Structure and function of pea, lentil and faba bean proteins treated by high pressure processing and heat treatment

Exploring Volatile Profiles and De-Flavoring Strategies for Enhanced Acceptance of Lentil-Based Foods: A Review

Lentils are marketed as dry seeds, fresh sprouts, flours, protein isolates, and concentrates used as ingredients in many traditional and innovative food products, including dairy and meat analogs. Appreciated for their nutritional and health benefits, lentil ingredients and food products may be affected by off-flavor notes described as "beany", "green", and "grassy", which can limit consumer acceptance. This narrative review delves into the volatile profiles of lentil ingredients and possible de-flavoring strategies, focusing on their effectiveness. Assuming that appropriate storage and processing are conducted, so as to prevent or limit undesired oxidative phenomena, several treatments are available: thermal (pre-cooking, roasting, and drying), non-thermal (high-pressure processing, alcohol washing, pH variation, and addition of adsorbents), and biotechnological (germination and fermentation), all of which are able to reduce the beany flavor. It appears that lentil is less studied than other legumes and more research should be conducted. Innovative technologies with great potential, such as high-pressure processing or the use of adsorbents, have been not been explored in detail or are still totally unexplored for lentil. In parallel, the development of lentil varieties with a low LOX and lipid content, as is currently in progress for soybean and pea, would significantly reduce off-flavor notes.

Transglutaminase-Induced Polymerization of Pea and Chickpea Protein to Enhance Functionality

Pulse proteins, such as pea and chickpea proteins, have inferior functionality, specifically gelation, compared to soy protein, hindering their applications in different food products, such as meat analogs. To close the functionality gap, protein polymerization via targeted modification can be pursued. Accordingly, transglutaminase-induced polymerization was evaluated in pea protein isolate (PPI) and chickpea protein isolate (ChPI) to improve their functionality. The PPI and ChPI were produced following a scaled-up salt extraction coupled with ultrafiltration (SE-UF) process. Transglutaminase (TGase)-modified PPI and ChPI were evaluated in comparison to unmodified counterparts and to commercial protein ingredients. Protein denaturation and polymerization were observed in the TG PPI and TG ChPI. In addition, the TGase modification led to the formation of intermolecular β-sheet and β-turn structures that contributed to an increase in high-molecular-weight polymers, which, in turn, significantly improved the gel strength. The TG ChPI had a significantly higher gel strength but a lower emulsification capacity than the TG PPI. These results demonstrated the impact of the inherent differences in the protein fractions on the functional behavior among species. For the first time, the functional behavior of the PPI and ChPI, produced on a pilot scale under mild processing conditions, was comprehensively evaluated as impacted by the TGase-induced structural changes.

Pulse Protein Isolates as Competitive Food Ingredients: Origin, Composition, Functionalities, and the State-of-the-Art Manufacturing

The ever-increasing world population and environmental stress are leading to surging demand for nutrient-rich food products with cleaner labeling and improved sustainability. Plant proteins, accordingly, are gaining enormous popularity compared with counterpart animal proteins in the food industry. While conventional plant protein sources, such as wheat and soy, cause concerns about their allergenicity, peas, beans, chickpeas, lentils, and other pulses are becoming important staples owing to their agronomic and nutritional benefits. However, the utilization of pulse proteins is still limited due to unclear pulse protein characteristics and the challenges of characterizing them from extensively diverse varieties within pulse crops. To address these challenges, the origins and compositions of pulse crops were first introduced, while an overarching description of pulse protein physiochemical properties, e.g., interfacial properties, aggregation behavior, solubility, etc., are presented. For further enhanced functionalities, appropriate modifications (including chemical, physical, and enzymatic treatment) are necessary. Among them, non-covalent complexation and enzymatic strategies are especially preferable during the value-added processing of clean-label pulse proteins for specific focus. This comprehensive review aims to provide an in-depth understanding of the interrelationships between the composition, structure, functional characteristics, and advanced modification strategies of pulse proteins, which is a pillar of high-performance pulse protein in future food manufacturing.

