Mung bean protein isolate: Extraction, structure, physicochemical properties, modifications, and food applications

The intake of plant-based proteins is rapidly growing around the world due to their nutritional and functional properties, as well as growing demand for vegetarian and vegan diets. Mung bean seeds have been traditionally consumed in Asian countries due to their unique botanical and health-promoting characteristics. In recent years, mung bean protein isolate (MBPI) has attracted much attention due to its ideal techno-functional features, such as water and oil absorption capacity, solubility, emulsifying, foaming, and thermal properties. Therefore, it can be utilized in a native or modified form in different food sectors, such as biodegradable/edible films, colloidal systems, and plant-based alternative products. This study provides a comprehensive review on the extraction methods, amino acid profile, structure, physicochemical properties, modifications, and food applications of MBPI.

Research progress on plant-based protein Pickering particles: Stabilization mechanisms, preparation methods, and application prospects in the food industry

At present, there have been many research articles reporting that plant-based protein Pickering particles from different sources are used to stabilize Pickering emulsions, but the reports of corresponding review articles are still far from sufficient. This study focuses on the research hotspots and related progress on plant-based protein Pickering particles in the past five years. First, the article describes the mechanism by which Pickering emulsions are stabilized by different types of plant-based protein Pickering particles. Then, the extraction, preparation, and modification methods of various plant-based protein Pickering particles are highlighted to provide a reference for the development of greener and more efficient plant-based protein Pickering particles. The article also introduces some of the most promising applications of Pickering emulsions stabilized by plant-based protein Pickering particles in the food field. Finally, the paper also discusses the potential applications and challenges of plant-based protein Pickering particles in the food industry.

Blended-protein changes body weight gain and intestinal tissue morphology in rats by regulating arachidonic acid metabolism and secondary bile acid biosynthesis induced by gut microbiota

PURPOSE

The impact of dietary nutrients on body growth performance and the composition of gut microbes and metabolites is well-established. In this study, we aimed to determine whether dietary protein can regulate the physiological indexes and changes the intestinal tissue morphology in rats, and if dietary protein was a crucial regulatory factor for the composition, function, and metabolic pathways of the gut microbiota.

METHOD

A total of thirty male Sprague Dawley (SD) rats (inbred strain, weighted 110 ± 10 g) were randomly assigned to receive diets containing animal-based protein (whey protein, WP), plant-based protein (soybean protein, SP), or a blended protein (soybean-whey proteins, S-WP) for a duration of 8 weeks. To investigate the effects of various protein supplement sources on gut microbiota and metabolites, we performed a high throughput 16S rDNA sequencing association study and fecal metabolomics profiling on the SD rats. Additionally, we performed analyses of growth indexes, serum biochemical indexes, and intestinal morphology.

RESULTS

The rats in S-WP and WP group exhibited a significantly higher body weight and digestibility of dietary protein compared to the SP group (P < 0.05). The serum total protein content of rats in the WP and S-WP groups was significantly higher (P < 0.05) than that in SP group, and the SP group exhibited significantly lower (P < 0.05) serum blood glucose levels compared to the other two groups. The morphological data showed the rats in the S-WP group exhibited significantly longer villus height and shallower crypt depth (P < 0.05) than the SP group. The gut microbial diversity of the SP and S-WP groups exhibited a higher level than that of the WP group, and the microbiomes of the WP and S-WP groups are more similar compared to those of the SP group. The Arachidonic acid metabolism pathway is the most significant KEGG pathway when comparing the WP group and the SP group, as well as when comparing the SP group and the S-WP group.

CONCLUSION

The type of dietary proteins exerted a significant impact on the physiological indices of SD rats. Intake of S-WP diet can enhance energy provision, improve the body's digestion and absorption of nutrients, as well as promote intestinal tissue morphology. In addition, dietary protein plays a crucial role in modulating fecal metabolites by regulating the composition of the gut microbiota. Metabolomics analysis revealed that the changes in the levels of arachidonic acid metabolites and secondary bile acid metabolite induced by Clostridium_sensu_stricto_1 and [Eubacterium]_coprostanoligenes_group maybe the primarily causes of intestinal morphological differences.

