Starter culture fermentation of Chinese sauerkraut: Growth, acidification and metabolic analyses

Chinese sauerkraut is a kind of traditional and typical fermented food. Four lactic acid bacteria (LAB) strains, Leuconostoc mesenteroides NCU1426, Lactococcus lactis NCU1315, Lactobacillus plantarum NCU1121 and Lactobacillus casei NCU1222 isolated from Chinese sauerkraut, were used in single starter cultures. Microbiological changes and pH values were monitored during fermentation. Metabolic substrates and products during the fermentation were examined using high performance liquid chromatography (HPLC) technology. Results have shown that Leu. mesenteroides and Lc. lactis grew faster, produced lactic acid earlier and were poorly acid-resistant, whereas Lb. plantarum and Lb. casei produced much more lactic acid throughout fermentation and showed better acid-tolerance. Two Lactococcus had outstanding performance in sucrose utilization while the other two Lactobacillus were likely to use glucose and fructose during fermentation. Unexpectedly, Leu. mesenteroides and Lc. lactis showed weak citric acid metabolism in fermentation. All the four LAB strains were able to utilize malic acid in early fermentation. In conclusion, these LAB strains have shown notable differences in growth and fermentative properties during starter culture fermentation of Chinese sauerkraut, probably resulting from LAB fermentative function and a mixture of complex substrates.