Pea Protein Hydrolysate Research Articles

<i>In </i><i>v</i><i>itro</i> Antioxidant Properties of Mango Powder Produced from Blends of <i>Brokin </i>and <i>Julie </i>Cultivars Fortified with Yellow Pea protein hydrolysate

The aim of the this study was to evaluate the in vitro antioxidant potential of mango powder prepared from blends of Brokin and Julie cultivars fortified with Yellow Pea protein hydrolysates. Six blends were used: *BCI, *JCII, *B80J20, *B70J30, *B60J40 and *B50J50. The fortified blends were derived by obtaining 90% of each of the original unfortified blend and incorporating to each of them, 10% of Yellow pea protein hydrolysate (YPPH). The results of the antioxidant assays were: % inhibition for DPPH radical scavenging activity includes 0.70(*BCI)-5.08%(*B70J30), 2.24(*JCII)-8.69%(*B60J40), 7.79 (*JCII)-12.46% (*BCI), 12.42 (*B60J40)-21.87% (*BCI), 20.60 (*B60J40)-38.57% (*BCI) and 30.08 (*B60J40)-69.64% (*BCI)} at dose concentration levels of 62.50g mL-1, 125.00g mL-1, 250.00µg/mL, 500.00g mL-1, 1000.00g mL-1 and 2000.00g mL-1 respectively; Metal chelating abilities include 51.84 (*B60J40)-66.98 (*B80J20), 64.49 (*JCII)-72.64 (*B50J50), 65.11 (*B60J40)-73.58 (*B80J20), 67.95 (*JCII)-74.59 (*B70J30) and 60.37(*JCII)-75.44% (*B70J30)} at concentrations of 50.00-250.00g mL-1 accordingly; ferric reducing antioxidant power (265.42-411.08µg.AAE mg-1) at those concentration level of 1000.00g mL-1 The % inhibition of hydroxyl radical scavenging activity showed that among all the samples at the concentration range of 62.50-2000.00g mL-1 respectively, samples, *B80J20 and *B50J50 exhibited highest and lowest radical scavenging activities accordingly. Clearly, the best antioxidant activity was observed to be metal chelating ability assay. Based on the aforementioned results, it is concluded that the fortified mango powder samples have good antioxidant activity in vitro which can treat and manage chronic disease condition such as oxidative stress.

Study of the functional properties and anti-oxidant activity of pea protein irradiated by electron beam

The effects of electron bean irradiation (EBI) on pea protein hydrolysates were examined. The EBI treatment of pea proteins results in an increase in the emulsifying properties of their hydrolysates. A dose-dependent phenomenon was observed, with the maximum effect occurring at 50 kGy. Both foaming capacity and stability increase as the irradiation dose increases and reaches a maximum at 10 kGy. Additionally, hydrolysates pre-irradiated at 50 kGy have the strongest scavenging effect, with the DPPH radical and ABTS+ radical scavenging activity levels increasing by 32.73% and 52.80%, respectively, compared to the control. Pretreatment with EBI prior to protease hydrolysis markedly increases surface hydrophobicity values of the hydrolysates when compared to the control. As the irradiation dose increases, the surface hydrophobicity values increase and eventually reach a maximum value of 174.09%. The molecular weight percentages for < 3 kDa fractions increases from 83.97% to 94.07% after 50 kGy electron beam irradiation treatment.

Immunomodulatory activity of protein hydrolysates derived from Virgibacillus halodenitrificans SK1-3-7 proteinase.

Modulation of inflammation-related immune response on THP-1 macrophages of protein hydrolysates derived from tilapia mince, casein and pea protein, were investigated. The protein substrates were hydrolyzed by Virgibacillus halodenitrificans SK1-3-7 proteinase. The degree of hydrolysis (DH) of casein was observed to be the highest throughout the course of hydrolysis. When challenging THP-1 macrophages, tilapia mince hydrolysate (TMH) enhanced innate immunity through induction of IL-1β and COX-2 expression. Anti-inflammatory activity was observed in casein hydrolysate (CH) and pea protein hydrolysate (PPH) by attenuating lipopolysaccharide- (LPS) induced pro-inflammatory gene expression in THP-1 macrophages. CH suppressed IL-1β, IL-6, IL-8, TNF-α and COX-2, while PPH reduced LPS-induced IL-6 and TNF-α responses. In addition, CH and PPH showed stronger suppression of LPS-induced pro-inflammatory gene expression compared with non-hydrolyzed casein and pea protein. These results suggest that TMH, CH and PPH prepared from V. halodenitrificans SK1-3-7 proteinase are potential functional food ingredients with immunomodulatory activity.

