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

Authors:
  • Zuyderland Medical Center

Abstract and Figures

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.
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Vol.:(0123456789)
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Amino Acids (2018) 50:1685–1695
https://doi.org/10.1007/s00726-018-2640-5
ORIGINAL ARTICLE
Protein content andamino acid composition ofcommercially available
plant‑based protein isolates
StefanH.M.Gorissen1· JulieJ.R.Crombag1· JoanM.G.Senden1· W.A.HuubWaterval2· JörgenBierau2·
LexB.Verdijk1· LucJ.C.vanLoon1
Received: 19 March 2018 / Accepted: 24 August 2018 / Published online: 30 August 2018
© The Author(s) 2018
Abstract
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.
Keywords Essential amino acid· Leucine· Plant-based protein· Muscle protein synthesis· Protein blend
Introduction
Dietary protein intake stimulates muscle protein synthesis
(Rennie etal. 1982). The muscle protein synthetic response
to protein intake can vary substantially between different
dietary protein types or sources. The differential muscle
protein synthetic response is largely dependent on the post-
prandial availability of essential amino acids (and leucine in
particular) to the muscle (Atherton etal. 2010; Volpi etal.
2003). Postprandial essential amino acid availability is
regulated by a number of physiological processes including
dietary protein digestion, amino acid absorption, splanchnic
amino acid retention, and skeletal muscle perfusion (Groen
etal. 2015) as well as various dietary factors including
amino acid composition, essential amino acid content, and
the presence of anti-nutritional factors.
Numerous studies have assessed the postprandial muscle
protein synthetic response to the ingestion of dairy (Burd
etal. 2012; Gorissen etal. 2016; Pennings etal. 2011, 2012;
Tang etal. 2009; Witard etal. 2014; Yang etal. 2012a)
and meat (Beals etal. 2016; Burd etal. 2015; Pennings
etal. 2013; Symons etal. 2007, 2009, 2011; Phillips 2012;
Robinson etal. 2013). The robust postprandial increase in
muscle protein synthesis rates after the ingestion of these
animal-based proteins is associated with the rapid rise in
plasma essential amino acid concentrations, and leucine
Handling Editor: F. Blachier.
* Luc J. C. van Loon
L.vanLoon@maastrichtuniversity.nl
1 NUTRIM School ofNutrition andTranslational Research
inMetabolism, Maastricht University Medical Centre+, PO
Box616, 6200MDMaastricht, TheNetherlands
2 Department ofClinical Genetics, Maastricht University
Medical Centre+, Maastricht, TheNetherlands
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1686 S.H.M.Gorissen et al.
1 3
in particular. In comparison, the muscle protein synthetic
responses to the ingestion of plant-based proteins such as soy
(Phillips 2012; Tang etal. 2009; Wilkinson etal. 2007; Yang
etal. 2012b) and wheat (Gorissen etal. 2016) have been
shown to be of a lesser magnitude compared with animal-
based proteins. The lesser anabolic properties of plant-based
proteins have been attributed to lower essential amino acid
content or shortage of specific amino acids such as leucine,
lysine, and/or methionine (WHO/FAO/UNU Expert Consul-
tation 2007; van Vliet etal. 2015; Young and Pellett 1994).
All amino acids are required for protein synthesis, and lack
of one or more amino acids may compromise the postpran-
dial muscle protein synthetic response. Interestingly, the
anabolic properties of plant-based proteins have only been
studied for a few protein sources, such as soy (Fouillet etal.
2002, 2009; Hartman etal. 2007; Phillips 2012; Tang etal.
2009; Wilkinson etal. 2007; Yang etal. 2012b; Brown etal.
2004; Volek etal. 2013), wheat (Gorissen etal. 2016; Nor-
ton etal. 2009, 2012), and rice (Joy etal. 2013), despite
the great diversity in plant-based protein sources (van Vliet
etal. 2015).
The use of plant-based protein isolates in food formula-
tions has recently become of interest due to greater sustain-
ability and lower production costs. The current market offers
a wide selection of plant-based proteins, but the lack of
studies comparing plant-based proteins makes it difficult to
select the most optimal plant-based proteins. We previously
reported substantial differences in dietary protein character-
istics between various plant-based protein sources (van Vliet
etal. 2015). However, this report included data from a large
number of research studies that used independent analyses
and assessed only a single protein source or compared a
few plant-based protein sources. In the current study, we
applied the same analytical procedures on a large selection
of commercially available protein isolates to provide a more
comprehensive overview of the dietary protein characteris-
tics of the main plant and animal-based protein isolates that
are now widely available on the market.
In the present study, we characterized various plant-based
protein isolates (oat, lupin, wheat, hemp, microalgae, soy,
brown rice, pea, corn, and potato), animal-based protein iso-
lates (whey, milk, caseinate, casein, and egg), and human
skeletal muscle protein. Using ultra-performance liquid
chromatography tandem mass spectrometry (UPLC–MS/
MS), we assessed the amino acid composition of these pro-
tein types and sources. This study provides the basis for the
identification of plant-based proteins with a high anabolic
potential and for defining new plant-based protein blends
that provide a complete spectrum of essential amino acids
similar to most animal-based protein sources.
Methods
Protein sources
Thirty-five protein samples were selected that are pres-
ently commercially available as isolated protein powder
suitable for application in human nutrition or animal feeds.
Ten different plant-based protein sources including oat
(n = 1), lupin (n = 1), wheat (n = 7), hemp (n = 1), micro-
algae (n = 1), soy (n = 7), brown rice (n = 1), pea (n = 3),
corn (n = 3), and potato (n = 2) were compared with ani-
mal-based proteins including milk (n = 1), whey (n = 3),
caseinate (n = 1), casein (n = 2), and egg (n = 1) as well as
human skeletal muscle protein (n = 10). The plant-based
protein sources selected for the current analyses account
for approximately 67% of total plant-based protein intake,
with oat providing 0.3%, wheat providing 32.3%, soy pro-
viding 2.7%, brown rice providing 20.6%, pea providing
1.0%, corn providing 7.3%, and potato providing 3.1%
of total plant-based protein intake (FAOSTAT 2013). In
addition, we included lupin, hemp, and microalgae in the
current analyses. Lupin is a native European legume with
a protein quality score similar to soy, and has become of
interest as an alternative to the import of soy (Lucas etal.
2015; Mariotti etal. 2002). Microalgae have received con-
siderable attention due to their high protein content (simi-
lar to meat, egg, soybean, and milk), presence of other
beneficial nutrients, and a production that requires less
water and land than other crops or animal foods (Bleakley
and Hayes 2017). All protein samples were provided in
kind by various suppliers: Agri Nutrition, Doetinchem,
The Netherlands; Agridient, Hoofddorp, The Netherlands;
Avebe, Veendam, The Netherlands; Cargill, Minnetonka,
Minnesota, USA; Chamtor, Bazancourt, France; Cosucra,
Warcoing, Belgium; FrieslandCampina DMV, Veghel, The
Netherlands; FrieslandCampina Domo, Beilen, The Neth-
erlands; L.I. Frank, Twello, The Netherlands; MRM Meta-
bolic Response Modifiers, Oceanside, CA, USA; Roquette,
Lestrem, France; Selecta, Goiânia-GO, Brazil; Tate and
Lyle, Kimstad, Sweden; Tereos, Marckolsheim, France;
Volac, Orwell, United Kingdom; Vitablend, Wolvega, The
Netherlands; Wulro, Weert, The Netherlands. Protein sam-
ples were transported and stored in unopened packaging in
a clean, dry, well-ventilated area at ambient temperature
and humidity until further analysis. We included human
skeletal muscle protein as reference protein with an ‘ideal’
amino acid composition when focusing on muscle protein
synthesis. Human skeletal muscle samples were obtained
from the m. vastus lateralis from ten volunteers who par-
ticipated in a previously published trial (Gorissen etal.
2014). Protein samples were requested, obtained, and ana-
lyzed between December 2014 and June 2018.
