The proteomic evidence on protein oxidation in pea protein concentrate-based low-moisture extrudates and its inhibition by antioxidants derived from plant extracts.

This study aimed to assess the antioxidant activity of golden chlorella (GoC) and grape pomace (GrP) extracts both in vitro and in pea protein-based extrudates. We hypothesized that GoC/GrP would limit oxidation of proteins in the extrudates compared with commercial antioxidants. The results showed that GoC extract was effective in metal chelation and GrP extract possessed excellent radical scavenging activity and reducing power. Protein oxidation inevitably occurred after low-moisture extrusion in terms of elevated level of protein carbonyls and the gradual loss of thiols. LC-MS/MS revealed that the monoxidation and 4-hydroxynonenal adduction were the major oxidative modifications, and legumin was the most susceptible globulin for oxidation. The GoC/GrP extracts effectively retarded the oxidation progress in extrudates by lower intensity of oxidized peptides, whereas protein electrophoretic profiles remained unaffected. This study highlighted the great potential of GoC/GrP as natural antioxidants in plant-based foods.

Protein content and amino acid composition in the diet of Danish vegans: a cross-sectional study.

BACKGROUND: A growing proportion of the population are replacing their dietary animal protein with plant protein. A particular example of this trend is the vegan diet, which excludes all food items of animal origin. However, the DIAAS score for individual plant proteins is generally lower than that of animal proteins due to an unbalanced amino acid composition and lower bioavailability. Care must therefore be taken to meet the nutritional recommendations in the daily food intake. METHODS: A three-day dietary food record was carried out by 40 Danish vegans in a cross-sectional study. The data were analysed, with particular emphasis on protein requirements and the essential amino acid composition of the diet. RESULTS: The protein recommendations were met on all three days by 60% of the participants. In contrast, 18% did not meet the protein recommendations on any of the three days and 7% met the recommendations on only one of the days. Lysine was the most limiting amino acid (only 50% met the recommendations every day) followed by the sulphur-containing amino acids (recommendations met by 67.5%), leucine and valine (recommendations met by 70%). Combining both the amount of protein and the intake of the essential amino acids showed that less than half of the participants met the recommendations on all three days (47.5%) and 35% did not meet the recommendations on any days or on one day only. CONCLUSION: In conclusion, our study showed that many of the participants in the present study failed to meet the daily protein intake requirements, both on single days and on all three days. Furthermore, the food intake was found to have an inadequate amino acid composition and was particularly limited by the essential amino acids lysine, the sulphur-containing amino acids, and leucine and valine. This could be ascribed to the fact that only a limited number of protein sources were consumed during a day.

Applications of Enzyme Technology to Enhance Transition to Plant Proteins: A Review.

As the plant-based food market grows, demand for plant protein is also increasing. Proteins are a major component in foods and are key to developing desired structures and textures. Seed storage proteins are the main plant proteins in the human diet. They are abundant in, for example, legumes or defatted oilseeds, which makes them an excellent candidate to use in the development of novel plant-based foods. However, they often have low and inflexible functionalities, as in nature they are designed to remain densely packed and inert within cell walls until they are needed during germination. Enzymes are often used by the food industry, for example, in the production of cheese or beer, to modify ingredient properties. Although they currently have limited applications in plant proteins, interest in the area is exponentially increasing. The present review first considers the current state and potential of enzyme utilization related to plant proteins, including uses in protein extraction and post-extraction modifications. Then, relevant opportunities and challenges are critically discussed. The main challenges relate to the knowledge gap, the high cost of enzymes, and the complexity of plant proteins as substrates. The overall aim of this review is to increase awareness, highlight challenges, and explore ways to address them.

Protein blends and extrusion processing to improve the nutritional quality of plant proteins.

