Kinetic studies on the Maillard reaction between glucose and glycine in buffered solution at pH 6, 7 and 8 (65C)

Date

4-2001

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Ernesto J Del Rosario

Abstract

RIVERA, MARK JONAS B. University of the Philippines Los Batlos. April 2001. Kinetic Studies on the Maillard Reaction Between Glucose and Glycine in Buffered Solution at pH 6, 7 and 8 (65°C).

Adviser: Dr. Ernesto J. del Rosario

Committee members: Dr. Marivic S. Lacsamana

Dr. Norriel S. Nipales

The Maillard reaction was studied by heating solutions of glucose and glycine (at 1:1. 1:0.75, 1:0.5, 1:0.125, 1:0.0625 molar ratios) in a constant temperature bath at 65 °C for 2 hours in buffered solution (0.35 M phosphate) at pH 6,7 and 8. Aliquots were taken at certain time intervals and stored in a freezer until required for analysis. Glucose loss was monitored by polarimetry and polymeric product formation of melanoidin was monitored by absorbance measurements at 283 nm. The order of the Maillard reaction was determined as well as the rate of the reaction at each pH and molar proportion of the reactants.

The Maillard reaction between glucose and glycine was found to follow first order kinetics with respect to each reactant and second order over-all. For a given proportion of glucose and glycine, the rate of the reaction increased with the pt-I. At a selected pH, the rate constant was found to be greater when glycine was in excess compared to that when glucose was in excess./This was attributed to the fact that the anionic form of glycine with the unshared pair of electrons on the nitrogen, is the reactive form and increases in concentration at higher pH. It is also rate-limiting when glycine is not in excess. Based on the kinetic results, the mechanism for the actual tnelanoidin formation might be more complex than that which was proposed.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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