Egg White Protein Hydrolysates Research Articles

Antidiabetic activity of egg white protein hydrolysate in streptozotocin-induced diabetic rats

Egg white protein hydrolysate (EWH) has been reported to work as a cardiovascular protective agent. EWH exert antioxidant, vascular relaxing, anti-inflammatory properties and antihypertensive properties. This study aimed to assess the anti-diabetic and antihypertensive effect of the EWH in streptozotocin (STZ)-induced diabetic rats. Adult male Wistar rats were randomly divided into 2 main groups: normal and STZ-induced diabetes mellitus (DM) groups. Five subgroups of each main group were given distilled water, metformin (200 mg/kg), and EWH (300, 600, 1200 mg/kg) by oral gavage for 28 days (n=10 per each group). Fasting blood sugar level and OGTT were evaluated before and at the end of experiment. Each rat underwent monitoring of blood pressure using femoral artery. STZ-induced diabetic rats showed higher fasting blood glucose concentration and area under curve from OGTT than normal rats, which was significantly reduced by 600 mg/kg of EWH (p<0.05). STZ-induced diabetic rats showed higher mean arterial blood pressure than normal rats, which was significantly reduced by metformin (p<0.05). A decrease in hypertension in STZ-induced diabetic rats following EWH, but without significant difference, was observed. EWH may be useful in controlling the blood glucose level in diabetes mellitus and is therefore recommended for further studies. This work was supported by Suranaree University of Technology (SUT), Thailand Science Research and Innovation (TSRI), and National Science Research and Innovation Fund. (NSRF) (FF1-111-65-12-30(08)). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Influence of hydrodynamic cavitation on functional, nutritional, and structural characteristics of egg-white protein hydrolysates

The present work demonstrates the effect of hydrodynamic cavitation (HC) (2 mm Orifice plate) as a pretreatment for egg white protein hydrolysates (EWPH) production. The obtained EWPH was evaluated for various physiochemical (degree of hydrolysis), functional (emulsifying, foaming), structural and nutritional properties (antioxidant activity and in-vitro digestibility). The egg white solutions (5% solid content) were pretreated for 10, 15 and 20 min with HC and later hydrolyzed using papain enzyme for 90 min. The structural analysis revealed that HC unfolded the protein structure which was confirmed through the formation of β-sheet (from 15 to 46%) and loss of α-helix (34 to 14%) content with increasing treatment time. Through the exposure of hydrophobic bonds, the degree of hydrolysis and surface hydrophobicity increased, which eventually improved the nutritional and functional properties of EWPH. The HC-15 min treated samples had the highest zeta potential (-25.4 mV) with the lowest average particle size (346.5 nm) and denaturation temperature (70.67°C). Further increase in treatment time led to instability of hydrolysates. HC effectively improved the functional and nutritional properties of EWPH and a treatment time of 15 min is recommended for obtaining EWPH with improved properties.

Development of a Ready-to-Eat Fish Product Enriched with Fish Oil Entrapped in a κ-Carrageenan Egg White Fish Protein Hydrolysate Dry Powder.

This work describes the development of a ready-to-eat (RTE) product based on an equal mixture of fish mince from three undervalued fish species with different fat contents and protein gelling capacity, which was enriched with fish oil entrapped in a κ-carrageenan egg white fish protein hydrolysate powder, obtained by either spray drying (SD) or heat drying (HD) at 80 °C (HD80). Previously, the spray-dried (SD) powder and heat-dried powders obtained at 45 °C, 60 °C and 80 °C (HD45, HD60 and HD80) were characterised in terms of water solubility, lipid oxidation (TBARS), hygroscopicity and ζ potential. All HD powders showed higher hygroscopicity and lower TBARS than the SD powder. The dry powder was incorporated into a blend composed of salt-ground batter and raw mince to improve binding and textural properties. Changes in water-holding capacity, colour, shear strength and microorganisms were monitored during the processing steps. The RTE product presented a high protein content and a noticeable amount of long-chain ω-3 fatty acids. The use of undervalued fish species together with fish oil and a protein hydrolysate from fish waste contribute to improving the sustainability of fishery resources, being conducive to obtaining a potentially functional RTE product.

Egg white protein hydrolysate decreased blood pressure via the competing endogenous RNA regulatory networks in female spontaneously hypertensive rats.