Functionality of pea protein isolate solutions is affected by reconstitution conditions

Pea protein isolate (PPI), a high-concentration protein ingredient derived from peas, is increasingly utilized in food applications, including beverages, meat or dairy alternatives, and baked goods. The protein extraction process typically used to manufacture PPI renders the protein highly denatured, which can have a negative impact on its functionality. Therefore, it is critical to understand how to prepare and utilize PPI to maximize its functionality. The current study evaluates the effect of select reconstitution conditions on the structure and functionality of PPI, across a range of protein concentrations (4%-10%) relevant to a variety of food applications. Temperature during reconstitution with water and hydration time impacted both protein hydration and its functionality. Increasing reconstitution temperature from 20 to 60°C and increasing hydration time from 10 to 40 min decreased PPI particle size in solution and increased PPI solubility. Viscosity of PPI solutions also increased with mild heating and longer hydration time, whereas their flow behavior was highly dependent on protein concentration. Experimental data demonstrates that reconstitution conditions have a significant impact on PPI functionality. These findings can help food formulators develop high-quality food products that utilize PPI as a functional ingredient. PRACTICAL APPLICATION: Protein in commercially available pea protein isolates (PPIs) is usually highly denatured, and thus, it is important to find ways to maximize its functionality in practical applications. The findings of this study inform food scientists how to leverage PPI at various protein concentrations with optimal reconstitution conditions to develop high-quality products. Generally, mild heating and longer hydration times improve PPI functional performance.

Yellow Field Pea Protein (Pisum sativum L.): Extraction Technologies, Functionalities, and Applications

Yellow field peas (Pisum sativum L.) hold significant value for producers, researchers, and ingredient manufacturers due to their wealthy composition of protein, starch, and micronutrients. The protein quality in peas is influenced by both intrinsic factors like amino acid composition and spatial conformations and extrinsic factors including growth and processing conditions. The existing literature substantiates that the structural modulation and optimization of functional, organoleptic, and nutritional attributes of pea proteins can be obtained through a combination of chemical, physical, and enzymatic approaches, resulting in superior protein ingredients. This review underscores recent methodologies in pea protein extraction aimed at enhancing yield and functionality for diverse food systems and also delineates existing research gaps related to mitigating off-flavor issues in pea proteins. A comprehensive examination of conventional dry and wet methods is provided, in conjunction with environmentally friendly approaches like ultrafiltration and enzyme-assisted techniques. Additionally, the innovative application of hydrodynamic cavitation technology in protein extraction is explored, focusing on its prospective role in flavor amelioration. This overview offers a nuanced understanding of the advancements in pea protein extraction methods, catering to the interests of varied stakeholders in the field.

Impact of emerging food processing technologies on structural and functional modification of proteins in plant-based meat alternatives: An updated review

In the past decade, the plant-based meat alternative industry has grown rapidly due to consumers' demand for environmental-friendly, nutritious, sustainable and humane choices. Consumers are not only concerned about the positive relationship between food consumption and health, they are also keen on the environmental sustainability. With such increased consumers' demand for meat alternatives, there is an urgent need for identification and modification of protein sources to imitate the functionality, textural, organoleptic and nutritional characteristics of traditional meat products. However, the plant proteins are not readily digestible and require more functionalization and modification are required. Proteins has to be modified to achieve high quality attributes such as solubility, gelling, emulsifying and foaming properties to make them more palatable and digestible. The protein source from the plant source in order to achieve the claims which needs more high protein digestibility and amino acid bioavailability. In order to achieve these newer emerging non-thermal technologies which can operate under mild temperature conditions can reach a balance between feasibility and reduced environmental impact maintaining the nutritional attributes and functional attributes of the proteins. This review article has discussed the mechanism of protein modification and advancements in the application of non-thermal technologies such as high pressure processing and pulsed electric field and emerging oxidation technologies (ultrasound, cold plasma, and ozone) on the structural modification of plant-based meat alternatives to improve, the techno-functional properties and palatability for successful food product development applications.

