Sugarbeet Biochemical Quality Changes During Pile Storage. Part 1. Sugars

Abstract

Sucrose and quality losses in pile-stored sugarbeets have financial implications for growers and processers alike. Groups of locally adapted varieties were grown and pile stored at Sidney MT, Worland WY, and Hereford TX, to investigate varietal effect on losses during storage. Paired root samples were prepared at harvest. One of each pair immediately was analyzed for sucrose by polarimetry (pol), and a portion of each sucrose filtrate was frozen for later HPLC analysis for true sucrose, glucose, fructose, and raffinose. 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 the unstored samples. Data were analyzed separately for each location. Both at harvest and after storage, pol sucrose overestimated true sucrose concentration as determined by HPLC. At the three locations, the average pol error, the percentage by which pol sucrose minus HPLC sucrose differed from the HPLC sucrose value, was +2% to +19% at harvest, and +9% to +14% after storage. Glucose and fructose concentrations were low at harvest and increased significantly with storage at each location. Significant varietal difference after storage occurred for glucose at Worland and for fructose at Sidney and Worland. Raffinose concentrations at harvest were low at Sidney and Worland increasing significantly with storage. Varietal difference for raffinose after pile storage occured at Worland? The raffinose concentration was unexpectedly high at harvest at Hereford, but did not increase significantly during pile storage.