Nutritional evaluation of rapeseed protein compared to soy protein for quality, plasma amino acids, and nitrogen balance--a randomized cross-over intervention study in humans

Exploring the Nutritional Potential and Functionality of Hemp and Rapeseed Proteins: A Review on Unveiling Anti-Nutritional Factors, Bioactive Compounds, and Functional Attributes

Plant-based proteins, like those derived from hemp and rapeseed can contribute significantly to a balanced diet and meet human daily nutritional requirements by providing essential nutrients such as protein, fiber, vitamins, minerals, and antioxidants. According to numerous recent research papers, the consumption of plant-based proteins has been associated with numerous health benefits, including a reduced risk of chronic diseases such as heart disease, diabetes, and certain cancers. Plant-based diets are often lower in saturated fat and cholesterol and higher in fiber and phytonutrients, which can support overall health and well-being. Present research investigates the nutritional attributes, functional properties, and potential food applications of hemp and rapeseed protein for a potential use in new food-product development, with a certain focus on identifying anti-nutritional factors and bioactive compounds. Through comprehensive analysis, anti-nutritional factors and bioactive compounds were elucidated, shedding light on their impact on protein quality and digestibility. The study also delves into the functional properties of hemp and rapeseed protein, unveiling their versatility in various food applications. Insights from this research contribute to a deeper understanding of the nutritional value and functional potential of hemp and rapeseed protein, paving the way for their further utilization in innovative food products with enhanced nutritional value and notable health benefits.

A Review of the Utilization of Canola Protein as an Emulsifier in the Development of Food Emulsions

Canola is the second-largest cultivated oilseed crop in the world and produces meal consisting of about 35-40% proteins. Despite this, less than 1% of the global plant-based protein market is taken up by canola protein. The reason behind such underutilization of canola protein and its rapeseed counterpart could be the harsh conditions of the industrial oil extraction process, the dark colour of the meal, the presence of various antinutrients, the variability in the protein composition based on the source, and the different properties of the two major protein components. Although academic research has shown immense potential for the use of canola protein and its rapeseed counterpart in emulsion development and stabilization, there is still a vast knowledge gap in efficiently utilizing canola proteins as an effective emulsifier in the development of various emulsion-based foods and beverages. In this context, this review paper summarizes the last 15 years of research on canola and rapeseed proteins as food emulsifiers. It discusses the protein extraction methods, modifications made to improve emulsification, emulsion composition, preparation protocols, and emulsion stability results. The need for further improvement in the scope of the research and reducing the knowledge gap is also highlighted, which could be useful for the food industry to rationally select canola proteins and optimize the processing parameters to obtain products with desirable attributes.

Effect of heat treatment on protein quality of rapeseed protein isolate compared with non-heated rapeseed isolate, soy and whey protein isolates, and rice and pea protein concentrates

BACKGROUND

Rapeseed protein isolate is used in the food industry, and heating is often used during rapeseed processing. However, the digestible indispensable amino acid score (DIAAS) for heat-treated rapeseed protein isolate is unknown. The present study aimed to test the hypothesis that heating rapeseed protein isolate improves protein quality resulting in DIAAS that is greater than for pea and rice protein concentrates, and comparable to that of soy and whey protein isolates.

RESULTS

Standardized ileal digestibility (SID) of amino acids (AA), except leucine and methionine, was not different between heat-treated rapeseed protein isolate and soy protein isolate, but SID of most AA was greater (P < 0.001) for heat-treated rapeseed protein isolate than for brown rice protein concentrate, pea protein concentrate, rapeseed protein isolate and soy protein isolate, but not whey protein isolate. Non-heated rapeseed protein isolate had a reduced (P < 0.001) DIAAS for 6-month-old to 3-year-old children compared with soy protein isolate, but this was greater (P < 0.001) than for pea and brown rice protein concentrates. The DIAAS for heat-treated rapeseed protein isolate was greater (P < 0.001) than for non-heated rapeseed protein isolate for all age groups. Heat-treated rapeseed protein isolate and whey protein isolate had a DIAAS > 100 for individuals older than 3 years.

CONCLUSION

Rapeseed protein isolate had a DIAAS comparable to soy protein isolate, but heat-treated rapeseed protein isolate and whey protein isolate had DIAAS ≥ 100, qualifying these proteins as 'excellent'. Rice and pea protein concentrates had DIAAS < 75. © 2023 Society of Chemical Industry.

Use of titanium dioxide doped multi-wall carbon nanotubes as promoter for the growth, biochemical indices of Sesamum indicum L. under heat stress conditions

The behavior of multi-walled carbon nanotubes (MWCNTs) and titanium dioxide nanoparticles (TiO2 NPs) as plant growth enhancers was still unclear; however, in this study, the effects of MWCNTs, TiO2NPs, 5%TiO2@MWCNTs, 10%TiO2@MWCNTs and 15%TiO2@MWCNTs on physical and biochemical contents in Sesamum indicum L. under heat stress conditions were studied. The content of malondialdehyde (MDA) and hydrogen peroxide (H2O2) concentrations were reduced by the spraying MWCNTs and TiO2 NPs on plants. The hydrogen peroxide (H2O2) content was reduced by 49.02% in plants treated with 15%TiO2@MWCNTs while 42.14% reduction was found in plants treated with 10%TiO2@MWCNTs. The proportion of oil and the peroxidase enzyme activity in plants treated with 15%TiO2@MWCNTs were increased by 48.99%, for the oil content, and 2.39 times for POD activity respected to the stressed plants. The proportion of unsaturated fatty acids increased in plants treated with 15%TiO2@MWCNTs, 10%TiO2@MWCNTs and TiO2 NPs by 2.7, 2.52, and 2.09 times, respectively, greater than the control of the Shandweel-3 variety. Finally, plants treated with 15%TiO2@MWCNTs showed increases in seed yield and weight 1000-seeds by 4.42 and 1.67 times, respectively. These findings suggest that TiO2@MWCNTs more effective than separated MWCNTs and TiO2 NPs in improve plant growth. In addition, the cultivar Shandweel-3 showed an improvement in growth indicators more than the Giza-32 cultivar.

