Use Of Plant Proteins Research Articles

Understanding the synergistic effect of pea protein and rice bran protein interaction in stabilizing palm kernel oil-in-water emulsion assisted by high-pressure homogenization.

Plant-based beverages have recently seen a significant increase in market demand. However, many of these products suffer from poor emulsion stability and low protein content. Gums have commonly been used to enhance emulsion stability but they do not improve the amino acid profile. This study investigated the use of multiples plant proteins to enhance both the stability and nutritional value of plant-based beverages. Pea and rice bran proteins both enhanced emulsion stability. Pea protein enhanced the viscosity of the continuous phase whereas rice bran protein lowered interfacial tension. When applied synergistically, competitive adhesion occurred. Rice bran protein gradually displaced pea protein from the oil droplet surface as its concentration increased, leading to emulsion destabilization due to the displaced pea protein. The use of high-pressure homogenization further enhanced the stability of the emulsion by unfolding protein partially. However, increasing homogenization pressure (>500 Bar) and homogenization cycle (>2 cycles) led to protein aggregation due to excessive exposure of its hydrophobic core. The emulsion formed was resistant to coalescence at 4 °C for 28 days and was stable under high pH and low ionic conditions. The synergistic combination of plant proteins and the effective utilization of co-processing (homogenization) can enhance the functionality of the individual proteins significantly, leading to the formation of a stable emulsion. The use of plant protein mixture as a stabilizer not only improved the emulsion stability but also ensured a plant-based beverage with a complete amino acid profile for the vegan community. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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.

Oil binding capacity and related physicochemical properties of commercial plant protein products

Providing sufficient food to a growing population while addressing the rise of food-related diseases requires innovative solutions. The use of plant proteins as structuring agents for oils has shown potential because of their healthier fatty acid profiles compared to solid fats. Thus, this study aims to investigate the potential correlations between the properties of proteins and their oil binding capacity (OBC) to provide insights into their applicability in structuring oil. Two samples each of sunflower, rapeseed, and soy protein products obtained from different manufacturers were denatured by heat and dispersed in oil after freeze-drying. Whey protein isolate (WPI) was used as a reference. The results indicate that, with some modifications, rapeseed and sunflower proteins can bind amounts of oil (3.7 oil [g]/protein [g]) comparable to that of WPI (4.04 oil [g]/protein [g]). However, the extraction process affects the final results and the texture of the protein-oil dispersion. Moreover, the protein solubility in NaCl, carbohydrate content, particle size, and the quantity of α-helical structures are positively correlated with the OBC, whereas an increase in the firmness of the dispersion is negatively associated with it. There was no correlation found between the changed β-sheet structure resulting from the heat treatment and the OBC. This study emphasizes the ability of plant proteins to structure oil and explains how to evaluate the physical and structural properties of plant proteins. Technical insights that may lead to the production of more sustainable and healthier food products are provided.

Production of Plant Proteins and Peptides with Pharmacological Potential.

The use of plant proteins or peptides in biotechnology is based on their identification as possessing bioactive potential in plants. This is usually the case for antimicrobial, fungicidal, or insecticidal components of the plant's defense system. They function in addition to a large number of specialized metabolites. Such proteins can be classified according to their sequence, length, and structure, and this has been tried to describe for a few examples here. Even though such proteins or peptides can be induced during plant-pathogen interaction, they are still present in rather small amounts that make the system not suitable for the production in large-scale systems. Therefore, a suitable type of host needs to be identified, such as cell cultures or adult plants. Bioinformatic predictions can also be used to add to the number of bioactive sequences. Some problems that can occur in production by the plant system itself will be discussed, such as choice of promoter for gene expression, posttranslational protein modifications, protein stability, secretion of proteins, or induction by elicitors. Finally, the plant needs to be set up by biotechnological or molecular methods for production, and the product needs to be enriched or purified. In some cases of small peptides, a direct chemical synthesis might be feasible. Altogether, the process needs to be considered marketable.