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

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

Effects of plant- and animal-based-protein meals for a day on serum nitric oxide and peroxynitrite levels in healthy young men

Plant-based diets that replace animal-based proteins with plant-based proteins have received increased attention for cardiovascular protection. Nitric oxide (NO) plays an essential role in the maintenance of endothelial function. However, under higher oxidative stress, NO generation produces peroxynitrite, a powerful oxidant and vasoconstrictor. Diet-replaced protein sources has been reported to decrease oxidative stress. However, the effects of plant-based protein on NO and peroxynitrite have not yet been clarified. Therefore, this study aimed to compare the effects of plant- and animal-based-protein meals for a day on NO, peroxynitrite, and NO/peroxynitrite balance. A crossover trial of two meal conditions involving nine healthy men was performed. Participants ate standard meals during day 1. On day 2, baseline measurements were performed and the participants were provided with plant-based-protein meals or animal-based-protein meals. The standard and test meals consisted of breakfast, lunch, and dinner and were designed to be isocaloric. Plant-based-protein meals contained no animal protein. Blood samples were collected in the morning after overnight fasting before and after the test meals consumption. In the plant-based-protein meal condition, serum NOx levels (the sum of serum nitrite and nitrate) significantly increased, while serum peroxynitrite levels did not change significantly. Animal-based-protein meals significantly increased serum peroxynitrite levels but showed a trend of reduction in the serum NOx levels. Furthermore, serum NO/peroxynitrite balance significantly increased after plant-based-protein meals consumption, but significantly decreased after animal-based-protein meals consumption. These results suggest that, compared with animal-based-protein meals, plant-based-protein meals increase NO levels and NO/peroxynitrite balance, which reflects increased endothelial function.

In vitro DIAAS of Swiss soybean cultivars using the INFOGEST model: Increase in protein quality from soybean to soymilk and tofu

To support the transition towards more sustainable and healthy diets, viable alternatives to foods of animal origin need to be identified. Many plant-based protein sources are currently marketed with claims of minimal environmental impact, but very limited consideration has been given to their protein quality and bioavailable mineral content considering the fact that animal-based foods are typically the primary source of both in Western diets. In this study, traditionally consumed soy foods (cooked soybeans, soymilk, tofu) from different Swiss soybean cultivars were nutritionally characterized and the in vitro digestibility of individual amino acids and total protein were assessed using an in vitro model based on the static INFOGEST protocol; the protein quality was evaluated using the in vitro digestible indispensable amino acid score (DIAAS). The results reveal an increase in total protein in vitro digestibility across the traditional soy food production value chain: 52.1-62.7% for cooked soybeans, 84.1-90.6% for soymilk, and 94.9-98.4% for tofu. Protein quality, determined using the recommended amino acid pattern for 0.5-3 years old, was "low" (no claim) for cooked soybeans (DIAAS < 60), while soymilk (DIAAS = 78-88) and tofu products (DIAAS = 79-91) were of similar "good" protein quality, with considerably higher DIAAS values than those of cooked soybeans (P < 0.001). The iron and zinc contents in soy foods were substantial, but high molar ratios of phytic acid (PA) to iron (PA/Fe; >8) and PA to zinc (PA/Zn; >15) indicate a possible strong inhibition of iron and zinc bioavailability. Based on the DIAAS results, soymilk and tofu would be suitable plant-based alternatives to animal-based foods, while future efforts should focus on optimizing soybean preparation to overcome the negative effects of the plant tissue matrix as well as processing steps to reduce mineral absorption inhibiting substances.

Delivery of a telehealth supported home exercise program with dietary advice to increase plant-based protein intake in people with non-alcoholic fatty liver disease: a 12-week randomised controlled feasibility trial