The Protein Composition and In Vitro Digestive Characteristics of Animal- versus Plant-Based Infant Nutritional Products

The protein composition and digestive characteristics of four commercially available infant formulae (IF) manufactured using bovine (B-IF), caprine (C-IF), soy (S-IF), and rice (R-IF) as a protein source were examined in this study. Plant-based formulae had significantly higher crude protein and non-protein nitrogen (NPN) concentrations. Static in vitro gastrointestinal digestion of these formulae, and subsequent analysis of their digestates, revealed significantly higher proteolysis of B-IF at the end of gastrointestinal digestion compared to the other formulae, as indicated by the significantly higher concentration of free amine groups. Furthermore, differences in structure formation during the gastric phase of digestion were observed, with formation of a more continuous, firmer coagulum by C-IF, while R-IF demonstrated no curd formation likely due to the extensive hydrolysis of these proteins during manufacture. Differences in digestive characteristics between formulae manufactured from these different protein sources may influence the bio-accessibility and bioavailability of nutrients, warranting additional study.

Impact of Metal Nanoparticles on the Phytochemical and Antioxidative Properties of Rapeseed Oil

The agricultural uses of nanoparticles continue to be considered as innovative methods that require more in-depth research into their impact on product quality. In our study, we investigated the effects of fertilizers containing metal nanoparticles (silver AgNPs and copper CuNPs) during the plant growth stage of winter rape cultivation, and in most experimental variants, with the exception of the (x2) application of AgNPs, we observed a decrease in the mass of one thousand seeds (MTS). The obtained result was 11.55% higher relative to the control sample in 2019, and also increased after the (x1) 4.36% and (x2) 11.11% application of CuNPS in 2020. The analyzed oxidative stability of the oil increased in both experimental years (2019-2020), with the highest values recorded after the (x1) and (x2) application of CuNPS-4.94% and 8.31%, respectively, in the first year of cultivation, and after the (x2) application of CuNPS-12.07% in the subsequent year. It was also observed that the content of polyphenols, flavonoids, squalene, tocopherols α and δ, chlorophylls, and carotenoids increased in the oil. Moreover, spectral FTIR analysis was performed on the oil samples obtained from cultivations sprayed with solutions containing Ag or Cu nanoparticles and revealed changes in several spectral regions with the maxima at ~1740, 1370, 1230, and ~1090 cm^-1. Additionally, a FTIR analysis conducted in combination with multivariate analysis allowed us to classify the studied oils into the most similar groups and to study the structure of data variability. The conducted analyses revealed that the use of nanoparticles resulted in decreased size of the produced seeds and improved antioxidative properties of rapeseed oil.

Protein quality of soy and the effect of processing: A quantitative review

There is a growing demand for plant-based protein-rich products for human consumption. During the production of plant-based protein-rich products, ingredients such as soy generally undergo several processing methods. However, little is known on the effect of processing methods on protein nutritional quality. To gain a better understanding of the effect of processing on the protein quality of soy, we performed a quantitative review of in-vivo and in-vitro studies that assessed the indispensable amino acid (IAA) composition and digestibility of varying soy products, to obtain digestibility indispensable amino acids scores (DIAAS) and protein digestibility corrected amino acid scores (PDCAAS). For all soy products combined, mean DIAAS was 84.5 ± 11.4 and mean PDCAAS was 85.6 ± 18.2. Data analyses showed different protein quality scores between soy product groups. DIAAS increased from tofu, soy flakes, soy hulls, soy flour, soy protein isolate, soybean, soybean meal, soy protein concentrate to soymilk with the highest DIAAS. In addition, we observed broad variations in protein quality scores within soy product groups, indicating that differences and variations in protein quality scores may also be attributed to various forms of post-processing (such as additional heat-treatment or moisture conditions), as well as study conditions. After excluding post-processed data points, for all soy products combined, mean DIAAS was 86.0 ± 10.8 and mean PDCAAS was 92.4 ± 11.9. This study confirms that the majority of soy products have high protein quality scores and we demonstrated that processing and post-processing conditions can increase or decrease protein quality. Additional experimental studies are needed to quantify to which extent processing and post-processing impact protein quality of plant-based protein-rich products relevant for human consumption.

Genomic Regions Associated With Seed Meal Quality Traits in Brassica napus Germplasm

The defatted Brassica napus (rapeseed) meal can be high-protein feed for livestock as the protein value of rapeseed meal is higher than that of the majority of other vegetable proteins. Extensive work has already been carried out on developing canola rapeseed where the focus was on reducing erucic acid and glucosinolate content, with less consideration to other antinutritional factors such as tannin, phytate, sinapine, crude fiber, etc. The presence of these antinutrients limits the use and marketing of rapeseed meals and a significant amount of it goes unused and ends up as waste. We investigated the genetic architecture of crude protein, methionine, tryptophan, total phenols, β-carotene, glucosinolates (GLSs), phytate, tannins, sinapine, and crude fiber content of defatted seed meal samples by conducting a genome-wide association study (GWAS), using a diversity panel comprising 96 B. napus genotypes. Genotyping by sequencing was used to identify 77,889 SNPs, spread over 19 chromosomes. Genetic diversity and phenotypic variations were generally high for the studied traits. A total of eleven genotypes were identified which showed high-quality protein, high antioxidants, and lower amount of antinutrients. A significant negative correlation between protein and limiting amino acids and a significant positive correlation between GLS and phytic acid were observed. General and mixed linear models were used to estimate the association between the SNP markers and the seed quality traits and quantile-quantile (QQ) plots were generated to allow the best-fit algorithm. Annotation of genomic regions around associated SNPs helped to predict various trait-related candidates such as ASP2 and EMB1027 (amino acid biosynthesis); HEMA2, GLU1, and PGM (tryptophan biosynthesis); MS3, CYSD1, and MTO1 (methionine biosynthesis); LYC (β-carotene biosynthesis); HDR and ISPF (MEP pathway); COS1 (riboflavin synthesis); UGT (phenolics biosynthesis); NAC073 (cellulose and hemicellulose biosynthesis); CYT1 (cellulose biosynthesis); BGLU45 and BGLU46 (lignin biosynthesis); SOT12 and UGT88A1 (flavonoid pathway); and CYP79A2, DIN2, and GSTT2 (GLS metabolism), etc. The functional validation of these candidate genes could confirm key seed meal quality genes for germplasm enhancement programs directed at improving protein quality and reducing the antinutritional components in B. napus.