Looking for a Novel Vegan Protein Supplement from Faba Bean, Lupine, and Soybean: a Dietary and Industrial Standpoint

Global population growth poses a threat to sustainable development. Meanwhile, the use of plant proteins as healthy and sustainable alternatives to animal proteins needs further research. Therefore, this investigation was designed to study the nutritive, structural, and thermal properties of isolated protein fractions from different legumes, i.e., faba bean (FPI), soybean (SPI), and lupine (LPI). As a prospective plant-based protein powder, an equal mixture (MPI) of the three prior legume samples was formulated to study its properties compared to each sole sample. The alkaline extraction and isoelectric precipitation (AE-IP) technique was used for protein isolation. Results showed that all protein isolates had reasonable levels of protein with maximum protein content in SPI (96.15%). The MPI sample, however, came out on top in terms of amino acid profile followed by FBI. Compared to SPI and LPI, it had the highest isoleucine content and higher methionine, valine, leucine, phenylalanine, and lysine. Moreover, MPI showed a median particle charge (−37.1 mV) compared to FPI, SPI, and LPI samples. MPI sample peak showed resistance to heat denaturation at a temperature greater than 200 °C when the DSC test was conducted. With respect to its rheological characteristics, it outperformed the other three protein isolates and exhibited the highest values of storage modulus G’ and loss modulus G”. Consequently, our study suggests that pulse-derived protein isolate mixture can be used as a unique type of nutritious dietary protein supplement. It could be a good nutritional alternative to proteins derived from animals.

Dry fractionation process operations in the production of protein concentrates: A review.

The market for plant proteins is expanding rapidly as the negative impacts of animal agriculture on the environment and resources become more evident. Plant proteins offer competitive advantages in production costs, energy requirements, and sustainability. Conventional plant-protein extraction is water and chemical-intensive, posing environmental concerns. Dry fractionation is an energy-efficient and environmentally friendly process for protein separation, preserving protein's native functionality. Cereals and pulses are excellent sources of plant proteins as they are widely grown worldwide. This paper provides a comprehensive review of the dry fractionation process utilized for different seeds to obtain protein-rich fractions with high purity and functionality. Pretreatments, such as dehulling and defatting, are known to enhance the protein separation efficiency. Factors, such as milling speed, mill classifier speed, feed rate, seed type, and hardness, were crucial for obtaining parent flour of desired particle size distribution during milling. The air classification or electrostatic separation settings are crucial in determining the quality of the separated protein. The cut point in air classification is targeted based on the starch granule size of the seed material. Optimization of these operations, applied to different pulses and seeds, led to higher yields of proteins with higher purity. Dual techniques, such as air classification and electrostatic separation, enhance protein purity. The yield of the protein concentrates can be increased by recycling the coarse fractions. Further research is necessary to improve the quality, purity, and yield of protein concentrates to enable more efficient use of plant proteins to meet global protein demands.

High carbohydrate to protein ratio promotes changes in intestinal microbiota and host metabolism in rainbow trout (Oncorhynchus mykiss) fed plant-based diet

To ensure the sustainability of aquaculture, it is necessary to change the “menu” of carnivorous fish such as rainbow trout from a fish-based diet to one with plant-based ingredients. However, there is a major problem with the growth performance decrease of fish fed with a 100% plant-based diet due to the reduction in feed intake and feed efficiency. For the first time, we incorporated high levels of digestible carbohydrates (high-starch diet) in a 100% plant-based diet during a 12-week feeding trial in order to improve protein utilization for growth (protein sparing effect) and reduce nitrogen waste.We measured the changes in the intestinal microbiota, Short-Chain Fatty Acid (SCFA) levels and metabolic responses in liver. Dietary carbohydrates had a strong effect on alpha and beta diversity and abundance of 12 genera, including Ralstonia and Bacillus in digesta associated microbiota whereas mucosa associated microbiota was less affected. The change in microbial diversity might be linked to the change observed in SCFA production. High levels of Mycoplasma were observed in the intestinal mucosa. Overall, hepatic gene expression was significantly altered by the CHO/protein ratio. Up-regulation of genes involved in glucose metabolism (gcka, gckb, g6pcb2a), down-regulation of genes involved in lipid metabolism (hadh, acox3, srebp2a, and cyp51a) were associated with higher enzymatic activities (such as glucokinase or pyruvate kinase) and higher glycogen levels in the liver, suggesting adequate adaptation to diet. Interestingly, strong correlations were observed between abundances of certain bacterial OTUs and gene expression in the liver.The inclusion of digestible carbohydrates in combination with a 100% plant-based diet, could be a promising way to improve and reduce the use of plant proteins in rainbow trout. In addition, the relationship between intestinal microbiota and host metabolism needs further investigation to better understand fish nutrition.

Can flavour and texture defects of plant-based burger patties be mitigated by combining them with a bun and tomato sauce?

