Molecular orbital calculation on the Maillard reaction of glucose

Junhee Kang

Date

5-2005

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Alma O Gonzales

Co-adviser

Jelynne P Tamayo

Committee Member

Katherine Ann C. Israel

Abstract

Two Maillard reaction model systems consisting of glucose or fructose as sugar reactant and lysine as the amine reactant were simulated using Hyperchem software Solvation was accomplished by placing the solute in a periodic box with 195 to 210 water molecules based on the TIP3P model for water. Geometry optimization was carried out using molecular mechanics (AMBER or OPLS), while single point calculations were accomplished using the PM3 semiempirical method The calculated heats of formation showed that dimerization is favored over the formation of the rearrangement products Straight chain dimerization is favored compared to the formation of the cyclic dieter The computed HOMO-LUMO energy gaps among the R (rearrangement product), S (sugar reactant) and A (amine reactant) of the glucose-lysine and fructose-lysine were minimal for the R-A interaction The interaction is achieved by a nucleophilic attack of a pair of electrons available in the nitrogen atom to the carbonyl carbon of the rearrangement product forming a carbon nitrogen double bond Among the proposed melanoidin structures, the Yaylayan-Kaminsky (1998) structure is the most thermodynamically stable, followed by Kato-Tsuchida (1981) and Cammerer and Kroh (1995) The Yaylayan-Kaminsky mechanism is supported by the decreasing trend of the heat of formation of the oligomers as the number of monomers increases.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2005 C4 K36

Document Type

Thesis

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