Highest ACE-inhibitory Activity Research Articles

Identification of a Novel ACE Inhibitory Hexapeptide from Camellia Seed Cake and Evaluation of Its Stability.

The camellia seed cake proteins (CP) used in this study were individually hydrolyzed with neutral protease, alkaline protease, papain, and trypsin. The results showed that the hydrolysate had the highest ACE inhibitory activity at 67.36 ± 0.80% after four hours of neutral protease hydrolysis. Val-Val-Val-Pro-Gln-Asn (VVVPQN) was then obtained through ultrafiltration, Sephadex G-25 gel chromatography separation, LC-MS/MS analysis, and in silico screening. VVVPQN had ACE inhibitory activity with an IC50 value of 0.13 mg/mL (198.66 μmol/L), and it inhibited ACE in a non-competitive manner. The molecular docking indicated that VVVPQN can combine with ACE to form eight hydrogen bonds. The results of the stability study showed that VVVPQN maintained high ACE-inhibitory activity in weakly acidic and neutral environments and that heat treatment (20-80 °C) and Na+, Mg2+, as well as Fe3+ metal ions had little effect on the activity of VVVPQN. Moreover, it remained relatively stable after in vitro simulated gastrointestinal digestion. These results revealed that VVVPQN identified in camellia seed cake has the potential to be applied in functional food or antihypertensive drugs.

ACE Inhibitory Peptides Derived from Muscovy Duck (Cairina moschata) Plasma.

In this study, angiotensin-converting enzyme inhibitory peptides (ACE-IPs) derived from Muscovy duck (Cairina moschata) plasma hydrolysate (MDPH) were investigated. According to the general research protocol for bioactive peptides, the crude ACE-IPs of Muscovy duck plasma were separated and purified by ultrafiltration, gel chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC). Then the components with the highest ACE inhibition potential were selected for identification. Finally, the inhibition mechanism was explored by molecular docking and in silico simulated digestion. A total of 121 peptides was detected, and five were screened for synthesis verification and molecular docking. The peptide VALSSLRP revealed high ACE inhibitory activity (91.67 ± 0.73%) because this peptide bound tightly to the S1' pocket and formed 3 hydrogen bonds. Meaningfully, this work provides some new information about the generation of ACE-IPs derived from duck blood plasma.

Impact of Gastrointestinal Digestion Simulation on the Formation of Angiotensin-I-Converting Enzyme Inhibitory (ACE-I) Peptides from Germinated Lamtoro Gung Flour.

The germination of lamtoro gung has been shown to increase the angiotensin-I-converting enzyme inhibitory (ACE-I) activity in previous studies. The 48 h germinated flour had the highest ACE-I activity. Administration of the gastrointestinal digestion (GID) simulation with commercial enzymes was expected to increase the ACE-I activity. However, the GID simulation to increase ACE-I in the germinated lamtoro gung flour has not been found. Therefore, this study aimed to evaluate the GID simulation of ACE-I peptides in sprouted lamtoro gung flour. This study also identified and characterised the peptide with the ACE-I activity. The GID simulation was performed using commercial pepsin (pH 2) and pancreatin (pH 7.5). Both simulations occurred at 37 °C for 240 min. The degree of hydrolysis, peptide concentration, and ACE-I activity was analysed. Samples with the highest ACE-I activity were then fractionated and identified, to determine the peptide responsible for the ACE-I activity. The 180 min GID simulation in the test sample showed the highest ACE-I activity (89.70%). This result was supported by an increased degree of hydrolysis (DH) and peptide concentrations throughout the GID simulation. The <1 kDa peptide fraction had the highest inhibitory activity and had the most elevated peptide portion (54.69%). Peptide sequences containing crucial amino acids were found in the <1 kDa peptide fraction. PRPPKPP, PPPPPGARAP, and PFPPSNPPP had proline in the C and N terminal residues. The peptides obtained also had other biological activities, such as a DPP IV inhibitor, an alpha-glucosidase inhibitor, and antioxidative activity. Based on the toxicity prediction, those peptides are non-toxic and safe to consume.

Novel angiotensin I-converting enzyme (ACE) inhibitory peptides from walnut protein isolate: Separation, identification and molecular docking study.