Antihypertensive Properties of a Pea Protein Hydrolysate during Short- and Long-Term Oral Administration to Spontaneously Hypertensive Rats.

This study investigated short-term (24 h) and long-term (5 wk) systolic blood pressure (SBP)-lowering effects in spontaneously hypertensive rats (SHR) of a 5 kDa membrane pea protein hydrolysate permeate (PPH-5) produced through thermoase hydrolysis of pea protein isolate (PPI). Amino acid analysis showed that the PPH-5 had lower contents of sulfur-containing amino acids than the PPI. Size-exclusion chromatography indicated mainly low molecular weight (<10 kDa) peptides in PPH-5 but not in the PPI. The PPH-5 had renin and angiotensin converting enzyme inhibition IC50 values of 0.57 and 0.10 mg/mL (P < 0.05), respectively, and consisted mainly of peptides with 2 to 6 amino acids. Mass spectrometry analysis revealed mainly hydrophilic tetrapeptide sequences. After a single oral administration (100 mg/kg body weight) to SHR, the unheated PPI showed weakest (P < 0.05) SBP-lowering effect with a -4 mm Hg maximum when compared to -25 mm Hg for heat-treated PPI and -36 mm Hg for PPH-5. Incorporation of the PPH-5 as 0.5% or 1% (w/w) casein substitute in the SHR diet produced maximum SBP reductions of -22 or -26 mm Hg (P < 0.05), respectively after 3 wk. In comparison, the unhydrolyzed PPI produced a maximum SBP reduction of -17 mm Hg also after 3 wk. Potency of the pea products decreased in the 4th and 5th wk, though SBP values of the treated rats were still lower than the untreated control. We conclude that the antihypertensive potency of PPH-5 may have been due to the presence of easily absorbed hydrophilic peptides.

Functional properties of pea protein hydrolysates in emulsions and spray-dried microcapsules

In the present study the impact of partial enzymatic hydrolysis on the functional properties of pea protein isolate (PPI) was investigated. PPI and pea protein hydrolysates (PPH) with various degrees of hydrolysis (DH) were characterised by molecular weight distribution, interfacial activity and dilatational rheology (pendant drop tensiometry) and emulsion properties (oil droplet size and ζ-potential). Their suitability for the microencapsulation of nutritional oils by spray-drying and prevention of hydroperoxide formation during storage was evaluated. Only at very low DH (1%), could stable emulsions be produced using alcalase PPH as emulsifier, most likely due to enhanced bulk aggregation, however the oil droplet size was increased compared to PPI-stabilised emulsions. In contrast, trypsin PPH-stabilised emulsions exhibited smaller oil droplets and an increased surface charge (ζ-potential) with increasing DH in comparison to PPI-stabilised emulsions. Differences observed were reflected in dilatational rheological experiments. Depending on the enzyme used to produce PPH, the dilatational moduli increased and the phase angle decreased (trypsin), i.e. stronger and more elastic interfacial layers were formed, or vice versa (alcalase). The PPI- and trypsin-derived PPH-containing emulsions were stable during atomisation and drying, resulting in high microencapsulation efficiencies (94.5–95.6%). Trypsin PPH exhibited a higher potential than PPI to reduce lipid oxidation of rapeseed oil in spray-dried emulsions during storage as demonstrated by hydroperoxide formation. This effect may be attributed to the altered physical properties of the interfacial film as well as the antioxidative effects of the hydrolysed proteins.