Mapping‑by‑Sequencing Reveals Genomic Regions Associated with Seed Quality Parameters in Brassica napus

Rapeseed (Brassica napus L.) is an important oil crop and has the potential to serve as a highly productive source of protein. This protein exhibits an excellent amino acid composition and has high nutritional value for humans. Seed protein content (SPC) and seed oil content (SOC) are two complex quantitative and polygenic traits which are negatively correlated and assumed to be controlled by additive and epistatic effects. A reduction in seed glucosinolate (GSL) content is desired as GSLs cause a stringent and bitter taste. The goal here was the identification of genomic intervals relevant for seed GSL content and SPC/SOC. Mapping by sequencing (MBS) revealed 30 and 15 new and known genomic intervals associated with seed GSL content and SPC/SOC, respectively. Within these intervals, we identified known but also so far unknown putatively causal genes and sequence variants. A 4 bp insertion in the MYB28 homolog on C09 shows a significant association with a reduction in seed GSL content. This study provides insights into the genetic architecture and potential mechanisms underlying seed quality traits, which will enhance future breeding approaches in B. napus.

Extraction, nutrition, functionality and commercial applications of canola proteins as an underutilized plant protein source for human nutrition

Concerns about sustainability and nutrition security have encouraged the food sector to replace animal proteins in food formulations with underutilized plant protein sources and their co-products. In this scenario, canola protein-rich materials produced after oil extraction, including canola cold-pressed cakes and meals, offer an excellent opportunity, considering their nutritional advantages such as a well-balanced amino acid composition and their potential bioactivity. However, radical differences among major proteins (i.e., cruciferin and napin) in terms of the physicochemical properties, and the presence of a wide array of antinutritional factors in canola, impede the production of a highly pure protein extract with a reasonable extraction yield. In this manuscript, principles regarding the extraction methods applicable for the production of canola protein concentrates and isolates are explored in detail. Alkaline and salt extraction methods are presented as the primary isolation methods, which result in cruciferin-rich and napin-rich isolates with different nutritional and functional properties. Since a harsh alkaline condition would result in an inferior functionality in protein isolates, strategies are recommended to reduce the required solvent alkalinity, including using a combination of salt and alkaline and employing membrane technologies, application of proteases and carbohydrases to facilitate the protein solubilization from biomass, and novel green physical methods, such as ultrasound and microwave treatments. In terms of the commercialization progress, several canola protein products have received a GRAS notification so far, which facilitates their incorporation in food formulations, such as bakery, beverages, salad dressings, meat products and meat analogues, and dairies.

Effect of Fractionation and Processing Conditions on the Digestibility of Plant Proteins as Food Ingredients

Plant protein concentrates and isolates are used to produce alternatives to meat, dairy and eggs. Fractionation of ingredients and subsequent processing into food products modify the techno-functional and nutritional properties of proteins. The differences in composition and structure of plant proteins, in addition to the wide range of processing steps and conditions, can have ambivalent effects on protein digestibility. The objective of this review is to assess the current knowledge on the effect of processing of plant protein-rich ingredients on their digestibility. We obtained data on various fractionation conditions and processing after fractionation, including enzymatic hydrolysis, alkaline treatment, heating, high pressure, fermentation, complexation, extrusion, gelation, as well as oxidation and interactions with starch or fibre. We provide an overview of the effect of some processing steps for protein-rich ingredients from different crops, such as soybean, yellow pea, and lentil, among others. Some studies explored the effect of processing on the presence of antinutritional factors. A certain degree, and type, of processing can improve protein digestibility, while more extensive processing can be detrimental. We argue that processing, protein bioavailability and the digestibility of plant-based foods must be addressed in combination to truly improve the sustainability of the current food system.

How Healthy Are Non-Traditional Dietary Proteins? The Effect of Diverse Protein Foods on Biomarkers of Human Health

Future food security for healthy populations requires the development of safe, sustainably-produced protein foods to complement traditional dietary protein sources. To meet this need, a broad range of non-traditional protein foods are under active investigation. The aim of this review was to evaluate their potential effects on human health and to identify knowledge gaps, potential risks, and research opportunities. Non-traditional protein sources included are algae, cereals/grains, fresh fruit and vegetables, insects, mycoprotein, nuts, oil seeds, and legumes. Human, animal, and in vitro data suggest that non-traditional protein foods have compelling beneficial effects on human health, complementing traditional proteins (meat/poultry, soy, eggs, dairy). Improvements in cardiovascular health, lipid metabolism, muscle synthesis, and glycaemic control were the most frequently reported improvements in health-related endpoints. The mechanisms of benefit may arise from their diverse range of minerals, macro- and micronutrients, dietary fibre, and bioactive factors. Many were also reported to have anti-inflammatory, antihypertensive, and antioxidant activity. Across all protein sources examined, there is a strong need for quality human data from randomized controlled intervention studies. Opportunity lies in further understanding the potential effects of non-traditional proteins on the gut microbiome, immunity, inflammatory conditions, DNA damage, cognition, and cellular ageing. Safety, sustainability, and evidence-based health research will be vital to the development of high-quality complementary protein foods that enhance human health at all life stages.

Sustaining Protein Nutrition Through Plant-Based Foods

Proteins are essential components of the human diet. Dietary proteins could be derived from animals and plants. Animal protein, although higher in demand, is generally considered less environmentally sustainable. Therefore, a gradual transition from animal- to plant-based protein food may be desirable to maintain environmental stability, ethical reasons, food affordability, greater food safety, fulfilling higher consumer demand, and combating of protein-energy malnutrition. Due to these reasons, plant-based proteins are steadily gaining popularity, and this upward trend is expected to continue for the next few decades. Plant proteins are a good source of many essential amino acids, vital macronutrients, and are sufficient to achieve complete protein nutrition. The main goal of this review is to provide an overview of plant-based protein that helps sustain a better life for humans and the nutritional quality of plant proteins. Therefore, the present review comprehensively explores the nutritional quality of the plant proteins, their cost-effective extraction and processing technologies, impacts on nutrition, different food wastes as an alternative source of plant protein, and their environmental impact. Furthermore, it focuses on the emerging technologies for improving plant proteins' bioavailability, digestibility, and organoleptic properties, and highlights the aforementioned technological challenges for future research work.

