Effects of Different Production Methods on the Quality and Microbial Diversity of Sauerkraut in Northeast China

Sauerkraut is a popular fermented food in Northeast China. However, owing to the different production methods used, the quality of commercial sauerkraut is often quite different, which is reflected mainly in the differences between starter culture (Group-L), additive addition (Group-P) and natural fermentation (Group-H) methods. The purpose of this study was to explore the differences among the three fermentation methods by measuring physical and chemical indices, microbial diversity indices, flavour indices and volatile substances. The results revealed that there was no significant difference in the physical or chemical indices among the groups. The content of esters and alcohols in Group-L was the highest, and the taste richness, aftertaste-a and aftertaste-b were the highest, which had a positive effect on flavour. The highest level of microbial diversity was found in Group-H, which contained many pathogenic bacteria, such as Janibacter, Pseudomonas, and Vagococcus, which reduced the food safety of sauerkraut. At the genus level, the dominant bacterial genera in the starter and additive groups included Lactobacillus and Pediococcus. The correlation analysis revealed that Group-L was positively correlated with the contents of Lactobacillus plantarum, Lactobacillus brevis, Pediococcus, ethyl oleate and vanillin. In summary, this study evaluated the different production methods of northeast sauerkraut, providing theoretical support for the production of high-quality northeast sauerkraut.