Enzymatic protein hydrolysates from high pressure-pretreated isolated pea proteins have better antioxidant properties than similar hydrolysates produced from heat pretreatment

Isolated pea protein (IPP) dispersions (1%, w/v) were pretreated with high pressure (HP) of 200, 400, or 600MPa for 5min at 24°C or high temperature (HT) for 30min at 100°C prior to hydrolysis with 1% (w/w) Alcalase. HP pretreatment of IPP at 400 and 600MPa levels led to significantly (P<0.05) improved (>40%) oxygen radical absorption capacity (ORAC) of hydrolysates. 2,2-Diphenyl-1-picrylhydrazyl, superoxide radical and hydroxyl radical scavenging activities of pea protein hydrolysates were also significantly (P<0.05) improved (25%, 20%, and 40%, respectively) by HP pretreatment of IPP. Protein hydrolysates from HT IPP showed no ORAC, superoxide or hydroxyl scavenging activity but had significantly (P<0.05) improved (80%) ferric reducing antioxidant power. The protein hydrolysates had weaker antioxidant properties than glutathione but overall, the HP pretreatment was superior to HT pretreatment in facilitating enzymatic release of antioxidant peptides from IPP.

Structural and functional characterization of yellow field pea seed (Pisum sativum L.) protein-derived antihypertensive peptides

The aim of this study was to identify and test the in vivo effectiveness of antihypertensive peptides present in a pea protein hydrolysate. Yellow field pea protein isolate was digested with thermolysin and the hydrolysate passed through a 3kDa ultrafiltration membrane. The permeate was collected as the PPH-3 and separated on a reverse-phase HPLC column into 10 peptide fractions. Fractions 3–8 showed inhibition of in vitro renin activity that ranged from approx. 21–68% while ACE activity was inhibited by fractions 2–10 in the range of 22–95%. Fraction 7 had the highest dual inhibitions of the two enzymes with 52.16 and 95.17% for renin and ACE, respectively. Fraction 7 was therefore, chosen for peptide characterization by tandem mass spectrometry, which led to sequencing of the following five peptides: LTFPG (534Da); IIPLEN (698Da); LSSGDVF (724Da); IFENLQN (877Da); and FEGTVFENG (999Da). LTFPG, IFENLQN and FEGTVFENG had significantly (P<0.05) higher inhibitions of ACE and renin activities and were orally administered to spontaneously hypertensive rats at a dose of 30mg/kg body weight. LTFPG showed significantly (P<0.05) the fastest decrease in systolic blood pressure (SBP) with a maximum of −37mmHg after 2h. In contrast the maximum effects of IFENLQN (−37mmHg) and FEGTVFENG (−25mmHg) were observed after 4h. Overall, the three peptides had significantly (P<0.05) better SBP-reducing effects than the PPH-3, which gave a maximum of −14mmHg after 6h.

Antioxidant activity of pea protein hydrolysates produced by batch fermentation with lactic acid bacteria

Nine Lactobacillus strains known for surface proteinase activity were chosen from our collection and tested for their ability to grow in pea seed protein-based medium, and to hydrolyze purified pea proteins in order to produce peptides with antioxidant (AO) activity. Two strains, Lactobacillus rhamnosus BGT10 and Lactobacillus zeae LMG17315, exhibited strong proteolytic activity against pea proteins. The AO activity of the pea hydrolysate fraction, MW &lt;10 kDa, obtained by the fermentation of purified pea proteins with Lactobacillus rhamnosus BGT10, was tested by standard spectrophotometric assays (DPPH, ABTS, Fe3+-reducing capacity) and the recently developed direct current (DC) polarographic assay. The low molecular weight fraction of the obtained hydrolysate was separated using ion exchange chromatography, while the AO activity of eluted fractions was determined by means of a sensitive DC polarographic assay without previous concentration of samples. Results revealed that the fraction present in low abundance that contained basic peptides possessed the highest antioxidant activity. Based on the obtained results, it can be concluded that Lactobacillus rhamnosus BGT10 should be further investigated as a candidate strain for large-scale production of bioactive peptides from legume proteins.

