Eco-innovative technologies for extraction of proteins for human consumption from renewable protein sources of plant origin

Recent progress in plant-based proteins: From extraction and modification methods to applications in the food industry

Plant proteins can meet consumers' demand for healthy and sustainable alternatives to animal proteins. It has been reported to possess numerous health benefits and is widely used in the food industry. However, conventional extraction methods are time-consuming, energy-intensive, as well as environmentally unfriendly. Plant proteins are also limited in application due to off-flavors, allergies, and anti-nutritional factors. Therefore, this paper discusses the challenges and limitations of conventional extraction processes. The current advances in green extraction technologies are also summarized. In addition, methods to improve the nutritional value, bioactivity, functional and organoleptic properties of plant proteins, and strategies to reduce their allergenicity are mentioned. Finally, examples of applications of plant proteins in the food industry are presented. This review aims to stimulate thinking and generate new ideas for future research. It will also provide new ideas and broad perspectives for the application of plant proteins in the food industry.

Unlocking the nutritional and functional potential of legume waste to produce protein ingredients

Worldwide, many production supply chains generate a considerable amount of legume by-products (e.g., leaves, husks, broken seeds, defatted cakes). These wastes can be revalorized to develop sustainable protein ingredients, with positive economic and environmental effects. To separate protein from legume by-products, a broad spectrum of conventional (e.g., alkaline solubilization, isoelectric precipitation, membrane filtration) and novel methodologies (e.g., ultrasound, high-pressure homogenization, enzymatic approaches) have been studied. In this review, these techniques and their efficiency are discussed in detail. The present paper also provides an overview of the nutritional and functional characteristics of proteins extracted from legume by-products. Moreover, existing challenges and limitations associated with the valorization of by-product proteins are highlighted, and future perspectives are proposed.

Physicochemical and functional characteristics of a gourd (Cucurbita argyrosperma Huber) seed protein isolate subjected to high-intensity ultrasound

The impact of high-intensity ultrasound (HIU, 20 kHz) on the physicochemical and functional characteristics of gourd seed protein isolate (GoSPI) was studied. GoSPI was prepared from oil-free gourd seed flour through alkaline extraction (pH 11) and subsequent isoelectric precipitation (pH 4). The crude protein concentration of GoSPI ranged from 91.56 ± 0.17 % to 95.43 ± 0.18 %. Aqueous suspensions of GoSPI (1:3.5 w/v) were ultrasonicated at powers of 200, 400, and 600 W for 15 and 30 min. Glutelins (76.18 ± 0.15 %) were the major protein fraction in GoSPI. HIU decreased the moisture, ash, ether extract, and nitrogen-free extract contents and the hue angle, available water and a* and b* color parameters of the GoSPI in some treatments. The L* color parameter increased (7.70 %) after ultrasonication. HIU reduced the bulk density (52.63 %) and particle diameter (39.45 %), as confirmed by scanning electron microscopy, indicating that ultrasonication dissociated macromolecular aggregates in GoSPI. These structural changes enhanced the oil retention capacity and foam stability by up to 62.60 and 6.84 %, respectively, while the increases in the solvability, water retention capacity, and emulsifying activity index of GoSPI were 90.10, 19.80, and 43.34 %, respectively. The gelation, foaming capacity, and stability index of the emulsion showed no improvement due to HIU. HIU altered the secondary structure of GoSPI by decreasing the content of α-helices (49.66 %) and increasing the content of β-sheets (52.00 %) and β-turns (65.00 %). The electrophoretic profile of the GoSPI was not changed by HIU. The ultrasonicated GoSPI had greater functional attributes than those of the control GoSPI and could therefore be used as a functional food component.

Rice proteins: A review of their extraction, modification techniques and applications

Rice protein is highly nutritious and easy to digest and absorb. Its hydrolyzed peptides have significant effects on lowering blood pressure and cholesterol. First, a detailed and comprehensive explanation of rice protein extraction methods was given, and it was found that the combination of enzymatic and physical methods could improve the extraction rate of rice protein, but it was only suitable for laboratory studies. Second, the methods for improving the functional properties of rice protein were introduced, including physical modification, chemical modification, and enzymatic modification. Enzymatic modification of the solubility of rice protein to improve its functional properties has certain limitations due to the low degree of hydrolysis, the long time required, the low utilization of the enzyme, and the possible undesirable taste of the product. Finally, the development and utilization of rice protein was summarized and the future research direction was suggested. This paper lists the advantages and disadvantages of various extraction techniques, points out the shortcomings of existing extraction techniques, aims to fill the gap in the field of rice protein extraction, and then provides a possible improvement method for the extraction and development of rice protein in the future.

Oilseed meal proteins: From novel extraction methods to nanocarriers of bioactive compounds

The global demand for animal proteins is predicted to increase twofold by 2050. This has led to growing environmental and health apprehensions, thereby prompting the appraisal of alternative protein sources. Oilseed meals present a promising alternative due to their abundance in global production and inherent dietary protein content. The alkaline extraction remains the preferred technique for protein extraction from oilseed meals in commercial processes. However, the combination of innovative techniques has proven to be more effective in the recovery and functional modification of oilseed meal proteins (OMPs), resulting in improved protein quality and reduced allergenicity and environmental hazards. This manuscript explores the extraction of valuable proteins from sustainable sources, specifically by-products from the oil processing industry, using emerging technologies. Chemical structure, nutritional value, and functional properties of the main OMPs are evaluated with a particular focus on their potential application as nanocarriers for bioactive compounds.

Sesame Seeds: A Nutrient-Rich Superfood

Sesame seeds (Sesamum indicum L.) have been cultivated for thousands of years and have long been celebrated for their culinary versatility. Beyond their delightful nutty flavor and crunchy texture, sesame seeds have also gained recognition for their remarkable health benefits. This article provides an in-depth exploration of the numerous ways in which sesame seeds contribute to overall well-being. Sesame seeds are a powerhouse of phytochemicals, including lignans derivatives, tocopherol isomers, phytosterols, and phytates, which have been associated with various health benefits, including the preservation of cardiovascular health and the prevention of cancer, neurodegenerative disorders, and brain dysfunction. These compounds have also been substantiated for their efficacy in cholesterol management. Their potential as a natural source of beneficial plant compounds is presented in detail. The article further explores the positive impact of sesame seeds on reducing the risk of chronic diseases thanks to their rich polyunsaturated fatty acids content. Nevertheless, it is crucial to remember the significance of maintaining a well-rounded diet to achieve the proper balance of n-3 and n-6 polyunsaturated fatty acids, a balance lacking in sesame seed oil. The significance of bioactive polypeptides derived from sesame seeds is also discussed, shedding light on their applications as nutritional supplements, nutraceuticals, and functional ingredients. Recognizing the pivotal role of processing methods on sesame seeds, this review discusses how these methods can influence bioactive compounds. While roasting the seeds enhances the antioxidant properties of the oil extract, certain processing techniques may reduce phenolic compounds.