Walnut protein isolate was hydrolyzed using alcalase® to obtain angiotensin-I-converting enzyme (ACE) inhibitory (ACEI) peptides. The components with high ACEI activity were successfully purified from walnut protein isolate hydrolysates (WPIH) by ultrafiltration and G-25 gel chromatography. The 1520 peptides were identified by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Then the screening model of ACEI peptides was established by in silico approach. It was found that four ACEI active peptides (PPKP, YPQY, YLPP, and PKPP) were obtained with IC50 values ranging from 506 to 89 μmol/L, among which PPKP had the highest ACEI activity (IC50 =89 ± 1μmol/L). The four peptides mentioned above were novel, non-toxic, and resistant to gastrointestinal digestion. The molecular docking studies showed that the ACEI effect of ACEI peptide was mainly due to the interaction with residues of Gln281 and His353 in the ACE active pockets. In vivo availability of ACEI peptides showed that the probability of PPKP binding to ACE was 37.9% in the human body. Our studies suggest that the ACEI peptides derived from the WPIH can be considered functional foods that can prevent hypertension. PRACTICAL APPLICATIONS: Hypertension is a significant risk factor for cardiovascular and cerebrovascular disease, the leading cause of death worldwide. This study used a cost-effective method to isolate and identify potential ACEI peptides from the walnut meal. Since the walnut meal is often discarded in the processing of walnut products and thus pollutes the environment, the preparation of walnut meal into ACEI peptides can reduce the impact of hypertension on people and reduce environmental pollution. The experimental results show that walnut ACEI peptides are a safe and healthy nutritional product.

Single and Co-Cultures of Proteolytic Lactic Acid Bacteria in the Manufacture of Fermented Milk with High ACE Inhibitory and Antioxidant Activities

In this study, single and co-cultures of proteolytic Lactobacillus delberueckii subsp. bulgaricus ORT2, Limosilactobacillus reuteri SRM2 and Lactococcus lactis subsp. lactis BRM3 isolated from different raw milk samples were applied as starter cultures to manufacture functional fermented milks. Peptide extracts from fermented milk samples were evaluated after fermentation and 7 days of cold storage for proteolytic, angiotensin-converting enzyme (ACE) inhibitory and antioxidant activity by different methods including 2, 2′-diphenyl-1-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP), OH-radical scavenging, and total antioxidant (molybdate-reducing activity). The highest proteolysis was found in milk fermented by co-cultures of three strains. Fermentation with the mentioned bacteria increased ACE inhibitory and antioxidant activity of the final products which were dependent on peptide concentration. The crude peptide extract obtained from fermented milk with triple co-culture showed the highest ACE inhibitory activity (IC50 = 0.61 mg/mL) which was reduced after 7 days of cold storage (IC50 = 0.78 mg/mL). Similar concentration-dependent activities were found in antioxidant activity at different antioxidant assays. Overall, high proteolytic activity resulted in increased ACE inhibitory and antioxidant activities, but the highest activity was not necessarily found for the samples with the highest proteolytic activity. The results of this study suggest the potential of using co-cultures of L. delberueckii subsp. bulgaricus, L. reuteri and L. lactis subsp. Lactis to manufacture antihypertensive fermented milk.

Effects of dual-frequency slit ultrasound on the enzymolysis of high-concentration hydrolyzed feather meal: Biological activities and structural characteristics of hydrolysates

Ultrasound-assisted enzymolysis has been applied to improve conventional enzymolysis, while there are rare reports on the application of ultrasound to high-concentration feather protein enzymolysis. Therefore, the feasibility of dual-frequency slit ultrasound (DFSU) for enzymolysis of high-concentration hydrolyzed feather meal (HFM), as well as the biological activities and structural characteristics of hydrolysates were investigated. The single-factor test was used to optimize the ultrasonic processing parameters: substrate concentration, frequency mode, intermittent ratio, power density, and time. The results showed that protein recovery rate and conversion rate increased by 6.08% and 18.63% under the optimal conditions (200 g/L, 28/80 kHz, 5:2 s/s, 600 W/L, and 3 h) compared with conventional enzymolysis, respectively. The macromolecular proteins in hydrolysates were converted into micromolecular peptides (< 500 Da) when treated by DFSU, and antioxidant activity and angiotensin-I-converting enzyme (ACE) inhibitory activity of hydrolysates were increased. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images illustrated the microstructure changes of feather protein particles in the ultrasound-assisted enzymatic hydrolysates of HFM (UEH), including more porous, smaller, and more uniform. Additionally, the conformation of protein molecules was significantly affected (P < 0.05), including the increase in free sulfhydryl (SH), the decrease in disulfide bond (SS) and surface hydrophobicity (H0). Fourier transform infrared (FTIR) spectra analysis further showed that the secondary structure of feather proteins was modified with a reduction in α-helix, β-turn, and β-sheet, while an increase in random coil content was observed. These results indicated that DFSU could be a promising method to enhance high-concentration HFM for preparing peptide-rich hydrolysates with high antioxidant activity and ACE inhibitory activity.