Nordic Crops as Alternatives to Soy-An Overview of Nutritional, Sensory, and Functional Properties

Soy (Glycine max) is used in a wide range of products and plays a major role in replacing animal-based products. Since the cultivation of soy is limited by cold climates, this review assessed the nutritional, sensory, and functional properties of three alternative cold-tolerant crops (faba bean (Vicia faba), yellow pea (Pisum sativum), and oat (Avena sativa)). Lower protein quality compared with soy and the presence of anti-nutrients are nutritional problems with all three crops, but different methods to adjust for these problems are available. Off-flavors in all pulses, including soy, and in cereals impair the sensory properties of the resulting food products, and few mitigation methods are successful. The functional properties of faba bean, pea, and oat are comparable to those of soy, which makes them usable for 3D printing, gelation, emulsification, and extrusion. Enzymatic treatment, fermentation, and fibrillation can be applied to improve the nutritional value, sensory attributes, and functional properties of all the three crops assessed, making them suitable for replacing soy in a broad range of products, although more research is needed on all attributes.

A Comprehensive Review of Pea (Pisum sativum L.): Chemical Composition, Processing, Health Benefits, and Food Applications

Pisum sativum L., commonly referred to as dry, green, or field pea, is one of the most common legumes that is popular and economically important. Due to its richness in a variety of nutritional and bioactive ingredients, the consumption of pea has been suggested to be associated with a wide range of health benefits, and there has been increasing focus on its potential as a functional food. However, there have been limited literature reviews concerning the bioactive compounds, health-promoting effects, and potential applications of pea up to now. This review, therefore, summarizes the literature from the last ten years regarding the chemical composition, physicochemical properties, processing, health benefits, and potential applications of pea. Whole peas are rich in macronutrients, including proteins, starches, dietary fiber, and non-starch polysaccharides. In addition, polyphenols, especially flavonoids and phenolic acids, are important bioactive ingredients that are mainly distributed in the pea coats. Anti-nutritional factors, such as phytic acid, lectin, and trypsin inhibitors, may hinder nutrient absorption. Whole pea seeds can be processed by different techniques such as drying, milling, soaking, and cooking to improve their functional properties. In addition, physicochemical and functional properties of pea starches and pea proteins can be improved by chemical, physical, enzymatic, and combined modification methods. Owing to the multiple bioactive ingredients in peas, the pea and its products exhibit various health benefits, such as antioxidant, anti-inflammatory, antimicrobial, anti-renal fibrosis, and regulation of metabolic syndrome effects. Peas have been processed into various products such as pea beverages, germinated pea products, pea flour-incorporated products, pea-based meat alternatives, and encapsulation and packing materials. Furthermore, recommendations are also provided on how to better utilize peas to promote their development as a sustainable and functional grain. Pea and its components can be further developed into more valuable and nutritious products.

The Impact of High-Pressure Homogenization and Thermal Processing on the Functional Properties of De-Fatted Chickpea Flour Dispersion

Defatted chickpea flour (DCF), a rich source of protein and starch, is frequently utilized in the food industry. Two crucial methods of modifying food materials are high-pressure homogenization (HPH) and heat treatment (HT). This study investigates the effect of co-treatment (HPH-HT) on the particle size, rheological behavior, and thermal characteristics of DCF suspensions. The results indicate that both HPH and HT can result in a more uniform distribution of particle size in the suspensions. The effect of HPH on G' was observed to be reductionary, whereas HT increased it. Nevertheless, the HPH-HT treatment further amplified G' (notably in high-concentration DCF), which demonstrates that the solid properties of DCF are improved. The apparent viscosity of the suspensions increased with individual and combined treatments, with the HPH-HT treatment of DCF12% exhibiting the most significant increase (from 0.005 to 9.5 Pa·s). The rheological behavior of DCF8% with HPH-HT treatment was found to be comparable to that of DCF12% treated only with HT. In conclusion, HPH-HT treatment shows a synergistic impact of HPH and HT on the rheological properties of DCF suspensions, however, it has limited effect on the particle size distribution and freeze-thaw stability.