Biochemical Investigation of Therapeutic Efficacy of Berberine-Enriched Extract in Streptozotocin-Induced Metabolic Impairment

Metabolic disorders pose significant global health challenges, necessitating innovative therapeutic approaches. This study focused on the multifaceted therapeutic potential of berberine-enriched extract (BEE) in mitigating metabolic impairment induced by streptozotocin (STZ) in a rat model and compared the effects of BEE with berberine (BBR) and metformin (MET) to comprehensively evaluate their impact on various biochemical parameters. Our investigation reveals that BEE surpasses the effects of BBR and MET in ameliorating metabolic impairment, making it a promising candidate for managing metabolic disorders. For this, 30 male Wistar rats were divided into five groups (n = 6): control (CN), STZ, STZ + MET, STZ + BBR, and STZ + BEE. The treatment duration was extended over 4 weeks, during which various biochemical parameters were monitored, including fasting blood glucose (FBG), lipid profiles, inflammation, liver and kidney function biomarkers, and gene expressions of various metabolizing enzymes. The induction of metabolic impairment by STZ was evident through an elevated FBG level and disrupted lipid profiles. The enriched extract effectively regulated glucose homeostasis, as evidenced by the restoration of FBG levels, superior to both BBR and MET. Furthermore, BEE demonstrated potent effects on insulin sensitivity, upregulating the key genes involved in carbohydrate metabolism: GCK, IGF-1, and GLUT2. This highlights its potential in enhancing glucose utilization and insulin responsiveness. Dyslipidemia, a common occurrence in metabolic disorders, was effectively managed by BEE. The extract exhibited superior efficacy in regulating lipid profiles. Additionally, BEE exhibited significant anti-inflammatory properties, surpassing the effects of BBR and MET in lowering the levels of inflammatory biomarkers (IL-6 and TNF-α), thereby ameliorating insulin resistance and systemic inflammation. The extract's superior hepatoprotective and nephroprotective effects, indicated by the restoration of liver and kidney function biomarkers, further highlight its potential in maintaining organ health. Moreover, BEE demonstrated potent antioxidant properties, reducing oxidative stress and lipid peroxidation in liver tissue homogenates. Histopathological examination of the pancreas underscored the protective effects of BEE, preserving and recovering pancreatic β-cells damaged by STZ. This collective evidence positions BEE as a promising therapeutic candidate for managing metabolic disorders and offers potential benefits beyond current treatments. In conclusion, our findings emphasize the remarkable therapeutic efficacy of BEE and provide a foundation for further research into its mechanisms, long-term safety, and clinical translation.

Dairy, Plant, and Novel Proteins: Scientific and Technological Aspects

Alternative proteins have gained popularity as consumers look for foods that are healthy, nutritious, and sustainable. Plant proteins, precision fermentation-derived proteins, cell-cultured proteins, algal proteins, and mycoproteins are the major types of alternative proteins that have emerged in recent years. This review addresses the major alternative-protein categories and reviews their definitions, current market statuses, production methods, and regulations in different countries, safety assessments, nutrition statuses, functionalities and applications, and, finally, sensory properties and consumer perception. Knowledge relative to traditional dairy proteins is also addressed. Opportunities and challenges associated with these proteins are also discussed. Future research directions are proposed to better understand these technologies and to develop consumer-acceptable final products.

Does protein deamidation enhance rice protein concentrate's ability to produce and stabilize high internal phase emulsions?

Rice is one of the most consumed grains in the world. Rice protein has great nutritional value as a hypoallergenic protein and due to its high lysine content, a limiting amino acid in several other plant protein sources. However, rice protein has low solubility, hampering its use in many applications in the food industry. In this context, alkaline deamidation (0.5 h, 343 K, and pH 11) was applied to modify the protein structure of rice protein concentrate (RPC). After deamidation, two protein powders were produced: (i) one containing the whole protein fraction recovered after RPC deamidation (DT) and (ii) another containing only the soluble fraction recovered after RPC deamidation (DS). Protein dispersions were characterized by SDS-PAGE, zeta potential, solubility, surface hydrophobicity, and capacity to hold water and oil. RPC could not structure canola oil into a high internal phase emulsion (HIPE) due to its low solubility. DT and DS dispersions displayed solubility much higher than RPC and enabled the structuration of HIPEs with 75 % (w/w) canola oil and 25 % of DT or DS dispersions (2, 4, and 6 % w/w). HIPEs were characterized regarding particle size, microstructure, Turbiscan and oil loss stabilities, and rheological behavior for 60 days. Turbiscan analysis and oil loss measurements showed high stability, and the thixotropy tests showed high recovery in all HIPEs. Higher protein concentrations and DS dispersions produced HIPEs with smaller particle sizes. However, rheological measurements indicate that HIPEs produced with DT dispersions had better results, maintaining their structure over the 60 days. Furthermore, DT is cheaper to produce; therefore, DT 4 and 6 % w/w were the most promising for producing HIPEs. The HIPEs produced in this study displayed great potential as fat replacers.

Alternating current electric field modifies structure and flavor of peanut proteins

The impacts of intensity and treating time of alternating current (AC) electric field (EF) on structure and volatile compounds of peanut protein were investigated for low denaturation. The secondary and tertiary structures, polar and weakly polar volatiles were characterized qualitatively and quantitatively using ultraviolet and fluorescence photospectrometry, free sulfhydryl and disulfide groups determination, and combination of gas chromatography and mass spectrometry. The results showed that the ACEF affected significantly proportions of α-helices, β-sheets, β-turns, and random coils as evidenced by Fourier transform infrared spectrometry. Blue shifts of UV and fluorescence spectra, increased surface hydrophobicity and disulfide bonds could be observed after ACEF treatments. The DB-WAX and DB-5MS columns for the polar and weakly polar volatile compound separation revealed that ACEF caused either disappearance or emerging of volatile compounds. The PCA demonstrated that the two principal components contributed about 70 % or more to the flavor and PLS-DA discriminated 18 key compounds.