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1687
Protein content andamino acid composition ofcommercially available plant-based protein…
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Protein content analysis
Approximately 10mg of protein powder (in duplicate) or
freeze-dried human skeletal muscle tissue was collected in
steel crucibles. The Dumas combustion method was used to
determine nitrogen using the vario MAX cube CN (Elemen-
tar Analysensysteme, Germany). Protein content was calcu-
lated by multiplying the determined nitrogen content by 6.25
as the standard nitrogen-to-protein conversion factor. There
is an ongoing debate on the preferred use of protein source
specific nitrogen-to-protein conversion factors that are
known for some but not all of the protein sources included
in the current analyses (Mariotti etal. 2008). In the present
study, we used a single conversion factor (6.25) to enable
direct comparisons between the various protein sources.
Amino acid prole analysis
Approximately 6mg of protein powder or freeze-dried
human skeletal muscle tissue was hydrolyzed in 3mL 6M
HCl for 12h at 110°C. After hydrolysis, samples were
cooled down to 4°C to stop the hydrolyzation process. HCl
was evaporated under nitrogen stream and the dried amino
acids were reconstituted in 5mL water. Amino acid stand-
ards were obtained from Sigma-Aldrich (A9906) and diluted
to final concentrations of 500, 375, 250, 125, 62.5, and
31.25µM. 10µL of the hydrolyzed protein sample or amino
acid standard solution was mixed with 1500µL 0.5mM
tridecafluoroheptanoic acid (TDFHA; Sigma) in water and
10µL internal standard solution containing stable isotope-
labeled amino acids (Cambridge Isotopes Laboratories) in
0.1M HCl. Amino acid concentrations were determined
using ultra-performance liquid chromatography (UPLC)
tandem mass spectrometry (Waterval etal. 2009). Liquid
chromatography was performed at 30°C using a Acquity
UPLC BEH C18, 1.7μm, 2.1 × 100mm column (Waters,
Milford, MA, USA) and a gradient system with the mobile
phase consisting of buffer A (0.5mM TDFHA in water)
and buffer B (0.5mM TDFHA in acetonitrile) at a flow
rate of 650μL/min (split less). The gradient program used
was: initial 99.5% A and 0.5% B; linear gradient to 70%
A and 30% B in 14min; hold for 3.5min, return to initial
conditions in 1min at a flow rate of 700μL/min, followed
by equilibration for 10min. One minute prior to the next
sample injection the flow was set to 650μL/min. Run-to-
run time was 30min. The injected volume was 5μL. Mass
spectrometry was performed using a Micromass Quattro
Premier XE Tandem Mass Spectrometer (Waters, Milford,
MA, USA). The mass spectrometer was used in the multiple
reaction-monitoring mode (MRM) in the ESI-positive mode.
The desolvation temperature was 450°C, and the source
temperature was 130°C. The capillary voltage was set at
0.5kV and the cone voltage was set at 25V. Nitrogen gas
was used as desolvation gas and as cone gas. Nitrogen gas
was produced using an NM30L nitrogen generator (Peak
Scientific, Renfrewshire, Scotland). The cone gas flow was
50L/h and the desolvation gas flow was 800L/h. Optimal
detection conditions were determined by constant infusion
of standard solutions (50μM) in solvent A using a split sys-
tem. MRM and daughter-ion scans were performed using
argon as the collision gas at a pressure of 3.8 × 10−3mbar
and a flow of 0.2mL/min.
During acid hydrolysis, the non-essential amino acids
asparagine and glutamine are converted into aspartic acid
and glutamic acid, respectively, and the essential amino acid
tryptophan is decomposed, which precludes the ability to
detect these amino acids (Fountoulakis and Lahm 1998).
As tryptophan was not measured, the sum of essential
amino acids includes threonine, methionine, phenylalanine,
histidine, lysine, valine, isoleucine, and leucine. The acid
hydrolysis was performed in the absence of oxygen and the
hydrolyzation process was terminated after 12h of incuba-
tion to minimize the reduction of cysteine and methionine.
Although the acid hydrolysis is not optimal for all amino
acids, we used this procedure for all protein samples to ena-
ble direct comparisons between the various protein sources.
Results
Protein content
Protein contents ranged between 51 and 86% of raw mate-
rial (Fig.1). Plant-based protein sources ranged between
51 and 81% and protein content was lower in hemp (51%),
lupin (61%), oat (64%), and corn (65%) and higher in brown
rice (79%), pea (80%), potato (80%), and wheat (81%). The
Oat
Lupin
Wheat
Hemp
Microalgae
Soy
Brown rice
Pea
Corn
Potato
Whey
Milk
Caseinate
Casein
Egg
Human muscle
0
20
40
60
80
100
Protein content, %
Fig. 1 Mean (± SEM) protein content (% of raw material) of various
dietary protein sources and human skeletal muscle tissue based on the
determined nitrogen content multiplied by 6.25 as the standard con-
version factor. White bars represent plant-based protein sources, grey
bars represent animal-derived protein sources, and black bar repre-
sents human skeletal muscle protein
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1688 S.H.M.Gorissen et al.
1 3
protein content of animal-based proteins ranged between
51% in egg and 86% in calcium caseinate. Freeze-dried
human skeletal muscle tissue contained 84% protein. Protein
contents of various samples from the same protein source
differed between suppliers, with protein contents of wheat
protein ranging from 74 to 88%, soy protein ranging from
61 to 91%, pea protein ranging from 77 to 81%, corn protein
ranging from 58 to 75%, potato protein ranging from 77 to
83%, whey protein ranging from 72 to 84%, and casein rang-
ing from 67 to 78%.
Essential amino acid content
Essential amino acid contents are shown in Fig.2. Essential
amino acid contents were lower in plant-based (26 ± 2% of
total protein) when compared with animal-based proteins
(37 ± 2% of total protein) and human skeletal muscle protein
(38% of total protein). The essential amino acid contents
of the plant-based proteins oat (21%), lupin (21%), wheat
(22%), hemp (23%), and microalgae (23%) are below the
WHO/FAO/UNU amino acid requirements (WHO/FAO/
UNU Expert Consultation 2007). Thus, the essential amino
acid requirement would not be met when one of these pro-
teins would be the only protein source consumed. Note that
the requirement is based on a recommended adult protein
intake of 0.66g/kg body weight/day. Plant-based proteins
that do meet the requirements for essential amino acids
include soy (27%), brown rice (28%), pea (30%), corn (32%),
and potato (37%). Of the animal-based proteins, whey pro-
tein had the highest essential amino acid content of 43%.
Milk protein (39%) and calcium caseinate (38%) showed
an intermediate and casein (34%) and egg (32%) a lower
essential amino acid content. All animal-based proteins were
well above the WHO/FAO/UNU amino acid requirements.
