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Rapid Colorimetric Determination of Methylglyoxal Equivalents for Manuka Honey

Kwok, TH, Kirkpatrick, G, Mohd Yusof, HI, Portokalakis, I, Nigam, P and Owusu-Apenten, R (2016) Rapid Colorimetric Determination of Methylglyoxal Equivalents for Manuka Honey. Journal of Advances in Biology & Biotechnology, 7 (1). pp. 1-6. [Journal article]

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URL: http://sciencedomain.org/issue/2138

DOI: 10.9734/JABB/2016/26592

Abstract

Aims: Realization of a rapid colorimetric assay for monitoring levels of methylglyoxal and otherdicarbonyl compounds from Manuka honey.Methods: N-acetyl cysteine (NAC) and 2, 4-dinitrophenylhydrazine (DNPH) were adopted asreagents for methylglyoxal colorimetric analysis of honey at 288 or 525 nm, respectively.Results and Discussion: NAC and DNPH produced linear responses for methylglyoxal with:(i)regression coefficient (R2) equal to 0.99 or 0.97, (ii) molar absorptivity (measure of sensitivity) equal to 287±11 or 14189±498 M-1 cm-1, (iii) a minimum detectable concentration (MDC) of 0.18 mM vs 7.3 μM, (iv) upper linearity limit of linearity (ULL) equal to 4mM or 83 μM, and (v) a day-to-day precision of 16.0 and 18.3%, respectively. Low interferences occurred with reducing sugars, glyoxal or 3-deoxy-D-glucosone. For honey with a unique manuka factor (UMF) rating 5+ to UMF18+, the net concentration of dicarbonyl compounds ranged from 1069 mg-methylglyoxal equivalence per kg (mg MeGEq /kg) to 2208 (mg MeGEq /kg) using the NAC assay. For the DNPH assay, the apparent dicarbonyl concentration was 350 to 1009-mg MeGEq /kg honey. Measures of methylglyoxal equivalences were strongly correlated with the UMF rating for honeys (R2=0.98-0.99).Conclusion: The proposed colorimetric analysis of methylglyoxal equivalence in Manuka honey isfeasible proposition. Further work is needed for method validation.

Item Type:Journal article
Keywords:Rapid determination; dicarbonyl compounds; n-acetyl cysteine; carbonyl reagents; 2, 4- dinitrophenylhydrazine; methylglyoxal; 3-deoxy-D-glucosone, Advanced glycation endproducts (AGES)
Faculties and Schools:Faculty of Life and Health Sciences > School of Biomedical Sciences
Faculty of Life and Health Sciences
Research Institutes and Groups:Biomedical Sciences Research Institute > Nutrition Innovation Centre for Food and Health (NICHE)
Biomedical Sciences Research Institute
ID Code:34888
Deposited By: Dr Richard Owusu-Apenten
Deposited On:21 Jun 2016 08:44
Last Modified:17 Oct 2017 16:23

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