• Journal of Dairy Science and Biotechnology
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• 제39권1호
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• pp.36-50
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• 2021

This study aimed to evaluate the biological potential of functional food, i.e., specific peptides obtained from the hydrolysis of milk protein, by assessing their antioxidant and antibacterial properties. For the preparation of casein hydrolysates, commercial enzymes were added to 10% casein solution in a 1:200 (w/v) ratio, and samples were collected each hour. Based on the assessment of the degree of hydrolysis (DH) of casein hydrolysates, it was observed that the concentration of all enzymatic hydrolysates increased rapidly from 30 to 40 minutes. However, no change was observed in their concentrations after 150 minutes. Protamex® and Neutrase® exhibited the highest DH when compared to other enzymes. Furthermore, SDS-PAGE was performed for analyzing the proteolytic pattern of each enzyme, except for Flavourzyme®, and peptides in the size range of 20-25 kDa were identified. Subsequently, peptides produced by two enzymes were isolated using a preparative liquid chromatography system. Overall, NF3, NF4, PF5, and PF6 showed higher antioxidant potential than other peptide fractions. Moreover, NF7 and PF3 exhibited the highest antibacterial activity. In this study, we evaluated the biological potential of novel casein-derived peptides that may find application in the food and healthcare industry.

• Journal of Microbiology and Biotechnology
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• 제31권1호
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• pp.33-42
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• 2021

Due to the potential of antioxidants to scavenge free radicals in human body, it is important to be able to prepare antioxidant peptides that meet the industrial requirements for cosmetics and food. Here, we determined in vivo/in vitro activities of antioxidant peptide from P. fucata (PFAOP) prepared by bio-fermentation method. The antioxidant property test results showed the DPPH, hydroxyl, superoxide radical-scavenging, and cellular antioxidant activity. EC50 values of PFAOPs were 0.018 ± 0.005, 0.126 ± 0.008, 0.168 ± 0.005, and 0.105 ± 0.005 mg/ml, respectively, exhibiting higher antioxidant activities than glutathione (p < 0.05). Moreover, anti-proliferation and cytotoxicity activity results illustrated PFAOP has a potent anti-proliferative activity against HepG2, Caco-2, and MCF-7 carcinoma cells with no cytotoxicity. Moreover, the protocols we developed in this work demonstrated several excellent advantages in PFAOP preparation compared to enzymatic hydrolysis or chemical synthesis methods and provide a theoretical foundation for higher-value application of marine-derived functional peptides.

• 대한의생명과학회지
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• 제24권3호
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• pp.263-269
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• 2018

This study aims to investigate the biological activities related to hair loss of short anti-oxidant peptides (DK peptides) $5{\alpha}$-reductase inhibition and anti-oxidation. The series of DK peptides were generated amphipathic helical properties using leucines, lysines and tryptophan residues. Cell viability and free radical scavenging activities were performed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. The DK peptides were investigated for inhibitory activity against $5{\alpha}$-reductase. Antioxidant activities were determined by means of, 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assays. All peptides could inhibit $5{\alpha}$-reductase in lipopolysaccharide-stimulated macrophage. In conclusion, DK peptides was suggested as the most attractive ingredients for improving hair loss, because of the high inhibitory against $5{\alpha}$-reductase inhibition.

• 한국조리학회지
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• 제24권2호
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• pp.103-111
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• 2018

The objectives of the present study were to examine the antioxidant activity of autofocusing fractions from egg white protein hydrolysates and obtain higher antioxidant peptide fraction, which could be applied to the food model system. Alkaline protease hydrolysate of egg white protein exerted higher antioxidant activities than other protein hydrolysates and were fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing without toxic solvents and reagents, which is termed autofocusing. Neutral and basic fractions showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than the acidic fractions. The acidic and neutral fractions showed higher hydroxyl (OH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) values than the basic fractions. The acidic fractions showed higher metal chelating activity than basic fractions. Antioxidant activities of some autofocusing fractions except for ORAC showed higher compared to the crude hydrolysate. These results suggest that peptides fractions from egg white protein are effective antioxidant, and that autofocusing could be useful to increase antioxidant activity for application to food system.