Plant proteins have low protein nutritional quality due to their unbalanced indispensable amino acid (IAA) profile and the presence of antinutritional factors (ANFs) that limit protein digestibility. The blending of pulses with cereals/pseudocereals can ensure a complete protein source of IAA. In addition, extrusion may be an effective way to reduce ANFs and improve protein digestibility. Thereby, we aimed to improve the protein nutritional quality of plant protein ingredients by blending different protein sources and applying extrusion processing. Protein blends were prepared with pea, faba bean, quinoa, hemp, and/or oat concentrates or flours, and extrudates were prepared either rich in pulses (texturized vegetable proteins, TVPs) or rich in cereals (referred to here as Snacks). After extrusion, all samples showed a reduction in trypsin inhibitor activity (TIA) greater than 71%. Extrusion caused an increase in the total in vitro protein digestibility (IVPD) of TVPs, whereas no significant effect was shown for the snacks. According to the molecular weight distribution, TVPs presented protein aggregation. The results suggest that the positive effect of decreased TIA on IVPD is partially counteracted by the formation of aggregates during extrusion which restricts enzyme accessibility. After extrusion, all snacks retained a balanced amino acid score whereas a small loss of methionine + cysteine was observed in the TVPs, resulting in a small reduction in IAA content. Thus, extrusion has the potential to improve the nutritional quality of TVPs by reducing TIA and increasing protein digestibility.

Associating Compositional, Nutritional and Techno-Functional Characteristics of Faba Bean (Vicia faba L.) Protein Isolates and Their Production Side-Streams with Potential Food Applications.

Faba beans (Vicia faba L.) show exciting prospects as a sustainable source of protein and fibre, with the potential to transition to a more sustainable food production. This study reveals the compositional, nutritional and techno-functional characteristics of two protein isolates from faba beans (Vicia faba L.), a high-starch fraction and a high-fibre side-stream. During the analysis of those four ingredients, particular attention was paid to the isolates' protein profile and the side-streams' carbohydrate composition. The isoelectric precipitated protein isolate 1 showed a protein content of 72.64 ± 0.31% DM. It exhibited low solubility but superior digestibility and high foam stability. High foaming capacity and low protein digestibility were observed for protein isolate 2, with a protein content of 71.37 ± 0.93% DM. This fraction was highly soluble and consisted primarily of low molecular weight proteins. The high-starch fraction contained 83.87 ± 3.07% DM starch, of which about 66% was resistant starch. Over 65% of the high-fibre fraction was insoluble dietary fibre. The findings of this study provide a detailed understanding of different production fractions of faba beans, which is of great value for future product development.

Perceptions toward Plant-Based Milk Alternatives among Young Adult Consumers and Non-Consumers in Denmark: An Exploratory Study.

The objective of this study was to determine associations among plant-based milk alternatives (PBMAs), sources of information on the PBMAs used, and the consumption of PBMAs among Danish young adult consumers and non-consumers of PBMAs. An online survey was conducted in May 2019. A total of 341 participants (consumers: n = 171; non-consumers: n = 170) aged 16-35 years old completed the survey. Most consumers drank less than one glass of PBMAs per week, and oat drink was the most frequently consumed PBMAs. Oat drinks were primarily consumed with coffee/tea or porridge, while soy drinks were preferred to be consumed alone. Participants who perceived PBMAs as natural, good for health, tasty, or nutritionally equal to cow's milk were more likely to be consumers of PBMAs. Additionally, participants who perceived PBMAs as highly processed or artificial were less likely to be consumers of PBMAs. For consumers, the most used sources of information on PBMAs were package labeling, followed by social media. The study´s results can help to improve marketing campaigns concerning the Danish retail of PBMA, whereby nutritional and sensory characteristics of PBMAs are highlighted through social networks and marketing strategies with product package labeling.

Texturized Vegetable Protein as a Source of Protein Fortification of Wheat Buns.

