False Polarization: Quantitation and Characterization in Sugarbeet Processing Juices

Abstract

Sugarbeets rank high among the important agricultural plOducts lD the United States and are grown in 23 of the 50 states. In recent years, sugarbeet companies have attempted to perfect a system by which the growers could be paid on recovera ble sucrose rather than on sucrose content or tonnage of fa ctory delivered beets. Generally, sucrose values are based on polarizing saccharimeter readings made in factory tare laborator ies on representative samplings of delivered sugarbeets (7)3. Sucrose measured by this means is fre­ quently termed sugar or sugar. Estimated recoverable sucrose can be calculated from the polarimetric (pol) rf'ad ings and a correction factor based on the assessed quality of the sugarbeets. The assessed quality is deter mined by the concentration of certain non­ sucrose compone nts that cannot be re moved during factory juice purification. These materials prevent the optimum extraction of su­ crose during crystallization (1,2, 7, 8). Several classes of compounds make up the bulk of the non removable impurities. Nitrogen compo­ nents, especially those containing alpha amino nitrogen, rank high among these deleterious compounds (I, 2, R). Pol sucrose readings are subject to inaccuracies causeci by the presence, in varying amounts, of other optically active compounds, such as other saccharides, and amino acids, amides , a nd relaLed nit­ rogen (N) compounds (3, 7). Although gas liquid chrol1l'-!,tography (GLC) provides accurate, reliable values in sucrose analysis, it is not applicable to ' the tare laboratory, where utmost analytical speed is required on a large number of samples (6). The purpose of this experiment was to compare pol and GLC sucrose readings in sugarbeet factory processingjuices and to quantita­ tively assess the effect of some optically active nonsucrose components on the pol readings.