Effect of pH on the reaction between naringenin and methylglyoxal: a kinetic study

TY - JOUR

T1 - Effect of pH on the reaction between naringenin and methylglyoxal

T2 - a kinetic study

AU - Zhu, Hongkai

AU - Poojary, Mahesha M.

AU - Andersen, Mogens L.

AU - Lund, Marianne N.

PY - 2019/11/15

Y1 - 2019/11/15

N2 - Methylglyoxal (MGO) is a highly reactive alpha-dicarbonyl compound that may adversely impact food quality and human health by modifying proteins. The kinetics of the reaction of naringenin with MGO was studied at pH 6-8 and 37 degrees C by UV-Vis spectrophotometry and reaction products were characterized by liquid chromatography-mass spectrometry (LC-MS/MS). The apparent second order rate constant (k(2)) increased at pH above the lowest pKa value of naringenin, indicating deprotonated naringenin as the main reactant. A Lederer-Manasse type reaction mechanism is suggested, with dehydration of the MGO-dihydrate as a rate determining step. The quantitative data obtained in the present study was used to simulate the competitive reaction between MGO and nucleophilic amino acid residues (Lys, Arg and Cys) and naringenin in milk. It is predicted that naringenin will be able to efficiently trap MGO during storage of milk, although the reversible trapping of MGO by Cys residues is initially kinetically favourable.

AB - Methylglyoxal (MGO) is a highly reactive alpha-dicarbonyl compound that may adversely impact food quality and human health by modifying proteins. The kinetics of the reaction of naringenin with MGO was studied at pH 6-8 and 37 degrees C by UV-Vis spectrophotometry and reaction products were characterized by liquid chromatography-mass spectrometry (LC-MS/MS). The apparent second order rate constant (k(2)) increased at pH above the lowest pKa value of naringenin, indicating deprotonated naringenin as the main reactant. A Lederer-Manasse type reaction mechanism is suggested, with dehydration of the MGO-dihydrate as a rate determining step. The quantitative data obtained in the present study was used to simulate the competitive reaction between MGO and nucleophilic amino acid residues (Lys, Arg and Cys) and naringenin in milk. It is predicted that naringenin will be able to efficiently trap MGO during storage of milk, although the reversible trapping of MGO by Cys residues is initially kinetically favourable.

KW - Methylglyoxal

KW - alpha-Dicarbonyls

KW - Maillard reactions

KW - Naringenin

KW - Kinetics

KW - pH

KW - Simulation

KW - UHT milk

U2 - 10.1016/j.foodchem.2019.125086

DO - 10.1016/j.foodchem.2019.125086

M3 - Journal article

C2 - 31272050

SN - 0308-8146

VL - 298

JO - Food Chemistry

JF - Food Chemistry

M1 - 125086

ER -