Physicochemical and Functional Properties of Moringa Seed Protein Treated with Ultrasound

Functional and structural properties of Moringa protein concentrate (MPC), obtained from defatted Moringa oleifera seed, were investigated after treating it with an ultrasonic technique. For this purpose, dried M. oleifera seed powder was defatted and subjected to a simple protein precipitation method to generate a MPC with 73.2% protein contents. Then, a Box-Behnken design was applied to optimize the sonication treatment of MPC where ultrasound amplitude (20-80%), treatment time (5-25 min), and solute-to-solvent ratio (0.1-0.3 g/mL) were studied as factors that influence the protein solubility (PS), emulsion capacity (EC), and foaming capacity (FC) of MPC. The optimal conditions were amplitude of 58%, time of 18 min, and solute to solvent ratio of 0.18 g/mL. At these conditions, PS, EC, and FC were increased to 42, 33, and 73%, respectively, in comparison to untreated one. The structural modification by ultrasound was further confirmed by using Fourier transform infrared spectroscopy which illustrated the MPC modification through the changes in the peak width of amide-I band. Similarly, the intrinsic fluorescence spectral signature also showed a significant increase in the amino residues of MPC. In conclusion, the exposure of hydrophilic groups and the alteration of secondary and tertiary structures induced by ultrasonic treatment improved the functional characteristics of MPC.

Replacing animal proteins with plant proteins: Is this a way to improve quality and functional properties of hybrid cheeses and cheese analogs?

The growing emphasis on dietary health has facilitated the development of plant-based foods. Plant proteins have excellent functional attributes and health-enhancing effects and are also environmentally conscientious and animal-friendly protein sources on a global scale. The addition of plant proteins (including soy protein, pea protein, zein, nut protein, and gluten protein) to diverse cheese varieties and cheese analogs holds the promise of manufacturing symbiotic products that not only have reduced fat content but also exhibit improved protein diversity and overall quality. In this review, we summarized the utilization and importance of various plant proteins in the production of hybrid cheeses and cheese analogs. Meanwhile, classification and processing methods related to these cheese products were reviewed. Furthermore, the impact of different plant proteins on the microstructure, textural properties, physicochemical attributes, rheological behavior, functional aspects, microbiological aspects, and sensory characteristics of both hybrid cheeses and cheese analogs were discussed and compared. Our study explores the potential for the development of cheeses made from full/semi-plant protein ingredients with greater sustainability and health benefits. Additionally, it further emphasizes the substantial chances for scholars and developers to investigate the optimal processing methods and applications of plant proteins in cheeses, thereby improving the market penetration of plant protein hybrid cheeses and cheese analogs.

Lignin Modification for Enhanced Performance of Polymer Composites

The biopolymer lignin, which is heterogeneous and abundant, is usually present in plant cell walls and gives them rigidity and strength. As a byproduct of the wood, paper, and pulp manufacturing industry, lignin ranks as the second most prevalent biopolymer worldwide, following cellulose. This review paper explores the extraction, modification, and prospective applications of lignin in various industries, including the enhancement of thermosetting and thermoplastic polymers, biomedical applications such as vanillin production, fuel development, carbon fiber composites, and the creation of nanomaterials for food packaging and drug delivery. The structural characteristics of lignin remain undefined due to its origin, separation, and fragmentation processes. This comprehensive overview encompasses state-of-the-art techniques, potential applications, diverse extraction methods, chemical modifications, carbon fiber utilization, and the extraction of vanillin. Moreover, the review focuses on the utilization of lignin-modified polymer blends across multiple manufacturing sectors, providing insights into the advantages and limitations of this innovative approach for the development of environmentally friendly materials.

Plant-Based Meat Proteins: Processing, Nutrition Composition, and Future Prospects

The growing need for plant-based meat alternatives promotes the rapid progress of the food industry. Processing methods employed in plant-based meat production are critical to preserving and enhancing their nutritional content and health benefits, directly impacting consumer acceptance. Unlike animal-based food processing, the efficiency of protein extraction and processing methods plays a crucial role in preserving and enriching the nutritional content and properties. To better understand the factors and mechanisms affecting nutrient composition during plant-based meat processing and identify key processing steps and control points, this work describes methods for extracting proteins from plants and processing techniques for plant-based products. We investigate the role of nutrients and changes in the nutrients during plant protein product processing. This article discusses current challenges and prospects.

Plant-based proteins: advanced extraction technologies, interactions, physicochemical and functional properties, food and related applications, and health benefits

Even though plant proteins are more plentiful and affordable than animal proteins in comparison, direct usage of plant-based proteins (PBPs) is still limited because PBPs are fed to animals as feed to produce animal-based proteins. Thus, this work has comprehensively reviewed the effects of various factors such as pH, temperature, pressure, and ionic strength on PBP properties, as well as describes the protein interactions, and extraction methods to know the optimal conditions for preparing PBP-based products with high functional properties and health benefits. According to the cited studies in the current work, the environmental factors, particularly pH and ionic strength significantly affected on physicochemical and functional properties of PBPs, especially solubility was 76.0% to 83.9% at pH = 2, while at pH = 5.0 reduced from 5.3% to 9.6%, emulsifying ability was the lowest at pH = 5.8 and the highest at pH 8.0, and foaming capacity was lowest at pH 5.0 and the highest at pH = 7.0. Electrostatic interactions are the main way for protein interactions, which can be used to create protein/polysaccharide complexes for food industrial purposes. The extraction yield of proteins can be reached up to 86-95% with high functional properties using sustainable and efficient routes, including enzymatic, ultrasound-, microwave-, pulsed electric field-, and high-pressure-assisted extraction. Nondairy alternative products, especially yogurt, 3D food printing and meat analogs, synthesis of nanoparticles, and bioplastics and packaging films are the best available PBPs-based products. Moreover, PBPs particularly those that contain pigments and their products showed good bioactivities, especially antioxidants, antidiabetic, and antimicrobial.

Polyphenol Extraction from Food (by) Products by Pulsed Electric Field: A Review

Nowadays, more and more researchers engage in studies regarding the extraction of bioactive compounds from natural sources. To this end, plenty of studies have been published on this topic, with the interest in the field growing exponentially. One major aim of such studies is to maximize the extraction yield and, simultaneously, to use procedures that adhere to the principles of green chemistry, as much as possible. It was not until recently that pulsed electric field (PEF) technology has been put to good use to achieve this goal. This new technique exhibits many advantages, compared to other techniques, and they have successfully been reaped for the production of extracts with enhanced concentrations in bioactive compounds. In this advancing field of research, a good understanding of the existing literature is mandatory to develop more advanced concepts in the future. The aim of this review is to provide a thorough discussion of the most important applications of PEF for the enhancement of polyphenols extraction from fresh food products and by-products, as well as to discuss the current limitations and the prospects of the field.