Isolation, identification, molecular docking analysis, and cytoprotection of seven novel angiotensin I-converting enzyme inhibitory peptides from miiuy croaker byproducts-swim bladders

For efficiently utilizing the processing byproducts of miiuy croaker to prepare novel angiotensin I-converting enzyme (ACE) inhibitory (ACEi) peptides, in vitro gastrointestinal (GI) digestion method was screened and employed to prepare swim bladder hydrolysate with the highest ACEi activity. Subsequently, seven novel ACEi peptides were isolated from the hydrolysate and identified as DEGPE, EVGIQ, SHGEY, GPWGPA, GPFGTD, SPYGF, and VIGPF with molecular weights of 545.49, 544.58, 591.55, 583.63, 592.59, 569.60, and 531.63 Da, respectively. SHGEY and SPYGF exhibited remarkable ACEi activity with IC50 values of 0.86 ± 0.12 and 0.37 ± 0.06 mg/mL. Molecular docking experiment illustrated that the significant ACEi activity of SHGEY and SPYGF with the affinity of -8.7 and -9.7 kcal/mol mainly attributed to effectively combining with the ACEi active sites by hydrophobic interaction, electrostatic force and hydrogen bonding. Moreover, SHGEY and SPYGF could significantly up-regulate the nitric oxide (NO) production and decrease the endothelin-1 (ET-1) secretion in human umbilical vein endothelial cells (HUVECs), but also abolished the negative impacting of norepinephrine to the levels of NO and ET-1. Furthermore, SHGEY and SPYGF showed significant protection to HUVECs against H2O2 damage by increasing superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activity to lower the contents of reactive oxide species and malondialdehyde. Consequently, ACEi peptides derived from miiuy croaker swim bladders, especially SHGEY and SPYGF, are health-promoting ingredients for functional products as a supplementary treatment to hypertension and cardiovascular diseases.

Effects of Inherent Lactic Acid Bacteria on Inhibition of Angiotensin I-Converting Enzyme and Antioxidant Activities in Dry-Cured Meat Products.

The aim of this study was to investigate the inherent bacteria that contribute to expressing the angiotensin I-converting enzyme (ACE) inhibitory activity and the antioxidant activity of dry-cured meat products without a bacterial starter. Among the ten dry-cured meat product samples, Coppa and Milano salami exhibited high ACE inhibitory activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability, and oxygen radical absorbance capacity (ORAC). No consistent trend was observed in the pH values or the total peptide and imidazole dipeptide concentration of the products that exhibited high ACE inhibitory and antioxidant activities in the tested samples. To investigate the bacteria contributing to the ACE inhibitory and antioxidant activities of the product, 16S rRNA sequencing analysis, isolation, and identification of bacteria were performed using not only Coppa and Milano salami but also the Jamon Serrano and Parma prosciutto products that had low functional activities. Results suggest the Lactobacillales order, particularly the species Latilactobacillus sakei and Pediococcus pentosaceus, were the main inherent bacteria in Coppa and Milano salami, respectively, compared with the Jamon Serrano and Parma prosciutto products. Therefore, the inherent lactic acid bacteria in dry-cured meat products without bacterial starter is important for ACE inhibitory and antioxidant activities of the products.