Increasing interest in plant-based proteins is particularly relevant in the food service sector. For specific groups, e.g., older adults, it may be challenging to ensure the consumption of protein of sufficient quality. One way of doing this could be through the fortification of a staple food such as bread. This study examined wheat buns, in which 0%, 20%, 35% and 50% of the flour was replaced with three different milled texturized vegetable proteins (TVP) of different plant protein combinations. Sensory and baking qualities were evaluated through sensory profiling and measurements of rising ability, baking loss, protein content and colour. An expert assessment and a robustness test were conducted to evaluate potential use in the food service sector. By substituting 35% of the wheat flour with milled TVP, it was possible to increase the protein content of the buns by 83% (up to 25% of DM) and still maintain an acceptable quality. The different TVPs showed that pea and faba bean or pea, faba bean and quinoa were more suitable in bread fortification than pea, faba bean and hemp. The study demonstrates the potential for producing quality bread for people who need a high protein intake in all their meals.

Lipid composition of the Amazonian 'Mountain Sacha Inchis' including Plukenetia carolis-vegae Bussmann, Paniagua & C.Téllez.

Several Amazonian species of Plukenetia are remarkably rich sources of polyunsaturated fatty acids, in particular α-linolenic acid. The lipid composition of the large-seeded, recently described 'Mountain Sacha Inchi' Plukenetia carolis-vegae is reported here for the first time, and compared with Plukenetia huayllabambana, two cultivars of Plukenetia volubilis, and a newly developed hybrid between P. volubilis and P. carolis-vegae. All species and cultivars had a very high content of polyunsaturated fatty acids, 82.6-86.7% of total fatty acids, and at least 46.6% α-linolenic acid of total fatty acids. The highest content was found in P. carolis-vegae which had 57.4%. The exceptionally high α-linolenic acid content suggests that P. carolis-vegae may be an important plant-derived dietary source of this essential fatty acid and that the species has considerable potential for further domestication and commercialisation of its seeds and seed oil. A TAG analysis was carried out for the two P. volubilis cultivars, in which LLnLn and LnLL were most prevalent, and for P. huayllabambana, in which LLnLn constituted the largest fraction, followed by LnLnLn, indicating that this large-seeded species also has interesting dietary properties.

Design of a Functional Pea Protein Matrix for Fermented Plant-Based Cheese.

The production of a fermented plant-based cheese requires understanding the behavior of the selected raw material prior to fermentation. Raw material processing affects physicochemical properties of plant protein ingredients, and it determines their ability to form fermentation-induced protein gels. Moreover, the addition of oil also influences structure formation and therefore affects gel firmness. This study focuses on identifying and characterizing an optimal pea protein matrix suitable for fermentation-induced plant-based cheese. Stability and gel formation were investigated in pea protein matrices. Pea protein isolate (PPI) emulsions with 10% protein and 0, 5, 10, 15, and 20% olive oil levels were produced and further fermented with a starter culture suitable for plant matrices. Emulsion stability was evaluated through particle size, ζ-potential, and back-scattered light changes over 7 h. Gel hardness and oscillation measurements of the fermented gels were taken after 1 and 7 days of storage under refrigeration. The water-holding capacity of the gels was measured after 7 days of storage and their microstructure was visualized with confocal microscopy. Results indicate that all PPI emulsions were physically stable after 7 h. Indeed, ζ-potential did not change significantly over time in PPI emulsions, a bimodal particle size distribution was observed in all samples, and no significant variation was observed after 7 h in any of the samples. Fermentation time oscillated between 5.5 and 7 h in all samples. Higher oil content led to weaker gels and lower elastic modulus and no significant changes in gel hardness were observed over 7 days of storage under refrigeration in closed containers. Water-holding capacity increased in samples with higher olive oil content. Based on our results, an optimal pea protein matrix for fermentation-induced pea protein gels can be produced with 10% protein content and 10% olive oil levels without compromising gel hardness.

Formulation, pilot-scale preparation, physicochemical characterization and digestibility of a lentil protein-based model infant formula powder.