Amino acid proles
Amino acid profiles differed substantially among plant-
based proteins with leucine contents as low as 5.1% in
hemp, 5.2% in lupin, and 5.8% in microalgae and as high
as 13.5% in corn and 8.3% in potato compared to 7.6% in
human skeletal muscle protein (Fig.3a). Despite the high
leucine content of corn and potato, the average leucine con-
tent of plant-based proteins was lower (7.1 ± 0.8%) when
compared with animal-based proteins (8.8 ± 0.7%). Lysine
and methionine contents are particularly low in plant-based
proteins (3.6 ± 0.6 and 1.0 ± 0.3%, respectively) when com-
pared with animal-based proteins (7.0 ± 0.6 and 2.5 ± 0.1%,
Oat
Lupin
Wheat
Hemp
Microalgae
Soy
Brown ri
ce
Pea
Corn
Potato
Whey
Milk
Caseinate
Casein
Egg
Human musc
le
0
10
20
30
40
50
EAA, % of total protein
Fig. 2 Mean (± SEM) essential amino acid (EAA) contents (% of
total protein) of various dietary protein sources and human skeletal
muscle protein. White bars represent plant-based protein sources,
grey bars represent animal-derived protein sources, and black bar
represents human skeletal muscle protein. Dashed line represents the
amino acid requirements for adults (WHO/FAO/UNU Expert Consul-
tation 2007). Note: EAA is the sum of His, Ile, Leu, Lys, Met, Phe,
Thr, and Val. Trp was not measured
0
5
10
15
A
Leucine, % of total protein
0
2
4
6
B
Isoleucine, % of total protein
Oat
Lupin
Wheat
Hemp
Mi
croalgae
Soy
Brown rice
Pea
Corn
Potato
Whey
Milk
C
aseinate
Casein
Egg
Hu
m
an muscle
0
2
4
6
C
Valine, % of total protein
Fig. 3 Mean (± SEM) leucine (a), isoleucine (b), and valine (c)
contents (% of total protein) of various dietary protein sources and
human skeletal muscle protein. White bars represent plant-based pro-
tein sources, grey bars represent animal-derived protein sources, and
black bar represents human muscle. Dashed line represents the amino
acid requirements for adults (WHO/FAO/UNU Expert Consultation
2007)
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1689
Protein content andamino acid composition ofcommercially available plant-based protein…
1 3
respectively) and human skeletal muscle protein (7.8 and
2.0%, respectively), but with great variability between
plant-based protein sources (Fig.4a, b). The lysine content
of wheat (1.4%), corn (1.5%), oat (2.1%), brown rice (2.4%),
hemp (2.8%), and lupin (3.5%) is below the WHO/FAO/
UNU requirements and substantially lower when compared
with soy (4.6%), microalgae (5.3%), pea (5.9%), and potato
(6.0%). Methionine contents were low in microalgae (0.0%),
oat (0.2%), lupin (0.3%), pea (0.4%), soy (0.4%), and wheat
(0.9%), but reached the WHO/FAO/UNU requirements in
potato (1.6%), corn (1.7%), hemp (2.0%), and brown rice
(2.5%). Less pronounced variability was observed between
plant-based and animal-based proteins in isoleucine, valine,
histidine, phenylalanine, and threonine contents. Except for
potato protein, the contents of the branched-chain amino
acids isoleucine and valine were lower in plant-based when
compared to animal-based proteins and did not reach the
WHO/FAO/UNU requirements. A complete overview of the
amino acid profiles as expressed in g/100g raw material is
presented in Table1.
Relative protein intake
Table2 shows representative amounts of protein or raw
material that need to be consumed to allow 2.7g of leu-
cine or 10.9g essential amino acids to be ingested, which
is the amount of leucine or essential amino acids present in
25g whey protein that has been shown to stimulate muscle
protein synthesis in humans (Gorissen etal. 2017; Mitchell
etal. 2015; Witard etal. 2014; Yang etal. 2012a). Between
20 and 54g of plant-based protein needs to be consumed to
ingest 2.7g leucine, which would be provided by, e.g., 31g
corn protein powder or 105g hemp protein powder. This
again highlights the variability among plant-based protein
sources.
Discussion
This study measures and compares amino acid composi-
tion of various plant-based protein isolates including oat,
lupin, wheat, hemp, microalgae, soy, brown rice, pea, corn,
and potato with animal-derived proteins and human skel-
etal muscle protein. We observed that plant-based proteins
have relatively low essential amino acid and leucine con-
tents when compared with animal-based proteins and human
0
2
4
6
8
10
A
Lysine, % of total protein
0
1
2
3
B
Methionine, % of total protein
0
1
2
3
4
C
Hisdine, % of total protein
0
2
4
6
D
Phenylalanine, % of total protein
Oat
Lupin
Wheat
Hemp
Microalgae
Soy
Brown rice
Pea
Corn
Potato
Whey
Milk
Casein
ate
Casein
Egg
H
um
an mu
scle
0
2
4
6
8
E
Threonine, % of total protei
n
Fig. 4 Mean (± SEM) lysine (a), methionine (b), histidine (c), phe-
nylalanine (d), and threonine (e) contents (% of total protein) of vari-
ous dietary protein sources and human skeletal muscle protein. White
bars represent plant-based protein sources, grey bars represent ani-
mal-derived protein sources, and black bar represents human muscle.
Dashed line represents the amino acid requirements for adults (WHO/
FAO/UNU Expert Consultation 2007)
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1690 S.H.M.Gorissen et al.
1 3
Table 1 Amino acid content of various dietary protein sources and human skeletal muscle
Values are presented in g per 100g raw material. Tryptophan, aspartic acid, asparagine, and glutamine were not measured
ΣEAA sum of all essential amino acids, ΣNEAA sum of all non-essential amino acids
Oat Lupin Wheat Hemp Microalgae Soy Brown rice Pea Corn Potato Whey Milk Caseinate Casein Egg Human muscle
Essential amino acids
Threonine 1.5 1.6 1.8 1.3 2.1 2.3 2.3 2.5 1.8 4.1 5.4 3.5 3.5 2.6 2.0 2.9
Methionine 0.1 0.2 0.7 1.0 0.0 0.3 2.0 0.3 1.1 1.3 1.8 2.1 2.2 1.6 1.4 1.7
Phenylalanine 2.7 1.8 3.7 1.8 2.1 3.2 3.7 3.7 3.4 4.2 2.5 3.5 4.2 3.1 2.3 3.8
Histidine 0.9 1.2 1.4 1.1 0.7 1.5 1.5 1.6 1.1 1.4 1.4 1.9 2.2 1.7 0.9 2.8
Lysine 1.3 2.1 1.1 1.4 3.6 3.4 1.9 4.7 1.0 4.8 7.1 5.9 5.9 4.6 2.7 6.6
Valine 2.0 1.4 2.3 1.3 2.1 2.2 2.8 2.7 2.1 3.7 3.5 3.6 3.8 3.0 2.0 4.3
Isoleucine 1.3 1.5 2.0 1.0 1.2 1.9 2.0 2.3 1.7 3.1 3.8 2.9 3.0 2.3 1.6 3.4
Leucine 3.8 3.2 5.0 2.6 4.0 5.0 5.8 5.7 8.8 6.7 8.6 7.0 7.8 5.8 3.6 6.3
ΣEAA 13.7 13.1 18.0 11.6 15.7 19.9 22.1 23.6 21.0 29.3 34.1 30.3 32.8 24.8 16.5 31.8
Non-essential amino acids
Serine 2.2 2.5 3.5 2.3 2.1 3.4 3.4 3.6 2.9 3.4 4.0 4.0 4.2 3.4 3.3 2.3
Glycine 1.7 2.1 2.4 2.1 2.6 2.7 3.4 2.8 1.6 3.2 1.5 1.5 1.5 1.2 1.4 3.1
Glutamic acid 11.0 12.4 26.9 7.4 5.7 12.4 12.7 12.9 13.1 7.1 15.5 16.7 16.0 13.9 5.1 13.1
Proline 2.5 2.0 8.8 1.8 2.3 3.3 3.4 3.1 5.2 3.3 4.8 7.3 8.7 6.5 1.8 0.0
Cysteine 0.4 0.2 0.7 0.2 0.1 0.2 0.6 0.2 0.3 0.3 0.8 0.2 0.1 0.1 0.4 0.0
Alanine 2.2 1.7 1.8 1.9 4.0 2.8 4.3 3.2 4.8 3.3 4.2 2.6 2.6 2.0 2.6 4.1
Tyrosine 1.5 1.9 2.4 1.3 1.2 2.2 3.5 2.6 2.7 3.8 2.4 3.8 4.4 3.4 1.8 2.0
Arginine 3.1 5.5 2.4 5.3 3.4 4.8 5.4 5.9 1.7 3.3 1.7 2.6 2.9 2.1 2.6 4.4
ΣNEAA 24.7 28.2 48.9 22.4 21.4 31.9 36.8 34.4 32.3 27.8 34.9 38.6 40.4 32.5 19.0 29.0
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1691
Protein content andamino acid composition ofcommercially available plant-based protein…
1 3
skeletal muscle protein. In addition, some but not all plant-
based protein isolates are low in lysine and/or methionine
contents. As there is a large variability in amino acid com-
position among the various plant-based protein sources, a
balanced combination of different plant-based proteins may
provide a high(er) quality protein blend.