Red and brown seaweeds extracts: A source of biologically active compounds

The biological activities of Porphyra sp., Gracilaria gracilis, Alaria esculenta and Saccharina latissima extracts prepared by enzymatic and ball milling-assisted methods and hot water were evaluated. Enzyme-assisted methods allowed the highest extraction yields. Alcalase-assisted extraction (EAA) was the most effective in the recovery of polyphenolic compounds and Porphyra sp. had the highest content. The efficiency of flavonoids extraction was highly dependent on the used method. Globally, Porphyra sp. and EAA extracts exhibited the highest antioxidant and chelating activities. The highest α-amylase inhibitory activity was determined in HW Porphyra sp. extract while EAA A. esculenta extract had the highest α-glucosidase inhibitory activity. The highest ACE inhibitory activity was obtained in EAA from S. latissima. None of the extracts showed antimicrobial activity against the tested bacteria. The results showed that Porphyra sp. and S. latissima are potentially useful as ingredient in functional foods and nutraceuticals.

Purification and Identification of an ACE-Inhibitory Peptide from Gracilaria tenuistipitata Protein Hydrolysates

Edible marine species are valuable sources of bioactive peptides. This study investigated the ACE-inhibitory activity of protein hydrolysates from the red algae Gracilaria tenuistipitata. Fifteen groups of protein hydrolysates were prepared by a two-step enzymatic hydrolysis of G. tenuistipitata: initial hydrolysis with several glycolytic enzymes, followed by three separate proteolytic reactions (Alcalase, Neutrase and Flavourzyme) for 2–10 h. Results showed that the hydrolysate GTN4H had the highest ACE-inhibitory activity in vitro. Furthermore, oral administration of GTN4H significantly reduced systolic blood pressure in spontaneously hypertensive rats. Fraction A derived from GTN4H displayed the highest ACE-inhibitory activity among fractions. Further purification of fraction A by RP-HPLC obtained a purified peptide (MW: 1776 Da) with 17 amino acids and 95.4% ACE-inhibitory activity.

전통누룩에서 분리한 non-Saccharomyces cerevisiae의 이화학적 및 기능적 특성

This study was conducted to evaluate the alcohol-producing abilities and functional characteristics of five strains of non-Saccharomyces cerevisiae (NSC), namely, Kluyveromyces marxianus KJ-L, Wickerhamomyces anomalus KJ-1, W. anomalus CP-2, Pichia anomalus HAN-1, and Meyerozyma guilliermondii SU-L, which were isolated from Korean traditional nuruk. The selected yeast strains produced large amounts of alcohol using a carbon source of 20% glucose and were identified as NSC based on their 18S rDNA sequences. The optimal growth temperature and pH of the NSC except for M. guilliermondii SU-L were 25°C and 4.0, respectively. Two NSC strains, KJ-L and CP-2, produced 5–10% more alcohol compared to that produced by S. cerevisiae LP (SC LP) control. Although the α-amylase and ß-glucosidase activities were slightly lower in the NSC strains than in the SC LP, glucoamylase activity was 1.4-fold higher in the NSC strains than in the SC LP. The α-glucosidase inhibition activity evaluated using 1% acarbose was 29-fold higher for K. marxianus KJ-L and P. anomalus HAN-1 than that of SC LP. The five strains of NSC exhibited higher angiotensin-converting enzyme inhibitory activity with inhibition rates of 51.7–61.7% compared to that of SC LP (37.3%). The tyrosinase inhibition activities of NSC (86.4-91.5%) and SC LP (94.9%) were significantly higher than that of the positive control, kojic acid. These NSC yeast show high potential for industrial application as domestic starters for manufacturing fermented foods and cosmetics based on their physiological activities and functional characteristics.

Angiotensin‐converting enzyme (ACE) inhibitory peptides from fermented sausages inoculated with Lactobacillus plantarum CD101 and Staphylococcus simulans NJ201

AbstractNatural ACE inhibitory peptides derived from food are considered to be an effective supplement for lowering blood pressure. This study investigated the effects of Lactobacillus plantarum CD101 and Staphylococcus simulans NJ201 on proteolysis and the sequence composition of ACE inhibitory peptides in fermented sausages. The ACE inhibitory activity of the inoculated group reached the maximum values on day 35 during the production of fermented sausages. A more positive effect in the hydrolysis of the sarcoplasmic and myofibrillar protein was observed in the inoculated group through sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS‐PAGE). The free amino acid content of the inoculated group was 865.21 ± 12.55 mg/100 g, which was significantly higher (P &lt; 0.05) than that of the control group. The molecular weight distribution showed a significant increase (P &lt; 0.05) in peptides with a molecular weight less than 1 kDa in the inoculated group. A total of thirty‐four peptides with high hydrophobicity were identified by liquid chromatograph‐mass spectrometer/mass spectrometer (LC–MS/MS). Furthermore, the peptides were isolated and purified using gel filtration chromatography (GFC) and reversed‐phased high‐performance liquid chromatography (RP‐HPLC). Eleven novel peptides were identified by Nano‐LC‐ESI‐MS/MS, in which VALSLSRP with X‐Pro structure exhibited the highest ACE inhibition rate (75.36 ± 2.45%). These results indicated that mixed starters are conducive to protein degradation and the formation of peptides with high ACE inhibitory activity, especially peptides less than 1 kDa, and could be used as a functional material for antihypertensive drugs.