Stabilization of cooked cured beef color by radical-scavenging pea protein and its hydrolysate

The study was to investigate the role of pea protein for color stability of cooked cured beef and to understand potential mechanisms of color stabilization. Ground beef was either untreated or treated with 2 g/100 g pea flour (PF), pea protein isolate (PPI), or pea protein hydrolysate (PPH), nitrite-cured, then cooked to 72 °C. During storage at 2 °C up to 9 days in PVC package, color parameters (L*, a*, b*, nitrosylhemochrome, and pigment UV spectrum) were analyzed. Radical-scavenging activity [2,2′-azino-di-(3-ethylbenzthiazoline-6-sulfonic acid)] and ferric-reducing power of PF, PPI, and PPH and their inhibition of protein and lipid oxidation in the sarcoplasmic protein fraction were measured. All three pea protein products, most notably PPH, retarded color fading (7.0–16.9% less a* reductions, P < 0.05) and decomposition of nitrosylhemochrome (reduction rates of 41.4%, 37.7% and 28.1% for PF, PPI, and PPH, respectively, compared to 69.5% for control, P < 0.05) of cured beef after 9 days. These color protections corresponded with improved oxidative stability of sarcoplasmic proteins and residual lipids, corroborating the remarkable radical-scavenging and reducing power of these pea products. Meanwhile, the affinity of certain nitrogen-containing constituents for porphyrin iron was implicated in the cured meat color protection.

Synergistic inhibition of lipid oxidation by pea protein hydrolysate coupled with licorice extract in a liposomal model system.

Fourteen pea protein hydrolysates (PPHs) were prepared using different proteases and tested for antioxidant activity in a liposomal model system under oxidative stress (100 μM FeCl3/2 mM ascorbate). Almost all PPHs inhibited lipid oxidation, and those prepared from heated protein with Flavourzyme (Fla-PPH) or Protamex (Pro-PPH) were the most effective. Remarkable synergistic effects were observed on both Fla-PPH and Pro-PPH with licorice extract (LE). Electron microscopy revealed a self-assembled network that appeared to provide crucial protection of liposome against oxidation. The presence of LE enhanced the antioxidant potential by producing a more compact network apparently via PPH-LE complexation. Zeta-potential measurements suggested electrostatic interactions are important driving forces for the accumulation of active peptides at the liposome interface. Peptides rich in leucine, lysine, glutamic acid, glutamine, valine, or proline with a hydrophobic N-terminus, as identified by mass spectrometry, were implicated in the antioxidative protection.

Shrinking preoperative fast time with maltodextrin and protein hydrolysate in gastrointestinal resections due to cancer

ObjectiveProlonged preoperative fasting increases postoperative hospital length of stay and current evidence recommends patients drink a carbohydrate-based liquid drink 2 h before surgery. The aim of this study was to investigate whether the addition of hydrolyzed protein to a carbohydrate-based drink would reduce both the inflammatory response and hospital length of stay. MethodsWe evaluated 22 patients of both sexes, undergoing gastrointestinal resection due to cancer. Patients were randomized into two groups: control group (n = 12; 6–8 h fast) and the intervention group (n = 10; fasted to solids for 6 h; and given a beverage containing 11% pea protein hydrolysate and 89% carbohydrates (79% maltodextrin and 21% sucrose), 400 mL the night before and 200 mL 3 h before surgery. Blood samples were collected the morning before surgery and on postoperative day 2. ResultsOverall mortality was 4.5% (one case, control group). The duration of postoperative hospital stay was twofold longer in the control group (P = 0.04). A significant increase of serum C-reactive protein/albumin ratio was observed in controls compared with the intervention group (P = 0.04). ConclusionThe abbreviation of preoperative fasting time to 3 h using a solution containing carbohydrates and hydrolyzed pea proteins reduces the acute-phase inflammatory response and decreases the postoperative length of stay in patients undergoing major surgery for a malignancy.

