Sugarbeet Biochemical Quality Changes During Factory Pile Storage. Part II. Non-sugars

Abstract

Processing sugarbeet for sucrose production begins with an aqueous extraction. Besides sucrose, the extract also contains other water soluble root chemicals, which are viewed as undesirable impurities by the processor. Many impurities are removed or greatly diminished during processing, but some of those that remain reduce sucrose recovery, resulting in a loss of sugar to molasses. We investigated sugarbeet varietal differences in accumulation of several important impurities at harvest and after pile storage at three locations: Sidney MT, Worland WY, and Hereford TX. At each location a group of locally adapted varieties was used. Paired root samples were prepared at harvest. One of each pair immediately was analyzed for sucrose by polarimetry, and a portion of each sucrose filtrate was frozen for subsequent analysis by HPLC for sugars and quality components (Na, K, amino N, betaine). The second sample of each pair, in an air-permeable bag, was placed into the factory storage pile for 110 d at Sidney, 90 d at Worland, or 56 d at Hereford, then recovered and analyzed similarly to unstored samples. Data were analyzed separately for each location. Analyses of the sugar components (sucrose, glucose, fructose, and raffinose) have been reported previously. Component concentrations were expressed in g per 100 g sucrose (g/100S) as a relevant way to evaluate processing characteristics. Small but significant differences among cultivars for Na and K occurred at all three locations at harvest and at Sidney and Worland after storage. Sodium at harvest ranged from 0.49 to 0.65 g/100S at Sidney, 0.16 to 0.40 at Worland, and 0.34 to 0.59 at Hereford. Ranges for potassium at harvest were 0.87 to 0.99 g/100S at Sidney, 0.54 to 0.79 at Worland, and 1.51 to 1.79 at Hereford. Across cultivars, increases in at-harvest and post-storage concentrations (g/100S) occurred at all locations for K and at Sidney and Hereford for Na. Cultivars differed in amino N and betaine (g/100S) at harvest at Sidney and Worland, in amino N post-storage at Sidney, and in betaine post-storage at all three locations. Across cultivars, amino N concentration as g/100S increased with storage at all locations. Across cultivars, total impurity values incorporating all determined quality components (2.5Na + 3.5K + 9amino N + glucose + fructose + raffinose + betaine) were greatest at Hereford (16.6 and 24.2 g/100 S at harvest and after storage, respectively), least at Worland (6.0 and 9.9), and intermediate at Sidney (9.1 and 14.5).