples containing protein led to higher levels of ammonia and SCFA compared to only fibres. Blends produced higher amounts of valerate, i-valerate and caproate, and lower amounts of ammonia. Reduced fermentation of proteins in the presence of fibres was also reflected in a more intact microstructure of the protein particles in the digesta. Although thermal treatment of blends caused particle swelling and induced gelation, only small differences could be discerned in the in vitro colonic fermentation outcomes. Our results highlight that potentially harmful fermentation products from protein, such as ammonia, were reduced in the presence of pea hull fibre., The study was performed within the PANSweden project which acknowledge financial support from the Swedish research council, FORMAS grant number 2020-02843. We acknowledge Orkla for providing fibre samples and Lantmannen ¨ for providing protein samples

The incorporation of fibre into pea protein matrices influences their microstructure, yet our understanding of their gut fermentability remains unexplored. In this study, dietary fibres and protein from yellow pea were investigated for their physico-chemical properties and impact on in vitro colonic fermentation using human inoculum. Pea fibre and pea protein blends were studied at different pH and after thermal treatment at 95 °C for 30 min with oscillatory rheology, static light scattering and confocal laser scanning microscopy. The effect on in vitro colonic fermentation was evaluated measuring gas production, ammonia, and short chain fatty acid (SCFA) production. Rheology indicated that during thermal treatment a firmer gel is formed close to the protein isoelectric point with a structure characterised by aggregation, but less particle swelling compared to other pH. Addition of fibre led to higher storage modulus (G′), with the fibre dominating the rheological properties. Fermentation of samples containing protein led to higher levels of ammonia and SCFA compared to only fibres. Blends produced higher amounts of valerate, i-valerate and caproate, and lower amounts of ammonia. Reduced fermentation of proteins in the presence of fibres was also reflected in a more intact microstructure of the protein particles in the digesta. Although thermal treatment of blends caused particle swelling and induced gelation, only small differences could be discerned in the in vitro colonic fermentation outcomes. Our results highlight that potentially harmful fermentation products from protein, such as ammonia, were reduced in the presence of pea hull fibre., The study was performed within the PANSweden project which acknowledge financial support from the Swedish research council, FORMAS grant number 2020-02843. We acknowledge Orkla for providing fibre samples and Lantmannen ¨ for providing protein samples

The pressure-induced (400 MPa for 15 min) gelation of blended skim milk (SMP) and pea protein concentrate (PPC) suspensions (15% w/w) at different ratios (SMP:PPC = 10:0, 8:2, 6:4, 5:5, 4:6, 2:8, 0:10) were studied. Blending milk and pea proteins reduced the gel strength markedly, indicating that milk and pea proteins do not interact with each other to the same extent. The secondary structure of the proteins was not significantly changed after HP treatment. The PPC dominating gels (0:10 and 2:8) had a large increase in surface hydrophobicity indicating higher exposure of hydrophobic clusters. Based on a differential solubility method it was established that the SMP dominating gels are govern mostly by electrostatic and hydrophobic interactions, while disulphide bonds, hydrogen bonds and electrostatic interactions contributed most to the PPC dominating gel networks. The weak 5:5 gel was established solely by hydrophobic interaction between milk and plant proteins. It is suggested that in the milk protein dominant gel (8:2), the milk proteins formed the primary gel structure likely filled with the pea protein secondary gel network and/or aggregates, whereas the inverse occurred in the pea protein dominant gel (2:8). Replacing milk proteins with pea proteins offers a great potential for produce innovative dairy products using high pressure processing, like for example dairy desserts with a neutral pH and textural properties similar to yogurt.