Combined Effect of High Hydrostatic Pressure, Sous-Vide Cooking, and Carvacrol on the Quality of Veal, Plant-Based, and Hybrid Patties during Storage

The effect of carvacrol added to patties stored at 4 °C for 14 days, previously pressurized and vacuum-cooked (HPP-SVCOOK), was investigated. Three formulations were prepared (veal, plant-based product, and hybrid product). An emulsion made with olive and linseed oils was added. The physicochemical and microbiological qualities were assessed. Microbial tests indicated negligible growth of spoilage organisms in treated patties. No significant effect of carvacrol on the microbial loads of patties was noticed. Sulfite-reducing clostridia and Enterobacteriaceae were absent in the treated patties, whereas, in the treated veal and hybrid samples, 3 and 2 units of log cfu/g reduction for lactic acid bacteria and molds and yeasts were noted, respectively. On day 7 of storage, veal patties exhibited a significant reduction (p < 0.05) in the L* (53.9−49.3), hardness (32.3−21.4 N), springiness (0.8−0.7 N), cohesiveness (0.49−0.46), and chewiness (12.2−7.1) and a hike in the a* value (5.3−9.4). No significant changes in L* (59.1−58.6), a* (8.57−8.61), hardness (11.6−10.6 N), or cohesiveness (0.27−0.26) were observed in plant-based patties over the storage times, whereas reductions in springiness (0.5−0.4), chewiness (1.9−1.3), and b* (26.6−29.1) were noted in them. In hybrid patties, the L* (53.9−52.5) and b* values (24.9−24.3) were consistent but had a significant decrease in a* value (5.9−3.5) along the days of storage under study. The texture parameters of the hybrid patties altered were similar to those of veal patties during the 14-day storage time. In all samples, pH decreased with storage time. HPP-SVCOOK was effective on rendering safe and shelf-stable, ready-to-eat patties regardless of their matrix formulation. The addition of carvacrol had limited effects on the textural qualities of the HPP-SVCOOK products. Future studies need to be undertaken to assess the treated patties’ consumer acceptability and sensory profile. The study provides the basis for the development of novel meat-based and plant-based products that are microbiologically safe, with minimum physicochemical alterations during storage.

Comparison of High Hydrostatic Pressure Processed Plus Sous-Vide Cooked Meat-Based, Plant-Based and Hybrid Patties According to Fat Replacement

The impact of high-pressure processing (HPP) alone and combined with sous-vide cooking (SVCOOK) on the physicochemical and sensory traits of patties from different fat and protein matrices was evaluated. Hydro-gelled and soya emulsions were tested in meat (M), hybrid (H) and plant-based (P) patties (six formulations). M patties with pork backfat were used as reference formulation. All samples were pressurized (350 MPa, 10 min) and the HPP + SVCOOK patties were subsequently vacuum-cooked (55 °C). Significant changes (p < 0.05) in physicochemical parameters were detected in HPP and HPP + SVCOOK samples. Hardness reached the maximum value (11.0 N) in HPP treated P patties with soya emulsion. The HPP + SVCOOK M patties with backfat recorded the highest hardness (29.9 N). Irrespective of the fat formulations, the sensory characteristics of the HPP and HPP + SVCOOK M patties showed a well differentiated profile compared to H and P patties. The highest intensities for fatness, flavor, chewiness and the lowest for friability were recorded in HPP + SVCOOK M patties with backfat. The differences in physicochemical and sensory parameters of HPP + SVCOOK patties were minimal. Successful fat replacement using either one of the soya or hydro-gelled emulsion could be conducted in HPP + SVCOOK patties.

Effect of high hydrostatic pressure processing on the structure, functionality, and nutritional properties of food proteins: A review

Proteins are important food ingredients that possess both functional and nutritional properties. High hydrostatic pressure (HHP) is an emerging nonthermal food processing technology that has been subject to great advancements in the last two decades. It is well established that pressure can induce changes in protein folding and oligomerization, and consequently, HHP has the potential to modify the desired protein properties. In this review article, the research progress over the last 15 years regarding the effect of HHP on protein structures, as well as the applications of HHP in modifying protein functionalities (i.e., solubility, water/oil holding capacity, emulsification, foaming and gelation) and nutritional properties (i.e., digestibility and bioactivity) are systematically discussed. Protein unfolding generally occurs during HHP treatment, which can result in increased conformational flexibility and the exposure of interior residues. Through the optimization of HHP and environmental conditions, a balance in protein hydrophobicity and hydrophilicity may be obtained, and therefore, the desired protein functionality can be improved. Moreover, after HHP treatment, there might be greater accessibility of the interior residues to digestive enzymes or the altered conformation of specific active sites, which may lead to modified nutritional properties. However, the practical applications of HHP in developing functional protein ingredients are underutilized and require more research concerning the impact of other food components or additives during HHP treatment. Furthermore, possible negative impacts on nutritional properties of proteins and other compounds must be also considered.