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.

Extraction of protein from apricot kernel oil press cake (AKOPC) through innovative techniques and the formulation of supplemented yogurt

The apricot kernel oil press cake (AKOPC) is a high protein natural by-product of oil mechanical expression with potential uses in cosmetics, medicines, and food. The purpose of this research was to improve the protein extraction process from apricot kernel oil press cake by using enzymatic extraction (EEP), aqueous extraction (AEP), and ultrasound extraction (UEP) process. Protein extraction by AEP was facilitated by a low solid-liquid ratio (SLR) (1:15.97) and prolonged reaction durations (3.30 h), resulting in extraction yields of 68%. When compared to the AEP by similar reaction time, increased enzyme utilization (0.90%) in the EEP resulted in greater protein extraction yields (70%) in a shorter reaction time. In addition to AEP and EEP, ultrasound extraction was also used to improve protein extractability. Temperature (50°C), power density (225 W/L), and extraction duration (20 min) were shown to be the best extraction points. Protein yield was found to be 56.47% at ideal UEP conditions. The experimental values for these reactions were found to be equivalent to the predicted values formed by the mathematical models. When supplementary skimmed milk powder (SMP) was substituted with apricot kernel protein (AKP) in the yogurt manufacturing process, the total solids, average titratable acidity, total protein, and fat contents of the yogurt were increased. In contrast, pH and syneresis values decreased as AKP increased in the resulting yogurt, whether fresh or after 7 days of cold storage. Substitution of additional SMP with AKP in yogurt production might be recommended up to 35%.

Protein Hydrolysate from Underutilized Legumes: Unleashing the Potential for Future Functional Foods

Proteins play a vital role in human development, growth, and overall health. Traditionally, animal-derived proteins were considered the primary source of dietary protein. However, in recent years, there has been a remarkable shift in dietary consumption patterns, with a growing preference for plant-based protein sources. This shift has resulted in a significant increase in the production of plant proteins in the food sector. Consequently, there has been a surge in research exploring various plant sources, particularly wild, and underutilized legumes such as Canavalia, Psophocarpus, Cajanus, Lablab, Phaseolus, and Vigna, due to their exceptional nutraceutical value. This review presents the latest insights into innovative approaches used to extract proteins from underutilized legumes. Furthermore, it highlights the purification of protein hydrolysate using Fast Protein Liquid Chromatography. This review also covers the characterization of purified peptides, including their molecular weight, amino acid composition, and the creation of three-dimensional models based on amino acid sequences. The potential of underutilized legume protein hydrolysates as functional ingredients in the food industry is a key focus of this review. By incorporating these protein sources into food production, we can foster sustainable and healthy practices while minimizing environmental impact. The investigation of underutilized legumes offers exciting possibilities for future research and development in this area, further enhancing the utilization of plant-based protein sources.

Plant Protein Can Be as Efficient as Milk Protein to Maintain Fat Free Mass in Old Rats, Even When Fat and Sugar Intakes Are High

BACKGROUND

Alternative, sustainable, and adequate sources of protein must be found to meet global demand.

OBJECTIVES

Our aim was to assess the effect of a plant protein blend with a good balance of indispensable amino acids and high contents of leucine, arginine, and cysteine on the maintenance of muscle protein mass and function during aging in comparison to milk proteins and to determine if this effect varied according to the quality of the background diet.

METHODS

Old male Wistar rats (n = 96, 18 mo old) were randomly allocated for 4 mo to 1 of 4 diets, differing according to protein source (milk or plant protein blend) and energy content (standard, 3.6 kcal/g, with starch, or high, 4.9 kcal/g, with saturated fat and sucrose). We measured: every 2 mo, body composition and plasma biochemistry; before and after 4 mo, muscle functionality; after 4 mo, in vivo muscle protein synthesis (flooding dose of L-[1-13C]-valine) and muscle, liver, and heart weights. Two-factor ANOVA and repeated measures 2-factor ANOVA were conducted.

RESULTS

There was no difference between protein type on the maintenance during aging of lean body mass, muscle mass, and muscle functionality. The high-energy diet significantly increased body fat (+47%) and heart weight (+8%) compared to the standard energy diet but had no effect on fasting plasma glucose and insulin. Muscle protein synthesis was significantly stimulated by feeding to the same extent in all groups (+13%).

CONCLUSIONS

Since high-energy diets had little impact on insulin sensitivity and related metabolism, we could not test the hypothesis that in situations of higher insulin resistance, our plant protein blend may be better than milk protein. However, this rat study offers significant proof of concept from the nutritional standpoint that appropriately blended plant proteins can have high nutritional value even in demanding situations such as aging protein metabolism.

Technological advances in protein extraction, structure improvement and assembly, digestibility and bioavailability of plant-based foods

Plant-based foods are being considered seriously to replace traditional animal-origin foods for various reasons. It is well known that animals release large amounts of greenhouse gases into the environment during feeding, and eating animal-origin foods may also cause some health problems. Moreover, animal resources will likely be in short supply as the world population grows. It is highly likely that serious health problems ascribed to insufficient protein intake in some areas of the world will occur. Studies have shown that environmentally friendly, abundant, and customizable plant-based foods can be an effective alternative to animal-based foods. However, currently, available plant-based foods lack nutrients unique to animal-based foods. Innovative processing technologies are needed to improve the nutritional value and functionality of plant-based foods and make them acceptable to a wider range of consumers. Therefore, protein extraction technologies (e.g., high-pressure extraction, ultrasound extraction, enzyme extraction, etc.), structure improvement and assembly technologies (3D printing, micro-encapsulation, etc.), and technologies to improve digestibility and utilization of bioactive substances (microbial fermentation, physical, etc.) in the field of plant-based foods processing are reviewed. The challenges of plant-based food processing technologies are summarized. The advanced technologies aim to help the food industry solve production problems using efficient, environmentally friendly, and economical processing technologies and to guide the development of plant-based foods in the future.