The pressure-induced (400 MPa for 15 min) gelation of blended skim milk (SMP) and pea protein concentrate (PPC) suspensions (15% w/w) at different ratios (SMP:PPC = 10:0, 8:2, 6:4, 5:5, 4:6, 2:8, 0:10) were studied. Blending milk and pea proteins reduced the gel strength markedly, indicating that milk and pea proteins do not interact with each other to the same extent. The secondary structure of the proteins was not significantly changed after HP treatment. The PPC dominating gels (0:10 and 2:8) had a large increase in surface hydrophobicity indicating higher exposure of hydrophobic clusters. Based on a differential solubility method it was established that the SMP dominating gels are govern mostly by electrostatic and hydrophobic interactions, while disulphide bonds, hydrogen bonds and electrostatic interactions contributed most to the PPC dominating gel networks. The weak 5:5 gel was established solely by hydrophobic interaction between milk and plant proteins. It is suggested that in the milk protein dominant gel (8:2), the milk proteins formed the primary gel structure likely filled with the pea protein secondary gel network and/or aggregates, whereas the inverse occurred in the pea protein dominant gel (2:8). Replacing milk proteins with pea proteins offers a great potential for produce innovative dairy products using high pressure processing, like for example dairy desserts with a neutral pH and textural properties similar to yogurt.

Mild wet fractionation can separate pea proteins into a soluble and a non-soluble fraction. Soluble proteins and solutes are extracted into the soluble protein fraction, insoluble proteins are collected in the non-soluble protein fraction. The protein composition in the respective fractions was investigated by further fractionating the protein fractions with isoelectric precipitation. The molecular mass of the proteins in the fractions was determined by SDS-PAGE and size exclusion chromatography. The protein fractions' solubility was determined in excess water, and the gelation properties were investigated at the same protein concentration. With mild wet fractionation, compared to conventional wet fractionation, both globulins and albumins are extracted. The protein fractions were mixtures of both proteins, although the non-soluble protein fraction contained mainly globulins. Solubility and gelation properties varied with protein type, composition and protein state; isoelectric precipitation decreased the gelation capacity of the protein fractions.

Pea proteins are widely studied as emulsifying and gelling agents in soft food materials. However, their extraction process consumes energy and often focuses only on protein purity. To reduce extraction-related energy consumption, unpurified pea protein-starch mixtures could be used directly as functional ingredients. Such mixtures provide additional advantages due to their binary role, such as using proteins as emulsifiers and starch as a gelling agent. Therefore, we investigated the heat-induced gelation of emulsions (30 or 50% oil), stabilized by pea flour (PF) containing 20 wt% protein and 50 wt% starch. To understand the effect of starch on gelation, starch was removed from pea flour by filtration. Heat-induced gelation behavior of the pea protein mixture (PPM) stabilized emulsions was investigated and compared with PF emulsions. Both the PF and PPM stabilized emulsions gelled upon temperature treatment, monitored by oscillatory shear rheology. At pH 7, starch (in PF) contributed to a higher G' (2000Pa) compared with the emulsions without starch (PPM:∼1000 Pa). Whereas, at pH 3, the presence of starch did not contribute to a higher G′ in the emulsions. The presence of starch at both pH values affected the microstructure of the emulsion gels. The PF emulsions after heating were more brittle upon applying strain compared to the PPM emulsions. The brittle nature of the emulsions containing starch was most likely due to the starch gel's disruption of the oil droplet network. Our results provide insight into emulsion gelation when using a native pea protein-starch mixture. Our study demonstrates that depending on the pH conditions, native protein blends could have better gelling functionality.

Background: Pea (Pisum sativum) proteins are emerging as a popular alternative to those conventional (deriving from animal and soy) due to their high protein content with interesting functionality, sustainability, availability, affordability and hypo-allergenicity. This popularity has been parallel to an intensive research from protein isolation to their applications. Pea protein ingredients can be obtained through wet extraction, dry fractionation or more recently mild fractionation. As such, commercial pea proteins ingredients include flour (20–25% protein), concentrate (50–75% protein), and isolate (>80% protein). Beside protein content, these ingredients differ in their chemical composition, thereby affecting their functionality. Scope and approach: In this perspective, this review offers the latest update on essential knowledge for developing innovative food and beverages using pea proteins through emphasizing the production and the characteristics of pea proteins, addressing the efficiency of pea proteins as functional ingredients in foodstuffs making, and discussing the challenges encountered for pea protein popularization. Key findings and conclusions: Current research indicates the importance of developing extraction and drying technologies to reach target techno-functional and organoleptic attributes of pea proteins. A better modulation of processing steps can enable designing high-quality pea protein rich food and beverage.

