The sugar beet campaign of 1998 in the Netherlands suffered from severe weather conditions; i.e. subsequent periods of plentiful rainfall, frost and thaw. Thus, the harvest and processing quality of the beets became troublesome, which affected the processing capacity of the sugar factories. This paper will focus on the processing of frozen respectively thawed beets. A high-performance liquid chromatography method (HPAEC-PAD) was rapidly developed in order to be able to monitor the degree of deterioration of the frost-damaged beets. Both the invert sugar and dextran levels were analysed daily in raw juice samples. About 10 days after the outdoor temperature came again above 0 °C, the concentration of both sugar types sharply increased, thus causing processing problems. Even at relative low levels of dextran in raw juice (i.e. 75 mg/l), the filtration rate of the 2nd carbonation slurry dropped markedly and, consequently, the slicing capacity decreased to 50%. The dosage of 10 ppm dextranase NOVO 50L enzyme to the extraction appeared to be sufficient to restore the slicing capacity to 90% of the nominal capacity. In fact, it was the high level of invert sugar in thawed beets (up to 4 g/l in raw juice !) which made the processing of this low-quality beet material most uneconomic. The high invert sugar content consumed (in juice purification) a lot of alkalinity, which could only be compensated by the addition of excessive amounts of caustic soda. Nevertheless, both the juice quality became very moderate (e.g. low juice purity, high lime salts content, high juice as well as sugar colour) and the amount of sugar that ended up in the molasses reached an unacceptable high level.
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