World population growth in combination with increas-
ingly limited resources (arable land and fresh water) has
resulted in the need for alternative protein sources to meet
global protein requirements. The production of plant-based
foods requires less land and water and is associated with
lower greenhouse gas emissions compared with animal-
based foods. However, studies suggest that plant-based
proteins are of lesser quality with respect to their ability to
increase postprandial muscle protein synthesis rates. This
belief is mainly based on the very few studies that assessed
the muscle protein synthetic response to the ingestion of
soy protein (Phillips 2012; Tang etal. 2009; Wilkinson
etal. 2007; Yang etal. 2012b). Lower essential amino acid
contents and/or relative shortage of leucine, lysine, and/or
methionine in the protein may contribute to the lower ana-
bolic capacity of plant-based proteins. However, there is a
large variability in amino acid composition among different
plant-based protein sources. In a recent literature review, we
compared data on essential amino acid, leucine, lysine, and
methionine contents between various plant and animal-based
protein sources (van Vliet etal. 2015). This review used data
obtained from a large selection of publications that applied
many different analytical procedures to assess protein char-
acteristics such as nitrogen content and amino acid compo-
sition. In the current study, we collected a large number of
commercially available dietary protein powders and applied
the same analytical procedures on all protein sources, includ-
ing the Dumas combustion method to determine the protein
content of the protein powder (Jung etal. 2003) and ultra-
performance liquid chromatography tandem mass spectrom-
etry to assess the amino acid composition of the protein
sources (Waterval etal. 2009). Consequently, we compared
protein contents as well as essential and non-essential amino
acid contents and, more specifically, leucine, lysine, and
methionine contents between different plant-based proteins,
animal-based proteins, and human skeletal muscle protein.
Of the amino acids, the essential amino acids seem to
be primarily responsible for the postprandial stimulation
of muscle protein synthesis (Tipton etal. 1999a, b; Volpi
etal. 2003). There is a dose-dependent relationship between
the amount of essential amino acids ingested and the post-
prandial muscle protein synthetic response until a plateau
is reached (Cuthbertson etal. 2005). When identifying die-
tary protein sources that could effectively be used in dietary
interventions to promote muscle growth or prevent muscle
loss, it is important to consider the essential amino acid con-
tent of the dietary protein source. Although we observed
that the average essential amino acid contents of plant-based
proteins are generally lower when compared with animal-
based proteins and human skeletal muscle protein, certain
plant-based proteins have a relatively high essential amino
acid content. Soy, brown rice, pea, corn, and potato protein
have essential amino acid contents that meet the require-
ments as recommended by the WHO/FAO/UNU (WHO/
FAO/UNU Expert Consultation 2007) (Fig.2). In addition,
the essential amino acid content of potato protein (37%) is
in fact greater when compared with casein (34%) and egg
(32%). These data suggest that certain plant-based proteins
could theoretically provide sufficient essential amino acids
to allow a robust postprandial stimulation of muscle protein
synthesis.
Upon digestion and absorption, dietary protein provides
amino acids that serve as precursor for de novo muscle pro-
tein synthesis. Besides serving as precursors for de novo pro-
tein synthesis, certain amino acids can directly activate the
muscle protein synthetic machinery by activating mTORC1
and downstream anabolic signaling (Atherton etal. 2010).
Specifically, leucine has been shown to be sensed by Ses-
trin2 that promotes translocation of mTORC1 to the lyso-
somal membrane, where it becomes activated (Laplante
and Sabatini 2012; Saxton etal. 2016; Wolfson etal. 2016),
leading to activation of downstream signaling and subse-
quent stimulation of muscle protein synthesis. As such, the
Table 2 Representative amount of protein
Amount of a certain protein source that needs to be consumed to
provide 2.7g leucine or 10.9 g essential amino acids (i.e., the same
amount of leucine or essential amino acids ingested when consuming
25g whey protein)
ΣEAA sum of all essential amino acids
Matched for leucine Matched for ΣEAA
Amount of
protein (g)
Amount of
raw material
(g)
Amount of
protein (g)
Amount of
raw material
(g)
Oat 47 73 51 79
Lupin 52 86 50 83
Wheat 45 55 49 60
Hemp 54 105 48 93
Microalgae 48 69 48 69
Soy 40 55 40 55
Brown rice 37 47 39 49
Pea 38 48 37 46
Corn 20 31 34 52
Potato 33 41 30 37
Whey 25 32 25 32
Milk 31 39 28 36
Caseinate 30 35 28 33
Casein 34 47 32 44
Egg 39 77 34 66
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
1692 S.H.M.Gorissen et al.
1 3
leucine content of the ingested protein source forms a key
characteristic that modulates activation of the muscle protein
synthetic machinery after protein ingestion. In this regard,
we observed that hemp (5.1% leucine) and lupin (5.2% leu-
cine) do not meet the WHO/FAO/UNU requirements for leu-
cine of 5.9% (WHO/FAO/UNU Expert Consultation 2007),
whereas microalgae, oat, and wheat provide close to the
leucine requirements, and soy, pea, brown rice, potato, and
corn provide well above the leucine requirements (Fig.3a).
Interestingly, the leucine content of potato (8.3%) is greater
when compared with casein (8.0%) and egg (7.0%) and the
leucine content of corn (13.5%) is greater than whey (11.0%)
protein (compared to 7.6% in human skeletal muscle pro-
tein). It has been well established that the ingestion of 25g
whey protein (providing 2.7g leucine) results in a robust
stimulation of muscle protein synthesis rates (Gorissen etal.
2017; Mitchell etal. 2015; Witard etal. 2014; Yang etal.
2012a). Plant-based proteins could provide the same amount
of leucine by adjusting the amount of protein ingested. Due
to the greater leucine content of corn, ‘merely’ 20g of pro-
tein needs to be ingested to provide 2.7g leucine, while the
dietary protein dose of the other plant-based proteins would
need to be increased to 33g (potato), 37g (brown rice), 38g
(pea), 40g (soy), 45g (wheat), 47g (oat), 48g (microalgae),
52g (lupin), and 54g (hemp) (Table2). Ingesting these
amounts of protein may be sufficient to activate the muscle
protein synthetic machinery, assuming that 2.7g leucine is
sufficient to trigger this activation. Once activated, all amino
acids are required to serve as precursors for de novo tissue
protein synthesis and shortage of one or more specific amino
acids could compromise a sustained elevation in postpran-
dial muscle protein synthesis rates.
The lysine and methionine contents are generally low(er)
in plant-based when compared with animal-derived proteins
(WHO/FAO/UNU Expert Consultation 2007; van Vliet etal.
2015; Young and Pellett 1994). The current analysis con-
firms these findings and shows that methionine and lysine
contents are 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 human skeletal muscle protein (2.0 and
7.8%, respectively). Interestingly, we observed a greater
variability among the plant-based proteins, with some plant-
based proteins providing the requirements of lysine (4.5%)
and others providing the requirements of methionine (1.6%).
More specifically, soy, microalgae, and pea contain 4.6, 5.3,
and 5.9% lysine, respectively, but are low in methionine.
Alternatively, corn, hemp, and brown rice contain 1.7, 2.0,
and 2.5% methionine, respectively, but are low in lysine
(Fig.4a, b). Oat, lupin, and wheat protein are low in both
lysine and methionine, whereas potato protein contains suf-
ficient levels of both lysine (6.0%) and methionine (1.6%).
Studies investigating the anabolic properties of plant-
based proteins have shown that the muscle protein synthetic
response to the ingestion of soy (Tang etal. 2009; Wilkinson
etal. 2007; Yang etal. 2012b) and wheat protein (Gorissen
etal. 2016) is lower when compared with dairy protein. In
an attempt to increase the muscle protein synthetic response
to soy protein, Yang and colleagues (Yang etal. 2012b)
increased the protein dose from 20 to 40g, but the ingestion
of this higher dose of soy protein was not able to induce a
greater stimulation of muscle protein synthesis. We recently
showed that increasing the amount of wheat protein hydro-
lysate from 35 to 60g, thereby matching for the leucine con-
tent of 35g whey protein, was able to substantially increase
postprandial muscle protein synthesis rates (Gorissen etal.