Common challenges for plant-based meat replacers are undesired (inherent) off-flavours (flavour defects) such as beany flavour or bitter taste, which are often associated with the use of plant proteins in meat replacers. Furthermore, plant-based meat replacers are often perceived as dry and lack juiciness and tenderness (texture defects). However, many foods are not consumed in isolation and sensory properties, and their acceptance, can be altered by the addition of other food components or condiments.The study aimed to compare the sensory properties and acceptance of commercially available plant-based burger patties eaten alone and in combination with other foods and/or condiments. Liking and sensory properties of a beef and two plant-based (soy and hemp) patties consumed alone, with a bun, with tomato sauce, and with a bun and tomato sauce were determined using a hedonic scale and Rate-All-That-Apply (RATA) methodology, respectively.For both plant-based patties (hemp, soy) bitter taste, beany and nutty flavour intensity remained but decreased with addition of a bun and/or sauce, but positive liking drivers such as meaty and fat flavour were also reduced. This suggests that these off-flavours can only be partly mitigated by the addition of a bun and/or sauce, but clearly cannot be masked completely. Hemp patties were perceived to have a high amount of chunks, which was a driver of disliking. This texture defect decreased with the addition of a bun and a bun with sauce. Off-flavours and texture defects of the hemp- and soy-based patties were too intense to be fully masked and could only be mitigated to a limited extent by the addition of a bun and/or tomato sauce. Notably, these reductions in off-flavour and texture defects were not sufficient to impact liking. The results highlight the importance of understanding product performance in realistic consumption scenarios. Addition of further ingredients and condiments, as is typical in a burger context, may be advantageous, but further research is required to test such a hypothesis.

Updates on Plant-Based Protein Products as an Alternative to Animal Protein: Technology, Properties, and Their Health Benefits.

Plant-based protein products, represented by "plant meat", are gaining more and more popularity as an alternative to animal proteins. In the present review, we aimed to update the current status of research and industrial growth of plant-based protein products, including plant-based meat, plant-based eggs, plant-based dairy products, and plant-based protein emulsion foods. Moreover, the common processing technology of plant-based protein products and its principles, as well as the emerging strategies, are given equal importance. The knowledge gap between the use of plant proteins and animal proteins is also described, such as poor functional properties, insufficient texture, low protein biomass, allergens, and off-flavors, etc. Furthermore, the nutritional and health benefits of plant-based protein products are highlighted. Lately, researchers are committed to exploring novel plant protein resources and high-quality proteins with enhanced properties through the latest scientific and technological interventions, including physical, chemical, enzyme, fermentation, germination, and protein interaction technology.

Intrinsic labelling of common beans with 2H2O to enable estimates of protein digestibility

ABSTRACT Background: The use of plant protein intrinsically labelled with stable isotopes provides an innovative solution to assess the efficiency of protein intake by humans. Here, the incorporation of 2H has been applied to intrinsically labelled plant protein in the common bean. This study aimed to evaluate which is the best phenological phase of seed maturation to incorporate the heavy hydrogen isotope 2H into seed amino acids. Common beans (Phaseolus vulgaris L.) were grown in pots, then, after 50 days sowing, 2H2O dissolved in irrigation water was applied, then again at an interval of either 3, 6, 9, and 12 days. Results: Applications of 2H2O at 6, 9, and 12 days after the first application, in the full-flowering stage, were the best treatments for enriching protein-bound amino acids in the bean seed with 2H. Conclusion: All treatments resulted in enrichment above 500 ppm, so the treatments (quantity and timing of 2H2O addition) were deemed successful for enriching bean seeds. This makes the intrinsically labelled seeds suitable for preparing test meals to assess the digestion and essential amino acid absorption of common bean amino acids in human subjects.

Preparation of water-in-oil Pickering emulsion stabilized by Camellia oleifera seed cake protein and its application as EGCG delivery system

The use of plant proteins as stabilizers for Pickering emulsions is attracting attention in the food industry. Herein, a protein extract with a high hydrophobic content (extraction ratio up to 21.6%) was obtained from the byproduct generated by the extraction of oil from Camellia oleifera. The effects of different oil-towater ratios and protein concentrations on the stability and rheological properties of the Pickering emulsions were investigated. A stabile emulsion that exhibited gel characteristics was made using an oil:water ratio of 6.5:3.5 and a protein concentration of 3%. The EGCG encapsulation efficiency of the Pickering emulsion was 82.3%. The emulsion remained stable during different environmental pressures (pH, ionic strength, heat, UV) and long-term storage, effectively protecting EGCG from chemical degradation in extreme environments. In vitro digestion results showed that the Pickering emulsion significantly delayed the release of EGCG from 80.52% to 26.81% and that the bioaccessibility of the EGCG was increased by 30.8% in the intestine when incorporated into the Pickering emulsion compared to free EGCG. This research indicates that Camellia oleifera seed cake could be used in plant-based protein emulsions for improved nutrient delivery.