Effects of isolation, enzymatic hydrolysis, heating, hydratation and Maillard reaction on the antioxidant capacity of cereal and legume proteins

The antioxidant capacity of maize proteins, wheat gluten, pea protein isolates and hydrolysates and melanoproteins (MRPs) was evaluated as a radical scavenging activity against ABTS (2,2-azino-bis/3-ethil-benothiazoline-6-sulfonic acid) reagent by the direct procedure. In addition, the effect of high temperature and water during thermal treatments on changes of the antioxidant capacity of proteins was investigated. The concentration of total cysteine, free sulfhydryl groups (−SH) and disulfide bonds (−S–S) were determined using Ellman's reagent, 5,5′-dithiobis (2-nitrobenzoic acid) (DTNB) and disodium 2-nitro-5-thiosulfobenzoate (NTSB2−). Wheat gluten, as the most complex protein, had higher concentration of disulfide bonds (45.37nmol/mg) and total cysteine (93.88nmol/mg) compared to other tested proteins and showed the highest ABTS radical scavenging activity (74.39mmol Trolox/kg). The antioxidative capacity of tested proteins was correlated negatively with free –SH group concentration and positively with total cysteine and –S–S bond concentration indicating a high effect of physical structure of a protein on its antioxidative properties. The antioxidant activity of melanoproteins formed in pea protein isolate/glucose model system during heating was threefold higher than that of initial pea protein. However, the highest amount of furosine was also formed in this model system under the same heating conditions.

Experimental immunology Pea protein hydrolysate as a factor modulating the adhesion of bacteria to enterocytes, epithelial proliferation and cytokine secretion – an in vitro study

Experimental immunology Pea protein hydrolysate as a factor modulating the adhesion of bacteria to enterocytes, epithelial proliferation and cytokine secretion – an in vitro study

Blood pressure lowering effect of a pea protein hydrolysate in hypertensive rats and humans.

The blood pressure lowering effect of a pea protein hydrolysate (PPH) that contained <3 kDa peptides, isolated by membrane ultrafiltration from the thermolysin digest of pea protein isolate (PPI), was examined using different rat models of hypertension as well as hypertensive human subjects. The PPH showed weak in vitro activities against renin and angiotensin converting enzyme (ACE) with inhibitory activities of 17 and 19%, respectively, at 1 mg/mL test concentration. Oral administration of the PPH to spontaneously hypertensive rats (SHR) at doses of 100 and 200 mg/kg body weight led to a lowering of hourly systolic blood pressure (SBP), with a maximum reduction of 19 mmHg at 4 h. In contrast, orally administered unhydrolyzed PPI had no blood pressure reducing effect in SHR, suggesting that thermolysin hydrolysis may have been responsible for releasing bioactive peptides from the native protein. Oral administration of the PPH to the Han:SPRD-cy rat (a model of chronic kidney disease) over an 8-week period led to 29 and 25 mmHg reductions in SBP and diastolic blood pressure, respectively. The PPH-fed rats had lower plasma levels of angiotensin II, the major vasopressor involved in development of hypertension, but there was no effect on plasma activity or renal mRNA levels of ACE. However, renal expression of renin mRNA levels was reduced by approximately 50% in the PPH-fed rats, suggesting that reduced renin may be responsible for the reduced levels of angiotensin II. In a 3-week randomized double blind placebo-controlled crossover human intervention trial (7 volunteers), significant (p<0.05) reductions (over placebo) in SBP of 5 and 6 mmHg were obtained in the second and third weeks, respectively, for the PPH group. Therefore, thermolysin derived bioactive peptides from PPH reduced blood pressure in hypertensive rats and human subjects, likely via effects on the renal angiotensin system.

Intragastric infusion of pea-protein hydrolysate reduces test-meal size in rats more than pea protein

