Degradation of Dextrose during Heating under Simulated Sterilization

Abstract

A practical approach for studying the breakdown of dextrose under simulated sterilization conditions has been developed using a special laboratory instrument. The instrument allows for control of pressure, temperature, and time of heating of the solutions under investigation. The effects of the presence of various group la and lla elemental salts, temperature, concentration, and time of heating on the rate of degradation of dextrose in aqueous solutions were studied. The decomposition of dextrose was followed by monitoring the rate of formation of 5hydroxymethylfurfural and intermediate species spectrophotometrically. A proposed mechanism indicates the degradation to be pseudo zero order with respect to dextrose. The intermediates are formed initially pseudo zero order with respect to dextrose and their disappearance is first order based on their own concentration. The initial formation of 5-hydroxymethylfurfural is first order with respect to the concentration of the intermediates. After the intermediates have reached a limiting concentration, the formation of 5-hydroxymethylfurfural follows pseudo zero-order kinetics. Rate constants were calculated from the data of the various solutions and the energy of activation associated with the production of 5-hydroxymethylfurfural under these experimental conditions is reported. The calculated rate constants and energies of activation from the accelerated studies were used to predict the concentration of 5-hydroxymethylfurfural in dextrose solutions after 1-year storage. The results were compared with actual experimental values obtained from 1-year storage samples.