Despite numerous studies having reported the effects and mechanisms of antihypertensive peptides including peptides derived from egg white proteins, the role of peptides in a female hypertensive animal model is unknown. On the other hand, the role of epigenetic modulation by peptide treatment has rarely been investigated. This study sought to investigate the effect of egg white protein hydrolysate (EWH) in female spontaneously hypertensive rats (SHRs) as well as to explore the underlying mechanisms from the perspectives of the transcriptome and the profiles of non-coding RNAs. Young (12-14-week-old) female SHRs were orally administered 250 mg per kg body weight (low-dose) or 1000 mg per kg body weight (high-dose) EWH daily for 10 weeks. The blood pressure of the rats was monitored weekly. The mRNA and non-coding RNAs (miRNA, lncRNA, and circRNA) in the aorta were profiled by the high-throughput RNA-seq technique. Differentially expressed (DE) RNAs in the aorta were identified for the construction of the competing endogenous RNA (ceRNA) networks and key molecules were validated by qRT-PCR. The treatment of the high-dose EWH showed a significant effect on reducing blood pressure in female SHRs. Bioinformatic analyses revealed 813, 90, 347 and 869 DE-mRNAs, DE-miRNAs, DE-lncRNAs and DE-circRNAs, respectively. The CNTN5-LncRNA-XR_001835895.1-miR-384-5p was identified as the central network which was validated in the aorta and circulation of female SHRs. The results from this study demonstrated that the treatment with EWH reduced blood pressure via regulating the ceRNA networks in female SHRs, which provided novel insights into the mechanisms of food protein-derived antihypertensive peptides.

Self-assembly and Hydrogelation Properties of Peptides Derived from Peptic Cleavage of Aggregation-prone Regions of Ovalbumin.

Egg white protein hydrolysate generated with pepsin was investigated for the presence of peptides with self-assembly and hydrogelation properties. Incubation of the hydrolysates for 16 h resulted in aggregates with significantly (p < 0.05) lower free amino nitrogen and sulfhydryl contents, and higher particle diameter and surface hydrophobicity compared to the hydrolysates. LC-MS/MS analysis of the aggregates resulted in identification of 429 ovalbumin-derived peptides, among which the top-six aggregation-prone peptides IFYCPIAIM, NIFYCPIAIM, VLVNAIVFKGL, YCPIAIMSA, MMYQIGLF, and VYSFSLASRL were predicted using AGGRESCAN by analysis of the aggregation “Hot Spots”. NIFYCPIAIM had the highest thioflavin T fluorescence intensity, particle diameter (5611.3 nm), and polydispersity index (1.0) after 24 h, suggesting the formation of β-sheet structures with heterogeneous particle size distribution. Transmission electron microscopy of MMYQIGLF, and VYSFSLASRL demonstrated the most favorable peptide self-assembly, based on the formation of densely packed, intertwined fibrils. Rheological studies confirmed the viscoelastic and mechanical properties of the hydrogels, with IFYCPIAIM, NIFYCPIAIM, VLVNAIVFKGL, and VYSFSLASRL forming elastic solid hydrogels (tan δ < 1), while YCPIAIMSA and MMYQIGLF formed viscous liquid-like hydrogels (tan δ > 1). The results provide valuable insight into the influence of peptide sequence on hydrogelation and self-assembly progression, and prospects of food peptides in biomaterial applications.

Egg white protein hydrolysate ameliorated sepsis-induced inflammatory injuries in kidney and liver based on metabolomics analysis

Sepsis caused by infection could induce systemic inflammation and various organ damages. Bioactivities of peptides derived from eggs were proved by lots of researchers; hence they might be further developed for therapeutic use. In this study, the hydrolysate named “PEP” was obtained by enzymatic hydrolysis and purification. Rats were divided into control, LPS, PEP1 and PEP2 groups. The rat model was established using lipopolysaccharide (LPS) at 10 mg/kg by intraperitoneal injection. The results of blood counts, pro-inflammatory cytokines (TNF-α and IL-6), BUN and Cr levels and pathological damage in tissue or serum suggested that PEP alleviated LPS-induced injuries. Plasma metabolites of PEP were analyzed and identified using UPLC-MS/MS, which revealed that seven pathways might play critical roles in the protection process, involved in oxidative stress, energy and amino acid metabolism. Our data suggest that PEP ameliorated LPS-induced acute liver and kidney injuries, which is helpful for further development and research.