BACKGROUND: Infant formula is a human milk substitute for consumption during the first months of life. The protein component of such products is generally of dairy origin. Alternative sources of protein, such as those of plant origin, are of interest due to dairy allergies, intolerances, and ethical and environmental considerations. Lentils have high levels of protein (20-30%) with a good amino acid profile and functional properties. In this study, a model lentil protein-based formula (LF), in powder format, was produced and compared to two commercial plant-based infant formulae (i.e., soy; SF and rice; RF) in terms of physicochemical properties and digestibility. RESULTS: The macronutrient composition was similar between all the samples; however, RF and SF had larger volume-weighted mean particle diameters (D[4,3] of 121-134 µm) than LF (31.9 µm), which was confirmed using scanning electron and confocal laser microscopy. The larger particle sizes of the commercial powders were attributed to their agglomeration during the drying process. Regarding functional properties, the LF showed higher D[4,3] values (17.8 µm) after 18 h reconstitution in water, compared with the SF and RF (5.82 and 4.55 µm, respectively), which could be partially attributed to hydrophobic protein-protein interactions. Regarding viscosity at 95 °C and physical stability, LF was more stable than RF. The digestibility analysis showed LF to have similar values (P < 0.05) to the standard SF. CONCLUSION: These results demonstrated that, from the nutritional and physicochemical perspectives, lentil proteins represent a good alternative to other sources of plant proteins (e.g., soy and rice) in infant nutritional products. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Combining high-protein ingredients from pseudocereals and legumes for the development of fresh high-protein hybrid pasta: enhanced nutritional profile.

BACKGROUND: The fortification of wheat-based staple foods, such as pasta, with pseudocereal and legume flours has received growing research interest in recent years. While it is associated with many challenges regarding technological and sensory quality of the products, it promises a substantial improvement of the nutritional value of pasta. However, investigations of the nutritional quality of fortified pasta often focus on the carbohydrate/starch fraction, and information on changes in protein quality is relatively scarce. This study evaluates the nutritional profile of a high-protein hybrid pasta (HPHP) formulation in which a combination of three high-protein ingredients (HPIs) from buckwheat, faba bean and lupin is used to partially replace wheat semolina. The formulation's macronutrient composition, protein quality and the content of antinutritional compounds are assessed in comparison to regular wheat pasta. RESULTS: The HPHP formulation represents a more favourable macronutrient profile compared to regular wheat pasta, particularly in relation to the isocaloric replacement of wheat starch by non-wheat protein. Furthermore, a more balanced amino acid profile, improved N utilisation and increased protein efficiency ratio (in vivo) were determined for HPHP, which conclusively suggests a substantially enhanced protein quality. The cooking process was shown to significantly reduce levels of vicine/convicine and trypsin inhibitor activity originating from HPIs. The small remaining levels seem not to adversely affect HPHP's nutritional quality. CONCLUSION: This significant upgrade of pasta's nutritional value identifies HPHP, and similar hybrid formulations, as a healthy food choice and valuable alternative to regular wheat pasta, specifically for a protein supply of adequate quality in mostly plant-based diets. © 2020 Society of Chemical Industry.

Nutritional and anti-nutritional properties of lentil (Lens culinaris) protein isolates prepared by pilot-scale processing.

Lentil (Lens culinaris) is a high-protein crop with a promising potential as a plant-based protein source for human nutrition. This study investigated nutritional and anti-nutritional properties of whole seed lentil flour (LF) compared to lentil protein isolates (LPIs) prepared in pilot-scale by isoelectric precipitation (LPI-IEP) and ultrafiltration (LPI-UF). Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) profiles showed significant reductions in total galacto-oligosaccharides (GOS) contents by 58% and 91% in LPI-IEP and LPI-UF, respectively, compared to LF. Trypsin inhibitor activity (TIA) levels based on dry protein mass were lowered by 81% in LPI-IEP and 87% in LPI-UF relative to LF. Depending on the stage of digestion, the in vitro protein digestibility (IVPD) of LPIs was improved by 35-53% compared to LF, with both products showing a similar long-term protein digestibility to that of bovine serum albumin (BSA). This work supports the use of purified LPI products as a novel source of high quality protein for food applications.

Targeted inactivation of soybean proteinase inhibitors using zinc.