Breeding Canola (Brassica napus L.) for Protein in Feed and Food

Interest in canola (Brassica napus L.). In response to this interest, scientists have been tasked with altering and optimizing the protein production chain to ensure canola proteins are safe for consumption and economical to produce. Specifically, the role of plant breeders in developing suitable varieties with the necessary protein profiles is crucial to this interdisciplinary endeavour. In this article, we aim to provide an overarching review of the canola protein chain from the perspective of a plant breeder, spanning from the genetic regulation of seed storage proteins in the crop to advancements of novel breeding technologies and their application in improving protein quality in canola. A review on the current uses of canola meal in animal husbandry is presented to underscore potential limitations for the consumption of canola meal in mammals. General discussions on the allergenic potential of canola proteins and the regulation of novel food products are provided to highlight some of the challenges that will be encountered on the road to commercialization and general acceptance of canola protein as a dietary protein source.

Development and Characterization of Extrudates Based on Rapeseed and Pea Protein Blends Using High-Moisture Extrusion Cooking

Rapeseed protein is not currently utilized for food applications, although it has excellent physicochemical, functional, and nutritional properties similar to soy protein. Thus, the goal of this study was to create new plant-based extrudates for application as high-moisture meat analogs from a 50:50 blend of rapeseed protein concentrate (RPC) and yellow pea isolate (YPI) using high-moisture-extrusion (HME) cooking with a twin-screw extruder to gain a better understanding of the properties of the protein powders and resulting extrudates. The effects of extrusion processing parameters such as moisture content (60%, 63%, 65%, 70%), screw speed (500, 700, and 900 rpm), and a barrel temperature profile of 40-80-130-150 °C on the extrudates' characteristics were studied. When compared to the effect of varying screw speeds, targeted moisture content had a larger impact on textural characteristics. The extrudates had a greater hardness at the same moisture content when the screw speed was reduced. The specific mechanical energy (SME) increased as the screw speed increased, while increased moisture content resulted in a small reduction in SME. The lightness (L*) of most samples was found to increase as the target moisture content increased from 60% to 70%. The RPC:YPI blend was equivalent to proteins produced from other sources and comparable to the FAO/WHO standard requirements.

The effect of milk and rapeseed protein on growth factors in 7-8 year-old healthy children - A randomized controlled trial

OBJECTIVE

Milk protein may stimulate linear growth through insulin-like growth factor-1 (IGF-1). However, the effect of plant proteins on growth factors is largely unknown. This study assesses the effect of combinations of milk and rapeseed protein versus milk protein alone on growth factors in children.

DESIGN

An exploratory 3-armed randomized, double-blind, controlled trial was conducted in 129 healthy 7-8 year-old Danish children. Children received 35 g milk and rapeseed protein (ratio 54:46 or 30:70) or 35 g milk protein per day for 4 weeks. The primary outcome was difference in IGF-1 changes between intervention groups after 4 weeks. Secondary outcomes included changes in IGF-1 after 1 week and changes in insulin-like growth factor binding protein-3 (IGFBP-3), IGF-1/IGFBP-3, insulin, height, weight and body composition after 1 and 4 weeks. Results were analysed by multiple linear mixed-effect models.

RESULTS

There were no differences in changes of plasma IGF-1, insulin-like growth factor binding protein-3 (IGFBP-3), IGF-1/IGFBP-3 ratio or insulin between groups after 1 or 4 weeks based on 89 complete cases (P > 0.10). IGF-1 increased by 13.7 (95% CI 9.7;17.7) ng/mL and 18.0 (14.0;22.0) ng/mL from baseline to week 1 and 4, respectively, a 16% increase during the intervention. Similarly, insulin increased by 31% (14; 50) and 33% (16; 53) from baseline to week 1 and 4. Fat-free mass index (FFMI) increments were higher with milk alone than rapeseed blends (P < 0.05), coinciding with a trend towards a lower height increment. Body mass index increased within all groups (P < 0.05), mainly due to an increase in FFMI (P < 0.01).

CONCLUSION

There were no differences in changes of growth factors between the combinations of milk and rapeseed protein and milk protein alone in healthy, well-nourished children with a habitual intake of milk. Within groups, growth factors increased considerably. Future studies are needed to investigate how intakes of plant and animal proteins affect childhood growth.

A Structured Approach to Recover Valuable Compounds from Agri-food Side Streams

Food side streams contain useful compounds such as proteins, sugars, polyphenols, and amino acids that might get discarded during processing. The concentration of these components may be low (e.g., fruit side streams are mainly composed by water, around 90%, while polyphenol content in rapeseed meal is less than 3% dry weight) and therefore effective separation techniques should be evaluated. The aim of this review is to identify the different process steps (like pretreatment, volume reduction, phase change, solid removal, purification, and formulation) required to recover high-value products from agri-food residues. It reviews different plant-based byproducts as sources (cereal bran, fruit pomace, oilseed meals, fruit wastewater) of valuable compounds and discusses the relevant technologies required for processing (such as extraction, adsorption, crystallization, drying, among others). A structured approach to design recovery processes presented focused on high purity products. This work demonstrates that multiple high-value products can be recovered from a single agri-food side stream depending on the processing steps and the origin source (strong and soft structures and wastewater).