This study evaluated the feasibility and safety of a telehealth delivered exercise plus plant-based protein diet in adults with non-alcoholic fatty liver disease (NAFLD). This was a 12-week, randomised controlled feasibility trial including twenty-eight adults aged > 45 years with NAFLD randomised to a home muscle strengthening program (3 d/week) with increased protein intake (target ∼1·2-1·5 g/kg/d) from predominately plant-based sources and behavioural change support (3-4 text messages/week) (Pro-Ex n 14) or usual care (UC, n 14). Feasibility was assessed via retention (≤ 10 % attrition), adherence (exercise ≥ 66 %; recommended daily protein serves ≥ 80 %) and safety (adverse events). Secondary outcomes included macronutrient intake (3 × 24-h records), weight, moderate-to-vigorous physical activity (MVPA) and 30 s sit-to-stand (STS) performance. Study retention was 89 %. Mean exercise adherence (Pro-Ex) was 52 % with one adverse event from 241 sessions. In Pro-Ex, mean daily plant protein serves increased (0·9 to 1·4/d) and animal protein decreased (1·5 to 1·2/d) after 12-weeks, but overall adherence (serves/day) was 32[RD1] % (plant) and 42 % (animal). Relative to UC, Pro-Ex experienced a mean 2·7 (95 % CI: 0·9, 4·4) increase in 30 s STS number, 46-minute (95 % CI: -153, 245) increase in MVPA, 1·7 kg (95 % CI: -3·5, 0·2) decrease in weight, 35·2 g (95 % CI: 11·0, 59·3) increase in protein. In adults with NAFLD a telehealth home exercise and dietary intervention was safe and improved habitual plant and animal protein intake, but overall adherence was modest suggesting more intensive healthcare support may be required.

Olive leaf protein: Extraction optimization, in vitro digestibility, structural and techno-functional properties

Olive leaf, as an important by-product of olive farming, is generated from the pruning and harvesting of olive trees and represents >10 % of the total olive weight. The present study was conducted to evaluate the composition, functional and structural characterizations, as well as the in vitro digestibility of olive leaf proteins isolated from ultrasonic-assisted extraction, comparing to classical and industrial techniques. The ultrasound-assisted extraction of olive leaf protein was optimized by the simultaneous maximization of the yield and purity of protein using a Box-Behnken design (BBD) of response surface methodology (RSM). The results indicated that the optimal extraction conditions were as follows: pH of 10.99, temperature of 40.48 °C, sonication time of 47.25 min, and solvent/solid ratio of 24.08 mL/g. Under these conditions, the extraction yield and protein content were 11.67 and 51.2 %, respectively, which were significantly higher than those obtained by the conventional techniques. Regarding the functionality of protein, extraction technique had significant impacts on the structural and functional properties of proteins. In general, ultrasound assisted extraction had higher solubility, and better foaming and thermal properties and in vitro digestibility but lower emulsifying stability and fluid binding capacity compared to conventional ones. Ultrasound-assisted alkaline extraction has great potential to produce edible olive leaf protein with modified functional properties that can be used for various aims in the food applications.

A review of alternative proteins for vegan diets: Sources, physico-chemical properties, nutritional equivalency, and consumer acceptance

Alternate proteins are gaining popularity as a more sustainable and environmentally friendly alternative to animal-based proteins. These proteins are often considered healthier and are suitable for people following a vegetarian or vegan diet. Alternative proteins can be recovered from natural sources like legumes, grains, nuts, and seeds, while single cell proteins (mycoproteins), and algal proteins are being developed using cutting-edge technology to grow fungus, yeast and algal cells in a controlled environment, creating a more sustainable source of protein. Although, the demand for alternative protein products is increasing, there still happens to be a large gap in use among the general consumers mainly stemming from its lower bioavailability, lack of nutritional equivalency and reduced digestibility compared to animal proteins. The focus of the review is to emphasize on various sources and technologies for recovering alternative proteins for vegan diets. The review discusses physicochemical properties of alternative proteins and emphasise on the role of various processing technologies that can change the digestibility and bioavailability of these proteins. It further accentuates the nutritional equivalency and environmental sustainability of alternative protein against the conventional proteins from animals. The food laws surrounding alternative proteins as well as the commercial potential and consumer acceptance of alternative protein products are also highlighted. Finally, key challenges to improve the consumer acceptability and market value of plant-based proteins would be in achieving nutrient equivalency and enhance bioavailability and digestibility while maintaining the same physicochemical properties, taste, texture, as animal proteins, has also been highlighted.

Effects of Plant-Based Protein Consumption on Kidney Function and Mineral Bone Disorder Outcomes in Adults With Stage 3-5 Chronic Kidney Disease: A Systematic Review

INTRODUCTION

Plant-based protein is of growing interest for dietary management of chronic kidney disease (CKD) and is hypothesized to preserve kidney function and reduce CKD-mineral bone disorder (MBD) complications, among other benefits. This systematic review aimed to summarize the available clinical trial evidence for the effect of plant-based protein on kidney function and CKD-MBD outcomes in adults with stage 3-5 CKD not on dialysis.