Processing effects on the protein quality and functional properties of cold-pressed pumpkin seed meal

Environmental and food security challenges due to a growing world population may be overcome by using alternative protein sources for the human diet. By-products from edible oil processing industries are potential sources due to their high protein content. Pumpkin seed meals were evaluated regarding proximate composition, in vitro protein digestibility (IVPD), amino acid profile and score, and antinutritional factors. Conventional thermal processing, microwave, and ultrasound treatments impact on samples' nutritional quality were assessed using a central composite experimental design. Raw pumpkin seed meal presented up to 45% protein content and 86% IVPD. Processing increased IVPD up to 96%, with optimized conditions of 87.8 °C, pH8.0, and 37 min, for all processes. Lysine was the only limiting amino acid for raw and processed samples. Phytic acid decreased by 31%, while trypsin inhibitory activity was reduced by 84%. Pumpkin seed by-product is a promising high-quality plant protein source for food formulations.

Developing a Clean Labelled Snack Bar Rich in Protein and Fibre with Dry-Fractionated Defatted Durum Wheat Cake

The shift towards a vegetarian, vegan, or flexitarian diet has increased the demand for vegetable protein and plant-based foods. The defatted cake generated during the extraction of lipids from durum wheat (Triticum turgidum L. var. durum) milling by-products is a protein and fibre-containing waste, which could be upcycled as a food ingredient. This study aimed to exploit the dry-fractionated fine fraction of defatted durum wheat cake (DFFF) to formulate a vegan, clean labelled, cereal-based snack bar. The design of experiments (DoEs) for mixtures was applied to formulate a final product with optimal textural and sensorial properties, which contained 10% DFFF, 30% glucose syrup, and a 60% mix of puffed/rolled cereals. The DFFF-enriched snack bar was harder compared to the control without DFFF (cutting stress = 1.2 and 0.52 N/mm², and fracture stress = 12.9 and 9.8 N/mm² in the DFFF-enriched and control snack bar, respectively), due to a densifying effect of DFFF, and showed a more intense yellow hue due to the yellow-brownish colour of DFFF. Another difference was in the caramel flavour, which was more intense in the DFFF-enriched snack bar. The nutritional claims "low fat" and "source of fibre" were applicable to the DFFF-enriched snack bar according to EC Reg. 1924/06.

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.

Cereal bran proteins: recent advances in extraction, properties, and applications

The projected global population is expected to reach around 9.7 billion by 2050, indicating a greater demand for proteins in the human diet. Cereal bran proteins (CBPs) have been identified as high-quality proteins, with potential applications in both the food and pharmaceutical industries. In 2020, global cereal grain production was 2.1 billion metric tonnes, including wheat, rice, corn, millet, barley, and oats. Cereal bran, obtained through milling, made up 10-20% of total cereal grain production, varying by grain type and milling degree. In this article, the molecular composition and nutritional value of CBPs are summarized, and recent advances in their extraction and purification are discussed. The functional properties of CBPs are then reviewed, including their solubility, binding, emulsifying, foaming, gelling, and thermal properties. Finally, current challenges to the application of CBPs in foods are highlighted, such as the presence of antinutritional factors, low digestibility, and allergenicity, as well as potential strategies to improve the nutritional and functional properties by overcoming these challenges. CBPs exhibit nutritional and functional attributes that are similar to those of other widely used plant-based protein sources. Thus, CBPs have considerable potential for use as ingredients in food, pharmaceutical, and other products.

Agro-Industrial Plant Proteins in Electrospun Materials for Biomedical Application

Plant proteins are receiving a lot of attention due to their abundance in nature, customizable properties, biodegradability, biocompatibility, and bioactivity. As a result of global sustainability concerns, the availability of novel plant protein sources is rapidly growing, while the extensively studied ones are derived from byproducts of major agro-industrial crops. Owing to their beneficial properties, a significant effort is being made to investigate plant proteins' application in biomedicine, such as making fibrous materials for wound healing, controlled drug release, and tissue regeneration. Electrospinning technology is a versatile platform for creating nanofibrous materials fabricated from biopolymers that can be modified and functionalized for various purposes. This review focuses on recent advancements and promising directions for further research of an electrospun plant protein-based system. The article highlights examples of zein, soy, and wheat proteins to illustrate their electrospinning feasibility and biomedical potential. Similar assessments with proteins from less-represented plant sources, such as canola, pea, taro, and amaranth, are also described.

Trends and prospects in dairy protein replacement in yogurt and cheese

There is a growing demand for nutritional, functional, and eco-friendly dairy products, which has increased the need for research regarding alternative and sustainable protein sources. Plant-based, single-cell (SCP), and recombinant proteins are being explored as alternatives to dairy proteins. Plant-Based Proteins (PBPs) are commonly used to replace total dairy protein. However, PBPs are generally mixed with dairy proteins to improve their functional properties, which makes them dependent on animal protein sources. In contrast, single-Cell Proteins (SCPs) and recombinant dairy proteins are promising alternatives for dairy protein replacement since they provide nutritional components, essential amino acids, and high protein yield and can use industrial and agricultural waste as carbon sources. Although alternative protein sources offer numerous advantages over conventional dairy proteins, several technical and sensory challenges must be addressed to fully incorporate them into cheese and yogurt products. Future research can focus on improving the functional and sensory properties of alternative protein sources and developing new processing technologies to optimize their use in dairy products. This review highlights the current status of alternative dairy proteins in cheese and yogurt, their functional properties, and the challenges of their use in these products.

Modifications to functional and biological properties of proteins of cowpea pulse crop by ultrasound-assisted extraction

Natural resource depletion, negative environmental effects and the challenge to secure global food security led to the establishment of the Sustainable Development Goals (SDGs). In need to explore underutilized sustainable protein sources, this study aims at isolating protein from cowpea by ultrasound-assisted extraction (UAE), where the techno-functional characteristics of the protein isolates were studied at different sonication conditions i.e., 100 W and 200 W at processing times ranging from 5 to 20 min. The US at 200 W-10 min produced the optimal results for all properties. In this process combination, there was an increase in protein yield, solubility, water-holding capacity, foaming capacity and stability, emulsion activity and stability, zeta-potential, and in-vitro protein digestibility from 31.78% to 58.96%, 57.26% to 68.85%, 3.06 g/g to 3.68 g/g 70.64% to 83.74%, 30.76% to 60.01%, 47.48% to 64.26%, 56.59% to 87.71%, -32.9 mV to -44.2 mV and 88.27% to 89.99%, respectively and particle size dropped from 763 nm to 559 nm in comparison to control. The microstructure and secondary-structure alterations of proteins caused by sonication were validated by SEM images, SDS-PAGE, and FTIR analyses. Sonication leads to acoustic cavitation and penetrate the cell walls, improving extraction from the solid to liquid phase. After sonication, the hydrophobic protein groups were exposed and proteins were partially denatured which increased its functionality. The findings demonstrated that UAE of cowpea protein improved yield, modify characteristics to fit the needs of the food industry, and contribute to achieving SDGs 2, 3, 7, 12, and 13.