2016). Although effective, simply increasing the dose of
plant-based proteins to compensate for their lower anabolic
properties may not always be practical or feasible. Of the ten
plant-based proteins included in the current analysis, potato
protein is the only protein source containing the WHO/FAO/
UNU requirements for all essential amino acids. Thus, when
consuming potato protein as the only dietary protein source
at the recommended adult protein intake level of 0.66g/kg/
day, sufficient amounts of all essential amino acids should
be consumed. It remains to be investigated whether the
ingestion of a single meal-like amount of potato protein
has the capacity to stimulate muscle protein synthesis. The
other nine plant-based protein isolates included in the cur-
rent analysis contain insufficient amounts of lysine and/or
methionine according to the WHO/FAO/UNU requirements.
The low lysine or methionine content of corn, hemp, brown
rice, soy, and pea protein can be compensated for by ingest-
ing 2–4 times more protein. Alternatively, combining corn,
hemp, or brown rice (low in lysine) with soy, microalgae,
or pea (low in methionine) at a 50/50 ratio results in pro-
tein blends with a more ‘complete’ amino acid composition.
These blends contain intermediate amounts of lysine and
methionine and require only 10–90% more protein to be con-
sumed to provide sufficient amounts of all essential amino
acids (instead of the 2–4 times higher dose when a single
protein source would be consumed). Oat, lupin, and wheat
protein are low in both lysine and methionine, which could
be compensated for by ingesting 3–8 times more protein.
However, a more realistic approach would be to combine
oat, lupin, or wheat protein with animal-based proteins. At
a 50/50 ratio, these blends require only 5–40% more protein
to be consumed to provide sufficient amounts of all essential
amino acids. Certainly, many more protein blends combin-
ing two or more protein sources at various ratios could be
created. Creating protein blends seems to offer benefits over
increasing the dose of protein consumed, as protein blends
can provide sufficient amounts of all essential amino acids at
a lower protein dose. Whether the ingestion of a single meal-
size bolus of these protein blends increases muscle protein
synthesis rates remains to be assessed. Promising results
have been obtained in both young (Reidy etal. 2013, 2014,
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
1693
Protein content andamino acid composition ofcommercially available plant-based protein…
1 3
2016) and older individuals (Borack etal. 2016) when using
a protein blend composed of 50% caseinate, 25% whey pro-
tein, and 25% soy protein. Future studies should assess the
anabolic properties of protein blends with a greater relative
amount of plant-based proteins, protein blends composed of
solely plant-based proteins designed to provide a more bal-
anced essential amino acid profile, and/or individual plant-
based proteins with a more optimal amino acid composi-
tion. Dietary intervention can then implement plant-based
proteins or protein blends with greater anabolic properties
as a more sustainable protein source to meet global protein
requirements and support overall growth, health, as well as
muscle mass maintenance throughout the lifespan.
In conclusion, there are large differences in amino acid
content and amino acid composition between the various
plant-based protein sources. Combinations of various plant-
based protein sources or blends of animal- and plant-based
proteins may provide protein characteristics that closely
reflect the typical characteristics of animal-based protein
sources.
Acknowledgements We gratefully acknowledge Wendy Sluijsmans,
Hasibe Aydeniz, and Janneau van Kranenburg for their technical
assistance.
Author contributions The authors’ contributions to the manuscript
were as follows: SHMG, LBV, and LJCvL designed the research;
SHMG, JJRC, JMGS, WAHW, and JB conducted the research; and
SHMG and LJCvL wrote the paper. All authors have read and approved
the final manuscript.
Funding Supported by Top Institute Food and Nutrition, which is a
public–private partnership on precompetitive research in food and
nutrition.
Compliance with ethical standards
Conflict of interest SHMG, JJRC, JMGS, WAHW, and JB reported no
conflicts of interest. LJCvL and LBV have received speaking honoraria
or consulting fees from Friesland Campina and Nutricia Research. The
industrial partners have contributed to the project through regular dis-
cussions.
Ethical approval All procedures performed in studies involving human
participants were in accordance with the ethical standards of the insti-
tutional and/or national research committee and with the 1964 Helsinki
declaration and its later amendments or comparable ethical standards.
This article does not contain any studies with animals performed by
any of the authors.
Open Access This article is distributed under the terms of the Crea-
tive Commons Attribution 4.0 International License (http://creat iveco
mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribu-
tion, and reproduction in any medium, provided you give appropriate
credit to the original author(s) and the source, provide a link to the
Creative Commons license, and indicate if changes were made.
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... The optimum pH value for Spirulina growth is in the range 9-10, where bicarbonate prevails in the bicarbonate/carbonate equilibrium [5]. This microalga can also cope with relatively high temperatures, with the optimum growth temperature somewhere between 30 and 35 • C [6], and produce and accumulate large quantities of proteins with all the essential amino acids [7]. Spirulina also produce phycobiliproteins, which are bright blue (phycocyanin and allophycocyanin) or fuchsia (phycoerythrin) water-soluble proteins that can be used in the nutraceutical, cosmetic, or pharmaceutical industries [8]. ...
... The produced biomass had all the essential amino acids (except for tryptophan, which was not determined). When compared to the composition of other conventional protein sources such as egg white, soybean or pea, summarised elsewhere [30], the content of valine (6.8%), histidine (8.3%), and lysine (7.5%) in the isolated proteins was especially high. ...
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... The PCH fraction presented the highest total amino acid profiles (203.76 mg/g) compared to the PE and PS. We also compared the amino acid compositions (% based on total amino acid) of the PE, PCH and PS with various plant protein isolates including microalgae, soy, pea, lupin and oat from the review of Gorissen et al. [20] (Table 4). We observed that aspartic acid was the most abundant amino acid in the PE and PS, while the PCH was glutamic acid-rich, which was similar to other plant proteins. ...
... These three duckweed proteins from W. globosa were rich in histidine, which is an essential amino acid associated with several health benefits including inflammatory, glucoregulatory, antioxidant and body weight management [23]. A combination of different plant-based proteins may be an alternative choice to achieve s higher-quality protein blend, utilizing the large variability of amino acid compositions among plant-based protein sources [20]. ...
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... Our amino acid profiles were consistent with other findings in research. Gorissen et al. (2018) previously reported similarities of commercially available plant-based protein isolates regarding low methionine concentrations and high glutamic acid and lysine concentrations. ...
... Cadaverine, a metabolite of lysine metabolism, was significantly associated with lysine concentration across all proteins at 24 h and the proteins with higher lysine concentrations (i.e., plant proteins and milk) saw higher concentrations. Gorissen et al. (2018) reported that milk protein has high levels of lysine, while soy and pea have high concentrations when compared to other plant protein isolates. Cadaverine is a poorly studied fermentation metabolite, but has the ability to be toxic at high levels (del Rio et al., 2019; Oliphant & Allen-Vercoe, 2019). ...
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Protein isolates are a growing market share in the food industry both as food ingredients and as supplements. All dietary habits can influence and alter the gut microbiome; however, little is known about how protein isolates from different sources will change the composition and function of the gut microbiota under high and low fiber conditions. The study aims to determine the microbiome response to plant and animal protein isolates under high- and low-dietary fiber (H/LDF) conditions. Six commercially available protein isolates (beef, egg white, milk, pea, and two soy protein isolates) were subjected to in vitro enzymatic digestion and dialysis followed by in vitro fermentation with four microbiomes differing in dietary history. Two fermentation media containing 0.1% and 1% fermentable carbohydrate simulated LDF and HDF conditions, respectively. Plant protein isolates, which were all from legumes, had similar amino acid profiles, while the animal protein isolates had very different amino acid profiles depending on source. Under the HDF condition, the microbiome was primarily saccharolytic and there were minimal differences in fermentation properties among the different digested protein isolates. In contrast, under the LDF condition, the microbiome was proteolytic, as evidenced by decreases in peptide concentrations during fermentation and unique shifts in microbiome composition and function during fermentation of the digested protein isolates. Under the LDF condition, digested milk protein isolate increased the abundance of bacteria in the Clostridia class and the Firmicutes phylum with concomitant increases in butyrate production. Flavonifractor and Intestinimonas, genera with butyrate-producing pathways, were identified as differentially abundant genera associated with digested milk protein isolate after 24 h of fermentation. Soy proteins also resulted in high butyrate production, but induced increases in Uncl_Lachnospiraceae, Lachnoclostridium, and Butyricicoccus genera, suggesting a different pathway for butyrate production compared with digested milk protein isolate. Although digested milk protein and soy protein isolates resulted in high butyrate production, they also led to the highest concentrations of undesirable protein fermentation metabolites, ammonia and cadaverine, during fermentation. Several amino acids were found to be significantly correlated to metabolite production under the LDF condition, with glutamate and proline having a significantly positive correlation with butyrate production. In conclusion, digested protein isolates have differential effects on the gut microbiome, but only under conditions where dietary fiber is limited. Notably, digested milk and soy protein isolates were highly butyrogenic and increased abundance of some beneficial gut microbial taxa, but also led to high concentration of deleterious protein fermentation metabolites. Advisor: Devin J. Rose
... Balanced meal frequency and total protein intake at each meal are more beneficial to MSP in older people (Loenneke et al., 2016;Smeuninx et al., 2020). Notably, animal-derived proteins are more widely recommended than plant-based proteins for sarcopenia owing to their comprehensive amino acids (Gorissen et al., 2018;Churchward-Venne, 2019), high digestibility, and low anti-nutritional factors (Gilani et al., 2012). In particular, branched-chain amino acids, including leucine, valine, and isoleucine, can increase muscle mass by directly promoting protein synthesis through activation of the mTOR signaling pathway (Katsanos et al., 2006;Le Couteur et al., 2020). ...