The Performances of Hybrid Grouper, Epinephelus fuscoguttatus × E. lanceolatus Fed with Defatted Soybean Meal-Based Feeds with Supplementation of Phytase

Fish meal is the primary protein ingredient in fish feed and this material is expensive and non-renewable. However, the use of plant protein in marine fish feed such as soybean meal products are limited due to anti-nutritional factor that hindered fish performances. Therefore, hybrid grouper, a cross between tiger grouper (Epinephelus fuscoguttatus) and giant grouper (E. lanceolatus) was evaluated using defatted soybean meal (DSM) based feed and phytase. DSM- based feeds (30% of protein replacement) with supplementation of phytase at 0 and 2000 FTU/kg dosages, as well as a control feed (CON) comprised completely of fish meal (FM) was given to the hybrid grouper with an initial body weight of 6.2±0.0g. Each experimental feed was formulated with 50% of crude protein and 12% of crude lipid. The fish were raised in 100L fiberglass tanks equipped with a flow-through water system for each triplicate treatment. The hybrid grouper was fed with the respective feeds twice a day until the perceived satiation level for 12 weeks. Hybrid grouper fed CON and DSM-based feed did not exhibit any significant difference in growth. However, hybrid grouper fed with DSM-based feed grew larger compared to that fed with CON. Hybrid grouper fed with DSM-based feed showed significantly higher feed intake, lower net protein utilization, hepatosomatic index, viscerosomatic index, and apparent digestibility coefficient (ADC) protein values (p<0.05). The value of ADC of phosphorus was slightly higher in DSM-based feed supplemented with phytase at a dosage of 2000 FTU/kg. No significant effect was observed on body proximate composition, morphological condition of the intestine, and ADC of lipids in all the treatments. The results show that hybrid grouper can effectively consume 30% DSM-based feed and supplementing phytase did not affect the fish performances.

Method development and optimization for measuring chymotrypsin and chymotrypsin inhibitor activities.

Protease inhibitors of protein nature are rich in seeds of legume crops. There are two common types: Kunitz inhibitor, which mainly inhibits trypsin, and Bowman-Birk inhibitor, which inhibits both trypsin and chymotrypsin. Historically, trypsin inhibitor activity in legume products has been of primary interest for measurement. However, as plant proteins are increasingly used for food or feed in recent years, there is a growing interest in monitoring chymotrypsin inhibitor activity (CIA) in these products as well. Reported methods for CIA assay vary greatly and are incompletely described. No standardized or official method is available. The present study focused on developing a robust method for accurately measuring CIA, using N-benzoyl-L-tyrosine p-nitroanilide (BTpNA) as a substrate. Since BTpNA is not water soluble, a water-miscible organic solvent must be present. After investigating the effects of several factors, such as absorption spectra, organic solvent type and concentration, substrate and enzyme concentrations, inhibitor levels (which affected % chymotrypsin inhibition), the sequence of adding reagents, extractant and extraction time, and so forth, an optimized method for CIA measurement was finally developed. It features dimethylformamide as the organic solvent, the enzyme-last sequence, 5ml total assay volume, and calculation of the inhibitor activity based on 40% chymotrypsin inhibition. The method can also be slightly modified for measuring chymotrypsin activity. The robust performance of the method was verified by measuring 11 assorted protein products, paving a way for standardization. PRACTICAL APPLICATION: With an increasing use of plant proteins, there is an urgent need to measure chymotrypsin inhibitor activity in various protein products with accuracy. After thoroughly investigating several factors, an optimized method for measuring chymotrypsin inhibitor activity in various protein products was developed. The proposed method is sensitive and robust, providing a basis for standardization. It can also be used for measuring chymotrypsin activity.

Effective Use of Plant Proteins for the Development of "New" Foods.

