Inhibition Of Linoleic Acid Autoxidation Research Articles

Low-molecular-weight peptides as related to antioxidant properties of chicken essence

Different antioxidant measurements, including the inhibition of linoleic acid autoxidation, scavenging effect on α,α-diphenyl-β-picrylhydrazyl free radical, reducing power, and chelating abilities of metal ions Cu2+ and Fe2+, showed that the extract of chicken essence possessed antioxidant activities. The antioxidant activity increased with increasing concentration. Chicken essence contained a considerable amount of free amino acids, of which taurine was the predominant compound. Low-molecular-weight peptides were also present in a large quantity. An extraordinary feature was that the product contained high levels of potent antioxidants, anserine and carnosine. Three antioxidant peptide fractions of chicken essence were separated by size exclusion chromatography. The peptide with molecular weight of approximately 1400 Da possessed the strongest antioxidant activity, followed by peptides with 900 and 500 Da. Two antioxidant peptides were further isolated and identified, and their amino acid sequences were His-Val-Thr-Glu-Glu and Pro-Val-Pro-Ala-Glu-Gly-Val, respectively.

Antioxidant activities of carnosine, anserine, some free amino acids and their combination

For the evaluation of antioxidant activities of dipeptides (carnosine, anserine), and free amino acids (histidine, 1-methylhistidine, taurine, glycine, alanine, β-alanine), four methods were used, including the analysis of the inhibition of linoleic acid autoxidation, scavenging effect on α,α-diphenyl-β-picrylhydrazyl free radical, reducing power, and chelating ability of Cu2+. Results showed that carnosine and anserine were antioxidants preventing lipid peroxidation in linoleic acid systems. They also possessed effective abilities as free radical scavengers, reducing agents, and copper ion chelators. The activities increased with increasing concentration. However, the constituent amino acids of dipeptides, β-alanine, histidine and 1-methylhistidine, were not as effective in inhibiting oxidation regardless of individual or combined usage. Taurine, glycine, alanine and β-alanine showed much weaker antioxidant activities than carnosine, anserine, histidine and 1-methylhistidine. No synergistic effects on antioxidation were found among compounds used in combination. The results suggested that histidine-containing compounds were related to antioxidation abilities, and the peptide linkage between β-alanine, histidine and 1-methylhistidine was involved in the antioxidant activities of carnosine and anserine.

Antioxidant activities of the water-soluble fractions of glandless and glanded cottonseed protein

To promote application of cottonseed protein products in food industry, this work measured antioxidant activities of two water soluble protein samples (Gl-L and Gd-L) isolated in a lab scale from glandless and common glanded cottonseed meal, respectively, and one soluble protein samples (Gd-P) in a pilot scale from glanded cottonseed meal. SDS-gel electrophoresis showed that the distribution patterns of the peptide fragments in Gl-L and Gd-L were similar, but more fragments and higher molecular mass bands were observed in the Gd-P gel image. While Gd-P showed the highest activities, Gl-L and Gd-L exhibited comparable 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical-scavenging activities in most cases. In contrast, Gd-P showed lower capability of inhibition of linoleic acid autoxidation than Gl-L and Gd-L. It would be of great interest in further research on these protein fractions in food products and processes (such as roasting) involved in the protective effects of food spoilage.

Improving the antioxidant properties of quinoa flour through fermentation with selected autochthonous lactic acid bacteria

Lactic acid bacteria strains, previously isolated from the same matrix, were used to ferment quinoa flour aiming at exploiting the antioxidant potential. As in vitro determined on DPPH and ABTS radicals, the scavenging activity of water/salt-soluble extracts (WSE) from fermented doughs was significantly (P<0.05) higher than that of non-inoculated doughs. The highest inhibition of linoleic acid autoxidation was found for the quinoa dough fermented with Lactobacillus plantarum T0A10. The corresponding WSE was subjected to Reverse Phase Fast Protein Liquid Chromatography, and 32 fractions were collected and subjected to in vitro assays. The most active fraction was resistant to further hydrolysis by digestive enzymes. Five peptides, having sizes from 5 to 9 amino acid residues, were identified by nano-Liquid Chromatography-Electrospray Ionisation-Mass Spectra/Mass Spectra. The sequences shared compositional features which are typical of antioxidant peptides. As shown by determining cell viability and radical scavenging activity (MTT and DCFH-DA assays, respectively), the purified fraction showed antioxidant activity on human keratinocytes NCTC 2544 artificially subjected to oxidative stress.This study demonstrated the capacity of autochthonous lactic acid bacteria to release peptides with antioxidant activity through proteolysis of native quinoa proteins. Fermentation of the quinoa flour with a selected starter might be considered suitable for novel applications as functional food ingredient, dietary supplement or pharmaceutical preparations.