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Sarcopenia, a disorder characterized by age-related muscle loss and reduced muscle strength, is associated with decreased individual independence and quality of life, as well as a high risk of death. Skeletal muscle houses a normally mitotically quiescent population of adult stem cells called muscle satellite cells (MuSCs) that are responsible for muscle maintenance, growth, repair, and regeneration throughout the life cycle. Patients with sarcopenia are often exhibit dysregulation of MuSCs homeostasis. In this review, we focus on the etiology, assessment, and treatment of sarcopenia. We also discuss phenotypic and regulatory mechanisms of MuSC quiescence, activation, and aging states, as well as the controversy between MuSC depletion and sarcopenia. Finally, we give a multi-dimensional treatment strategy for sarcopenia based on improving MuSC function.
... The phosphorylation status (ratio of phosphorylated to total protein) of key proteins involved in the initiation of muscle protein synthesis are presented in Supplementary Eggs represent a high-quality protein source based upon a high and well-balanced essential amino acid content (well above the WHO/FAO/UNU requirements for adults) and a high digestible indispensable amino acid score (DIAAS) (16,17). Not surprisingly, ingestion of egg protein has been shown to robustly increase post-exercise muscle protein synthesis rates (18,19) with maximal muscle protein synthesis rates observed after ingesting 20-40 g protein (19). ...
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Background Egg protein is ingested during recovery from exercise to facilitate the post-exercise increase in muscle protein synthesis rates and, as such, to support the skeletal muscle adaptive response to exercise training. The impact of cooking egg protein on post-exercise muscle protein synthesis is unknown. Objectives To compare the impact of ingesting unboiled (raw) versus boiled eggs during post-exercise recovery on postprandial myofibrillar protein synthesis rates. Methods In a parallel design, forty-five healthy, resistance trained young men (age: 24 (95%CI: 23–25) y) were randomly assigned to ingest 5 raw eggs (∼30 g protein), 5 boiled eggs (∼30 g protein), or a control breakfast (∼5 g protein) during recovery from a single session of whole-body resistance-type exercise. Primed continuous L-[ring-13C6]-phenylalanine infusions were applied, with frequent blood sampling. Muscle biopsies were collected immediately after cessation of resistance exercise and at 2 and 5 h into the post-exercise recovery period. Primary (myofibrillar protein synthesis rates) and secondary (plasma amino acid concentrations) outcomes were analyzed using repeated-measures (Time*Group) ANOVA. Results Ingestion of eggs significantly increased plasma essential amino acid concentrations, with 20% higher peak concentrations following ingestion of boiled compared with raw eggs (Time*Group: P < 0.001). Myofibrillar protein synthesis rates were significantly increased during the post-exercise period when compared to basal, post-absorptive values in all groups (2–4 fold increase: P < 0.001). Postprandial myofibrillar protein synthesis rates were 20% higher after ingesting raw eggs (0.067%/h (95%CI:0.056–0.077); effect size (Cohen's d): 0.63), and 18% higher after ingesting boiled eggs (0.065%/h (95%CI:0.058–0.073); effect size: 0.69) when compared to the control breakfast (0.056%/h (95%CI:0.048–0.063), with no significant differences between groups (Time*Group: P = 0.077). Conclusions The ingestion of raw, as opposed to boiled, eggs attenuates the postprandial rise in circulating essential amino acid concentrations. However, post-exercise muscle protein synthesis rates do not differ after ingestion of 5 raw versus 5 boiled eggs in healthy young men. Trial registration: NL6506.
... This experiment was carried out by hydrolyzing approximately 50 milligrams of freeze-dried powder samples in 1 mL hydrochloric acid (6-N HCl, 24 h, 110 °C) [134]. After that, samples were cooled down to 4 °C and hydrochloric acid was evaporated under a nitrogen stream. ...
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This study examined the efficiency of fungal strain (Cunninghamella bertholletiae) isolated from the rhizosphere of Solanum lycopersicum to reduce symptoms of salinity, drought and heavy metal stresses in tomato plants. In vitro evaluation of C. bertholletiae demonstrated its ability to produce indole-3-Acetic Acid (IAA), ammonia and tolerate varied abiotic stresses on solid media. Tomato plants at 33 days' old, inoculated with or without C. bertholletiae, were treated with 1.5% sodium chloride, 25% polyethylene glycol, 3 mM cadmium and 3 mM lead for 10 days, and the impact of C. bertholletiae on plant performance was investigated. Inoculation with C. bertholletiae enhanced plant biomass and growth attributes in stressed plants. In addition, C. bertholletiae modulated the physiochemical apparatus of stressed plants by raising chlorophyll, carotenoid, glucose, fructose, and sucrose contents, and reducing hydrogen peroxide, protein, lipid metabolism, amino acid, an-tioxidant activities, and abscisic acid. Gene expression analysis showed enhanced expression of SlCDF3 and SlICS genes and reduced expression of SlACCase, SlAOS, SlGRAS6, SlRBOHD, SlRING1, SlTAF1, and SlZH13 genes following C. bertholletiae application. In conclusion, our study supports the potential of C. bertholletiae as a biofertilizer to reduce plant damage, improve crop endurance and remediation under stress conditions.
... PP was considered a high-quality protein because its balanced amino acid ratio can fulfil FAO/WHO recommendations [39]. Table 2 shows the results of the amino acid composition of PP with different DH samples. ...
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Pea protein (PP) was moderately hydrolyzed using four proteolytic enzymes including flavourzyme, neutrase, alcalase, and trypsin to investigate the influence of the degree of hydrolysis (DH) with 2%, 4%, 6%, and 8% on the structural and functional properties of PP. Enzymatic modification treatment distinctly boosted the solubility of PP. The solubility of PP treated by trypsin was increased from 10.23% to 58.14% at the 8% DH. The results of SDS-PAGE indicated the protease broke disulfide bonds, degraded protein into small molecular peptides, and transformed insoluble protein into soluble fractions with the increased DH. After enzymatic treatment, a bathochromic shift and increased intrinsic fluorescence were observed for PP. Furthermore, the total sulfhydryl group contents and surface hydrophobicity were reduced, suggesting that the unfolding of PP occurred. Meanwhile, the foaming and emulsification of PP were improved after enzymatic treatment, and the most remarkable effect was observed under 6% DH. Moreover, under the same DH, the influence on the structure and functional properties of PP from large to small are trypsin, alcalase, neutrase and flavourzyme. This result will facilitate the formulation and production of natural plant-protein-based products using PP.