METHODS

Searches of Medline, Embase, Agricola, CAB abstracts, Web of Science, Scopus, and hand searching were performed. Clinical trials with ≥8 participants ≥18 years of age with an estimated glomerular filtration rate <60 mL/min/1.73 m2 but not on dialysis were included. Additionally, only clinical trials with ≥1-week interventions with ≥50% dietary protein from plant-based sources and reported at least one outcome for both kidney function and CKD-MBD outcomes were included. Of the 10,962 identified abstracts, 32 met inclusion criteria and were assessed for risk of bias.

RESULTS

Results for kidney function and CKD-MBD outcomes were heterogenous, with most studies having suboptimal methodological quality. In most of the studies (27/32), protein source was altered only secondarily to low-protein diet interventions. Thus, data synthesis and interpretation were focused on a subset of five studies that investigated a change in protein source only (i.e., animal vs. plant). Of this subset, four studies reported no change in kidney function, while one study reported a decrease. Three studies reported no change in serum phosphorus, and one study reported lower serum phosphorus following a vegetarian diet. Further, limited data and inconclusive results were observed for phosphaturic hormones, parathyroid hormone, and fibroblast growth factor-23.

CONCLUSION

Current clinical trial evidence on plant-based protein interventions for preserving kidney function and preventing CKD-MBD is limited to inform clinical guidelines at this time. This systematic review emphasizes the ongoing need to research the effects of plant-based protein on kidney function and CKD-MBD outcomes.

Rheological properties of dry-fractionated mung bean protein and structural, textural, and rheological evaluation of meat analogues produced by high-moisture extrusion cooking

A closed cavity rheometer was used to study the rheology of dry-fractionated mung bean protein -DFMB- (55% protein d.m.). Then, the high-moisture extrusion cooking at 40% and 50% moisture contents and different temperatures (115, 125, 135 and 145 °C) was performed, investigating the impact on structural, textural, and rheological properties of extrudates. When subjected to a temperature ramp (40-170 °C), DFMB showed an increase of G* from 70 °C, as a consequence of starch gelatinization and protein gelation. The peak, indicating the end of aggregation reactions, was at 105 °C and 110 °C for DFMB at 50% and 40% moisture content, respectively. The time sweep analysis described the protein behavior in no-shear/shear conditions, highlighting a more pronounced effect of the temperatures compared to moisture content. During the extrusion cooking, the temperature increase led to a decrease of pressure, indicating a reduction of the melt viscosity. The microstructure of the extrudates showed a more pronounced anisotropic profile when higher temperatures were applied. Hardness, chewiness, and cohesion were directly correlated with the temperature, which also affected the rheological properties of extrudates. A combination of textural and rheological analyses can offer a clear overview of the structural characteristics of meat analogues.

Conventional solid-state fermentation impacts the white lupin proteome reducing the abundance of allergenic peptides

The demand for high-quality and sustainable protein sources is on the rise. Lupin is an emerging plant-based source of protein with health-enhancing properties; however, the allergenic potential of lupins limits their widespread adoption in food products. A combination of discovery and targeted quantitative proteome measurements was used to investigate the impact of solid-state fermentation induced by Rhizopus oligosporus on the proteome composition and allergenic protein abundances of white lupin seed. In total, 1,241 proteins were uniquely identified in the fermented sample. Moreover, the effectiveness of the solid-state fermentation in reducing the abundance of the tryptic peptides derived from white lupin allergens was demonstrated. Comparably, a greater decrease was noted for the major white lupin allergen based on β-conglutin peptide abundances. Hence, conventional solid-state fermentation processing can be beneficial for reducing the potential allergenicity of lupin-based foods. This finding will open new avenues for unlocking the potential of this under-utilised legume.

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.

Comparison of in vitro digestibility and DIAAR between vegan and meat burgers before and after grilling