Environmental Impacts of Rapeseed and Turnip Rapeseed Grown in Norway, Rape Oil and Press Cake

Many Norwegian consumers eat more red meat than is recommended by the Government. Of the protein currently consumed, 75% is of animal origin. Natural conditions in Norway favour the production of meat, dairy and seafood but high-protein plants can also be grown in the country. This study analysed the environmental impact of growing turnip rapeseed (Brassica rapa) and rapeseed (Brassica napus) and the processing of rapeseed into dietary oil and press cake. The results were then compared with some common animal protein food sources. Impacts were calculated for 24 impact indicators. The climate impact of dried seeds was 1.19 kg CO2-eq/kg, for rape oil—3.0 kg CO2-eq/kg and for rapeseed press cake—0.72 kg CO2-eq/kg. The environmental impact of rapeseed production is higher than in most other countries, predominantly due to lower yields. Press cake from rapeseed could be a valuable source of protein in foods. In Norway, the environmental impacts of this material (climate impact—2.5 kg CO2-eq/kg protein) are at the same level as other plant protein sources, but far lower than some of the most common animal protein sources (climate impact—16–35 kg CO2-eq/kg protein). When comparing the impacts while taking nutrient content into account, these differences remained the same. Improvements in the environmental performance of oilseed and its products can be achieved both by improving yields through better agronomic practices and increasing the proportion of winter rapeseed.

Plant Proteins: Assessing Their Nutritional Quality and Effects on Health and Physical Function

Consumer demand for plant protein-based products is high and expected to grow considerably in the next decade. Factors contributing to the rise in popularity of plant proteins include: (1) potential health benefits associated with increased intake of plant-based diets; (2) consumer concerns regarding adverse health effects of consuming diets high in animal protein (e.g., increased saturated fat); (3) increased consumer recognition of the need to improve the environmental sustainability of food production; (4) ethical issues regarding the treatment of animals; and (5) general consumer view of protein as a "positive" nutrient (more is better). While there are health and physical function benefits of diets higher in plant-based protein, the nutritional quality of plant proteins may be inferior in some respects relative to animal proteins. This review highlights the nutritional quality of plant proteins and strategies for wisely using them to meet amino acid requirements. In addition, a summary of studies evaluating the potential benefits of plant proteins for both health and physical function is provided. Finally, potential safety issues associated with increased intake of plant proteins are addressed.

A Rat Study to Evaluate the Protein Quality of Three Green Microalgal Species and the Impact of Mechanical Cell Wall Disruption

The present study was conducted to evaluate the protein quality of microalgae species Chlorella vulgaris (CV), Chlorella sorokiniana (CS), and Acutodesmus obliquus (AO) and assess the impact of mechanical cell wall disruption. Male Sprague-Dawley rats, around 156 g after adaptation, were placed in metabolic cages and fed experimental diets that were either protein-free or contained 10% protein solely from one of the undisrupted or disrupted CV, CS, and AO. After 3 days, feces were collected for a period of 5 days and analyzed together with diet samples for crude protein contents. Apparent protein digestibility, true protein digestibility, amino acid score, and protein digestibility-corrected amino acid score were calculated. In vitro protein digestibility was measured using the pepsin-pancreatin method and the in vitro protein digestibility-corrected amino acid score was calculated. The crude protein contents of CV, CS, and AO were 53.5, 50.2, and 40.3%, respectively. The amino acid score of the first limiting amino acid was 1.10, 1.27, and 0.86, true protein digestibility was 64.7, 59.3, and 37.9% and protein digestibility-corrected amino acid score was 0.63, 0.64, and 0.29, respectively, for CV, CS, and AO. Mechanical cell disruption significantly improved protein digestibility without a substantial impact on the amino acid profile and score, resulting in the increase of protein digestibility-corrected amino acid score to 0.77, 0.81, and 0.46, respectively, for disrupted CV, CS, and AO. There was a strong correlation between in vitro protein digestibility and apparent protein digestibility (r = 0.986), and also between in vitro protein digestibility-corrected amino acid score and in vivo protein digestibility-corrected amino acid score (r = 0.994). The results suggest that the CV and CS are acceptable sources of protein for humans and animals and quality can be markedly improved by mechanical cell wall disruption. Additionally, in vitro protein digestibility measured using the pepsin-pancreatin method may be used to screen protein product candidates, save animals, reduce cost, and accelerate product development.

Canola/rapeseed protein - nutritional value, functionality and food application: a review

Plant-based diet and plant proteins specifically are predestined to meet nutritional requirements of growing population of humans and simultaneously reduce negative effects of food production on the environment. While searching for new sources of proteins, special emphasis should be placed on oilseeds of Brassica family comprising varieties of rapeseed and canola as they contain nutritionally valuable proteins, which have potential to be used in food, but are now rarely or not used as food components. The purpose of the present work is to provide a comprehensive review of main canola/rapeseed proteins: cruciferin and napin, with the focus on their nutritional and functional features, putting special emphasis on their possible applications in food. Technological challenges to obtain rapeseed protein products that are free from anti-nutritional factors are also addressed. As molecular structure of cruciferin and napin differs, they exhibit distinct features, such as solubility, emulsifying, foaming or gelling properties. Potential allergenic effect of 2S napin has to be taken under consideration. Overall, rapeseed proteins demonstrate beneficial nutritional value and functional properties and are deemed to play important roles both in food, as well as, non-food and non-feed applications.

Postprandial Metabolic Response to Rapeseed Protein in Healthy Subjects

Plant proteins have become increasingly important for ecological reasons. Rapeseed is a novel source of plant proteins with high biological value, but its metabolic impact in humans is largely unknown. A randomized, controlled intervention study including 20 healthy subjects was conducted in a crossover design. All participants received a test meal without additional protein or with 28 g of rapeseed protein isolate or soy protein isolate (control). Venous blood samples were collected over a 360-min period to analyze metabolites; satiety was assessed using a visual analog scale. Postprandial levels of lipids, urea, and amino acids increased following the intake of both protein isolates. The postprandial insulin response was lower after consumption of the rapeseed protein than after intake of the soy protein (p < 0.05), whereas the postmeal responses of glucose, lipids, interleukin-6, minerals, and urea were comparable between the two protein isolates. Interestingly, the rapeseed protein exerted stronger effects on postprandial satiety than the soy protein (p < 0.05). The postmeal metabolism following rapeseed protein intake is comparable with that of soy protein. The favorable effect of rapeseed protein on postprandial insulin and satiety makes it a valuable plant protein for human nutrition.

