Graphite nanocomposites sensor for multiplex detection of antioxidants in food

Ng, Khan Loon; Tan, Guan Huat; Khor, Sook Mei

doi:10.1016/j.foodchem.2017.06.029

Cited by 39 publications

(17 citation statements)

References 34 publications

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“…Ultrapure water (18.2 MΩ, Merck Millipore) was used for the chemical preparations. The graphite electrode used in this study was fabricated according to the methods described in our previously published work. , …”

Section: Methodsmentioning

confidence: 99%

“…The graphite electrode used in this study was fabricated according to the methods described in our previously published work. 26,27 The electrochemical measurement was performed using an Autolab potentiostat/galvanostat PGSTAT 202 (Utrecht, The Netherlands). Liquid chromatography was performed using ultra performance liquid chromatography (UPLC).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Graphite-Based Nanocomposite Electrochemical Sensor for Multiplex Detection of Adenine, Guanine, Thymine, and Cytosine: A Biomedical Prospect for Studying DNA Damage

Khor

2017

Anal. Chem.

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Guanine (G), adenine (A), thymine (T), and cytosine (C) are the four basic constituents of DNA. Studies on DNA composition have focused especially on DNA damage and genotoxicity. However, the development of a rapid, simple, and multiplex method for the simultaneous measurement of the four DNA bases remains a challenge. In this study, we describe a graphite-based nanocomposite electrode (Au-rGO/MWCNT/graphite) that uses a simple electro-co-deposition approach. We successfully applied the developed sensor for multiplex detection of G, A, T, and C, using square-wave voltammetry. The sensor was tested using real animal and plant DNA samples in which the hydrolysis of T and C could be achieved with 8 mol L of acid. The electrochemical sensor exhibited excellent sensitivity (G = 178.8 nA/μg mL, A = 92.9 nA/μg mL, T = 1.4 nA/μg mL, and C = 15.1 9 nA/μg mL), low limit of detection (G, A = 0.5 μg mL; T, C = 1.0 μg mL), and high selectivity in the presence of common interfering factors from biological matrixes. The reliability of the established method was assessed by method validation and comparison with the ultraperformance liquid chromatography technique, and a correlation of 103.7% was achieved.

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Section: Methodsmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Graphite-Based Nanocomposite Electrochemical Sensor for Multiplex Detection of Adenine, Guanine, Thymine, and Cytosine: A Biomedical Prospect for Studying DNA Damage

Khor

2017

Anal. Chem.

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“…An antioxidant is a substance that counteracts the oxidative reaction caused by free radicals ( Lobo et al, 2010 ). The most widely used synthetic antioxidants are butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert -butylhydroquinone (TBHQ) but the use of synthetic antioxidants is under strict regulation because they are toxic to human health ( Ng, Tan & Khor, 2017 ). In recent years, natural antioxidants have attracted immense interest because of their beneficial functional properties and safety.…”

Section: Introductionmentioning

confidence: 99%

Assessment of antioxidant properties of membrane ultrafiltration peptides from mungbean meal protein hydrolysates

Sonklin

Laohakunjit

Kerdchoechuen

2018

PeerJ

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BackgroundBioactive peptides can prevent damage associated with oxidative stress in humans when consumed regularly. Recently, peptides have attracted immense interest because of their beneficial functional properties, safety and little or no side effects when used at high concentration. Most antioxidant peptides are small in size, less than 1 kDa, and contains a high proportion of hydrophobic amino acid. Particularly, tyrosine, leucine, alanine, isoleucine, valine, lysine, phenyalanine, cysteine, methionine and histidine in peptide chain exhibited high antioxidant activity. Mungbean meal protein (MMP) is highly abundant in hydrophobic amino acids. It indicated that MMP might be a good source of antioxidants. Therefore, the objectives were to optimize the conditions used to generate mungbean meal protein hydrolysate (MMPH) with antioxidant activity from bromelain and to investigate the antioxidant activities of different molecular weight (MW) peptide fraction.MethodsResponse Surface Methodology (RSM) was used for screening of the optimal conditions to produce MMPH. After that MMPH was fractionated using ultrafiltration membranes with different MW distributions. Crude-MMPH and four fractions were investigated for five antioxidant activities: 2,2,1-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, superoxide, ferric reducing antioxidant power (FRAP) and metal ion chelation activity.ResultsThe optimal condition to produce the MMPH was 15% (w/w) of bromelain and hydrolysis time for 12 h which showed the greatest DPPH and ABTS radical scavenging activity. After mungbean protein from optimal condition was separated based on different molecular weight, the DPPH radical scavenging activity was the highest for the F4 (less than 1 kDa) peptide fraction. Metal ion chelating activity was generally weak, except for the F4 that had a value of 43.94% at a protein concentration of 5 mg/mL. The F4 also exhibited high hydroxyl and superoxide activities (54 and 65.1%), but moderate activity for ferric reducing antioxidant power (0.102 mmole Fe2+/g protein) compared to other peptide fractions and crude-MMPH. Molecular weight and amino acid were the main factors that determined the antioxidant activities of these peptide fractions. Results indicated that F4 had strong antioxidant potentials.DiscussionThe lowest MW fraction (less than 1 kDa) contributed to the highest DPPH, superoxide, hydroxyl and metal chelation activity because influence of low MW and high content of hydrophobic amino acid in peptide chain. Results from this study indicated that MMPH peptides donate protons to free radicals because they had significantly high DPPH value compared to superoxide, hydroxyl and FRAP, which reactions were electron donation. Moreover, MMPH peptides had the ability to inhibit transition metal ions because of highly abundant glutamic acid and aspartic acid in peptide chain.

