Reduction of the microbiological action during sugar beet extraction with focus on nitrite contamination

Nitrite is one of the harmful pollutants for both people and animals. The formation of nitrite during the manufacturing of beet sugar was investigated. The results indicated that the cossettes contained lower nitrite content (1.23±0.1 mg/kg DM). However, the nitrite mainly formed during the extraction and purification processes. Most of the nitrite was transferred to molasses, with the remaining portion returning to the crystallization process through the circulation of juices. The nitrite content of raw juice was lower than 10 mg/kg DM in the aerobic extraction system, and it was reduced by 50% during the liming and carbonation. In the tower extraction system for both factories F1 and F2, the nitrite content increased from 5.5 and 25 mg/kg DM in the raw juice to 298 and 247%, 284 and 238%, 716 and 1032%, and 307 and 881% in the thin juice, thick juice, raw sugar green, and molasses, respectively. A significant reduction in the nitrite content of raw and de-foamed juice was achieved by the suggested point (L3) for dosing the disinfectant B (hop β -acids). The effect of the disinfectant lasted for more than 6 h at normal nitrite levels of juice and up to 90 min at high nitrite levels. Furthermore, the nitrite contents were reduced in thin juice, thick juice, and molasses by 58, 48 and 30%, respectively. By optimizing the dosing procedure and point of disinfectant hop β -acids dosage, the microbial load on the extraction system and formation rate of nitrite could be reduced significantly.