Kinetic studies on the glucose- glycine Maillard reaction in buffered solution (pH7) at 60°, 70° and 80°C

Date

6-2001

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Ernesto J Del Rosario

Abstract

ROSETE, ROSELLE R. University of the Philippines Los Banos. June 2001. Kinetic Studies on the Glucose-Glycine Maillard Reaction in Buffered Solution (p117) at 60°, 70° and 80°C.

Adviser: Dr. Ernesto J. del Rosario

Committee Members: Dr. Evamarie P. Capareda Dr. Macario P. Catahan

The kinetics or the Maillard reaction between glucose and glycine was studied in 0.35 phosphate buffer (pH7) at 60°C, 70°C and 80°C. The parameters used for the determination of the rate constant were optical rotation and absorbance at 290nm. The reaction was found to he first order with respect to each reactant based on the slope of the log-log plot of the initial velocity versus the initial concentration of the varying reactant.

The rate constant was calculated based on the steady-state mechanism

nA + nB --------------------- nC ------------------------ 1:2

----------------------

k2

where A and B are the reactants, C is the Amadori intermediate and P is the polymeric product consisting of n monomers. The kinetic equations were derived based on the measured molar optical rotations of glucose and melanoidin product as well as on the absorbance atoncevarvdueortovetnhe, low concentrations of the limiting neagent; this could be due to a varying mechanism resulting in different product composition

The intensity of browning was visually observed to increase as the molar ratio of glucose/glycine increased as well as when temperature was increased. The absorbance at 290nm reading for product formation increased as the time of heating was prolonged. Generally the rate constant increased as the temperature was increased. An increase in the molar ratio of glucose/glycine resulted in an overall reduction in the calculated activation energy. For IM glycine and varying glucose concentration (0.75, 0.5, 0.25, 0.125, 0.0625M), the Ea values were 880, 764, 1093, 399 and 907 J/mol respectively (based on optical rotation) and 203, 423, 887, 508 and 1709 J/mol (based on absorbance). For 1M glucose and varying glycine concentration (0.75, 0.5, 0.25, 0.125, 0.0625M), the Ea values were 882, 1001, 931, 1874 and 2932 J/mol respectively (based on optical rotation) and 1473, 1366, 1190, 1656 and 2056 J/mol respectively (based on absorbance).

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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