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“…An antioxidant is a substance that counteracts the oxidation reaction caused by free radicals (Lobo et al, 2010). The most widely used synthetic antioxidants are butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ) but the use of synthetic antioxidants is under strict regulation because they are toxic to human health (Ng, Tan & Khor, 2017). In recent years, natural antioxidants have attracted immense interest because of their beneficial functional properties and safety.…”

Section: Introductionmentioning

confidence: 99%

Assessment of antioxidant properties of membrane ultrafiltration peptides from mungbean meal protein hydrolysates

Sonklin

Laohakunjit

Kerdchoechuen

2018

Preprint

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Background Bioactive peptides can prevent damage associated with oxidative stress in the human body when consumed regularly. Recently year, peptides have attracted immense interest because of their beneficial functional properties, safety and little or no side effects when used at high concentration. Most antioxidant peptide has small size less than 1 kDa and contains high proportion of hydrophobic amino acid. Particularly Tyr, Leu, Ala, Ile, Val, Lys, Phe, Cys, Met and His exhibited high antioxidant activity. Mungbean protein contain high abundance of protein and hydrophobic amino acid contents, investigating its bioactivity is an important aspect of adding value to this by-product obtained from a growing industry. Therefore, the objectives of this study were to optimize the conditions used to generate MMPH with antioxidant activity form bromelain and to investigate the antioxidant activities of each molecular weight peptide fraction. Methods Response Surface Methodology (RSM) was used for screening the optimal conditions to produce Mungbean meal protein hydrolysate (MMPH). After that optimal MMPH was fractionated using ultrafiltration membranes with different molecular weight (MW) distribution. Crude-MMPH and four peptide fractions were investigated for five antioxidant activities: DPPH scavenging activity, Hydroxyl scavenging activity, Superoxide scavenging activity, Ferric reducing antioxidant power and metal ion chelation activity. Results The optimal condition of crude-MMPH production was 12 % (w/w) of bromelain and hydrolysis time for 12 h. The EC50 of DPPH was the highest for the F4 peptide fraction (MW<1 kDa) at 0.5320 mg/mL. Metal ion chelating activity was generally weak, except for the F4 that had a value of 43.94% at a protein concentration of 5 mg/mL. The F4 also exhibited high hydroxyl and superoxide radical scavenging activities (54 and 65.1%), but poor activity for ferric reducing antioxidant power (0.102 mM Fe2+/mg protein) compared to other peptide fractions and crude-MMPH. Molecular weight and amino acid were the main factors that determined the antioxidant activities of these peptide fractions. Results show that F4 have high antioxidant potentials. Discussion The lowest MW Fraction (less than 1 kDa) showed the highest DPPH activity, superoxide-, hydroxyl-scavenging activity and metal chelation activity. On the other hand, this fraction had poor ferric reducing power. This showed that low molecular weight has an important effect on antioxidant activities. According to the mechanism of the reaction, the potential of antioxidant activity was divided into two main groups: hydrogen atom transfer (HAT) and single electron transfer (SET). Therefore, this finding suggests that the antioxidant mechanism of peptides obtained mungbean could react with many species of free radicals by multiple mechanisms. Mungbean meal peptide can be developed into multiple functional foods which possess both antioxidant properties and aroma/taste.

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Graphite nanocomposites sensor for multiplex detection of antioxidants in food

Cited by 39 publications

References 34 publications

Graphite-Based Nanocomposite Electrochemical Sensor for Multiplex Detection of Adenine, Guanine, Thymine, and Cytosine: A Biomedical Prospect for Studying DNA Damage

Graphite-Based Nanocomposite Electrochemical Sensor for Multiplex Detection of Adenine, Guanine, Thymine, and Cytosine: A Biomedical Prospect for Studying DNA Damage

Assessment of antioxidant properties of membrane ultrafiltration peptides from mungbean meal protein hydrolysates

Assessment of antioxidant properties of membrane ultrafiltration peptides from mungbean meal protein hydrolysates

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