Synergistic actions of proteolytic enzymes for production of soy protein hydrolysates with antioxidant activities: An approach based on enzymes specificities

Abstract The objective of this study was to investigate the enzymatic hydrolysis of soy protein isolate by screening individual and blended commercial protease preparations using a statistical mixture design. Information about the modulation of thermal inactivation of the enzyme by substrate or products of hydrolysis and the determination of synergistic effects between the enzymes on production of soy protein hydrolysates with antioxidant activities were reported. The kinetic parameters for thermal inactivation measured under reactive and non-reactive conditions indicated that product inhibition was not significant on soy protein hydrolysis using the commercial proteases Flavourzyme® 500 L, Alcalase® 2.4 L and YeastMax A. For DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, the hydrolysates obtained with Flavourzyme® 500 L combined with Alcalase® 2.4 L showed the higher synergistic effect with increases of 10.9% and 13.2% in antioxidant activity as compared to the hydrolysates produced with individual enzymes. The hydrolysates obtained using the ternary mixtures of Flavourzyme® 500 L, Alcalase® 2.4 L and YeastMax A showed the highest power of inhibition of linoleic acid autoxidation. On the other hand, for reducing power assay and total antioxidant activity, the most of all interactions was antagonistic with high antioxidant activity detected for the hydrolysates produced using Flavourzyme® 500 L, individually.

ACE-Inhibitory and Antioxidant Activity of Temporin-Ra Peptide: Biochemical Characterization and Molecular Modeling Study

In this study, the inhibitory effect of Temporin-Ra (FP-14 peptide) on angiotensin converting enzyme (ACE) was evaluated. Inhibition mechanism was investigated by kinetic studies and molecular docking simulation. Lineweaver–Burk plot revealed that Temporin-Ra behaved as a non-competitive ACE inhibitor supported by the docking simulation. The IC50 and Ki values were determined to be 22.19 μM and 36 µg/ml, respectively. Molecular docking simulation showed that Temporin-Ra bound to both of N- and C-domains of ACE by forming hydrogen bonds and electrostatic interactions; Temporin-Ra displayed higher affinity to C-domain than N-domain. Antioxidant activity of Temporin-Ra was examined using different methods. The antioxidant activity of Temporin-Ra (0.2 mg/ml) in the inhibition of linoleic acid autoxidation was evaluated to be 57 %. 1,1-diphenyl-2-picrylhydrazyl and 2, 2-azino-bis (3-ethylbenzothiazoline-6-sulphonicacid) diammonium salt radicals scavenging activities were 60 % at 0.5 mg/ml and 37 % at 0.3 mg/ml, respectively. The hydroxyl radical scavenging of FP-14 peptide at 0.33 mg/ml was 55 %. The results suggest that Temporin-Ra is a multifunctional peptide that could be exploited to develop new anti-hypertension drugs and bio-compatible natural antioxidants.

Optimization of processing conditions to improve antioxidant activities of apple juice and whey based novel beverage fermented by kefir grains.

A central composite design (CCD) was used to evaluate the effects of fermentation temperature (20-30 ºC) and kefir grains amount (2-8%w/v) on total phenolic content and antioxidant activities of apple juice and whey based novel beverage fermented by kefir grains. The response surface methodology (RSM) showed that the significant second-order polynomial regression equation with high R(2) (>0.86) was successfully fitted for all response as function of independent variable. The overall optimum region was found to be at the combined level of 7.56%w/v kefir grains and temperature of 24.82 ºC with the highest value for total phenolic content (TPC) and antioxidant activities. At this optimum point TPC, 1, 1-Diphenyl-2-picrylhydrazyl radical scavenging, metal chelating effect, reducing power, inhibition of linoleic acid autoxidation and inhibition of ascorbate autoxidation were 165.02 mgGA/l, 0.38ml/1ml, 0.757 (absorbance at 700nm), 46.12%, 65.33% and 21%, respectively. No significant difference (p < 0.05) was found between actual values and predicated values.