Diversity in our diet mirrors modern society. Affluent lifestyles and extended longevity have caused the prevalence of diabetes and sarcopenia, which has led to the increased demand of low-carb, high-protein foods. Expansion of the global population and Westernization of Asian diets have surged the number of meat eaters, which has eventually disrupted the supply–demand balance of meat. In contrast, some people do not eat meat for religious reasons or due to veganism. With these multiple circumstances, our society has begun to resort to obtaining protein from plant sources rather than animal origins. This “protein shift” urges food researchers to develop high-quality foods based on plant proteins. Meanwhile, patients with food allergies, especially gluten-related ones, are reported to be increasing. Additionally, growing popularity of the gluten-free diet demands development of foods without using ingredients of wheat origin. Besides, consumers prefer “clean-label” products in which products are expected to contain fewer artificial compounds. These diversified demands on foods have spurred the development of “new” foods in view of food-processing technologies as well as selection of the primary ingredients. In this short review, examples of foodstuffs that have achieved tremendous recent progress are introduced: effective use of plant protein realized low-carb, high protein, gluten-free bread/pasta. Basic manufacturing principles of plant-based vegan cheese have also been established. We will also discuss on the strategy of effective development of new foods in view of the better communication with consumers as well as efficient use of plant proteins.

Metabolic Conversions by Lactic Acid Bacteria during Plant Protein Fermentations

To secure a sustainable food supply for the rapidly growing global population, great efforts towards a plant-based diet are underway. However, the use of plant proteins comes with several challenges, such as improvement or removal of undesired flavours, and generation of desired texture properties. Fermentation holds large potential to alter these properties, but compared to dairy fermentations, our knowledge on strain properties in different plant-based substrates is still limited. Here, we explored different lactic acid bacteria for their ability to grow, produce flavour compounds, or remove off-flavour compounds from different plant proteins. For this, 151 LAB strains from dairy and non-dairy origins were cultured in plant protein plus coconut oil emulsions supplemented with glucose. Pea, chickpea, mung, fava, and soybean proteins were used in the study and bacterial strains for screening included the genera Streptococcus, Lactococcus, Lactobacillus, and Leuconostoc. Efficient, high throughput, screening on plant proteins was developed and strains were assessed for their ability to (i) acidify and decrease the pH; (ii) express key enzymes involved in the formation of amino acid derived flavours, which included PepN (aminopeptidase N), PepXP (X-prolyl dipeptidyl peptidase), EstA (esterase), BcAT (branched chain aminotransferase), CBL (cystathione beta lyase), and ArAT (aromatic aminotransferase); and (iii) improve the overall aroma profile by generating dairy/cheesy notes and decreasing off flavours. Suitable screening conditions were determined, and highlighted the importance that a sufficient heat treatment must be applied to samples containing plant proteins, prior to fermentation, as an outgrowth of spore forming Bacillus cereus was observed if the material was only pasteurised. Enzyme activities for strains measured in rich broth vs. a buffered protein solution showed little-to-no correlation, which illustrated the importance of screening conditions to obtain predictive enzyme measurements. Aroma formation analysis allowed to identify strains that were able to increase key aromas such as diacetyl, acetoin, 2- and 3-methyl butanol, and 2,3-pentanedione, as well as decrease the off-flavours hexanal, pentanal, and nonanal. Our findings illustrate the importance of strain specific differences in the assessed functionalities and how a methodical approach to screening LAB can be applied to select suitable microorganisms that show promise in fermentation of plant proteins when applied in non-dairy cheese applications.

Physicochemical, structural, and functional properties of protein fractions and protein isolate from jackfruit seeds.

The physicochemical, structural, and functional properties of albumin, globulin, glutelin, and protein isolate (JSPI) extracted from jackfruit seeds were investigated. Protein fractions and JSPI were rich in amino acids, which can be comparable to soy protein. Other essential amino acids except histidine met the FAO/WHO/UNO-recommended intake for infants and adults. Jackfruit seed proteins were mainly composed of 17-26kDa polypeptides, β-sheet, and random coil were the main secondary structures. Glutelin (572.55) and JSPI (246.14) have higher H0 under neutral conditions, consistent with the solubility and emulsification properties results. Albumin and globulin had good solubility and were mostly soluble under neutral or weak alkaline conditions. In general, protein fractions and JSPI exhibited good foaming and emulsification properties. Therefore, jackfruit seed proteins have the potential to be nutritious functional ingredients in the food industry. PRACTICAL APPLICATION: Jackfruit seed proteins had high essential amino acids content and good functional properties. They can be used as a new type of functional ingredients in the food industry, which can not only reduce the environment pollution of discarded seeds but also improve use of plant protein.