3D printed materials are of great relevance to produce medicinal scaffolds and specialized foods. An approach to forming 3D printable materials is to use jammed oil droplets. Jammed oil droplets are highly viscous and can be extruded through the nozzle of a 3D printer, while after chemical cross-linking they acquire a self-standing ability. However, the molecules currently used to stabilize and cross-link the oil droplets have questionable biocompatibility. Therefore, this study aims to produce a 3D printable jammed emulsion using pea proteins. This jammed oil-in-water emulsion is remarkably stable and viscoelastic enough to be extruded through the printer nozzle. Adhesive pea protein particles formed by pH adjustment act as physical cross-links between the oil droplets, forming a scaffold with elastoplastic rheological properties that flows above critical stress while, without any additional treatment, exhibits the required self-standing properties for 3D printing. By understanding the properties of pea proteins and their behavior in bulk and on interfaces, pea protein-based 3D printable material is created for the first time.

Plant proteins have recently gained considerable attention as stabilizers of food-grade oil-in-water emulsions. However, the separation of plant proteins from their native matrix can be cumbersome due to the molecular complexity of plants. This issue could be alleviated by avoiding the protein purification step. In this work, we show that native pea flour containing 50 wt% starch and 20 wt% protein has similar interfacial properties compared to concentrated pea protein systems (~55 wt% protein). Interfacial tension profile of pea flour was similar to that of concentrated pea protein, indicating that proteins are the primary stabilizing agents of the interface. The fabricated oil-in-water emulsions (10.0 wt% oil) made with pea flour or pea protein concentrate containing 0.2 and 0.3 wt% protein showed a similar monomodal droplet size distribution. Moreover, both emulsions stabilized by the pea flour and the pea protein concentrate had similar rheological properties, showing that starch granules did not have any impact on the physical properties. This work clearly showed that stable oil-in-water emulsions can be produced with pea flour and further purification of pea proteins is not necessary.

The association of diabetes on celiac disease together with the high glycemic index of gluten-free breads makes necessary the pursuit of a solution to reduce this glycemic response. Protein enrichment and changes on hydration level may be tools to get it. Thus, the aim of this study was to analyze the effect of two proteins (pea and egg white) on the digestibility and physical characteristics of gluten-free breads, with either the same hydration or specific volume. Protein enriched breads were made blending starch and proteins (70:30). Breads prepared at constant hydration presented lower specific volume and weight loss during baking, and higher hardness than control. However, when the specific volume was matched, the breads with egg white protein presented lower weight loss and higher hardness, while the ones with pea protein were the less hard. Protein enriched breads showed higher SDS and lower RDS values than control with constant hydration, but lower SDS values and glucose release with constant specific volume. Therefore, the bread volume influenced not only the physical properties but also the bread digestibility.

This study investigated the influence of pH and processing conditions (autoclave at 93 °C/13 min or high pressure processing (HPP) at 600 MPa/5 min without/with follow-up reheating at 80 °C/30 min) on the digestibility of pea protein isolate. Both aqueous solutions and real food matrices (apple and carrot purees) containing pea protein was examined at 37 °C. In vitro gastrointestinal digestion was followed using sodium dodecyl sulphate polyacrylamide gel electrophoresis, titrimetric techniques and theoretical calculations. Pea protein with HPP followed by re-heating showed the highest rate of proteolysis in gastric conditions. In case of sequential intestinal digestion of the gastric chyme, pea protein at pH 6.2 demonstrated higher degree and rate of digestibility as compared to that at pH 3.6, the latter being close to the isoelectric point of pea protein. However, autoclave treatments overshadowed such pH effects. Processing-induced enhancement in digestibility might be attributed to the unfolding of the globular pea protein subunits. Pea protein in the carrot puree was more digestible than in the apple puree, due to apple procyanidins binding to pea protein. These new findings might have important implications in designing the process parameters and selection of appropriate food matrices for delivering pea protein.

