Submitted to: American Society of Sugarbeet Technologists
Publication Type: Proceedings
Publication Acceptance Date: October 1, 1997
Publication Date: N/A
Interpretive Summary: A more accurate measurement of sucrose losses during the refining process is needed. To accomplish this the loss of sucrose and degradation product formation, including colored compounds, across a beet factory's five-stage evaporator were investigated. Ion chromatography with integrated pulsed amperometric detection (IC-IPAD), was used as an accurate carbohydrate analysis technique to measure sucrose, glucose and fructose levels. Conventional methods used by the sugar industry to monitor sugar losses, were compared to IC-IPAD values and shown not to be viable for determining losses across the evaporator process. Losses and color formation were shown to be due to a complex of reactions which could be partially characterized by the identification of products at various stages of the process.
Technical Abstract: Sucrose chemical loss and degradation product formation including color compounds, across a beet factory's five-step evaporator were investigated. Kinetic samples of thin juice and evaporation syrups were obtained hourly, over a six hour sampling period. This sampling period occurred once in the 1995/96 and 1996/97 campaigns. Ion chromatography with integrated pulsed amperometric detection (IC-IPAD), an accurate carbohydrate analysis technique was used to measure sucrose, glucose and fructose levels, using a NaOH gradient method. IC-IPAD, with a strong NaOH/NaAcetate gradient method, was used to determine oligosaccharide degradation products. Conventional sugar factory analyses for monitoring sugar losses, i.e., pol, purity, pH and color, were compared to IC-IPAD analyses; purity was shown not to be viable for determining losses across the evaporator process. In the 1995/96 campaign, pH dropped approximately 0.22 pH units across the evaporators and there was a concomitant increase in color of 418 ICUMSA 420mm units. Color formation is due to a complex of reactions, including Maillard color reactions and alkaline thermal degradation reactions of sucrose and/or invert sugars. Maillard reactions are more dominant at the early stages of evaporation and alkaline degradation reactions at the latter stages. Excellent correlations existed between polarizations measured at 589 and 880 nm for the 1995/96 (r2=.997) and 1996/97 (r2=1.000) campaigns.