Plant-based meat alternatives of high quality and digestibility could be a way to reduce meat consumption and, consequently, the environmental impact. However, little is known about their nutritional characteristics and digestion behaviour. Therefore, in the present study, the protein quality of beef burgers, known as excellent source of protein, was compared with the protein quality of two highly transformed veggie burgers, based on soy or pea-faba proteins, respectively. The different burgers were digested according to the INFOGEST in vitro digestion protocol. After digestion, total protein digestibility was determined, either based on total nitrogen (Kjeldahl) analysis, or after acid hydrolysis based on total amino groups (o-phthalaldehyde method) or total amino acids (TAA; by HPLC). The digestibility of individual amino acids was also determined, and the digestible indispensable amino acid score (DIAAS) was calculated based on in vitro digestibility. The impact of texturising and grilling on in vitro protein digestibility and the digestible indispensable amino acid ratio (DIAAR) was evaluated at the level of the ingredients and the finished products. As expected, the grilled beef burger had the highest in vitro DIAAS values (Leu 124 %), and grilled soy protein-based burger reached in vitro DIAAS values that could be rated as good (soy burger, SAA 94 %) protein source, according to the Food and Agriculture Organization. The texturing process did not significantly affect the total protein digestibility of the ingredients. However, grilling led to a decrease in digestibility and DIAAR of the pea-faba burger (P < 0.05), which was not observed in the soy burger, but led to an increase in DIAAR in the beef burger (P < 0.005).

Beliefs underlying older adults' intention to consume plant-based protein foods: A qualitative study

The revised Canada's food guide released in 2019 promotes the consumption of plant-based protein foods (PBP). Yet, older adults consume little of them. This qualitative study aimed to identify older adults' beliefs about consuming PBP and to assess differences in beliefs by gender and baseline PBP consumption. Recruitment was done to obtain an equal number of men and women, 20 PBP-consumers and 40 non-consumers. Each participant completed an online questionnaire collecting sociodemographic data and took part in an individual semi-structured interview based on the Theory of Planned Behavior. A thematic analysis was performed using the Nvivo software. Health benefits, good taste and protecting the environment were perceived as advantages of consuming PBP, whereas difficulty digesting and not liking the taste were reported as disadvantages. Family members were frequently named as people who would approve and/or disapprove the consumption of PBP. Having more knowledge about PBP would facilitate consumption, while lack of motivation to change eating habits and lack of knowledge on how to prepare PBP meals were perceived barriers. Several differences in beliefs by gender and baseline PBP consumption were observed. Future interventions should focus on the beliefs that were identified as important to older adults (i.e., health benefits and food preparation skills), and should be tailored to their gender and PBP consumption.

Low variability of plant protein intake in the CKiD cohort does not demonstrate changes in estimated GFR nor electrolyte balance

BACKGROUND

Vegetable or plant-based sources of protein may confer health benefits in children with progressive kidney disease. Our aims were to understand the effect of the proportion of vegetable protein intake on changes in estimated GFR and to understand the effect of the proportion of vegetable protein intake on serum levels of bicarbonate, phosphorus, and potassium.

METHODS

Children with baseline eGFR between 30 and 90 mL/min/1.73 m² were recruited from 59 centers across North America as part of the chronic kidney disease in children (CKiD) study. The percentage of dietary vegetable protein (VP%) was gathered from annual Food Frequency Questionnaires. We performed longitudinal linear mixed models to determine the effect of VP% on eGFR and longitudinal logistic mixed models to determine the effect of VP% on electrolyte balance (potassium, phosphorus, bicarbonate).

RESULTS

Two thousand visits from 631 subjects. Across all dichotomized groups of children (sex, African American race, Hispanic ethnicity, glomerular etiology of CKD, hypertension, anemia, hyperkalemia, hyperphosphatemia, acidosis, BMI < 95th percentile), the median VP% was 32-35%. The longitudinal mixed model analysis did not show any effect of VP% on eGFR electrolyte (bicarbonate, phosphorus, and potassium) abnormalities (p > 0.1).

CONCLUSIONS

A diverse cohort of children with CKD has a narrow and homogeneous intake of vegetable protein. Due to the low variability of plant-based protein in the cohort, there were no associations between the percentage of plant protein intake and changes in eGFR nor electrolyte balance. A higher resolution version of the Graphical abstract is available as Supplementary information.

Physico-chemical Properties and Sensorial Appreciation of a New Fermented Probiotic Beverage Enriched with Pea and Rice Proteins

OBJECTIVES

The purpose of this study was to evaluate the physico-chemical stability, the sensorial properties, and the microbial quality of a fermented beverage enriched with pea and rice proteins (PRF) during storage at 4 °C. To investigate the effect of the protein enrichment and fermentation, the PRF beverage quality was compared with non-fermented and non-enriched beverages.