Because protein hydrolysates are digested faster than the corresponding proteins, they may increase or hasten the acute eating-inhibitory effect of protein. Potential mediating mechanisms include accelerated or greater release of satiating gut peptides and activation of metabolic signals that inhibit eating. We tested these hypotheses in adult male rats that were surgically equipped with intragastric (IG) cannulas and adapted to 30-min test meals at dark onset after 14-h food deprivation. Equiosmotic 12ml loads of saline–urea control (C), 13.6% pea protein (PP), or 13.6% PP hydrolysate (PPH, DSM/DFS, Delft, The Netherlands) solutions were IG infused in 1min just before test meals. PPH reduced test-meal size compared to C more than PP (−3.8±0.3g vs. −2.6±0.4g; P<0.0001). Plasma glutamate increased more after PPH than PP (P<0.0001). Plasma lactate, alanine, insulin, glucagon, GLP-1 and paracetemol (an index of gastric emptying) all increased similarly, and glucose decreased similarly, after PPH or PP. Finally, PPH still reduced test-meal size more than PP (−4.6±0.3g vs. −3.1±0.4g; P<0.001) in rats after subdiaphragmatic vagal deafferentation, indicating that abdominal vagal afferents are not necessary for the eating-inhibitory effects of PP and PPH and, by extension, that gut peptides whose satiating effects depend on intact vagal afferents (e.g., CCK and glucagon) do not play crucial roles. Thus, PPH reduced short-term food intake more than PP under our conditions, but the mechanism(s) involved remain unclear.

Green Production of Anionic Surfactant Obtained from Pea Protein

AbstractA pea protein isolate was hydrolyzed by a double enzyme treatment method in order to obtain short peptide sequences used as raw materials to produce lipopeptides‐based surfactants. Pea protein hydrolysates were prepared using the combination of Alcalase and Flavourzyme. The influence of the process variables was studied to optimize the proteolytic degradation to high degrees of hydrolysis. The average peptide chain lengths were obtained at 3–5 amino acid units after a hydrolysis of 30 min with the mixture of enzymes. Then, N‐acylation in water, in presence of acid chloride (C12 and C16), carried out with a conversion rate of amine functions of 90%, allowed to obtain anionic surfactant mixtures (lipopeptides and sodium fatty acids). These two steps were performed in water, in continuous and did not generate any waste. This process was therefore in line with green chemistry principles. The surface activities (CMC, foaming and emulsifying properties) of these mixtures were also studied. These formulations obtained from natural renewable resources and the reactions done under environmental respect, could replace petrochemical based surfactants for some applications,.

Anti-oxidant, anti-inflammatory and immunomodulating properties of an enzymatic protein hydrolysate from yellow field pea seeds.

Enzymatic protein hydrolysates of yellow pea seed have been shown to possess high anti-oxidant and anti-bacterial activities. The aim of this work was to confirm the anti-oxidant, anti-inflammatory and immunomodulating activities of an enzymatic protein hydrolysate of yellow field pea seeds. The anti-oxidant and anti-inflammatory properties of peptides from yellow field pea proteins (Pisum sativum L.) were investigated in LPS/IFN-γ-activated RAW 264.7 NO⁻ macrophages. The immunomodulating potential of pea protein hydrolysate (PPH) was then studied in a murine model. Pea protein hydrolysate, after a 12 h pre-treatment, showed significant inhibition of NO production by activated macrophages up to 20%. Moreover, PPH significantly inhibited their secretion of pro-inflammatory cytokines, TNF-α- and IL-6, up to 35 and 80%, respectively. Oral administration of PPH in mice enhanced the phagocytic activity of their peritoneal macrophages and stimulated the gut mucosa immune response. The number of IgA+ cells was elevated in the small intestine lamina propria, accompanied by an increase in the number of IL-4+, IL-10+ and IFN-γ+ cells. This was correlated to up-regulation of IL-6 secretion by small intestine epithelial cells (IEC), probably responsible for B-cell terminal differentiation to IgA-secreting cells. Moreover, PPH might have increased IL-6 production in IECs via the stimulation of toll-like receptors (TLRs) family, especially TLR2 and TLR4 since either anti-TLR2 or anti-TLR4 was able to completely abolish PPH-induced IL-6 secretion. Enzymatic protein degradation confers anti-oxidant, anti-inflammatory and immunomodulating potentials to pea proteins, and the resulted peptides could be used as an alternative therapy for the prevention of inflammatory-related diseases.