Real-Time Immunosensor for Small-Molecule Monitoring in Industrial Food Processes

Industrial food processes are monitored to ensure that food is being produced with good quality, yield, and productivity. For developing innovative real-time monitoring and control strategies, real-time sensors are needed that can continuously report chemical and biochemical data of the manufacturing process. Here, we describe a generalizable methodology to develop affinity-based biosensors for the continuous monitoring of small molecules in industrial food processes. Phage-display antibody fragments were developed for the measurement of small molecules, as exemplified with the measurement of glycoalkaloids (GAs) in potato fruit juice. The recombinant antibodies were selected for use in a competition-based biosensor with single-molecule resolution, called biosensing by particle motion, using assay architectures with free particles as well as tethered particles. The resulting sensor measures GAs in the micromolar range, is reversible, has a measurement response time below 5 min, and enables continuous monitoring of GAs in protein-rich solutions for more than 20 h with concentration measurement errors below 15%. The demonstrated biosensor gives the perspective to enable a variety of monitoring and control strategies based on continuous measurement of small molecules in industrial food processes.

Black Bean Hulls as a Byproduct of an Extraction Process to Enhance Nutraceutical and Glycemic-Related Properties of Nixtamalized Maize Tostadas

Black bean hulls (BBH) are rich in phenolic compounds, such as anthocyanins, which can be incorporated into common staple foods such as maize tostadas, enhancing the nutraceutical properties of these products. This study incorporates black bean hulls to produce nixtamalized maize tostadas with nutraceutical properties. Nixtamalized corn flour (NCF) and black bean hulls (BBH) were characterized in terms of protein, fat, crude and dietary fiber, anthocyanin concentration, and different starch fractions. NCF and BBH depicted 53.7 and 16.8% of total digestible starch (TDS), respectively, and 1.2 and 7.6% of resistant starch (RS), in the same order. BBH was incorporated into nixtamalized flour at 10, 15, and 20% w/w, and the resulting dough was thermo-mechanically characterized. Tostadas with BBH had higher protein, dietary fiber, and anthocyanin concentrations. Enriched tostadas did not show significant changes in texture or other sensory characteristics. However, a reduction in total digestible starch (61.97 up to 59.07%), an increase in resistant starch (0.46 to 2.3% from control tostadas to 20% BBH tostadas), and a reduction in the predicted glycemic index (52 to 49), among other parameters, indicated that BBH is a suitable alternative for developing nutraceutical food products.

Green Biorefinery systems for the production of climate-smart sustainable products from grasses, legumes and green crop residues

Grasses, legumes and green plant wastes represent a ubiquitous feedstock for developing a bioeconomy in regions across Europe. These feedstocks are often an important source of ruminant feed, although much remains unused or underutilised. In addition to proteins, these materials are rich in fibres, sugars, minerals and other components that could also be used as inputs for bio-based product development. Green Biorefinery processes and initiatives are being developed to better capitalise on the potential of these feedstocks to produce sustainable food, feed, materials and energy in an integrated way. Such systems may support a more sustainable primary production sector, enable the valorisation of green waste streams, and provide new business models for farmers. This review presents the current developments in Green Biorefining, focusing on a broad feedstock and product base to include different models of Green Biorefinery. It demonstrates the potential and wide applicability of Green Biorefinery systems, the range of bio-based product opportunities and highlights the way forward for their broader implementation. While the potential for new products is extensive, quality control approval will be required prior to market entry.

Impact of cavitation on the structure and functional quality of extracted protein from food sources - An overview

Increasing protein demands directly require additional resources to those presently and recurrently available. Emerging green technologies have witnessed an escalating interest in "Cavitation Processing" (CP) to ensure a non-invasive, non-ionizing and non-polluting extraction. The main intent of this review is to present an integrated summary of cavitation extraction methods specifically applied to food protein sources. Along with a comparative assessment carried out for each type of cavitation model, protein extraction yield and implications on the extracted protein's structural and functional properties. The basic principle of cavitation is due to the pressure shift in the liquid flow within milliseconds. Hence, cavitation emerges similar to boiling; however, unlike boiling (temperature change), cavitation occurs due to pressure change. Characterization and classification of sample type is also a prime candidate when considering the applications of cavitation models in food processing. Generally, acoustic and hydrodynamic cavitation is applied in food applications including extraction, brewing, microbial cell disruption, dairy processing, emulsification, fermentation, waste processing, crystallisation, mass transfer and production of bioactive peptides. Micro structural studies indicate that shear stress causes disintegration of hydrogen bonds and Van der Waals interactions result in the unfolding of the protein's secondary and/or tertiary structures. A change in the structure is not targeted but rather holistic and affects the physicochemical, functional, and nutritional properties. Cavitation assisted extraction of protein is typically studied at a laboratory scale. This highlights limitations against the application at an industrial scale to obtain potential commercial gains.

Structural and Functional Characteristics of Hemp Protein Isolate–Pullulan Polysaccharide Glycosylation Conjugate in an Aqueous Model System

Hemp protein, with its important nutritional and industrial value, has trickled into the aisles of protein demand; however, its poor functional properties have largely limited its implementation in food. Herein, we aimed to modify hemp protein isolate (HPI) via glycosylation coupling with pullulan polysaccharide, and we subsequently characterized its structural and functional properties. The conjugation variables were HPI to pullulan ratio (i.e., 3:1, 2:1, 1:1, 1:2, and 1:3 w/w), incubation temperature (i.e., 50, 60, 70, 80, and 90 °C), and incubation time (i.e., 3, 6, 12, 24, and 48 h). Native HPI was used as a control for comparison purposes. We found that DG tended to decrease when the pullulan to HPI ratio was greater than 1:1 and when the temperature exceeded 80 °C. SDS-PAGE analysis shows that when the DG is increased, wider and heavier molecular weight bands emerge near the top of the running gel, while such observations were absent in the control. Further, glycosylation could loosen the HPI’s secondary and tertiary structures, as well as increase surface hydrophobicity. The solubility of HPI after glycosylation significantly increased (p < 0.05) at pH 7.0 compared to HPI without glycosylation. Emulsifying activity improved significantly (p < 0.05), with glycosylation with HPI–pullulan at a ratio of 1:3 showing maximum emulsifying activity of 118.78 ± 4.48 m2/g (HPI alone: 32.38 ± 3.65 m2/g). Moreover, the HPI–pullulan glycosylation time of 24 h showed maximum foaming activity (23.04 ± 0.95%) compared to HPI alone (14.20 ± 1.23%). The foaming stability of HPI (79.61 ± 3.33%) increased to 97.78 ± 3.85% when HPI–pullulan was conjugated using a glycosylation temperature of 80 °C. Compared with the un-glycated HPI, HPI–pullulan also increased WHC (4.41 ± 0.73 versus 9.59 ± 0.36 g/g) and OHC (8.48 ± 0.51 versus 13.73 ± 0.59 g/g). Intriguingly, correlation analysis showed that protein functional characteristics were significantly and positively correlated with DG. Overall, our findings support the notion that pullulan conjugation provides further functional attributes to the HPI, thereby broadening its potential implementation in complicated food systems.