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To mitigate the age-related decline in skeletal muscle quantity and quality, and the associated negative health outcomes, it has been proposed that dietary protein recommendations for older adults should be increased alongside an active lifestyle and/or structured exercise training. Concomitantly, there are growing environmental concerns associated with the production of animal-based dietary protein sources. The question therefore arises as to where this dietary protein required for meeting the protein demands of the rapidly aging global population should (or could) be obtained. Various non-animal–derived protein sources possess favorable sustainability credentials, though much less is known (compared with animal-derived proteins) about their ability to influence muscle anabolism. It is also likely that the anabolic potential of various alternative protein sources varies markedly, with the majority of options remaining to be investigated. The purpose of this review was to thoroughly assess the current evidence base for the utility of alternative protein sources (plants, fungi, insects, algae, and lab-grown “meat”) to support muscle anabolism in (active) older adults. The solid existing data portfolio requires considerable expansion to encompass the strategic evaluation of the various types of dietary protein sources. Such data will ultimately be necessary to support desirable alterations and refinements in nutritional guidelines to support healthy and active aging, while concomitantly securing a sustainable food future.
Article
Dairy milk, likely through its bioactive proteins, has been reported to attenuate postprandial hyperglycemia-induced oxidative stress responses implicated in cardiovascular diseases (CVDs). However, how its major proteins, whey and casein, alter metabolic excursions of the lipidome in persons with prediabetes is unclear. Therefore, the objective of this study was to examine whey or casein protein ingestion on glucose-induced alternations in lipidomic responses in adults (17 males and 6 females) with prediabetes. In this clinical study, participants consumed glucose alone, glucose + nonfat milk (NFM), or glucose with either whey (WHEY) or casein (CASEIN) protein, and plasma samples were collected at multiple time points. Lipidomics data from plasma samples was acquired using an ultra-high-performance liquid chromatography-high-resolution mass spectrometry-based platform. Our results indicated that glucose ingestion alone induced the largest number of changes in plasma lipids. WHEY showed an earlier and stronger impact to maintain the stability of the lipidome compared with CASEIN. WHEY protected against glucose-induced changes in glycerophospholipid and sphingolipid (SP) metabolism, while ether lipid metabolism and SP metabolism were the pathways most greatly impacted in CASEIN. Meanwhile, the decreased acyl carnitines and fatty acid (FA) 16:0 levels could attenuate lipid peroxidation after protein intervention to protect insulin secretory capacity. Diabetes-associated lipids, the increased phosphatidylethanolamine (PE) 34:2 and decreased phosphatidylcholine (PC) 34:3 in the NFM-T90 min, elevated PC 35:4 and decreased CE 18:1 to a CE 18:2 ratio in the WHEY-T180 min, decreased lysophosphatidylcholine (LPC) 22:6 and LPC 22:0/0:0 in the CASEIN-T90 min, and decreased PE 36:1 in the CASEIN-T180 min, indicating a decreased risk for prediabetes. Collectively, our study suggested that dairy milk proteins are responsible for the protective effect of non-fat milk on glucose-induced changes in the lipidome, which may potentially influence long-term CVD risk.
Chapter
Food proteins, depending on their origin, possess unique characteristics that regulate blood glucose via multiple physiological mechanisms, including the insulinotropic effects of amino acids, the activation of incretins, and slowing gastric emptying rate. The strategies aimed at curbing high blood glucose are important in preventing impaired blood glucose control, including insulin resistance, prediabetes and diabetes. The effect of proteins on blood glucose control can be achieved with high-protein foods short-term, and high-protein diets long-term using foods that are naturally high in protein, such as dairy, meat, soy and pulses, or by formulating high-protein functional food products using protein concentrates and isolates, or blended mixtures of proteins from different sources. Commercial sources of protein powders are represented by proteins and hydrolysates of caseins, whey proteins and their fractions, egg whites, soy, yellow pea and hemp which will be reviewed in this chapter. The effective doses of food protein that are capable of reducing postprandial glycemia start from 7 to 10 g and higher per serving; however, the origin of protein, and macronutrient composition of a meal will determine the magnitude and duration of their effect on glycemia. The theoretical and methodological framework to evaluate the effect of foods, including food proteins, on postprandial glycemia for substantiation of health claims on food has been proposed in Canada and is discussed in the context of global efforts to harmonize the international food regulation and labeling.
Article
Full-text available
Background: Resistance exercise leads to net muscle protein accretion through a synergistic interaction of exercise and feeding. Proteins from different sources may differ in their ability to support muscle protein accretion because of different patterns of postprandial hyperaminoacidemia. Objective: We examined the effect of consuming isonitrogenous, isoenergetic, and macronutrient-matched soy or milk beverages (18 g protein, 750 kJ) on protein kinetics and net muscle protein balance after resistance exercise in healthy young men. Our hypothesis was that soy ingestion would result in larger but transient hyperaminoacidemia compared with milk and that milk would promote a greater net balance because of lower but prolonged hyperaminoacidemia. Design: Arterial-venous amino acid balance and muscle fractional synthesis rates were measured in young men who consumed fluid milk or a soy-protein beverage in a crossover design after a bout of resistance exercise. Results: Ingestion of both soy and milk resulted in a positive net protein balance. Analysis of area under the net balance curves indicated an overall greater net balance after milk ingestion (P < 0.05). The fractional synthesis rate in muscle was also greater after milk consumption (0.10 ± 0.01%/h) than after soy consumption (0.07 ± 0.01%/h; P = 0.05). Conclusions: Milk-based proteins promote muscle protein accretion to a greater extent than do soy-based proteins when consumed after resistance exercise. The consumption of either milk or soy protein with resistance training promotes muscle mass maintenance and gains, but chronic consumption of milk proteins after resistance exercise likely supports a more rapid lean mass accrual.
Article
Full-text available
Population growth combined with increasingly limited resources of arable land and fresh water has resulted in a need for alternative protein sources. Macroalgae (seaweed) and microalgae are examples of under-exploited “crops”. Algae do not compete with traditional food crops for space and resources. This review details the characteristics of commonly consumed algae, as well as their potential for use as a protein source based on their protein quality, amino acid composition, and digestibility. Protein extraction methods applied to algae to date, including enzymatic hydrolysis, physical processes, and chemical extraction and novel methods such as ultrasound-assisted extraction, pulsed electric field, and microwave-assisted extraction are discussed. Moreover, existing protein enrichment methods used in the dairy industry and the potential of these methods to generate high value ingredients from algae, such as bioactive peptides and functional ingredients are discussed. Applications of algae in human nutrition, animal feed, and aquaculture are examined.
Article
Full-text available
Background: Previous work demonstrated that a soy-dairy protein blend (PB) prolongs hyperaminoacidemia and muscle protein synthesis in young adults after resistance exercise. Objective: We investigated the effect of PB in older adults. We hypothesized that PB would prolong hyperaminoacidemia, enhancing mechanistic target of rapamycin complex 1 (mTORC1) signaling and muscle protein anabolism compared with a whey protein isolate (WPI). Methods: This double-blind, randomized controlled trial studied men 55-75 y of age. Subjects consumed 30 g protein from WPI or PB (25% soy, 25% whey, and 50% casein) 1 h after leg extension exercise (8 sets of 10 repetitions at 70% one-repetition maximum). Blood and muscle amino acid concentrations and basal and postexercise muscle protein turnover were measured by using stable isotopic methods. Muscle mTORC1 signaling was assessed by immunoblotting. Results: Both groups increased amino acid concentrations (P < 0.05) and mTORC1 signaling after protein ingestion (P < 0.05). Postexercise fractional synthesis rate (FSR; P ≥ 0.05), fractional breakdown rate (FBR; P ≥ 0.05), and net balance (P = 0.08) did not differ between groups. WPI increased FSR by 67% (mean ± SEM: rest: 0.05% ± 0.01%; postexercise: 0.09% ± 0.01%; P < 0.05), decreased FBR by 46% (rest: 0.17% ± 0.01%; postexercise: 0.09% ± 0.03%; P < 0.05), and made net balance less negative (P < 0.05). PB ingestion did not increase FSR (rest: 0.07% ± 0.03%; postexercise: 0.09% ± 0.01%; P ≥ 0.05), tended to decrease FBR by 42% (rest: 0.25% ± 0.08%; postexercise: 0.15% ± 0.08%; P = 0.08), and made net balance less negative (P < 0.05). Within-group percentage of change differences were not different between groups for FSR, FBR, or net balance (P ≥ 0.05). Conclusions: WPI and PB ingestion after exercise in older men induced similar responses in hyperaminoacidemia, mTORC1 signaling, muscle protein synthesis, and breakdown. These data add new evidence for the use of whey or soy-dairy PBs as targeted nutritional interventions to counteract sarcopenia. This trial was registered at clinicaltrials.gov as NCT01847261.