Preliminary physiological, phenotypic, and probiotic characterization of Lactobacillus strains isolated from Anbaris-traditional Lebanese fermented dairy product

ABSTRACT In the present study, 30 lactic acid bacteria (LAB) strains were isolated from Anbaris, a traditional fermented dairy product manufactured in rural villages of Lebanon from goat milk with a distinct sharp taste, and identified as members of the Lactobacillus genus. Among these strains, twelve showed potential probiotic characteristics with acid and bile tolerance, angiotensin-converting enzyme (ACE) inhibitory activity, and antimicrobial capacity against Staphylococcus aureus, but not against E-coli. Pooled isolates have displayed a very high ACE inhibitory activity (>70%). These isolates also had a high tolerance to all pH values between 3.0 and 5.0, making Anbaris contain probiotic LAB that can cross saliva, upper and lower stomach, and the intestines. The isolates were also characterized using pulse-field gel electrophoresis (PFGE). The obtained results are the first to be collected on Anbaris. This increases the marketability of this product as a source of probiotics, nutritional, economical, and empowering women cooperatives in rural areas.

Physico-chemical properties, antioxidant activity, and ACE inhibitory activity of protein hydrolysates from wild jujube seed.

Wild jujube seed protein (WJSP) as one kind of functional food material has attracted much attention due to its highly nutritive and medicinal value in anti‐inflammatory and improving immunomodulatory ability. However, owing to its large molecular weight and complex structure, biological activities of WJSP were greatly limited and cannot be fully utilized by the human body. Therefore, how to improve the bioavailability of WJSP and develop promising WJSP nutritious materials is a great challenge. In this work, wild jujube seed protein hydrolysates (WJSPHs) were prepared from WJSP via enzymatic hydrolysis method, and their physico‐chemical properties, antioxidant activity, and angiotensin converting enzyme (ACE) inhibitory activity in vitro have been investigated for the first time. SDS–PAGE electrophoresis and size–exclusion chromatographic results indicate that WJSPHs have lower molecular weight distribution (< 5,000 Da) than WJSP. Circular dichroism (CD) spectroscopy and Fourier transform infrared spectroscopy (FTIR) results illustrated that random coil is the main secondary structure of WJSPHs. Antioxidant experiments indicate that WJSPHs exhibit high radicals‐scavenging ability of 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radicals (94.60%), 2,2′‐azinobis‐(3‐ethylbenzthiazoline‐6‐sulfonate) (ABTS+) radicals (90.84%), superoxide radicals (44.77%), and hydroxyl radicals (47.77%). In vitro, WJSPHs can significantly decrease the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), and increase the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px) in HepG2 cells. Moreover, ACE activity was found that can be significantly inhibited by WJSPHs (73.02%). Therefore, all previously mentioned results suggest that WJSPHs may be a promising antioxidant food to prevent oxidative‐related diseases in future.Practical ApplicationThis study shows that WJSPHs exhibit high antioxidant activity and ACE inhibitory activity in vitro, which provide potential application value as antioxidant peptides to prevent oxidative‐related diseases.