Formulation and biochemical evaluation of designer diet enriched with botanicals for bone health

The study designed to evaluate the role of sesame, fenugreek flax, and nuts seeds as best alternatives for therapeutic agents to improve bone mineral status. Effect of these plant seeds on proximate composition, antioxidant potential, mineral, fatty acid, and amino acid profile of supplements was studied. The sesame, fenugreek, and flaxseeds were incorporated with nuts at level of 35% to develop supplement. Improved contents of protein, fat, and NFE were recorded in range of 25.72-32.23, 18.92-23.15, and 34.25%-39.59%, correspondingly. The antioxidant potential of supplements is high (450.56 mg GAE/ 100g) prepared with fenugreek followed by flaxseeds and sesame seeds. Calcium as fundamental bone mineral found greater (525.15%-790.21%) in seed-based supplement. Enhanced contents of Oleic, linoleic, and linolenic acids ranged 17.32-41.78, 21.72-44.23, and 1.00%-47.12%, respectively. Nutritional enriched supplements may be best alternatives for improving bone health by lowering osteoclast and increasing osteoblast mechanism in bone development.

Protein bioavailability of Wolffia globosa duckweed, a novel aquatic plant - A randomized controlled trial

BACKGROUND & AIMS

While the world is extensively looking for alternatives to animal protein sources, it is not clear which plant sources can provide the requisite full complement of essential amino acids (EAAs). Wolffia globosa is an aquatic, edible duckweed, the smallest plant on earth, and it offers all nine EAAs, dietary fibers, polyphenols, iron, zinc and B₁₂ vitamin. This work was designed to evaluate Mankai (a newly developed high-protein strain of W. globosa) as an optional bioavailable source of EAAs for humans (primary outcome), and of further nutrients such as vitamin B₁₂, in comparison to well-established animal and plant protein sources; cheese and peas, respectively.

METHODS

36 men, subjected for 3 days to a stable diet and subsequent overnight (12 h) fast, were randomized to consume one of three iso-protein (30 g) based test-meals (soft cheese, green peas, Mankai). Blood samples were collected at 0, 30, 90 and 180 min.

RESULTS

The 3 h blood concentrations of the EAAs: histidine, phenylalanine, threonine, lysine, and tryptophan, triggered by intake of Mankai, was essentially significant as compared to baseline (p < 0.05) and similar to that of soft cheese and pea changes (p > 0.05 between groups). Although branched-chain-amino-acids (leucine/isoleucine, valine) increased significantly by Mankai within 3 h (p < 0.05 vs. baseline), the change was relatively higher for cheese as compared to Mankai or peas (p < 0.05 between groups). The increase in vitamin B₁₂ by Mankai was higher as compared to changes induced by either cheese (p=0.007) or peas (p=0.047, between groups).

CONCLUSIONS

Mankai may provide a high-quality substitute source for animal protein, and a potential bioavailable source of vitamin B₁₂.

Controlled fermentation of rapeseed presscake by Rhizopus, and its effect on some components with relevance to human nutrition

The use of rapeseed protein could contribute to meeting the increasing demand for plant proteins with high biological value in human nutrition. In order to make rapeseed presscake fit for human consumption, the presscake was fermented by using the tempeh mould, Rhizopus microsporus var. oligosporus. Fermentation was satisfactory at initial levels of added acetic acid of 40-60 mmoles/Kg, a_w of 0.97, pasteurization, surface inoculation and incubation at 32 °C and 90-95% relative humidity. It was crucial to stop the fermentation once the mould had grown and metabolized sufficiently but before a major rise in pH and subsequent growth of acid-sensitive sporeforming bacteria occurred. Some degradation of glucosinolates, cell wall polysaccharides and phenolic compounds was found, but there was some evidence that growth and metabolism of the mould also depended on the texture of the presscake, as these factors affect the oxygen supply to the mould. In conclusion, it is possible to ferment rapeseed presscake by using the "Tempeh starter" Rhizopus oligosporus, but in order to use the resulting product to enrich various foods with protein or replace other proteins, the degree of degradation of undesired compounds should be further standardized, especially by the control of the pH, oxygen supply, and fermentation time.

A major QTL on chromosome C05 significantly reduces acid detergent lignin (ADL) content and increases seed oil and protein content in oilseed rape (Brassica napus L.)

A reduction in acid detergent lignin content in oilseed rape resulted in an increase in seed oil and protein content. Worldwide increasing demand for vegetable oil and protein requires continuous breeding efforts to enhance the yield of oil and protein crop species. The oil-extracted meal of oilseed rape is currently mainly used for feeding livestock, but efforts are undertaken to use the oilseed rape protein in food production. One limiting factor is the high lignin content of black-seeded oilseed rape that negatively affects digestibility and sensory quality of food products compared to soybean. Breeding attempts to develop yellow seeded oilseed rape with reduced lignin content have not yet resulted in competitive cultivars. The objective of this work was to investigate the inheritance of seed quality in a DH population derived from the cross of the high oil lines SGDH14 and cv. Express. The DH population of 139 lines was tested in field experiments in 14 environments in north-west Europe. Seeds harvested from open pollinated plants were used for extensive seed quality analysis. A molecular marker map based on the Illumina Infinium 60 K Brassica SNP chip was used to map QTL. Amongst others, one major QTL for acid detergent lignin content, explaining 81% of the phenotypic variance, was identified on chromosome C05. Lines with reduced lignin content nevertheless did not show a yellowish appearance, but showed a reduced seed hull content. The position of the QTL co-located with QTL for oil and protein content of the defatted meal with opposite additive effects, suggesting that the reduction in lignin content resulted in an increase in oil and protein content.

Characterization of protein isolate from Sesamum indicum seed: In vitro protein digestibility, amino acid profile, and some functional properties

This work evaluated the impacts of pH and sodium chloride (NaCl) concentration on some functional properties, in vitro protein digestibility, and amino acid profile of sesame (Sesamum indicum) protein isolate (SPI) produced using simultaneous recovery of protein and oil technique. The emulsion activity index (EAI), foam capacity (FC), and protein solubility varied with pH and ionic ability. Foam capacity rose with an increase in ionic strength. Protein solubility ranged from 8.39% at pH 4 to 55.08% at pH 10. In vitro protein digestibility of the SPI with pepsin-pancreatin enzyme systems was 89.57%. Amino acid profile showed that essential amino acids constituted 39.48%. The amino acids had good scores well above 50%. The results showed that SPI extracted by aqueous technique could be used as food ingredient, particularly as thickener, binder, and ingredient in baked food products.