In this study the potential targeted use of zinc to inactivate proteinase inhibitors (PI) has been investigated as an alternative to the widely applied heat treatment used industrially for inactivation of PI. Zinc was utilized for the reduction of disulfide bonds leading to the structural changes in proteins, thus affecting the decreased affinity between PI and proteinases. The protein disulfide bond reduction mechanism was studied using a newly developed micellar electrokinetic capillary chromatography (MECC) with the glutathione redox reaction with dithiothreitol (DTT) as model system. This model proved efficient in monitoring the reduction of disulfide bonds in the Kunitz trypsin inhibitor (KTI) and Bowman-Birk inhibitor (BBI). The use of zinc as a reductant resulted in a significant reduction of trypsin inhibitor activity (TIA) of 72% for KTI and 85% for BBI, highlighting zinc as a promising potential agent to reduce the activity of PI as an alternative to heat treatment.

In Vitro Protein Digestibility and Fatty Acid Profile of Commercial Plant-Based Milk Alternatives.

Plant-based milk alternatives (PBMA) are a new popular food trend among consumers in Europe and North America. The forecast shows that PBMA will double their value by 2023. The objective of this study was to analyze the nutritional value of commercial products in terms of their fatty acid profile and protein digestibility from commercial PBMA. Eight commercially available PBMA were selected for fatty acid analysis, performed with gas chromatography of methylated fatty acids (GC-FAME), and, from these, four commercial products (almond drink, hemp drink, oat drink, and soy drink) were selected for a short-term in vitro protein digestibility (IVPD) analysis. The fatty acid analysis results showed that most of the products predominantly contained oleic acid (C18:1 ω-9) and linoleic acid (C18:2 ω-6). Hemp drink contained the highest omega-6/omega-3 (ω6/ω3) ratio among all tested products (3.43). Oat drink and almond drink were the PBMA with the highest short-term protein digestibility, non-significantly different from cow's milk, while soy drink showed the lowest value of protein digestibility. In conclusion, PBMA showed a significant variability depending on the plant source, both in terms of fatty acid composition and protein digestibility. These results provide more in-depth nutritional information, for future product development, and for consumer's choice.

Protein-Rich Flours from Quinoa and Buckwheat Favourably Affect the Growth Parameters, Intestinal Microbial Activity and Plasma Lipid Profile of Rats.

In recent years, dietary products with quinoa and buckwheat have attracted attention mostly due to the high nutritive value of their protein fraction. However, their dietary effect on intestinal microbiota activity and related systemic responses are still poorly understood. Therefore, a 2 week study of twenty-eight growing male Wistar rats was conducted to investigate the effects of quinoa (QU) and buckwheat (BK) protein-rich flours on the growth parameters, intestinal microbial activity, plasma lipid profile, and inflammatory markers. The biological value of protein and body weight gain were considerably increased in the QU and BK groups compared with those in the soy protein isolate group. Moreover, both flours increased the microbial activity of α-glucosidase, ß-glucosidase, and α-galactosidase and the concentration of short-chain fatty acids in the caecum. The studied flours favourably reduced the plasma total cholesterol and LDL cholesterol. In rats fed a diet with QU, elevated levels of plasma interleukin 6 and alanine transaminase were observed. The effect of QU on inflammatory markers may be related to the increased expression of aryl hydrocarbon receptor in the liver and to the decreased level of plasma albumin. In conclusion, quinoa and buckwheat protein-rich flours are valuable sources of proteins that favourably affect growth parameters, gut metabolism, and blood lipid profile in rats; however, only the buckwheat flour has no effect on inflammatory processes.

Enhancing the nutritional profile of regular wheat bread while maintaining technological quality and adequate sensory attributes.