ACE-inhibitory activities of peptide fractions (

In this study, the effects of five adjunct lactobacilli on the formation of angiotensin-converting enzyme inhibitory (ACE-i) peptides in model cheeses were investigated. A total of seven peptide fractions (less than 3 kDa) were obtained by means of a fraction collector coupled with a HPLC system. ACE-i activity and peptide sequence analysis of the seven fractions were determined by RP-HPLC and then MALDI-ToF-MS techniques, respectively. Peptides produced from αs1- and κ-caseins had higher amounts compared to those produced by other caseins. There were considerable differences between the fractions in terms of peptide sequences and ACE-i activities. In general, the peptide fraction containing Lactobacillus delbrueckii ssp. bulgaricus exhibited a higher level of ACE-i activity (79.56%) than the other samples. The next highest ACE-i activity was determined in the cheese containing L. plantarum and significant differences were observed between the ACE-i activities of the fractions. The highest ACE-i activity was identified in fractions including f1 (51.39%) for L. casei, f6 (33.49%) for L. helveticus, f4 (46.62%) for L. helveticus DPC4571 and f1 (47.96%) for cheese containing non-adjunct culture. In conclusion, use of lactobacilli as an adjunct in model cheese increased the peptide types and amounts and also ACE-i activity.

Angiotensin Converting Enzyme (ACE) Inhibitory Activity and Extract Protein Profiles of Mung Beans (Vigna radiata L.) Tempeh which Fermented by Rhizopus sp

Angiotensin Converting Enzyme (ACE) is the enzyme which controls blood pressure. In patients with hypertension, ACE inhibitors are needed to decrease blood pressure. One type of ACE inhibitors is bioactive peptides from mung bean (Vigna radiata L.) tempeh. The aim of study is to know Angiotensin Converting Enzyme (ACE) inhibitory activity and profile of protein extract of mung beans (Vigna radiata L.) tempeh which fermented by Rhizopus sp. Mung beans were fermented with 0,2 and 0,4% Rhizopus sp for 42 hours, observations are made every 6 hours. The dissolved protein and degree of hydrolysis of mung bean protein tempeh extract were measured. The ACE inhibitory’s activity of this protein extract is expressed in percent and protein profile showed by SDS-PAGE. The result of study is the highest ACE inhibitory activity was obtained by mung beans tempeh fermented for 24 hours by 0.4% Rhizopus sp. Protein extract contains dissolved protein 351 mg/mL, the degree of hydrolysis was 18.68% and the ACE inhibitory activity was 75%. Profile protein from SDS-PAGE analysis showed the presence of proteins with molecular weights of 12, 54, 98 and 125 kDa. Therefore, mung beans tempeh has the potential to be developed to be functional antihypertensive foods.

Development of a low‐salt soy sauce with enhanced flavor and functionality with soy residue andTenebrio molitorlarvae powder

We developed a low-salt soy sauce from soy residue and T. molitor larvae powder. The salinity of low-salt soy sauce replaced by okara (LSO), T. molitor larvae powder (LST), or both okara and T. molitor larvae powder (LSOT) ranged between 9.87 and 12.47% with a pH of 5.4–6.3. LSO exhibited lower acidity (0.58) than LST (1.27) and LSOT (1.34). LSOT showed the highest protease activity, total nitrogen, and amino nitrogen content among the soy sauces. Glutamic acid was 10 times higher in LST and LSOT than in LSO. LST and LSOT had twice higher antioxidant capacities, whereas LSO had twice higher ACE inhibitory activity than low-salt or regular high-salt soy sauces. T. molitor larvae powder supplementation in soy sauce fermentation led to a significant increase in overall quality. Moreover, the synergistic effect of the mixture of okara and T. molitor larvae powder improved the functionality of low-salt soy sauce. Practical applications Soy sauce produced from fermented soybeans is widely used as a seasoning because of its unique flavor. However, it is classified as a high-salt seasoning. Okara is a soy product-derived waste material that is rich in dietary fibers, and Tenebrio molitor has become an alternative protein source with a low impact on the environment. Fermentation is a promising technique to approach consumers and gain acceptance of insect ingredients in food products, as well as to improve functionality. Using okara and T. molitor larvae powder for soy sauce production results in a savory low-salt product, which is expected to lower the risk of vascular disease and has high antioxidant capacities.