Comparison of the effect of different desugarization techniques on the functionality of egg white protein hydrolysates

Desugarization is an important technique in industrial egg processing to maintain the color and shelf life of egg white powder. Its effect on proteolysis of egg white protein is essential in understanding the functionality changes in the obtained hydrolysate. Two desugarization methods, including yeast fermentation and enzyme desugarization using glucose oxidase are commonly employed in industrial scale egg white processing but the suitable method which can improve egg white protein hydrolysates' functionality has not yet been reported. Thus, the present work compares the physicochemical, functional, and surface properties of egg white protein hydrolysates obtained through both the desugarization methods. Alcalase enzyme (2% w/w) was used for enzyme hydrolysis. The degree of hydrolysis of desugared egg white hydrolysate was higher than the non-desugared samples by 34.5%. The desugared samples (especially yeast fermented) had higher foaming and emulsifying ability than non-desugared samples; however, it showed emulsion activity index and surface hydrophobicity. Compared to native protein, the in-vitro trypsin digestibility of desugared hydrolysate samples was significantly (p<0.05) higher. The antioxidant properties increased with hydrolysis, with yeast desugared hydrolysate samples having the highest antioxidant activity (63.8%).

Dietary egg white protein hydrolysate improves orotic acid-induced fatty liver in rats by promoting hepatic phospholipid synthesis and microsomal triglyceride transfer protein expression

We investigated the effects of egg white protein hydrolysates (EWH) on orotic acid (OA)-induced nonalcoholic fatty liver (NAFL) in rats. Effects of the egg white protein (EWP) and EWH were also compared. Four groups of male Sprague-Dawley rats were separately fed AIN-76-based diets, supplemented with 20% casein for control, or with 1% OA, together with either 20% casein (OA), 20% EWP, or 20% EWH, respectively, for 3 d (developing stage) and 14 d (developed stage). In both feeding periods, animals from the OA group showed higher accumulation hepatic triacylglycerol (TAG) compared with those from the control group. In the 14-d experiment, dietary EWP and EWH significantly reduced the hepatic TAG levels. Intake of EWP reduced liver fat in OA-fed rats by 61%, while EWH reduced it by 92%. In addition, EWH restored the OA-induced high serum-TAG level to that seen in the control group. The 3 d experiment showed that consumption of EWH improved the expression of hepatic MTP, that was reduced by OA, without changing Mttp gene expression. It also increased the hepatic synthesis of PC and PE by enhancing the transcription of Pcyt1 and Pemt genes. Inclusion of EWP and EWH in the diet improves the OA-induced NAFL. EWH reduces the liver TAG better than EWP, and works more rapidly. Dietary EWH ameliorates OA-induced NAFL by promoting the secretion of hepatic TAG.

Production of egg white hydrolysate by digestion with pineapple bromelain: optimization, evaluation and antioxidant activity study.

Chicken egg white is known to be an excellent source of good quality proteins to make hydrolysate with potential bioactive properties. Enzymatic digestion is a well-known method to produce protein hydrolysates; however, the type of enzyme determines the bioactive potential of the protein hydrolysates due to difference in their catalytic specificity. In this study, process optimization, production and evaluation of whole egg white protein hydrolysate (WEWPH) using pineapple bromelain through the Box-Behnken design were carried out. The design experiment (r2 = 0.9557) displayed a significant (p < 0.01) effect of pH of egg white (9.0), hydrolysis time (24 h), and enzyme/substrate ratio (3.2 unit/g substrate) on hydrolysis and to form bioactive WEWPH. Antioxidant activity of the WEWPH was confirmed by DPPH radical scavenging assay. Gel filtration chromatography, SDS-PAGE and FTIR spectroscopy analysis of WEWPH revealed the digestion of egg white and the integrity of WEWPH in terms of secondary structure. The WEWPH exhibited strong scavenging activities of DPPH (EC50 = 238.3 µg/ml), ABTS ABTS (EC50 = 54.9 µg/ml), peroxyl (EC50 = 391.6 µg/ml) and superoxide radicals. The WEWPH also displayed reducing power and singlet oxygen quenching activity. These results reveal that the bioactive WEWPH could be a promising ingredient in health food and nutraceuticals.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13197-021-05188-0.

