Effects of salt concentration on Chinese sauerkraut fermentation

• The variation of LAB, fungi and Escherichia coli in sauerkraut with different salt content were analyzed.
• The content of sucrose, glucose, fructose, lactic acid and acetic acid in brine and cabbage were analyzed.
• The fermentation characteristics of sauerkraut with different salt concentrations were revealed.

The aim of the study was to determine the effects of salt concentration on traditional sauerkraut fermented spontaneously. Lactic acid bacteria (LAB), fungi and Escherichia coli (E. coli) in the brine were analyzed in the three kinds of sauerkraut. The contents of sugars (sucrose, glucose, fructose) and organic acids (lactic acid, acetic acid) in the brine and inside the cabbage were monitored by high-performance liquid chromatography (HPLC). In addition, the pH value was monitored in the brine. Results demonstrated that sucrose and glucose were consumed and fructose was accumulated gradually during fermentation. The whole fermentation process was dominated by LAB and a considerable accumulation of lactic acid was observed both in cabbage and brine at the end of fermentation. Salt concentration had a significant effect on sauerkraut fermentation at early stage. The LAB population and metabolic rate was reduced and the yield of lactic acid decreased with the increase of salt concentration. Suitable salt concentration can effectively inhibit the reproduction of fungi and E. coli. In comparison, high salt concentration delayed the maturation of sauerkraut and inhibited the metabolism of LAB.