The interactions between starch and proteins during processing influence pasting and rheological properties of starch and produce modifications on starch gel structure. Enzymatic modifications have been proposed for overcoming the limitations of using proteins as food ingredients. This work aimed to study the impact of native and enzymatically modified pea proteins on the properties of protein–starch (from cassava or corn) gels. Pea protein isolate (PPI) was incubated with endopeptidase (AL) or microbial transglutaminase (TG). Pasting profile, rheological behaviour and water retention capacity of protein–starch gels were analyzed. Protein (native and enzymatically modified) incorporation increased the viscosity of both corn and cassava starches during gel preparation. However, the hydrolyzed protein reduced drastically the increment of viscosity of protein–starch gels. The addition of PPI led to corn starch network that shifted from an elastic-like nature to a more viscous-like, whereas the opposite effect was observed in cassava gel network. TG- and AL-treated proteins led to a decrease of both G′ and G″ moduli of protein–starch gels, and AL-treated proteins showed the highest decrease on these parameters. Hydrolyzed proteins also favoured the syneresis of the protein–corn starch gel, whereas crosslinked proteins tended to reduce it. Enzymatic modifications of pea proteins affected significantly pasting and rheological properties of protein–starch gels.

Extractability, extractable protein compositions, technological-functional properties of pea (Pisum sativum) proteins from six genotypes grown in Serbia were investigated. Also, the relationship between these characteristics was presented. Investigated genotypes showed significant differences in storage protein content, composition and extractability. The ratio of vicilin: legumin concentrations, as well as the ratio of vicilin + convicilin: Legumin concentrations were positively correlated with extractability. Our data suggest that the higher level of vicilin and/or a lower level of legumin have a positive influence on protein extractability. The emulsion activity index (EAI) was strongly and positively correlated with the solubility, while no significant correlation was found between emulsion stability (ESI) and solubility, nor between foaming properties and solubility. No association was evident between ESI and EAI. A moderate positive correlation between emulsion stability and foam capacity was observed. Proteins from the investigated genotypes expressed significantly different emulsifying properties and foam capacity at different pH values, whereas low foam stability was detected. It appears that genotype has considerable influence on content, composition and technological-functional properties of pea bean proteins. This fact can be very useful for food scientists in efforts to improve the quality of peas and pea protein products.

Extractability, extractable protein compositions, technological-functional properties of pea (Pisum sativum) proteins from six genotypes grown in Serbia were investigated. Also, the relationship between these characteristics was presented. Investigated genotypes showed significant differences in storage protein content, composition and extractability. The ratio of vicilin: legumin concentrations, as well as the ratio of vicilin + convicilin: Legumin concentrations were positively correlated with extractability. Our data suggest that the higher level of vicilin and/or a lower level of legumin have a positive influence on protein extractability. The emulsion activity index (EAI) was strongly and positively correlated with the solubility, while no significant correlation was found between emulsion stability (ESI) and solubility, nor between foaming properties and solubility. No association was evident between ESI and EAI. A moderate positive correlation between emulsion stability and foam capacity was observed. Proteins from the investigated genotypes expressed significantly different emulsifying properties and foam capacity at different pH values, whereas low foam stability was detected. It appears that genotype has considerable influence on content, composition and technological-functional properties of pea bean proteins. This fact can be very useful for food scientists in efforts to improve the quality of peas and pea protein products.

Extractability, extractable protein compositions, technological-functional properties of pea (Pisum sativum) proteins from six genotypes grown in Serbia were investigated. Also, the relationship between these characteristics was presented. Investigated genotypes showed significant differences in storage protein content, composition and extractability. The ratio of vicilin: legumin concentrations, as well as the ratio of vicilin + convicilin: Legumin concentrations were positively correlated with extractability. Our data suggest that the higher level of vicilin and/or a lower level of legumin have a positive influence on protein extractability. The emulsion activity index (EAI) was strongly and positively correlated with the solubility, while no significant correlation was found between emulsion stability (ESI) and solubility, nor between foaming properties and solubility. No association was evident between ESI and EAI. A moderate positive correlation between emulsion stability and foam capacity was observed. Proteins from the investigated genotypes expressed significantly different emulsifying properties and foam capacity at different pH values, whereas low foam stability was detected. It appears that genotype has considerable influence on content, composition and technological-functional properties of pea bean proteins. This fact can be very useful for food scientists in efforts to improve the quality of peas and pea protein products.