Isolation And Identification Of An Antioxidant Peptide Prepared From Fermented Peanut Meal Using Bacillus Subtilis Fermentation

In order to recover and utilize peanut protein resource, peanut meal was fermented using Bacillus subtilis to prepare antioxidant peptides in this study. The antioxidant activities of the peanut peptides were evaluated via six in vitro tests, namely, 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) scavenging activity, inhibition of linoleic acid autoxidation, reducing power, and metal chelating capacity. The peanut peptides showed 63.28% of scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radical, 70.67% of scavenging effect on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and 39.32% of superoxide anion radical scavenging activity at 1.0 mg/ml, and 62.69% of inhibition on linoleic acid autooxidation at 0.8 mg/ml. Besides, the peanut peptides exhibited 32.8% of reducing power and 60.44% of Fe2+-chelating capacity at 2 mg/ml. Then the peanut peptides were desalted with macroporous resin; the fraction eluted with 75% ethanol showed the highest scavenging activity on 1,1-diphenyl-2-picrylhydrazyl radical. This fraction was subject to further purification using gel filtration chromatography and reverse phase-high performance liquid chromatography. At last, a peptide was gained, and it was identified to be Tyr-Pro with matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry. The results indicated that it is feasible to prepare natural antioxidants from peanut meal using B. subtilis fermentation.

Physical, chemical and biochemical properties of casein hydrolyzed by three proteases: Partial characterizations

Sodium caseinate (NaCas) was hydrolyzed by papain, pancreatin and trypsin from 10min to 24h, and the hydrolysates were partially characterized for several important properties. At the studied conditions, papain and trypsin were more effective in hydrolyzing NaCas than pancreatin. Pancreatin treatments showed an initial increase in surface hydrophobicity, contrasting with the consistent decrease for the other two treatments. The solubility of NaCas at acidic pH was improved, becoming pH-independent after 24h hydrolysis. The emulsifying properties generally showed improvements after hydrolysis. The DPPH free radical scavenging activity, reducing power, and inhibition of linoleic acid autoxidation were significantly enhanced after appropriate hydrolysis, while metal ion chelating effects were slightly attenuated. The angiotensin converting enzyme-inhibitory activity was significantly improved by up to 9times than that of NaCas. These findings indicate that physical, chemical and biochemical properties of casein hydrolysates can be improved by selecting proteolytic conditions to produce functional ingredients.

Antioxidant Properties of Maillard Reaction Products from Defatted Peanut Meal Hydrolysate-Glucose Syrup and its Application to Sachima

Antioxidant properties of defatted peanut meal (DPM) hydrolysate-glucose syrup Maillard reaction products (MRPs) were evaluated, and their effects on the oxidative stability and flavour property of Sachima during the storage were studied. DPM hydrolysate-glucose syrup was heated at 120°C for different time. With the heating time increasing, browning and intermediate products increased, free amino group content decreased. MRPs heating for 60 min had the best antioxidant properties, evaluated by 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, oxygen radical absorbance capacity and inhibition of linoleic acid autoxidation. Sachima added with 1% MRPs showed significantly (p < 0.05) lower acidity values and peroxide values than that without MRPs during 5 months storage. Results from GC-MS indicated that MRPs improved the flavour of Sachima. Based on these findings, MRPs derived from DPM hydrolysate-glucose syrup might be used in food lipids stabilization as potent natural antioxidant and flavour enhancer.

