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United States Department of Agriculture

Agricultural Research Service

Title: Model Studies to Characterize the Thermal Degradation of Concentrated Aqueous Solutions of Sucrose under Constant Ph Conditions

Author
item Eggleston, Gillian

Submitted to: Sugar Processing Research Conference Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 1996
Publication Date: N/A

Interpretive Summary: The thermal break down (degradation) of sucrose leads to many reaction products that can reduce the efficiency of sugar mill and refinery processes, and decrease sucrose industrial yield. This paper reports a study of sucrose degradation under modeled industrial process conditions, undertaken to underpin future technological improvements. Effects of constant reaction pH on sucrose degradation were studied. Reaction pH values ranged from pH 4.4 to 10.45. Color formation was shown to reflect the total organic acid formation. The technique of polarimetry was shown not to be viable for measuring sucrose degradation at the levels that occur in industrial unit processes where the pH is alkaline. An ion chromatography method was developed to separate larger carbohydrate molecules, oligosaccharides, which are sucrose degradation products.

Technical Abstract: The thermal degradation of sucrose leads to many reaction products that can reduce the efficiency of sugar mill and refinery processes, and decrease sucrose yield. Characterization of sucrose degradation under modeled industrial processing conditions will underpin further technological improvements. Effects of constant reaction pH on sucrose degradation were investigated using model systems (100 deg C; 65 Brix; N2; 0.05-3M NaOH titrant), with the use of an auto-titrator. Reaction pH values ranged from pH 4.4 to 10.45. Polarimetry (at 589 and 880nm), nad ion chromatography with integrated pulsed amperometric detection (IC-IPAD) iques were used to monitor the kinetics of sucrose and total organic acid formation were all markedly influenced by pH and temperature. Organic acid formation was detected using ion chromatography with conductivity detection. Separation and identification of oligomeric products, formed during acid and alkaline degradation of sucrose, using a developed IC-IPAD method with a NaOAc gradient in NaOH, are discussed.

Last Modified: 7/30/2014
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