Mechanisms of plastein formation influence the IgE-binding activity of egg white protein hydrolysates after simulated static digestion

Egg is the second most common food allergen among infants and young children. This work investigated the influence of plastein reaction on immunoglobulin E (IgE)-binding activities of egg white protein hydrolysates after simulated gastrointestinal (GIT) digestion. Compared to hydrolysate precursors, the IgE-binding activity of Pepsin-Plastein significantly decreased from 35 ± 7% to 8 ± 2% (P < 0.05), and Papain-Plastein from 70 ± 5% to 59 ± 4%. Further GIT hydrolysis of Pepsin-Plastein maintained the reduced IgE-binding activity (7 ± 3%) whereas Papain-Plastein digestion restored the IgE-binding reactivity to 66 ± 7%. This discrepancy is related to the different mechanisms of plastein formation. Covalent modifications (decreased free amino nitrogen and sulfhydryl contents) provided biostability for Pepsin-Plastein, whereas hydrophobic interactions (increased surface hydrophobicity) mainly contributed to Papain-Plastein formation. The latter can be destroyed during GIT digestion leading to re-exposure of hidden IgE-binding epitopes. Taken together, plastein reaction is a promising strategy for inducing structural modifications that reduce the immune reactivity of allergenic proteins.

Production of angiotensin I-converting enzyme inhibitor derived from egg white protein hydrolysates using a membrane reactor

Egg white proteins (EWP) were hydrolyzed with four proteolytic enzymes, including Thermolysin, Alcalase, Esperase and Chymotrysin, to produce hydrolysates with angiotensin I-converting enzyme (ACE) inhibitory activity. The result indicated that EWP hydrolyzed for 0.5-24 hr with Thermolysin produced the highest ACE inhibitory activity among the four enzymes. Therefore, EWP-Thermolysin hydrolysate was produced and further fractionated using several membranes with molecular weight cut-off (MWCO) of 10,000, 3,000 and 1,000 daltons, sequentially. The 1 kDa permeate obtained from the hydrolysate treatment using 1,000 daltons MWCO membrane could further reduce its IC50 value from 54.1 to 17.2 μg protein/mL. A lower IC50 value represented higher ACE inhibitory activity. The operation stability study showed that the membrane reactor system could maintain a steady production of EWP-Thermolysin hydrolysate over 8 hr. The gastrointestinal protease in vitro effect on the ACE inhibitory activity of 1 kDa permeate indicated that gastrointestinal proteases have no significant effect (p＞0.05) on the ACE inhibitory activity of 1 kDa permeate.

Fabrication egg white gel hydrolysates-stabilized oil-in-water emulsion and characterization of its stability and digestibility

This paper investigated the properties of egg white protein hydrolysate (EH) prepared from alkali-induced egg white gel as an oil-in-water emulsion stabilizer. The physicochemical properties of EH, including Fourier transform infrared (FTIR), surface hydrophobicity, particle size, zeta potential and polydispersity index were investigated. Meanwhile, the microstructure, emulsion stability, oil oxidative stability, in vitro digestive stability and antioxidant activity of emulsion prepared by EH were evaluated. Results suggested that the surface hydrophobicity of EH decreased due to the destruction of hydrophobic groups, and the particle size of most hydrolysates ranged from 124.24 to 197.7 nm, except neutrase and alcalase hydrolysates. FTIR revealed that the strength of each peak increased significantly after hydrolysis owing to the break of structure and peptide bond. Most EH-stabilized emulsions were stable against droplets aggregation as influenced by temperature, and emulsion prepared from trypsin hydrolysate exhibited better ionic strength and storage stability. Emulsion stabilized by trypsin and alcalase hydrolysates delayed the lipids oxidation during storage. Droplet aggregation occurred to emulsions after in vitro digestion due to the destruction of the emulsion structure and the accumulation of proteins and lipids, and the release rate of free fatty acids ranged from 55.72% to 77.29% in the 2 h vitro intestine digestion for six different emulsions. Additionally, most digested EH-stabilized emulsion enhanced its ability to scavenge DPPH, ABTS and O2− free radical, owing to the formation of antioxidant peptides. These results suggest that EH can be as a potential stabilizer for emulsions, especially trypsin hydrolysate, and possesses antioxidant properties after digestion.