Evaluation of biological activities of the short-term fermented soybean extract

The short-term fermented soybean extract (FSE) using soybean and wheat was prepared at a high temperature to accelerate proteolytic hydrolysis. The chemical composition and in vitro biological activities of FSE were investigated. FSE contained mainly the low molecular weight peptides of less than 3 kDa and was dominantly composed of glutamic acid, leucine, proline, and alanine. The EC50 value of DPPH radical scavenging activity of FSE was 1.63 mg/mL, and the inhibition of linoleic acid autoxidation by FSE was equivalent to 77% of the antioxidant activity of α-tocopherol. FSE showed a concentration-dependent antimicrobial activity against Bacillus subtilis and Escherichia coli. In addition, FSE at 1 mg/mL showed the strong inhibition effects on growth of MCF7 and HT1080 with 58 and 64%, respectively. In conclusion, FSE prepared by rapid fermentation may be useful as a functional food ingredient with antioxidant, antimicrobial, and antitumor activities.

An antioxidant peptide derived from Ostrich (Struthio camelus) egg white protein hydrolysates

Ostrich (Struthio camelus) egg white (OEW) proteins were hydrolyzed using various proteases (α-chymotrypsin, pepsin, trypsin and papain). Antioxidant activities of hydrolysates were evaluated using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and iron chelating activity. The hydrolysate obtained by trypsin exhibited the highest antioxidant activity. This hydrolysate was passed through an ultrafiltration membrane with a 3kDa-cut off, and the resulting filtrate was purified using reversed-phase high performance liquid chromatography (RP-HPLC). Eight peptide fractions were separated and their antioxidant activities were tested. The results showed that the F6 fraction possessed the highest antioxidant activity in the inhibition of linoleic acid autoxidation (86.4% at 20μg/ml), scavenging activity for DPPH radical (81% at 200μg/ml) and 2, 2-azino-bis (3-ethylbenzothiazoline-6-sulphonicacid) diammonium salt (ABTS) radical (37.6% at 90.9μg/ml). In addition, the iron chelating activity, hydroxyl radical scavenging and reducing power of the F6 fraction were 20% at 317.5μg/ml, 28.6% at 163.9μg/ml and 0.083 at 113.6μg/ml, respectively. The peptide sequence was found to be LTEQESGVPVMK (with a molecular mass of 1317.65Da) using mass spectrometry. The results suggest that the digestion of OEW proteins by trypsin protease could be exploited to produce natural antioxidants.

Selected Lactic Acid Bacteria Synthesize Antioxidant Peptides during Sourdough Fermentation of Cereal Flours

A pool of selected lactic acid bacteria was used for the sourdough fermentation of various cereal flours with the aim of synthesizing antioxidant peptides. The radical-scavenging activity of water/salt-soluble extracts (WSE) from sourdoughs was significantly (P < 0.05) higher than that of chemically acidified doughs. The highest activity was found for whole wheat, spelt, rye, and kamut sourdoughs. Almost the same results were found for the inhibition of linoleic acid autoxidation. WSE were subjected to reverse-phase fast protein liquid chromatography. Thirty-seven fractions were collected and assayed in vitro. The most active fractions were resistant to further hydrolysis by digestive enzymes. Twenty-five peptides of 8 to 57 amino acid residues were identified by nano-liquid chromatography-electrospray ionization-tandem mass spectrometry. Almost all of the sequences shared compositional features which are typical of antioxidant peptides. All of the purified fractions showed ex vivo antioxidant activity on mouse fibroblasts artificially subjected to oxidative stress. This study demonstrates the capacity of sourdough lactic acid bacteria to release peptides with antioxidant activity through the proteolysis of native cereal proteins.

Use of proteases to improve oxidative stability of fermented sausages by increasing low molecular weight compounds with antioxidant activity

Forty fermented sausages from Iberian pigs were manufactured using 3 different proteases with a potential antioxidant activity (batch 1: without proteases, batch 2: neutral bacterial protease, batch 3: fungal protease and batch 4: fungal protease concentrate). The antioxidant properties of extracts (< 3 kDa) from Iberian dry-cured sausages were assessed using four different methods: (i) 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (RSA), (ii) metal chelating assay (MQA), (iii) reducing power (RP) and (iv) inhibition of linoleic acid autoxidation (ILAA). Dry-cured sausage extracts from of all the manufactured batches showed antioxidant activity as indicated by RSA, MQA and ILAA. Manufacturing sausages with the used proteases increased the antioxidant activity of the sausage extracts, except for the MQA. Moreover, extracts from dry-cured sausages which were manufactured without proteases showed the highest levels of both thiobarbituric acid-reactive substances (TBARs) and hexanal content.