Potential Protein Production from Lignocellulosic Materials Using Edible Mushroom Forming Fungi

There is a need for new protein sources to feed the world in a sustainable way. Converting non-food-grade "woody" side streams into food containing proteins will contribute to this mission. Mushroom forming fungi are unique in their capability to convert lignocellulosic substances into edible biomass containing protein. Especially if substrate mycelium can be used instead of mushrooms, this technology could be a serious contribution to addressing the protein challenge. In this Perspective, we discuss challenges toward production, purification, and market introduction of mushroom mycelium based foods.

Improved Field-Based Soybean Seed Counting and Localization with Feature Level Considered

Developing automated soybean seed counting tools will help automate yield prediction before harvesting and improving selection efficiency in breeding programs. An integrated approach for counting and localization is ideal for subsequent analysis. The traditional method of object counting is labor-intensive and error-prone and has low localization accuracy. To quantify soybean seed directly rather than sequentially, we propose a P2PNet-Soy method. Several strategies were considered to adjust the architecture and subsequent postprocessing to maximize model performance in seed counting and localization. First, unsupervised clustering was applied to merge closely located overcounts. Second, low-level features were included with high-level features to provide more information. Third, atrous convolution with different kernel sizes was applied to low- and high-level features to extract scale-invariant features to factor in soybean size variation. Fourth, channel and spatial attention effectively separated the foreground and background for easier soybean seed counting and localization. At last, the input image was added to these extracted features to improve model performance. Using 24 soybean accessions as experimental materials, we trained the model on field images of individual soybean plants obtained from one side and tested them on images obtained from the opposite side, with all the above strategies. The superiority of the proposed P2PNet-Soy in soybean seed counting and localization over the original P2PNet was confirmed by a reduction in the value of the mean absolute error, from 105.55 to 12.94. Furthermore, the trained model worked effectively on images obtained directly from the field without background interference.

Emerging plant proteins as nanocarriers of bioactive compounds

The high prevalence of chronic illnesses, including cancer, diabetes, obesity, and cardiovascular diseases has become a growing concern for modern society. Recently, various bioactive compounds (bioactives) are shown to have a diversity of health-beneficial impacts on a wide range of disorders. But the application of these bioactives in food and pharmaceutical formulations is limited due to their poor water solubility and low bioaccessibility/bioavailability. Plant proteins are green alternatives for designing biopolymeric nanoparticles as appropriate nanocarriers thanks to their amphiphilic nature compatible with many bioactives and unique functional properties. Recently, emerging plant proteins (EPPs) are employed as nanocarriers for protection and targeted delivery of bioactives and also improving their stability and shelf-life. EPPs could enhance the solubility, stability, and bioavailability of bioactives by different types of delivery systems. In addition, the use of EPPs in combination with other biopolymers like polysaccharides was found to make a favorable wall material for food bioactives. This review article covers the various sources and importance of EPPs along with different encapsulation techniques of bioactives. Characterization of EPPs for encapsulation is also investigated. Furthermore, the focus is on the application of EPPs as nanocarriers for food bioactives.

Functional Proteins from Biovalorization of Peanut Meal: Advances in Process Technology and Applications

Environmental costs associated with meat production have necessitated researchers and food manufacturers to explore alternative sources of high-quality protein, especially from plant origin. Proteins from peanuts and peanut-by products are high-quality, matching industrial standards and nutritional requirements. This review contributes to recent developments in the production of proteins from peanut and peanut meal. Conventional processing techniques such as hot-pressing kernels, use of solvents in oil removal, and employing harsh acids and alkalis denature the protein and damage its functional properties, limiting its use in food formulations. Controlled hydrolysis (degree of hydrolysis between 1 and 10%) using neutral and alkaline proteases can extract proteins and improve peanut proteins' functional properties, including solubility, emulsification, and foaming activity. Peanut proteins can potentially be incorporated into meat analogues, bread, soups, confectionery, frozen desserts, and cakes. Recently, pretreatment techniques (microwave, ultrasound, high pressure, and atmospheric cold plasma) have been explored to enhance protein extraction and improve protein functionalities. However, most of the literature on physicochemical pretreatment techniques has been limited to the lab scale and has not been analysed at the pilot scale. Peanut-derived peptides also exhibit antioxidant, anti-hypertensive, and anti-thrombotic properties. There exists a potential to incorporate these peptides into high-fat foods to retard oxidation. These peptides can also be consumed as dietary supplements for regulating blood pressure. Further research is required to analyse the sensory attributes and shelf lives of these novel products. In addition, animal models or clinical trials need to be conducted to validate these results on a larger scale.

Control of Beany Flavor from Soybean Protein Raw Material in Plant-Based Meat Analog Processing

The development of plant-based meat analogs is currently hindered by the beany flavor generated by raw soybean protein and extrusion processing. Wide concern has led to extensive research on the generation and control of this unwanted flavor, as an understanding of its formation in raw protein and extrusion processing and methods through which to control its retention and release are of great significance for obtaining ideal flavor and maximizing food quality. This study examines the formation of beany flavor during extrusion processing as well as the influence of interaction between soybean protein and beany flavor compounds on the retention and release of the undesirable flavor. This paper discusses ways to maximize control over the formation of beany flavor during the drying and storage of raw materials and methods to reduce beany flavor in products by adjusting extrusion parameters. The degree of interaction between soybean protein and beany compounds was found to be dependent on conditions such as heat treatment and ultrasonic treatment. Finally, future research directions are proposed and prospected. This paper thus provides a reference for the control of beany flavor during the processing, storage, and extrusion of soybean raw materials used in the fast-growing plant-based meat analog industry.