Enzymatic Hydrolysis of Egg White Protein Exerts a Hypotensive Effect in Spontaneously Hypertensive Rats

This study was conducted to investigate the hypotensive effect of egg white protein (EWP) hydrolysate (EWH) in spontaneously hypertensive rats (SHRs). The hydrolysis of EWP was effectively performed with a combination of 0.5% bromelain and 1% papain at 50°C for 60 min. The resulting hydrolysate did not elicit an allergic reaction as confirmed by human mast cell activation test. The systolic and diastolic blood pressures of the SHRs fed the EWH diet were observed to be significantly or numerically lower than those of the other groups during the experimental period of 28 d. EWH treatment significantly (p<0.05) upregulated the nitric oxide levels in hCMEC/D3 cells and the plasma of the SHRs compared to those in the control. Moreover, EWH ingestion significantly (p<0.01) reduced the plasma angiotensin II level of the SHRs compared with that in the control. In conclusion, beyond its basic nutritional value, EWH prevents and manages hypertension, and thus can be an invaluable resource for functional food development.

Influence of ultrasound probe treatment time and protease type on functional and physicochemical characteristics of egg white protein hydrolysates.

The objective of this study was to discover the relationship between the ultrasound probe treatment (UPT) on egg white proteins (EWPs) before EWPs hydrolysis by different proteases, and the functional properties of the obtained hydrolysates. To fulfill this goal, the protein solubility, foaming, and emulsifying properties were studied as a function of the UPT time and then related to the surface characteristics and structural properties. The changes in the hydrolysates microstructures and macromolecular conformation, induced by the UPT, were followed using scanning electron microscope analyzis (SEM) and Fourier transforms infrared spectroscopy (FTIR). The results showed that UPT influenced (P < 0.05) the proteolysis of egg white proteins for all examined treatment times. Alcalase hydrolysates (AHs) and papain hydrolysates (PHs) were found to have a higher solubility, as a consequence of their relatively higher foaming, and emulsifying properties compared to the untreated hydrolysates. The changes in surface hydrophobicity, sulfhydryl content and surface charge of AHs and PHs indicated unfolding of EWPs affected by ultrasound. SEM analyzis showed that UPT destroyed the microstructures of AHs and PHs, while FTIR spectra indicated remarkable changes in the macromolecular conformation of AHs and PHs after UPT. This study revealed that by combining ultrasound pre-hydrolysis treatment under controlled conditions with thoughtful proteases selection, hydrolysates with improved functional properties could be produced, enhancing utilization of EWPs in food products.

Increase of Antioxidant Activities of Egg White Protein Hydrolysate by Fractionation without Using Toxic Chemical

Increase of Antioxidant Activities of Egg White Protein Hydrolysate by Fractionation without Using Toxic Chemical

Increase of Antioxidant Activities of Egg White Protein Hydrolysate by Fractionation without Using Toxic Chemical

Increase of Antioxidant Activities of Egg White Protein Hydrolysate by Fractionation without Using Toxic Chemical

Chemical structure, comparison antioxidant capacity and separation antioxidant of hen, duck and quail egg white protein hydrolysate

Amino acid linkages as proteins are nutritional substance which important for diet intake. Purification protein procesing undergo heating procedure process followed by additional of proteolytic enzymes or acid had been resulting in protein hydrolysates. A protein hydrolysate describe as many free amino acids bound together through a complex mixture of peptides. Egg white protein hydrolysates is one of subject interested to study for human health or industry product. The objectives of the research are to determine and identification the antioxidant derived from egg white hydrolysate protein. Identification of chemical structure of albumen and albumen protein hydrolysate was examine using IR Spectrophotometry. While comparison of antioxidant capacity and antioxidant separation egg albumen was also investigate using FTIR method (Fourier Transform Infrared Spectroscopy). Hen, duck and quail albumen egg white and on hydrolisate form were used as research materials. The results were showing that different time and enzyme of hydrolysis were not influence at secondary structure of hydrolysate albumen protein. Phytochemical content such as alcohol and hydroxyl compound which have potential as functional group of antioxidant were detected in all of the samples. Their results of radical scavenging activities samples hydrolyzed by pepsin were respectively 89.40%, 50.25% and 85.13%. Whereas the radical scavenging activities of hydrolysates hydrolyzed by papain were 72.85%, 61% and 76.45% respectively.