Isolation and Characterization of Antioxidant Protein Fractions from Melinjo (Gnetum gnemon) Seeds

The protein from the seeds of melinjo ( Gnetum gnemon ) was purified using a precipitation method and ion exchange chromatographic techniques to identify the potent antioxidant and free radical scavenging activities. Two antioxidant protein fractions were isolated from G. gnemon seed with molecular weights of approximately 30 kDa (Gg-AOPI) and 12 kDa (Gg-AOPII) by SDS-PAGE. The N-terminal amino acid sequence of Gg-AOPII is Gly-Asn-Gly-Lys-Ala-Thr-Val-Ala-Ile-Leu-Val-Lys-Glu-Lys-Val-Glu-Tyr-Gly-Glu-Glu, and the result of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis showed that they were distinct from each other; no protein in database matching was found to both Gg-AOPI and Gg-AOPII. The antioxidant or free radical scavenging activities of Gg-AOPs were investigated by employing in vitro assay systems including the inhibition of linoleic acid autoxidation, scavenging effect on α,α-diphenyl-β-picrylhydrazyl free radical (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), reducing power, chelating abilities of metal ions Cu(2+) and Fe(2+), and protections against hydroxyl radical-mediated DNA damages. The result showed that two protein fractions exhibited significant (p < 0.05) antioxidant activities against free radicals such as DPPH, ABTS, and superoxide anion and showed activities similar to those of glutathione (G-SH) and BHT in a linoleic acid emulsion assay system. Moreover, Gg-AOPI and Gg-AOPII also exhibited notable reducing power and strong chelating effect on Fe(2+) and protected hydroxyl radical induced oxidative DNA damage. The data obtained by the in vitro systems obviously established the antioxidant potency of Gg-AOPs.

Antioxidant and free radical-scavenging activities of chickpea protein hydrolysate (CPH)

Chickpea protein hydrolysate (CPH) was fractionated by gel filtration on Sephadex G-25. The antioxidant and free radical-scavenging activities of four CPH fractions (Fra.I, Fra.II, Fra.III, and Fra.IV) were measured using reducing power, inhibition of linoleic acid autoxidation, and 1,1-diphenyl-2- pycrylhydrazyl (DPPH)/superoxide/hydroxyl radical-scavenging assay. The antioxidant activity of Fra.IV (81.13%) was closer to that of α-tocopherol (83.66%) but lower than that of BHT (99.71%) in the linoleic acid oxidation system. Amino acid analyses showed that Fra.IV with the strongest antioxidant activity also had the highest total hydrophobic amino acids content (38.94% THAA) and hydrophobicity (125.62 kcal/mol amino acid residue) compared with the other three fractions. The molecular weight distribution of Fra.IV was found to vary from 200 to 3000 Da.

Free amino acids and peptides as related to antioxidant properties in protein hydrolysates of mackerel ( Scomber austriasicus)

Mackerel ( Scomber austriasicus) hydrolysates were prepared by an autolytic process and accelerated hydrolysis with a commercial enzyme, Protease N. Changes in the levels and compositions of free amino acids and small peptides during hydrolysis were investigated to find out their relationships with antioxidant activities. Increased levels of free amino acids, anserine, carnosine and other peptides of the hydrolysates obtained with protease were much higher than those by autolysis. Different antioxidant measurements including the inhibition of linoleic acid autoxidation, the scavenging effect on α,α-diphenyl-β-picrylhydrazyl free radical, and the reducing power showed that mackerel hydrolysates possessed noticeable antioxidant activities. A good correlation existed between the amount of peptides and antioxidant activity. Three peptide fractions were separated from the hydrolysate by size exclusion chromatography. Results revealed that the peptide with molecular weight of approximately 1400 Da possessed a stronger in vitro antioxidant activity than that of the 900 and 200 Da peptides.