title: Methylglyoxal is associated with bacteriostatic activity of high fructose agave syrups.
abstract: Three α-ketoaldehydes, potentially present in high fructose agave syrups (HFASs) as intermediates of the Maillard reaction, were determined. A previously reported HPLC-FLD procedure based on pre-column derivatisation with 4-methoxy-o-phenylenediamine was adopted, yielding the method quantification limits 0.11 mg/kg, 0.10mg/kg, 0.09 mg/kg for glyoxal, methylglyoxal (MGo) and diacetyl, respectively. The obtained results revealed high concentrations of methylglyoxal in HFASs (average 102 ± 91 mg/kg, range 15.6-315 mg/kg) as compared to commercial Mexican bee honeys or corn syrups. Hydrogen peroxide was generated in all HFASs upon dilution, yet to less extent than in bee honeys. HFASs presented bacteriostatic activity against Bacillus subtilis and Escherichia coli; catalase addition had minimum effect on the assay results in syrups with elevated MGo. Principal component analysis revealed direct association between growth inhibition and MGo. It is concluded that elevated concentration of MGo in HFASs is at least in part responsible for their non-peroxide bacteriostatic activity.
authors.affiliation: Chemistry Department, University of Guanajuato, L. de Retana 5, 36000 Guanajuato, Mexico.
authors.forename: Alma Rosa
authors.initials: AR
authors.lastname: Corrales Escobosa
authors.affiliation: Chemistry Department, University of Guanajuato, L. de Retana 5, 36000 Guanajuato, Mexico.
authors.forename: Armando
authors.initials: A
authors.lastname: Gomez Ojeda
authors.affiliation: Chemistry Department, University of Guanajuato, L. de Retana 5, 36000 Guanajuato, Mexico.
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Wrobel
authors.affiliation: Chemistry Department, University of Guanajuato, L. de Retana 5, 36000 Guanajuato, Mexico.
authors.forename: Armando Alcazar
authors.initials: AA
authors.lastname: Magana
authors.affiliation: Chemistry Department, University of Guanajuato, L. de Retana 5, 36000 Guanajuato, Mexico. Electronic address: katarzyn@ugto.mx.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Wrobel
mesh_terms: D027882:Agave / Q000737:chemistry*; D000818:Animals; D001516:Bees; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005632:Fructose / Q000737:chemistry*; D006722:Honey / Q000032:analysis*
chemical_list: D005632:Fructose
keywords: 4-Methoxy-o-phenylenediamine dihydrochloride (PubChem CID: 3085161); Bacteriostatic activity; Diacetyl (PubChem CID: 650); Glyoxal (PubChem CID: 7860); Hexane-3,4-dione (PubChem ID: 62539); High fructose agave syrup; Hydrogen peroxide; Methylglyoxal; Methylglyoxal (PubChem CID: 880)