Isolation and characterization, antioxidant, and antihypertensive activity of novel bioactive peptides derived from hydrolysis of King Boletus mushroom

King Boletus mushroom protein hydrolysate (KBMPH) was prepared using bromelain and isolated by membrane ultrafiltration into four molecular size fractions (>10, 3–10, 1–3, and <1 kDa). All fractions were assessed for their characteristics, antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities. KBMPHF4 (<1 kDa) showed the highest surface hydrophobicity (S0), and high levels of hydrophobic amino acid (HAA). KBMPHF4 at 1 mg/mL exhibited antioxidative against DPPH• and ABTS•+ and linoleic acid oxidation, and ACE inhibitory activity (IC50 = 0.12 mg/mL). Peptide fraction-51 from ion-exchange-chromatography (IEC) showed high protein content, and biological properties. Three novel peptides (SETGGGHTTSCETDLGEFL, AAPLPGP, and GTDPTGEMLT) from F1 fraction had the highest antioxidant capacity and moderate ACE inhibitory activity. Six novel peptides (DLDLLEKGIRKT, NGGNAPI, VSWNVLQEP, DTGRGLGASH, IDDNLDNLIIKL, and LIYAQGFSK) from F4 fraction had moderate antioxidant capacity and the highest ACE inhibitory activity. LIYAQGFSK peptide had the greatest ACE-binding energy (−9.2 kcal/mol) through hydrogen bonds. Overall, novel peptides from KBMPHF4 could be potential use as natural antioxidants and antihypertensives in functional food and nutraceutical.

Preparation, Identification, Molecular Docking Study and Protective Function on HUVECs of Novel ACE Inhibitory Peptides from Protein Hydrolysate of Skipjack Tuna Muscle.

To prepare bioactive peptides with high angiotensin-I-converting enzyme (ACE)-inhibitory (ACEi) activity, Alcalase was selected from five kinds of protease for hydrolyzing Skipjack tuna (Katsuwonus pelamis) muscle, and its best hydrolysis conditions were optimized using single factor and response surface experiments. Then, the high ACEi protein hydrolysate (TMPH) of skipjack tuna muscle was prepared using Alcalase under the optimum conditions of enzyme dose 2.3%, enzymolysis temperature 56.2 °C, and pH 9.4, and its ACEi activity reached 72.71% at 1.0 mg/mL. Subsequently, six novel ACEi peptides were prepared from TMPH using ultrafiltration and chromatography methods and were identified as Ser-Pro (SP), Val-Asp-Arg-Tyr-Phe (VDRYF), Val-His-Gly-Val-Val (VHGVV), Tyr-Glu (YE), Phe-Glu-Met (FEM), and Phe-Trp-Arg-Val (FWRV), with molecular weights of 202.3, 698.9, 509.7, 310.4, 425.6, and 606.8 Da, respectively. SP and VDRYF displayed noticeable ACEi activity, with IC50 values of 0.06 ± 0.01 and 0.28 ± 0.03 mg/mL, respectively. Molecular docking analysis illustrated that the high ACEi activity of SP and VDRYF was attributed to effective interaction with the active sites/pockets of ACE by hydrogen bonding, electrostatic force, and hydrophobic interaction. Furthermore, SP and VDRYF could significantly up-regulate nitric oxide (NO) production and down-regulate endothelin-1 (ET-1) secretion in HUVECs after 24 h treatment, but also abolish the negative effect of 0.5 μM norepinephrine (NE) on the generation of NO and ET-1. Therefore, ACEi peptides derived from skipjack tuna (K. pelamis) muscle, especially SP and VDRYF, are beneficial components for functional food against hypertension and cardiovascular diseases.

Improving the enzymolysis efficiency of lupin protein by ultrasound pretreatment: Effect on antihypertensive, antidiabetic and antioxidant activities of the hydrolysates

This study evaluated the impact of ultrasound pretreatment (UP) and enzyme type (flavourzyme, alcalase) on amino acid composition, antihypertensive, antidiabetic, and antioxidant activities of lupin protein hydrolysate (LPH). The UP altered molecular weight of the hydrolysates as revealed by SDS-PAGE and MALDI-TOF and their surface hydrophobicity and thermal stability. Amino acid analysis revealed that glutamic acid, aspartic acid, arginine, and leucine were the dominant amino acids lupin protein. Generally, sonicated hydrolysates exhibited higher biological activity than non-sonicated samples and the original LPI. Alcalase hydrolysate pretreated for 10 min showed the highest DPPH and metal chelating activities. Highest ACE inhibitory activity was observed in flavourzyme hydrolysate after 5 min of UP, while maximum α-amylase and glucosidase inhibitory activity was achieved after 10 min of UP in flavourzyme hydrolysate. The results obtained in this study demonstrated the potentials of UP as a valuable tool for enhancing the biological activity of lupin proteins.