METHODS

The beverage was supplemented with a 50/50 mixture of pea and rice protein concentrate to 13% concentration. Following inoculation with 108 CFU/mL of lactic acid bacteria, it was incubated at 37 °C for 14 h.

RESULTS

Results showed that the enrichment with protein induced an increase in pH, titratable acidity and viscosity of the PR products, while the fermentation led to a decrease of pH and viscosity. However, a significant increase of the viscosity of PRF from 39 to 57 cP was observed during the 143 days of storage (P ≤ 0.05). The PRF beverage contained significantly more peptides < 200 Da than the non-fermented one (PRNF) and these small peptides were also released during the storage. Despite the physico-chemical modifications, the sensorial properties of the PRF product were appreciated over the storage, particularly for the texture. Furthermore, the beverage maintained a high concentration of viable probiotics during the entire storage with 8.4 log colony form unit (CFU)/mL after 143 days.

CONCLUSION

Applying probiotics and the mixture of rice and pea proteins in the fermented beverage can enhance nutritional and nutraceutical value of the product.

Ultrasound-assisted processing: Science, technology and challenges for the plant-based protein industry

The present-day consumer is not only conscious of the relationship between food consumption and positive health, but also keen on environmental sustainability. Thus, the demand for plant-based proteins, which are associated with nutrition and environmental sustainability. However, the plant-based protein industry still demands urgent innovation due to the low yield and long extraction time linked with traditional extraction methods. Although ultrasound is an eco-innovative technique, there exist limited data regarding its impact with plant-based protein. In this paper, the scientific principles of ultrasonication with regards to its application in plant-based protein research were reviewed. After comparing the cavitational and shearing impacts of different ultrasonic parameters, the paper further reviewed its effects on extracted protein characteristics and techno-functional properties. Additionally, current technological challenges and future perspectives of ultrasonication for the plant-based protein industry were also discussed. In summary, this review does not only present the novelty and environmental sustainability of ultrasound as a plant-based protein assisted-extraction method, but also highlights on the correlation between protein source, structure and subsequent functional properties which are important crucial factors for maximum application of ultrasound in the growing plant-based protein market.

Effect of conductive hydro-drying on physiochemical and functional properties of two pulse protein extracts: Green gram (Vigna radiata) and black gram (Vigna mungo)

In this study, the effect of two drying methods (conductive hydro-drying - CHD and freeze-drying - FD) on the physical and functional properties of green gram (GG) and black gram (BG) protein powders was investigated. CHD dried protein powder showed excellent powder characteristics with moisture contents ranging from 3 to 6%, water activity of ~0.4 and Carr index ≤10. The CHD samples were dried in 210 min; with higher drying rates, CHD samples showed no significant changes in powder characteristics, color value, and water and oil absorption indices. The solubility of both proteins were found to be lower at pH 4 to 7 and higher at pH 1, 2, 8, 9 and 10; at certain pH, the solubility of CHD protein was higher than that of the FD counterparts. No significant differences were observed in the oil absorption capacity, surface hydrophobicity, protein gel formation, pasting and thermal properties. XRD and FTIR analyses were used to explain changes in protein structure and the presence of both α-helix and β-sheet was observed, with higher β-sheet levels in both pulses dried using CHD. Results confirmed that CHD, a variant of the refractance window drying (RWD) offered protein quality in par with FD.

The associations of plant-based protein intake with all-cause and cardiovascular mortality in patients on peritoneal dialysis

BACKGROUND AND AIMS

Plant-based protein intake is associated with all-cause and/or cardiovascular disease (CVD) mortality in general population, but such data are scarce in dialysis patients. Thus, we examined the associations of plant-based protein-total protein ratio with all-cause and CVD mortality in patients on peritoneal dialysis (PD).

METHODS AND RESULTS

The study enrolled 884 incident patients who started PD between October 2002 and August 2014. All demographic and laboratory data were recorded at baseline. Repeated measurements for laboratory and nutrition parameters were recorded at regular intervals and thus calculated as time-averaged values. Multivariable Cox regression models were used to estimate the hazard ratio (HR) of plant-based protein-total protein ratio and mortality based on baseline and time-averaged covariates, respectively. There were 437 (49%) patients died during a mean follow-up period of 45 months, of which 178 (40.8%) were due to CVD. Each 10% in increase in time-averaged plant-based protein-total protein ratio was associated with a reduction of 71% (95% CI, 90%-14%) and 89% (95% CI, 98%-29%) for all-cause and CVD mortality, respectively. Based on examination on interactive effects, we further found both baseline and time-averaged plant-based protein-total protein ratio were inversely associated with all-cause and CVD mortality in the subgroups of female, age ≥60 years, and albumin >35 g/L.