• Journal of Microbiology and Biotechnology
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• 제26권7호
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• pp.1216-1223
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• 2016

The aim of this study was to isolate antioxidant peptides from an enzymatic hydrolysate of Spirulina platensis. A novel antioxidant peptide was obtained by ultrafiltration, gel filtration chromatography, and reverse-phase high-performance liquid chromatography, with the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay used to measure the antioxidant activity, and the sequence was determined to be Pro-Asn-Asn (343.15 Da) by electrospray ionization tandem mass spectrometry. This peptide was synthesized to confirm its antioxidant properties, and it exhibited 81.44 ± 0.43% DPPH scavenging activity at 100 μg/ml, which was similar to that of glutathione (82.63 ± 0.56%). Furthermore, the superoxide anion and hydroxyl free-radical scavenging activities and the SOD activity of the peptide were 47.84 ± 0.49%, 54.01 ± 0.82%, and 12.55 ± 0.75%, respectively, at 10 mg/ml. These results indicate that S. platensis is a good source of antioxidant peptides, and that its hydrolysate may have important applications in the pharmaceutical and food industries.

• Journal of Microbiology and Biotechnology
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• 제28권1호
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• pp.1-11
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• 2018

An antioxidant peptide derived from Pinctada fucata meat using an Alcalase2.4L enzymatic hydrolysis method (named AOP) and identified by LC-TOF-MS has promising clinical potential for generating cosmetic products that protect skin from sunshine. To date, there have been few published studies investigating the structure-activity relationship in these peptides. To prepare antioxidant peptides better and improve their stability, the design and expression of an antioxidant peptide from Pinctada fucata (named DSAOP) was studied. The peptide contains a common precursor of an expression vector containing an ${\alpha}$-helix tandemly linked according to the BamHI restriction sites. The DNA fragments encoding DSAOP were synthesized and subcloned into the expression vector pET-30a (+), and the peptide was expressed mostly as soluble protein in recombinant Escherichia coli. Meanwhile, the DPPH radical scavenging activity, superoxide radical scavenging activity, and hydroxyl radical scavenging activity of DSAOP $IC_{50}$ values were $0.136{\pm}0.006$, $0.625{\pm}0.025$, and $0.306{\pm}0.015mg/ml$, respectively, with 2-fold higher DPPH radical scavenging activity compared with chemosynthesized AOP (p < 0.05), as well as higher superoxide radical scavenging activity compared with natural AOP (p < 0.05). This preparation method was at the international advanced level. Furthermore, pilot-scale production results showed that DSAOP was expressed successfully in fermenter cultures, which indicated that the design strategy and expression methods would be useful for obtaining substantial amounts of stable peptides at low costs. These results showed that DSAOP produced with recombinant Escherichia coli could be useful in cosmetic skin care products, health foods, and pharmaceuticals.

• Journal of Dairy Science and Biotechnology
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• 제41권3호
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• pp.113-125
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• 2023

In this study, we explored the synergistic effects of whey protein concentrate (WPC) and soybean protein components after fermentation with lactic acid bacteria isolated from kimchi, and identified several peptides with desirable physiological functions, proteolysis, and immune effects. Antioxidant activity was determined using 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid, 1,1-diphenyl-2-picrylhydrazyl, ferric-reducing antioxidant power, and hydroxyl radical scavenging assays, followed by cross-validation of the four antioxidant activities. These assays revealed that samples with a 8:2 and 9:1 whey to soy ratio possessed higher antioxidant activity than the control samples. Antibacterial potency testing revealed high antibacterial activity in the 9:1 and 8:2 samples. Cytotoxicity testing of samples using 3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide revealed that only the 10:0, 1:9, and 0:10 samples had <80% viable cells, indicating no significant cytotoxicity. Nitric oxide (NO) assays revealed that NO expression was reduced in 8:2, 5:5, and 0:10 protein ratio fermentations, indicating low inflammatory reaction stimulatory potential. Cytokine expression was confirmed using an enzyme-linked immunosorbent assay kit. The 8:2 sample had the lowest inflammatory cytokine (interleukin [IL]-1α, IL-6, and tumor necrosis factor-α) levels compared with the lipopolysaccharide-treated group. Amino acid profiling of the 8:2 sample identified 17 amino acids. These results suggest that inoculating and fermenting Lactobacillus plantarum DK203 and Lactobacillus paracasei DK209 with an 8:2 mixture of WPC and soybean protein releases bioactive peptides with excellent anti-inflammatory and antioxidant properties, making them suitable for functional food development.