Plant proteins, and legume proteins in particular, have become the centre of attention moving towards a more sustainable and, therefore, more plant-based human diet. Especially hybrid products, containing wheat and legume proteins, promise a balanced amino acid composition and an upgraded nutritional value of both protein sources. This study investigates a high-protein hybrid bread (HPHB) formulation, where wheat flour was partially replaced by high-protein ingredients from faba bean, carob and gluten. In addition to a detailed characterisation of technological quality and sensory profile, also the formulation's nutritional value was examined in comparison to regular wheat bread. Therefore, macronutrient composition, antioxidant potential, amino acid profile and contents of antinutritional compounds were analysed. Furthermore, protein digestibility was determined in an in vitro model and in vivo. Dough analysis revealed significant differences of the HPHB formulation compared to regular wheat dough. However, results obtained for bread quality characteristics prove HPHB to be equal to regular wheat bread and sensory results and the determined sensory attributes suggest high consumer acceptance. Nutritional analyses of HPHB showed a more favourable macronutrient composition in comparison to regular wheat bread; as well as low contents of antinutritional compounds and high antioxidant potential linked to high levels of phenolics. Also an improved amino acid profile, increased nitrogen utilisation rate (by 69%) and higher protein efficiency ratio were determined, which are associated with enhanced protein quality. This suggests HPHB, and similar formulations of its kind, as a valuable and healthy food choice, which can contribute to adequate protein supply in predominantly plant-based diets.

Amino Acid Composition of Novel Plant Drinks from Oat, Lentil and Pea.

Plant-based drinks (PBDs) as alternatives to milk is a fast-growing market in much of the western world, with the demand increasing every year. However, most PBDs from a single plant ingredient do not have an amino acid profile that matches human needs. Therefore, this study set out to combine plant ingredients to achieve a more balanced amino acid profile of novel plant drinks, by combining a high content of oat with the pulses pea (Pisum sativum) and lentil (Lens culinaris) in a solution. After removal of the sediment, the resulting plant drinks were composed of what could be kept in suspension. The amino acid and protein composition of the plant drinks were investigated with capillary electrophoresis, to identify the amino acids, and SDS-PAGE to assess the proteins present. The amino acid profile was compared against recommended daily intake (RDI). It was determined that the plant drinks with only oat and lentil did not have a strong amino acid profile, likely due to the higher pH of the lentil concentrate affecting which proteins could be kept in solution. Plant drinks with a combination of both lentil and pea, or only pea, added to the oat drink had an improved concentration of the amino acids that were otherwise in the low end compared to RDI. This includes a high content of phenylalanine, leucine and threonine, as well as a moderate amount of isoleucine, valine and methionine, and a contribution of histidine and lysine. An assessment of stability and sensory parameters was also conducted, concluding there was an advantage of combining oat with a legume, especially pea.

Comparison of Faba Bean Protein Ingredients Produced Using Dry Fractionation and Isoelectric Precipitation: Techno-Functional, Nutritional and Environmental Performance.

Dry fractionated faba bean protein-rich flour (FPR) produced by milling/air classification, and faba bean protein isolate (FPI) produced by acid extraction/isoelectric precipitation were compared in terms of composition, techno-functional properties, nutritional properties and environmental impacts. FPR had a lower protein content (64.1%, dry matter (DM)) compared to FPI (90.1%, DM), due to the inherent limitations of air classification. Of the two ingredients, FPR demonstrated superior functionality, including higher protein solubility (85%), compared to FPI (32%) at pH 7. Foaming capacity was higher for FPR, although foam stability was similar for both ingredients. FPR had greater gelling ability compared to FPI. The higher carbohydrate content of FPR may have contributed to this difference. An amino acid (AA) analysis revealed that both ingredients were low in sulfur-containing AAs, with FPR having a slightly higher level than FPI. The potential nutritional benefits of the aqueous process compared to the dry process used in this study were apparent in the higher in vitro protein digestibility (IVPD) and lower trypsin inhibitor activity (TIA) in FPI compared to FPR. Additionally, vicine/convicine were detected in FPR, but not in FPI. Furthermore, much lower levels of fermentable oligo-, di- and monosaccharides, and polyols (FODMAPs) were found in FPI compared to FPR. The life cycle assessment (LCA) revealed a lower environmental impact for FPR, partly due to the extra water and energy required for aqueous processing. However, in a comparison with cow's milk protein, both FPR and FPI were shown to have considerably lower environmental impacts.