Article
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Background: Muscle mass maintenance is largely regulated by basal muscle protein synthesis and the capacity to stimulate muscle protein synthesis after food intake. The postprandial muscle protein synthetic response is modulated by the amount, source, and type of protein consumed. It has been suggested that plant-based proteins are less potent in stimulating postprandial muscle protein synthesis than animal-derived proteins. However, few data support this contention. Objective: We aimed to assess postprandial plasma amino acid concentrations and muscle protein synthesis rates after the ingestion of a substantial 35-g bolus of wheat protein hydrolysate compared with casein and whey protein. Methods: Sixty healthy older men [mean ± SEM age: 71 ± 1 y; body mass index (in kg/m(2)): 25.3 ± 0.3] received a primed continuous infusion of l-[ring-(13)C6]-phenylalanine and ingested 35 g wheat protein (n = 12), 35 g wheat protein hydrolysate (WPH-35; n = 12), 35 g micellar casein (MCas-35; n = 12), 35 g whey protein (Whey-35; n = 12), or 60 g wheat protein hydrolysate (WPH-60; n = 12). Plasma and muscle samples were collected at regular intervals. Results: The postprandial increase in plasma essential amino acid concentrations was greater after ingesting Whey-35 (2.23 ± 0.07 mM) than after MCas-35 (1.53 ± 0.08 mM) and WPH-35 (1.50 ± 0.04 mM) (P < 0.01). Myofibrillar protein synthesis rates increased after ingesting MCas-35 (P < 0.01) and were higher after ingesting MCas-35 (0.050% ± 0.005%/h) than after WPH-35 (0.032% ± 0.004%/h) (P = 0.03). The postprandial increase in plasma leucine concentrations was greater after ingesting Whey-35 than after WPH-60 (peak value: 580 ± 18 compared with 378 ± 10 μM, respectively; P < 0.01), despite similar leucine contents (4.4 g leucine). Nevertheless, the ingestion of WPH-60 increased myofibrillar protein synthesis rates above basal rates (0.049% ± 0.007%/h; P = 0.02). Conclusions: The myofibrillar protein synthetic response to the ingestion of 35 g casein is greater than after an equal amount of wheat protein. Ingesting a larger amount of wheat protein (i.e., 60 g) substantially increases myofibrillar protein synthesis rates in healthy older men. This trial was registered at clinicaltrials.gov as NCT01952639.
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Background: To our knowledge the efficacy of soy-dairy protein blend (PB) supplementation with resistance exercise training (RET) has not been evaluated in a longitudinal study. Objective: Our aim was to determine the effect of PB supplementation during RET on muscle adaptation. Methods: In this double-blind randomized clinical trial, healthy young men [18-30 y; BMI (in kg/m(2)): 25 ± 0.5] participated in supervised whole-body RET at 60-80% 1-repetition maximum (1-RM) for 3 d/wk for 12 wk with random assignment to daily receive 22 g PB (n = 23), whey protein (WP) isolate (n = 22), or an isocaloric maltodextrin (carbohydrate) placebo [(MDP) n = 23]. Serum testosterone, muscle strength, thigh muscle thickness (MT), myofiber cross-sectional area (mCSA), and lean body mass (LBM) were assessed before and after 6 and 12 wk of RET. Results: All treatments increased LBM (P < 0.001). ANCOVA did not identify an overall treatment effect at 12 wk (P = 0.11). There tended to be a greater change in LBM from baseline to 12 wk in the PB group than in the MDP group (0.92 kg; 95% CI: -0.12, 1.95 kg; P = 0.09); however, changes in the WP and MDP groups did not differ. Pooling data from combined PB and WP treatments showed a trend for greater change in LBM from baseline to 12 wk compared with MDP treatment (0.69 kg; 95% CI: -0.08, 1.46 kg; P = 0.08). Muscle strength, mCSA, and MT increased (P < 0.05) similarly for all treatments and were not different (P > 0.10) between treatments. Testosterone was not altered. Conclusions: PB supplementation during 3 mo of RET tended to slightly enhance gains in whole-body and arm LBM, but not leg muscle mass, compared with RET without protein supplementation. Although protein supplementation minimally enhanced gains in LBM of healthy young men, there was no enhancement of gains in strength. This trial was registered at clinicaltrials.gov as NCT01749189.
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The differential ability of various milk protein fractions to stimulate muscle protein synthesis (MPS) has been previously described, with whey protein generally considered to be superior to other fractions. However, the relative ability of a whole milk protein to stimulate MPS has not been compared to whey. Sixteen healthy middle-aged males ingested either 20 g of milk protein (n = 8) or whey protein (n = 8) while undergoing a primed constant infusion of ring (13)C₆ phenylalanine. Muscle biopsies were obtained 120 min prior to consumption of the protein and 90 and 210 min afterwards. Resting myofibrillar fractional synthetic rates (FSR) were 0.019% ± 0.009% and 0.021% ± 0.018% h(-1) in the milk and whey groups respectively. For the first 90 min after protein ingestion the FSR increased (p < 0.001) to 0.057% ± 0.018% and 0.052% ± 0.024% h(-1) in the milk and whey groups respectively with no difference between groups (p = 0.810). FSR returned to baseline in both groups between 90 and 210 min after protein ingestion. Despite evidence of increased rate of digestion and leucine availability following the ingestion of whey protein, there was similar activation of MPS in middle-aged men with either 20 g of milk protein or whey protein.
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Background: Muscle mass maintenance is largely regulated by basal muscle protein synthesis rates and the ability to increase muscle protein synthesis after protein ingestion. To our knowledge, no previous studies have evaluated the impact of habituation to either low protein intake (LOW PRO) or high protein intake (HIGH PRO) on the postprandial muscle protein synthetic response. Objective: We assessed the impact of LOW PRO compared with HIGH PRO on basal and postprandial muscle protein synthesis rates after the ingestion of 25 g whey protein. Design: Twenty-four healthy, older men [age: 62 ± 1 y; body mass index (in kg/m(2)): 25.9 ± 0.4 (mean ± SEM)] participated in a parallel-group randomized trial in which they adapted to either a LOW PRO diet (0.7 g · kg(-1) · d(-1); n = 12) or a HIGH PRO diet (1.5 g · kg(-1) · d(-1); n = 12) for 14 d. On day 15, participants received primed continuous l-[ring-(2)H5]-phenylalanine and l-[1-(13)C]-leucine infusions and ingested 25 g intrinsically l-[1-(13)C]-phenylalanine- and l-[1-(13)C]-leucine-labeled whey protein. Muscle biopsies and blood samples were collected to assess muscle protein synthesis rates as well as dietary protein digestion and absorption kinetics. Results: Plasma leucine concentrations and exogenous phenylalanine appearance rates increased after protein ingestion (P < 0.01) with no differences between treatments (P > 0.05). Plasma exogenous phenylalanine availability over the 5-h postprandial period was greater after LOW PRO than after HIGH PRO (61% ± 1% compared with 56% ± 2%, respectively; P < 0.05). Muscle protein synthesis rates increased from 0.031% ± 0.004% compared with 0.039% ± 0.007%/h in the fasted state to 0.062% ± 0.005% compared with 0.057% ± 0.005%/h in the postprandial state after LOW PRO compared with HIGH PRO, respectively (P < 0.01), with no differences between treatments (P = 0.25). Conclusion: Habituation to LOW PRO (0.7 g · kg(-1) · d(-1)) compared with HIGH PRO (1.5 g · kg(-1) · d(-1)) augments the postprandial availability of dietary protein-derived amino acids in the circulation and does not lower basal muscle protein synthesis rates or increase postprandial muscle protein synthesis rates after ingestion of 25 g protein in older men. This trial was registered at clinicaltrials.gov as NCT01986842.
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