Effects of cationic property on the in vitro antioxidant activities of pea protein hydrolysate fractions

Yellow pea seed protein-derived peptides were produced through enzymatic hydrolysis of pea protein isolate, which was followed by ultrafiltration to isolate peptides with < 3 kDa sizes (PPH). The PPH was separated by cation-exchange chromatography into five peptide fractions (F1–F5) based on their affinity for the stationary phase. F1 contained peptides with the least amount (7.5%) of cationic amino acids while F5 contained peptides with more than 50% content of cationic amino acids. F1–F5 peptide fractions were evaluated for in vitro antioxidant activities in comparison to glutathione (GSH), an endogenous antioxidant peptide. Results showed that the peptide fraction with the least cationic property (F1) had significantly strongest (p < 0.05) scavenging activity against 1,1-diphenyl-2-picrylhydrazyl radical and hydrogen peroxide (H 2O 2) when compared to F2–F5. Generally, the scavenging of O 2˙ − and H 2O 2 was negatively related with the cationic property of the peptide fractions. Fractionation according to cationic property resulted in significantly increased (p < 0.05) O 2˙ − scavenging power of the peptide fractions (F1–F5) when compared to the unfractionated PPH. The peptide fractions showed weak or nil ferric reducing power and, regardless of cationic property, were significantly (p < 0.05) more effective at inhibiting lipid oxidation than GSH over a 7-day period. In contrast, with the exception of H 2O 2 scavenging, GSH was a more effective antioxidant than PPH and the peptide fractions. We concluded that the PPH and some of its fractions have the potential to be used as therapeutic agents against chronic diseases that develop from oxidative damage, and that the cationic property of amino acids contributed negatively to the antioxidant activity of the peptide fractions.

Identification and inhibitory properties of multifunctional peptides from pea protein hydrolysate.

Pea protein isolate was hydrolyzed with alcalase, and the hydrolysate passed through a 1 kDa cutoff ultrafiltration membrane. The permeate was freeze-dried and fractionated on a cationic solid-phase extraction (SPE) column. All fractions were tested for their inhibitory activities against angiotensin-converting enzyme (ACE), renin, and calmodulin-dependent phosphodiesterase 1 (CaMPDE). With the exception of the first eluted fraction, inhibitory properties of the SPE fractions against CaMPDE (but not ACE and renin) were directly related to cationic character (residence time on the column). However, the fraction that eluted with 1% ammonium hydroxide (SPE 1%) had the highest peptide yield and was subsequently fractionated using two consecutive rounds of reversed-phase high-performance liquid chromatography to obtain three peaks with major peptides identified as IR, KF, and EF by ultra performance liquid chromatography-tandem mass spectrometry. The three dipeptides showed weak inhibitory properties toward CaMPDE but strong inhibitions (IC50 values <25 mM) of ACE and renin. In general, the peptides had higher potency against ACE than against renin. It is indicated from our results that these peptides may be used as potential ingredients to formulate multifunctional food products and nutraceuticals.

Angiotensin I-converting enzyme inhibitory activity of chickpea and pea protein hydrolysates

ACE inhibitory activity was studied for different hydrolysates obtained from protein concentrates of chickpea ( kabuli and desi ) and yellow pea ( Golden ) using in vitro gastrointestinal simulation, alcalase/flavourzyme, and papain. Protein/peptide profiles studied by SDS–PAGE and SE-HPLC, showed a rich composition of the hydrolysates in small peptides having MWs under 4 kDa. Papain hydrolysed yellow pea proteins showed the highest ACE inhibitory activity. In addition, chickpea desi proteins hydrolysed by in vitro gastrointestinal simulation showed higher ACE inhibition (IC 50 of 140 ± 1 μg/ml) compared to its digests obtained by alcalase/flavourzyme (IC 50 of 228 ± 3 μg/ml) or papain (IC 50 of 180 ± 1 μg/ml) and to chickpea kabuli hydrolysed by gastrointestinal simulation (IC 50 of 229 ± 1 μg/ml). The results demonstrate that enzymatic hydrolysates of chickpea and pea proteins contain bioactive ACE inhibitory peptides; furthermore, the type of enzyme used for hydrolysis affects the ACE inhibitory activity.