Computation studies on the maillard reaction of xylose and glycine

Date

10-2003

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Ernesto J Del Rosario

Abstract

SANTOS, ARMI KATRINA S. University of the Philippines Los Banos October 2003. Computational Studies on the Maillard Reaction of Xylose and Glycine/Butylamine in Water.

Adviser: Dr. Ernesto J. Del Rosario

Advisory Committee Members: Alma 0. Gonzales Rommel S. Talus

Two Maillard reaction model systems consisting of xylose as the sugar reactant and glycine or butylamine as the amine reactant were simulated using Hyperchem software. Solvation was accomplished by placing the solute in a periodic box with 199 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 rearrangement of the Amadori compound into the 1,2-enaminol or 2,3-enediol forms is less favorable than dimerization. Straight-chain dimerization is favored over cyclic dimerization.

The computed HOMO-LUMO energy gaps among the R (Amadori rearrangement product), S (sugar reactant) and A (amine reactant) of the xylose-glycine and xylose-butylamine was least for the R-A and R-S interaction, respectively. An R-A interaction may result from the addition of the amine to the carbonyl group of the Amadori rearrangement product, forming a product containing a carbon-nitrogen double bond. The R-S interaction is supported by the reaction pathway proposed by Anet and Reynolds (1960) and Kato (1962).

The computed results indicate that the Maillard reaction is more complex than was originally thought and that there are other pathways for melanoidin formation other than those already proposed in literature. However, among the proposed melanoidin structures that were considered, the Yaylayan-Kaminsky (1998) structure is the most thermodynamically stable, followed by the structures of Kato-Tsuchida (1981), and then of Cammerer-Kroh (1995). The Yaylayan-Kaminsky mechanism is further supported by the decreasing trend of the heat of formation of the otigomers as the number of monomers increases.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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