• BMB Reports
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• 제34권3호
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• pp.219-224
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• 2001

To identify the antioxidative peptides in the gelatin hydrolysate of bovine skin, the gelatin was hydrolyzed with serial digestions in the order of Alcalase, pronase E, and collagenase using a three-step recycling membrane reactor. The second enzymatic hydrolysate (hydrolyzed with pronase E) was composed of peptides ranging from 1.5 to 4.5 kDa, and showed the highest antioxidative activity, as determined by the thiobarbituric acid method. Three different peptides were purified from the second hydrolysate using consecutive chromatographic methods. This included gel filtration on a Sephadex G-25 column, ion-exchange chromatography on a SP-Sephadex C-25 column, and high-performance liquid chromatography on an octadecylsilane chloride column. The isolated peptides were composed of 9 or 10 amino acid residues. They are: Gly-Glu-Hyp-Gly-Pro-Hyp-Gly-Ala-Hyp (PI), Gly-ProHyp-Gly-Pro-Hyp-Gly-Pro-Hyp-Gly (PII), and Gly-ProHyp-Gly-Pro-Hyp-Gly-Pro-Hyp (PIII), as characterized by Edman degradation and fast-atom bombardment mass spectrometry. The antioxidative activities of the purified peptides were measured using the thiobarbituric acid method, and the cell viability with a methylthiazol tetrazolium assay The results showed that PII had potent antioxidative activity on peroxidation of linoleic acid. Moreover, the cell viability of cultured liver cells was significantly enhanced by the addition of the peptide. These results suggest that the purified peptide, PII, from the gelatin hydrolysate of bovine skin is a natural antioxidant, which has potent antioxidative activity.

• Asian-Australasian Journal of Animal Sciences
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• 제31권2호
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• pp.287-292
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• 2018

Objective: The aim of present study was to assess the anti-oxidant potential of water-soluble peptides (WSPs) extract derived from buffalo and cow milk Cheddar cheeses at different stages of ripening. Methods: The antioxidant potential of WSPs extract was assessed through 2,2'-azinobis-3-ethylbenzothiazoline-6sulfonic acid (ABTS)-radical scavenging activity. In addition, impact of WSPs extract on cell viability and production of reactive oxygen species (ROS) in human colon adenocarcinoma Caco-2 (tert-butylhydroperoxide-induced) cell lines was also evaluated. Results: The ABTS-radical scavenging activity increased progressively with ripening period and dose-dependently in both cheeses. However, peptide extract from buffalo milk Cheddar cheese demonstrated relatively higher activity due to higher contents of water-soluble nitrogen. Intracellular ROS production in Caco-2 cells decreased significantly (p<0.05) till 150th day of cheese ripening and remained constant thereafter. Additionally, dose-dependent response of WSPs extract on antioxidant activity was noticed in the Caco-2 cell line. Conclusion: On the basis of current in vitro study, the Cheddar cheese WSPs extract can protect intestinal epithelium against oxidative stress due to their antioxidant activity.

• Fisheries and Aquatic Sciences
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• 제16권2호
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• pp.71-78
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• 2013

Subcritical water hydrolysis was carried out in a batch reactor to produce valuable materials, such as low-molecular weight (MW) peptides and essential amino acids with antioxidant properties, from heat-dried squid viscera. Hydrolysis of squid viscera was performed at 160 to $280^{\circ}C$ for 3 min. The yield was increased by increasing the temperature and pressure, while the protein content of squid viscera hydrolysate decreased with increasing temperature. Low-MW peptides were detected in all hydrolysates by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The highest yields of free and structural amino acids in heat-dried squid viscera hydrolysate were at $160^{\circ}C$ and were $411.95{\pm}1.15$ and $346.62{\pm}1.25$ mg/100 g, respectively. All essential amino acids were detected in viscera hydrolysates; leucine was the most abundant. Antioxidant activities of hydrolysates were highest at $220^{\circ}C$. Greater than $98{\pm}0.26%$ of the ABTS antioxidant activity was retained in hydrolysates after long-term heat treatment.