Effects of ultrasonic and graft treatments on grafting degree, structure, functionality, and digestibility of rapeseed protein isolate-dextran conjugates

Rapeseed protein isolate (RPI) and dextran conjugates were prepared by traditional and ultrasonic assisted wet-heating. The effects on the grafting degree (GD), structure, functionality, and digestibility of conjugates were studied. Ultrasonic frequency, temperature, and time all significantly affected the GD. Under the optimum conditions (temperature of 90 °C and time of 60 min), compared to traditional wet-heating, ultrasonic treatment at 28 kHz significantly increased the GD by 2.12 times. Compared to RPI, surface hydrophobicities of conjugates were significantly decreased by graft and ultrasonic treatments. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and amino acid composition results confirmed that traditional graft reaction involved cysteine (Cys) and lysine (Lys) whereas the ultrasonic assisted one involved only Cys. Both were from the 12S globulin subunit and cruciferin. Fourier transform infrared spectrum (FT-IR) and circular dichroism (CD) results showed that graft treatment significantly changed secondary structure and ultrasonic treatment had the greatest impact on the decrease in the β-sheet (19.1%) and the increase in the random coil (49.6%). Graft and ultrasonic treatments both made surface structure looser and more porous. The two treatments also caused molecular weight to become bigger, and ultrasonic treatment had the greatest effect on the increase (68.2%) in 110-20.5 kDa. Structural modifications of RPI by grafting to dextran caused improvements of solubility (at pH 5-6), emulsifying activity (at pH 4-10), emulsion stability (at pH 4-5 and 9-10), and thermal stability (at temperature 90-100 °C). The digestibility of conjugates was decreased by graft and ultrasonic treatments and the conjugates were mainly digested in the intestinal phase. The ultrasonic assisted wet-heating was an efficient and safe method for producing RPI-dextran conjugates and improving the utilization value of rapeseed meal.

Nitrogen balance after a single oral consumption of sacha inchi (Plukenetia volúbilis L.) protein compared to soy protein: a randomized study in humans

Sacha inchi is a seed produced in the Peruvian Amazonian and its oil is recognized by the lowering lipids effect in humans. The remaining material transformed to flour has a higher amount of protein, but, the nitrogen balance once ingested orally has not been studied. The present study was designed to evaluate the nitrogen balance after single consumption of 30 g of sacha inchi flour and compared with that obtained after consumption of 30 g soybean flour in adult men and women. This was a double-blind cohort study in 15 men and 15 women between 18 and 55 years old. Fifteen subjects received soy meal and 15 subjects received sacha inchi meal. Group receiving sacha inchi flour has comparable initial parameters as those receiving soybean flour (p > 0.05). Blood samples at different times were obtained. Urine for 24 h was collected to calculate nitrogen balance, p < 0.05 was considered significant. Plasma insulin levels increased post-prandial with a peak at 30 min. Thereafter, a reduction occurred. The magnitude of changes in insulin levels was similar in sacha inchi and soybean groups (p < 0.05). Lipid profile and inflammatory marker, C-reactive protein (CRP) and interleukin 6 (IL6) was not different at 0 or 24 h after sacha inchi or soy flour administration. The nitrogen balance was negative in the study but similar between both groups (p > 0.05). In conclusion, protein consumption of sacha inchi flour has the same nitrogen balance as soybean flour, shows acceptability for a single consumption and does not present serious adverse effects.

Recent Genetic Gains in Nitrogen Use Efficiency in Oilseed Rape

Nitrogen is essential for plant growth, and N fertilization allows farmers to obtain high yields and produce sufficient agricultural commodities. On the other hand, nitrogen losses potentially cause adverse effects to ecosystems and to human health. Increasing nitrogen use efficiency (NUE) is vital to solve the conflict between productivity, to secure the demand of a growing world population, and the protection of the environment. To ensure this, genetic improvement is considered to be a paramount aspect toward ecofriendly crop production. Winter oilseed rape (Brassica napus L.) is the second most important oilseed crop in the world and is cultivated in many regions across the temperate zones. To our knowledge, this study reports the most comprehensive field-based data generated to date for an empirical evaluation of genetic improvement in winter oilseed rape varieties under two divergent nitrogen fertilization levels (NFLs). A collection of 30 elite varieties registered between 1989 and 2014, including hybrids and open pollinated varieties, was tested in a 2-year experiment in 10 environments across Germany for changes in seed yield and seed quality traits. Furthermore, NUE was calculated. We observed a highly significant genetics-driven increase in seed yield per-se and, thus, increased NUE at both NFLs. On average, seed yield from modern open-pollinated varieties and modern hybrids was higher than from old open-pollinated varieties and old hybrids. The annual yield progress across all tested varieties was ~35 kg ha-1 year-1 at low nitrogen and 45 kg ha-1 year-1 under high nitrogen fertilization. Furthermore, in modern varieties an increased oil concentration and decreased protein concentration was observed. Despite, the significant effects of nitrogen fertilization, a surprisingly low average seed yield gap of 180 kg N ha-1 was noted between high and low nitrogen fertilization. Due to contrary effects of N fertilization on seed yield per-se and seed oil concentration an oil yield of 2.04 t ha-1 was measured at both N levels. Collectively, the data reveal that genetic improvement through modern breeding techniques in conjunction with reduced N fertilizer inputs has a tremendous potential to increase NUE of oilseed rape.

Production of hydrophobic amino acids from biobased resources: wheat gluten and rubber seed proteins

Protein hydrolysis enables production of peptides and free amino acids that are suitable for usage in food and feed or can be used as precursors for bulk chemicals. Several essential amino acids for food and feed have hydrophobic side chains; this property may also be exploited for subsequent separation. Here, we present methods for selective production of hydrophobic amino acids from proteins. Selectivity can be achieved by selection of starting material, selection of hydrolysis conditions, and separation of achieved hydrolysate. Several protease combinations were applied for hydrolysis of rubber seed protein concentrate, wheat gluten, and bovine serum albumin (BSA). High degree of hydrolysis (>50 %) could be achieved. Hydrophobic selectivity was influenced by the combination of proteases and by the extent of hydrolysis. Combination of Pronase and Peptidase R showed the highest selectivity towards hydrophobic amino acids, roughly doubling the content of hydrophobic amino acids in the products compared to the original substrates. Hydrophobic selectivity of 0.6 mol-hydrophobic/mol-total free amino acids was observed after 6 h hydrolysis of wheat gluten and 24 h hydrolysis of rubber seed proteins and BSA. The results of experiments with rubber seed proteins and wheat gluten suggest that this process can be applied to agro-industrial residues.