Application of plant proteins as alternative emulsifiers in double emulsions: using kappa‐carrageenan for complex coacervation and microencapsulation of riboflavin

SummaryCompared to animal proteins, this paper describes the use of plant proteins as alternative emulsifiers in double emulsion (DE) fabrication followed by complex coacervation. This is an additional way to improve stability, sustainability and lower production costs. In this study, kappa‐carrageenan (k‐carr) was used in complex coacervation with DE stabilised by pea protein isolate (PPI), mung bean protein isolate and chickpea protein concentrate (CPC) at pH 2 and 3 to form microcapsules (DECC). By investigating the particle sizes, microstructures and visual observations over 9 days at 4 °C, PPI/k‐carr DECC and CPC/k‐carr DECC at pH 2 were the most stable. Riboflavin encapsulation in PPI/k‐carr DECC achieved an encapsulation efficiency of 65.46%, preserving ~20% of riboflavin across the storage period. As compared to DE systems, complex coacervation significantly improved riboflavin encapsulation stability. The results highlight the potential of PPI as an alternative emulsifier in DECC for the delivery of bioactive compounds.

The role of cysteine in the formation of domain structures of papain and legumin in peas, involved in limited proteolysis

The limited use of plant proteins for food is explained by their low bioavailability and poor digestibility by enzymes of the gastrointestinal tract. Partially reproduced enzymatic processes of limited proteolysis that occur during seed germination are used to modify and improve the edibility characteristics of seed proteins. The present work discusses the possibility of reducing the duration of seed germination processes by optimising the conditions and parameters of limited proteolysis. To optimise manufacturing high-quality final product, enzymes (additional to the natural enzymes in the seed) and proteolysis conditions (in this case, temperature), as well as added substances (hydrolysis activators), were selected. The influence of cysteine on the formation of domain structures of proteins (enzymes and globulins) was evaluated. The proposed expressions can be used to determine those fragments of protein molecules that form stable domains and become unstructured when exposed to enzymes. Optimal conditions for limited proteolysis were identified based on the physical mechanism of action of papain-like proteolytic enzymes on pea legumin LegA (3KSC, CAA10722). It is shown that the decomposition of protein secondary structures takes 6–8 times longer, since the formed hydrogen bonds limit the access of enzymes to the corresponding amino-acid residues. It is also demonstrated that the decomposition of hydrogen bonds, e.g. by preliminary heat treatment of proteins, will broaden the prospects for limited proteolysis.

Plant-based proteins and their multifaceted industrial applications

Proteins serve as an imperative macronutrient in human nutrition and well-being. Their nutritional quality substantially varies with their digestibility, amino acid profile, bioavailability, processing and purity. From a nutritional viewpoint, the ideal integration of proteins from diverse plant sources can supply an adequate amount of essential amino acids to fulfil human health needs. The use of plant-derived proteins has recently gained momentum due to their multifaceted edible and nonedible applications and their biodegradable nature. The use of plant proteins will be essential when animal-derived proteins fail to satisfy the requirements of the global population. Physicochemical properties, structural properties, amino acid composition and functional attributes of plant-based proteins are of great interest to the food and processing industries. This review presents various applications of plant-based proteins as food supplements in human nutrition, edible coating materials for fruits and vegetables, emulsifiers in numerous food products, sources of bioactive peptides in nutra- and pharmaceutical products, hydrogels in drug delivery and nonedible applications as wood adhesives. Distinct biological properties of proteins obtained from plant sources such as peanuts, soybeans, kidney beans, rice, quinoa, sunflowers, cottonseed, camelina, maize and others are also conceptually discussed based on their diverse applications in human health and nutrition.

Brewery by-products (yeast and spent grain) as protein sources in gilthead seabream (Sparus aurata) feeds

Two trials were conducted to test the effect of partial replacement of fishmeal by two brewery industry by-products, yeast and spent grain, included in isoproteic and isolipidic diets for gilthead sea bream (Sparus aurata), having in mind the commercial availability of these by-products. According to the obtained results, the inclusion of up to 30% brewers' spent yeast and 15% spent grain in the feed for gilthead seabream gave similar results in terms of growth, food conversion and fillet final composition to a feed with fish meal as the main protein source and show a protein digestibility of 89–95%. Taking into account that these by-products are produced in large quantities in Europe, they can be a potential source of protein to reduce the use of plant proteins or fish/animal by-products (trimmings) and increase the sustainability of both sectors, brewery industry and aquaculture.