CONCLUSIONS

The present study suggested that a diet with a higher plant-based protein-total protein ratio is associated with lower all-cause and CVD mortality in PD patients, and is more significant in female and elderly patients, and those without hypoalbuminemia.

Postprandial amino acid, glucose and insulin responses among healthy adults after a single intake of Lemna minor in comparison with green peas: a randomised trial

A high protein content combined with its enormous growth capacity make duckweed an interesting alternative protein source, but information about postprandial responses in humans is lacking. The present study aimed to assess the postprandial serum amino acid profile of Lemna minor in healthy adults in comparison with green peas. A secondary objective was to obtain insights regarding human safety. A total of twelve healthy volunteers participated in a randomised, cross-over trial. Subjects received two protein sources in randomised order with a 1-week washout period. After an overnight fast, subjects consumed L. minor or peas (equivalent to 20 g of protein). After a baseline sample, blood samples were taken 15, 30, 45, 60, 75, 90, 120, 150 and 180 min after consumption to assess amino acid, glucose and insulin levels. Heart rate, blood pressure and aural temperature were measured before and after consumption, and subjects reported on gastrointestinal discomfort for four subsequent days. Compared with green peas, significantly lower blood concentrations of amino acids from L. minor were observed, indicating lower digestibility. L. minor consumption resulted in lower plasma glucose and insulin levels compared with peas, probably due to different glucose content. There were no significant differences concerning the assessed health parameters or the number of gastrointestinal complaints, indicating that a single bolus of L. minor - grown under controlled conditions - did not induce acute adverse effects in humans. Further studies need to investigate effects of repeated L. minor intake and whether proteins purified from L. minor can be digested more easily.

Comparison of the effects of a liquid breakfast meal with varying doses of plant-based soy protein on appetite profile, energy metabolism and intake

A dose dependent satiating and thermogenic effect of animal-based protein has been observed, however, less is known wherever plant-based protein elicits same response. The purpose of the study was to examine the effects of a breakfast meal containing varying doses of plant-based soy protein (SP) on appetite profile, hormone response, energy metabolism and energy intake.

METHODS

Seventeen participants (age: 27 ± 7 y, body fat: 21.5 ± 6.9%) in randomized order consumed one of three isoenergetic liquid breakfast meals (482 ± 5 kcals): high SP (HSP; 50 g), low SP (LSP; 25 g) and control (CON; 50 g carbohydrate) followed by an ad libitum lunch 3 h later. Appetite profile was measured before, immediately after and hourly during the 3 h postprandial period. Plasma concentrations of leptin and insulin were measured before, at 30 and 180 min.

RESULTS

Energy intake at lunch per kilogram of body weight was significantly higher after CON (11 ± 3.6 kcal/kg) compared to HSP (9.1 ± 3.0 kcal/kg) but not compared to LSP (10.2 ± 2.7 kcal/kg). Participants hunger was higher, whereas, satiety and fullness were lower after CON (p < 0.05). There were no significant differences (p > 0.05) observed in leptin or insulin responses between meals, however, a significant change over time was observed for insulin (p = 0.02) but not leptin (p > 0.05).

CONCLUSION

Liquid breakfast meals with higher dose of soy protein reduced energy intake when adjusted by body weight at lunch and was rated as more satiating compared to an isoenergetic CON meal.

KALGAE™ (Klebsormidium flaccidum var. ZIVO) dried algal biomass - 90-day dietary toxicity study and genotoxicity studies

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NOAEL of 7895.2 mg/kg bw/day (male) and 9708.09 mg/kg bw/day (female) rats.

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Non-mutagenic in in vitro bacterial reverse mutation assay.

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Non-genotoxic in the in vivo mammalian erythrocyte micronucleus test.