Study of total dry matter and protein extraction from canola meal as affected by the pH, salt addition and use of zeta-potential/turbidimetry analysis to optimize the extraction conditions

Total dry matter and proteins were differentially and preferentially extracted from canola meal (CM) under different conditions. The effect of the extraction medium pH, CM concentration and salt concentrations were found to have different influences on the extractability of total dry matter and proteins from CM. The pH of the extracting medium had the most significant effect. The maximal total dry matter (42.8±1.18%) extractability was obtained with 5% CM at pH 12 without salt addition, whereas the maximal for total protein (58.12±1.47%) was obtained with 15% CM under the same conditions. The minimal extractability for the dry matter (26.63±0.67%) was obtained with 5% CM at pH 10 without salt added and the minimal protein extractability was observed in a 10% CM at pH 10, in 0.01 NaCl. Turbidity and ζ-potential measurements indicated that pH 5 was the optimum condition for the highest protein extraction yield. SDS-PAGE analysis showed that salt addition contributes to higher solubility of canola proteins specifically cruciferin fraction, although it reduces napin extraction.

Rearing Tenebrio molitor L. (Coleptera: Tenebrionidae) in the "Lunar Palace 1" during a 105-day multi-crew closed integrative BLSS experiment

Yellow mealworm (Tenebrio molitor L.) is one of the animal candidates for space bioregenerative life support systems. In this study, T. molitor was involved in a 105-day multi-crew closed integrative BLSS experiment for a tentative rearing study. The results showed that the overall bioconversion rate (ratio of T. molitor gained to the total feed consumed) of T. molitor reared in the closed system was 8.13%, while 78.43% of the feed was excreted as frass. T. molitor reared in the closed system had a good nutritional composition. The eight essential amino acids (EAAs) in T. molitor larvae accounted for 41.30% of its total amino acids, and most EAA contents were higher than the suggested amino acid pattern recommended by the FAO/WHO. T. molitor sample obtained in this work was high in polyunsaturated fatty acids, and low in saturated fatty acids, indicating that the composition of fatty acids was beneficial to human health. In the open environment outside the experimental system, we simultaneously reared three parallel groups of larval T. molitor using the same feeding regime and temperature condition. Compared with T. molitor reared in the open environment, larvae reared in the closed system grew slower. With the course of time t, the growth rate of T. molitor in the open environment was 0.839e(0.017t) times that of larvae in the closed system. This paper can provide data for future design and improvement of BLSS containing a T. molitor rearing unit.

Characterization of the factors that influence sinapine concentration in rapeseed meal during fermentation

We analyzed and compared the difference in sinapine concentration in rapeseed meal between the filamentous fungus, Trametes sp 48424, and the yeast, Saccharomyces cerevisiae, in both liquid and solid-state fermentation. During liquid and solid-state fermentation by Trametes sp 48424, the sinapine concentration decreased significantly. In contrast, the liquid and solid-state fermentation process by Saccharomyces cerevisiae just slightly decreased the sinapine concentration (P ≤ 0.05). After the solid-state fermented samples were dried, the concentration of sinapine in rapeseed meal decreased significantly in Saccharomyces cerevisiae. Based on the measurement of laccase activity, we observed that laccase induced the decrease in the concentration of sinapine during fermentation with Trametes sp 48424. In order to eliminate the influence of microorganisms and the metabolites produced during fermentation, high moisture rapeseed meal and the original rapeseed meal were dried at 90°C and 105°C, respectively. During drying, the concentration of sinapine in high moisture rapeseed meal decreased rapidly and we obtained a high correlation coefficient between the concentration of sinapine and loss of moisture. Our results suggest that drying and enzymes, especially laccase that is produced during the solid-state fermentation process, may be the main factors that affect the concentration of sinapine in rapeseed meal.

Consuming a mixed diet enriched with lupin protein beneficially affects plasma lipids in hypercholesterolemic subjects: a randomized controlled trial

BACKGROUND & AIMS

The objectives of this study were to assess whether 25 g/d lupin protein, integrated into a mixed diet, might affect cardiovascular risk factors and whether l-arginine was responsible for these effects.

METHODS

Seventy-two hypercholesterolemic subjects participated in the randomized, controlled, double-blind three-phase crossover study. They were assigned to three diets with 25 g/d lupin protein (LP), milk protein (MP) or milk protein plus 1.6 g/d arginine (MPA) each for 28 d in a random order interrupted by 6-week washout periods. Lupin protein and the comparator milk protein were incorporated into complex food products (bread, roll, sausage, and vegetarian spread). Arginine was administered via capsules. Sixty-eight subjects were included in final analyses.

RESULTS

Compared with MP, LDL cholesterol was significantly lower after LP. Compared with MP and MPA, homocysteine was significantly lower after LP. Compared with baseline, concentrations of total, LDL, and HDL cholesterol significantly decreased after LP and MPA. Triacylglycerols and uric acid significantly decreased after LP. The relative changes in total and LDL cholesterol were significantly greater for subjects with severe hypercholesterolemia (>6.6 mmol/L) than those with moderate hypercholesterolemia (5.2-6.6 mmol/L).

CONCLUSIONS

The present study showed for the first time that incorporation of 25 g/d of lupin protein into a variety of complex food products lowers total and LDL cholesterol, triacylglycerols, homocysteine, and uric acid in hypercholesterolemic subjects. The hypocholesterolemic effect is stronger in subjects with severe hypercholesterolemia. Arginine might be responsible for some, but not all of the beneficial effects of lupin protein. This trial was registered at http://clinicaltrials.gov (study ID number NCT01598649).