Effect of Hydrothermal Treatment on the Structure and Functional Properties of Quinoa Protein Isolate

The aim of this study was to investigate the effects of hydrothermal treatment at different temperatures and times on the structure and functional properties of quinoa protein isolate (QPI). The structure of QPI was investigated by analyzing changes in the intrinsic fluorescence spectrum, ultra-violet (UV) spectrum, and Fourier transform infrared spectrum. The solubility, water/oil-holding capacity, emulsifying activity, and emulsion stability of QPI were studied, as were the particle size and the thermogravimetric properties of QPI. The results showed that the average particle size of QPI gradually increased with the increase in hydrothermal treatment time and temperature, and reached a maximum value of 121 °C for 30 min. The surface morphology also became rough and its thermal stability also increased. The endogenous fluorescence and UV spectral intensity at 280 nm decreased gradually with increasing hydrothermal treatment time and temperature, and reduced to the minimum values at 121 °C for 30 min, respectively. After hydrothermal treatment, the secondary structure of QPI tended to be disordered. The functional properties of QPI after treatment were all superior to those of the control. The results of this study might provide a basis for the processing and utilization of QPI.

Ultrasonic Assisted Extraction of Quinoa (Chenopodium quinoa Willd.) Protein and Effect of Heat Treatment on Its In Vitro Digestion Characteristics

To extract and utilise the protein in quinoa efficiently, we investigated the effect of rate of quinoa protein isolate (QPI) extraction by ultrasound-assisted alkaline extraction and traditional alkaline extraction methods using single-factor experiments and Box-Behnken design. The effect of different heat treatment temperature and time on QPI functional properties and in vitro digestion characteristics were also investigated. The results showed that the optimal conditions of ultrasound- assisted alkaline extraction process were: ultrasonic time 99 min, solid-liquid ratio 1:20 w:v, ultrasonic temperature 47 °C, and pH 10, and its extraction rate and purity were 74.67 ± 1.08% and 87.17 ± 0.58%, respectively. It was 10.18% and 5.49% higher than that of the alkali-soluble acid precipitation method, respectively. The isoelectric point (pI) of QPI obtained by this method was 4.5. The flexibility and turbidity of QPI had maximum values at 90 °C, 30 min, and 121 °C, 30 min, which were 0.42 and 0.94, respectively. In addition, heat treatment changed the 1.77–2.79 ppm protein characteristic region in QPI’s nuclear magnetic resonance hydrogen spectroscopy (¹H NMR). After heating at 90 °C and 121 °C for 30 min, the hydrolysis degree and total amino acid content at the end of digestion (121 °C, 30 min) were significantly lower than those of untreated QPI by 20.64% and 27.85%. Our study provides basic data for the efficient extraction and utilisation of QPI.

Functional Performance of Plant Proteins

Increasingly, consumers are moving towards a more plant-based diet. However, some consumers are avoiding common plant proteins such as soy and gluten due to their potential allergenicity. Therefore, alternative protein sources are being explored as functional ingredients in foods, including pea, chickpea, and other legume proteins. The factors affecting the functional performance of plant proteins are outlined, including cultivars, genotypes, extraction and drying methods, protein level, and preparation methods (commercial versus laboratory). Current methods to characterize protein functionality are highlighted, including water and oil holding capacity, protein solubility, emulsifying, foaming, and gelling properties. We propose a series of analytical tests to better predict plant protein performance in foods. Representative applications are discussed to demonstrate how the functional attributes of plant proteins affect the physicochemical properties of plant-based foods. Increasing the protein content of plant protein ingredients enhances their water and oil holding capacity and foaming stability. Industrially produced plant proteins often have lower solubility and worse functionality than laboratory-produced ones due to protein denaturation and aggregation during commercial isolation processes. To better predict the functional performance of plant proteins, it would be useful to use computer modeling approaches, such as quantitative structural activity relationships (QSAR).