Pulse Globulins 11S and 7S: Origins, Purification Methods, and Techno-functional Properties

A growing interest in pulse proteins in recent years results from their crucial role in the transition toward sustainable food systems. Consequently, current research is mainly focused on the production of protein ingredients and the evaluation of their nutritional and techno-functional properties for the development of animal product analogues. However, the individual impacts of the major proteins 11S legumin and 7S vicilin on pulse techno-functionalities remains unclear. Thus, this review aims to represent current knowledge on pulse 11S and 7S globulin origins, extraction, separation, and purification methods as well as their techno-functionalities. This paper also discusses the principal challenges related to pulse vicilin and legumin purification methods, such as efficiency and environmental concerns, as well as 11S/7S ratio variability. This review highlights the fact that 11S and 7S fractions serve different purposes in pulse functionality and that more efficient and eco-friendly purification techniques are required to properly assess their respective functional attributes. Such research would allow the determination of optimal 11S/7S ratios for the integration of pulse protein ingredients in various food formulations. Hence, food industries would be able to select species/varieties, agronomical methods, and processing methods to produce ingredients with suitable 11S/7S ratios, catering to consumers' ethical, environmental, and nutritional concerns.

Cold-Pressed Oilseed Cakes as Alternative and Sustainable Feed Ingredients: A Review

Due to the increasing demand for alternative protein feed ingredients, the utilization of oilseed by-products in animal nutrition has been sought as a promising solution to ensure cheap and environmentally sustainable feedstuffs. This review aimed to summarize the nutritional value of six cold-pressed cakes (rapeseed, hempseed, linseed, sunflower seed, camelina seed, and pumpkin seed) and the effects of their inclusion in diet for ruminant, pig, and poultry on nutrient digestibility, growth and productive performance, and quality of the products. The presented results indicated that these unconventional feed ingredients are a good protein and lipid source and have a balanced amino acid and fatty acid profile. However, contradictory results of animal production performances can be found in the literature depending on the cake type and chemical composition, dietary inclusion level, animal category, and trial duration. Due to the substantial amount of essential fatty acid, these cakes can be efficiently used in the production of animal products rich in n-3 and n-6 polyunsaturated fatty acids. However, the utilization of cakes in pig and poultry nutrition is limited because of the presence of antinutritive factors that can deteriorate feed intake and nutrient utilization.

Nutritional Quality of Plant-Based Meat and Dairy Imitation Products and Comparison with Animal-Based Counterparts

While consumers are increasingly adopting plant-based meat and dairy imitation products, the nutritional quality and adequacy of those foods to act as a substitute is still under discussion. The Greek Branded Food Composition Database (HelTH) was expanded to map currently available meat and dairy imitations in Greece. Their main ingredient used, nutritional composition, and promotion as a healthy, nutritious food were described, and their overall nutritional quality using the Nutri-Score algorithm was evaluated. A total of n = 421 plant-based imitations were analyzed, made primarily of wheat or wheat mixes (83.5%) for meat imitations and grain (19.8%) or vegetable oil (17.1%) for dairy imitations. All meat imitations were high in protein and fiber, while, for dairy, only yogurts carried a protein content claim (80.9%). Imitation sausages, milk, and yogurt products had lower total fat and saturated fat content compared to their animal-based counterparts. All dairy imitations had lower protein content than animal-based dairy. The nutritional quality of imitation cheeses was graded as D-E, under the Nutri-Score system, compared to A-C for the animal-based cheese. Plant-based imitations have variable composition based on their main ingredient, and the substitution of specific food groups with plant-based alternatives may not support an equivalent or improved diet.

Optimization of Grinding Process of Sunflower Meal for Obtaining Protein-Enriched Fractions

In this study, dry fractionation process was proposed in order to obtain protein-enriched sunflower meal fractions. The process includes two-stage grinding using a hammer mill and a roll mill, and fractionation of sunflower meal by sieving. Central composite design (CCD) with four variables on three levels within response surface methodology was applied in order to estimate the influence of grinding parameters (sieve openings diameter of the hammer mill: 2, 4, and 6 mm, roll gap: 0.15, 0.2, and 0.25 mm, feed rate: 0.1, 0.175, and 0.25 kg/cm min, and roll speed: 400, 500, and 600 rpm) on responses (protein content, fraction yield and grinding energy consumption). Sieve openings diameter expressed the highest impact on fraction yield while roll gap expressed the most dominant influence on protein content in the fraction and grinding energy consumption. The highest protein content obtained was 48.06%(dm) with fraction yield of 77.22%. A multi-response optimization procedure was performed and optimal values were: sieve openings diameter of 2 mm, roll gap of 0.25 mm, feed rate of 0.2 kg/cm min, and roll speed of 400 rpm, while predicted values for a desired range of responses were: protein content 45.5%(dm), fraction yield 77.89%, and grinding energy consumption 8.31 Wh/kg.

Legume Protein Extracts: The Relevance of Physical Processing in the Context of Structural, Techno-Functional and Nutritional Aspects of Food Development

Legumes are sustainable protein-rich crops with numerous industrial food applications, which give them the potential of a functional food ingredient. Legume proteins have appreciable techno-functional properties (e.g., emulsification, foaming, water absorption), which could be affected along with its digestibility during processing. Extraction and isolation of legumes’ protein content makes their use more efficient; however, exposure to the conditions of further use (such as temperature and pressure) results in, and significantly increases, changes in the structural, and therefore functional and nutritional, properties. The present review focuses on the quality of legume protein concentrates and their changes under the influence of different physical processing treatments and highlights the effect of processing techniques on the structural, functional, and some of the nutritional, properties of legume proteins.

Impact of ultrasound processing on alternative protein systems: Protein extraction, nutritional effects and associated challenges

Proteins from alternative sources including terrestrial and aquatic plants, microbes and insects are being increasingly explored to combat the dietary, environmental and ethical challenges linked primarily to conventional sources of protein, mainly meat and dairy proteins. Ultrasound (US) technologies have emerged as a clean, green and efficient methods for the extraction of proteins from alternative sources compared to conventional methods. However, the application of US can also lead to modifications of the proteins extracted from alternative sources, including changes in their nutritional quality (protein content, amino acid composition, protein digestibility, anti-nutritional factors) and allergenicity, as well as damage of the compounds associated with an increased degradation resulting from extreme US processing conditions. This work aims to summarise the main advances in US equipment currently available to date, including the main US parameters and their effects on the extraction of protein from alternative sources, as well as the studies available on the effects of US processing on the nutritional value, allergenicity and degradation damage of these alternative protein ingredients. The main research gaps identified in this work and future challenges associated to the widespread application of US and their scale-up to industry operations are also covered in detail.