Consumers are demanding plant-based alternative protein sources to complement traditional animal-based protein sources to fulfill their dietary protein requirements. KALGAE™, a dried algal biomass derived from Klebsormidium flaccidum var. ZIVO, is a potential source of plant-based protein that has been evaluated for safety to support its use as a food ingredient. There were no treatment-related adverse effects observed in the 14-day palatability/toxicity or 90-day dietary toxicity study in CRL Sprague-Dawley CD^® IGS rats. In the 90-day study, KALGAE™ was administered to rats in the diet at 0, 37,500, 75,000, or 150,000 ppm. No adverse effects were attributed to the test substance for the following parameters: body weight, body weight gain, mean food consumption and efficiency, hematology, clinical chemistry, urinalysis, gross pathology, histopathology, or organ weights. Although some statistically significant effects were recorded, the effects were not considered to be of toxicological relevance. A No Observable Adverse Effect Level (NOAEL) of 150,000 ppm, equivalent to dietary intakes of 7895.2 (male) and 9708.09 (female) mg KALGAE™/kg body weight/day in rats was established. KALGAE™ was non-mutagenic in the in vitro bacterial reverse mutation assay at concentrations up to 5000 μg/plate (with or without S9 metabolic activation), nor was KALGAE™ genotoxic in the in vivo mammalian erythrocyte micronucleus test in Swiss albino (ICR) mice. These results support the safe use of KALGAE™ as an ingredient in foods.

Protein content and amino acid composition of commercially available plant-based protein isolates

The postprandial rise in essential amino acid (EAA) concentrations modulates the increase in muscle protein synthesis rates after protein ingestion. The EAA content and AA composition of the dietary protein source contribute to the differential muscle protein synthetic response to the ingestion of different proteins. Lower EAA contents and specific lack of sufficient leucine, lysine, and/or methionine may be responsible for the lower anabolic capacity of plant-based compared with animal-based proteins. We compared EAA contents and AA composition of a large selection of plant-based protein sources with animal-based proteins and human skeletal muscle protein. AA composition of oat, lupin, wheat, hemp, microalgae, soy, brown rice, pea, corn, potato, milk, whey, caseinate, casein, egg, and human skeletal muscle protein were assessed using UPLC–MS/MS. EAA contents of plant-based protein isolates such as oat (21%), lupin (21%), and wheat (22%) were lower than animal-based proteins (whey 43%, milk 39%, casein 34%, and egg 32%) and muscle protein (38%). AA profiles largely differed among plant-based proteins with leucine contents ranging from 5.1% for hemp to 13.5% for corn protein, compared to 9.0% for milk, 7.0% for egg, and 7.6% for muscle protein. Methionine and lysine were typically lower in plant-based proteins (1.0 ± 0.3 and 3.6 ± 0.6%) compared with animal-based proteins (2.5 ± 0.1 and 7.0 ± 0.6%) and muscle protein (2.0 and 7.8%, respectively). In conclusion, there are large differences in EAA contents and AA composition between various plant-based protein isolates. Combinations of various plant-based protein isolates or blends of animal and plant-based proteins can provide protein characteristics that closely reflect the typical characteristics of animal-based proteins.

Ingestion of soy protein isolate attenuates eccentric contraction-induced force depression and muscle proteolysis via inhibition of calpain-1 activation in rat fast-twitch skeletal muscle

OBJECTIVE

Eccentric contraction (ECC) is a contraction in which skeletal muscles are stretched while contracting. The aim of this study was to determine how ingestion of soy protein isolate (SPI) or animal-based proteins affect force deficit, calpain activation, and proteolysis of calcium ion (Ca²⁺)-regulatory proteins in rat fast-twitch muscles subjected to ECC.

METHODS

In the first experiment, male Wistar rats were randomly assigned to a control and an SPI group, which were fed a 20% casein and a 20% SPI diet, respectively, for 28 d before the ECC protocol. Anterior crural muscles underwent 200 repeated ECCs and were excised 3 d later. In the second experiment, half of the SPI rats were given water containing N^G-nitro-l-arginine-methyl ester (L-NAME), an inhibitor of nitric oxide synthase, for 3 d of recovery after ECC.

RESULTS

SPI ingestion attenuated ECC-induced force deficit, proteolysis of Ca²⁺-regulatory proteins, and autolysis of calpain-1. Co-ingestion of L-NAME inhibited SPI-associated increases in nitrite and nitrate levels and negated the force recovery effects of SPI.

CONCLUSION

These results suggest that SPI ingestion inhibits ECC-elicited force deficit and proteolysis of Ca²⁺ regulatory proteins, which is caused by inhibited activation of calpain-1 via increased nitric oxide production.