Biodenitrification of concentrated red beet juice

摘要

The aim of the study was to determine the possibility to microbiologically remove nitrates from a concentrated red beet juice (3600 mOsm/kg) using halophilic bacteria, Halobacterium mediteranei, Halobacterium denitrificans, and Micrococcus halobius. As a result of microbiologic denitrification, dry matter content in the beet juice concentrate was reduced about 10 % and pH was found to decrease from 7.0 to 6.2. The content of nitrates in the concentrate decreased from 20 to 37 %, but in the diluted concentrate, the reduction rate of nitrates was higher, from 32 to 75 %. The highest denitrification rate was recorded for bacteria Micrococcus halobius. As a result of the fermentation process, changes in colour and contents of betalain pigments were observed. The content of betacyanin pigments decreased, while that of betaxanthin pigments increased.