Effects of different proteases on iron absorption property of egg white hydrolysates

One of the causes of iron deficiency in human is poor absorption of non-heme iron from the diet. While proteins from meats have been reported in the literature to enhance the absorption of non-heme iron, other proteins, such as those from egg, are known to inhibit iron absorption. The objective of this study is to investigate non-heme iron binding property of egg white proteins hydrolyzed using pepsin and a combination of bacterial/fungal proteases. The iron bioavailability of non-heme iron, in the presence of egg white (EW) hydrolysates, was evaluated in vitro using a tissues culture model system - rat intestinal epithelial cells (IEC-6). In the first treatment condition, EW was digested in the presence of ferrous gluconate (FeGluc), producing a peptide-FeGluc complex. In the second treatment, EW was digested in the absence of FeGluc followed by the addition of the non-heme iron. In both treatments, the resulting EW hydrolysates were further separated into >0.1–0.5kDa and >6–8kDa peptide fractions using dialysis. The hydrolysate and FeGluc complex or mixtures were applied to the IEC-6 cells and iron absorption was measured after 2h or 16h. Results showed that the peptide-FeGluc complex digested with a combined proteases from Bacillus licheniformis (SDAY) and from Aspergillus melluss (PP) increased the in vitro iron-binding property but did not enhance iron uptake by the in IEC-6 cells (p<0.05). Peptide-FeGluc complex digested with pepsin alone (>0.1–0.5kDa) resulted in significantly higher iron uptake in IEC-6 cells compared with the higher molecular weight complex (>6–8kDa) produced using the same hydrolysis treatment. Similarly, enhanced iron uptake was observed with the complexes produced with the combined SDAY and PP enzymatic treatments (>0.1–0.5kDa and >6–8kDa) (p<0.05). On the other hand, the enhanced iron absorption effect was not observed when pre-hydrolyzed free peptides were added to FeGluc. Overall, this study suggests that low molecular weight fractions of egg white protein hydrolysates can enhance the bioavailability of non-heme iron. Furthermore, the method by which the egg white proteins are being prepared, i.e., in the presence or absence of FeGluc, can affect the bioavailability of the non-heme iron.

Egg white protein hydrolysate reduces blood pressure, improves vascular relaxation and modifies aortic angiotensin II receptors expression in spontaneously hypertensive rats

Angiotensin converting enzyme (ACE) inhibitory peptides from egg have demonstrated reduction of blood pressure (BP) in vivo. In this study we evaluated the effects of egg white hydrolysate (EWH) prepared by thermolysin and pepsin in spontaneously hypertensive rats (SHRs). Fourteen to sixteen week old SHRs were implanted with telemetry devices. After recovery, the rats were divided randomly into three groups: untreated, EWH low dose (250 mg/kg BW), and EWH high dose (1000 mg/kg BW) for 12 days. BP showed a significant reduction in the EWH high dose group compared to untreated controls. BP reduction was associated with enhanced ex vivo vasodilation reduced oxidative/nitrosative stress, reduced angiotensin converting enzyme and angiotensin II type 1 receptor expression, while enhanced angiotensin II type 2 receptor expression. Circulating level of angiotensin II was unaffected. Thus, EWH exerted anti-hypertensive effects in SHRs through multiple mechanisms of vascular relaxation and RAS modulation.

Bioactive and ACE binding properties of three synthetic peptides assessed by various spectroscopy techniques

Abstract Peptides play an important role in metabolic regulation. In this study, one primary peptide derived from ostrich egg white protein hydrolysate and its truncated fragment and analogue were chemically synthesized. Peptide sequences were as follows: LTEQESGVPVMK (1317.54 Da, P1) with truncated fragment TEQESGVPVM (1076.187 Da, P2), and analogue TEQESGV H VM (1116.22 Da, P3). The antioxidant, angiotensin-converting enzyme (ACE) inhibitory, hemolytic activities and cytotoxicity of these peptides were investigated in vitro. The results showed that P3 has a potent antioxidant activity. The analogue peptide (P2) showed high efficiency for the inhibition of ACE (73% with IC 50 = 97 μg/mL). Fluorescence spectroscopic study of the interaction between the peptide and ACE showed that P2 had more affinity to ACE than P1 and P3. The results of circular dichroism (CD) showed that the significant conformation changes of ACE were related to P2 (unordered coil from 7.94 to 21.24%). Moreover, the synthetic peptides showed virtually no hemolytic activity and cytotoxicity against human peripheral blood mononuclear cells (PBMCs). Our results suggested that truncate and a proline-to-histidine substitution in the sequence could be useful to increase the efficiency of bioactive peptide.