Lactobacillus casei starter culture improves vitamin content, increases acidity and decreases nitrite concentration during sauerkraut fermentation

To investigate the effects of Lactobacillus casei on Chinese sauerkraut fermentation, L.casei 11MZ-5-1 was inoculated into Chinese sauerkraut. Physicochemical indexes were measured, and the microbial dynamics during the fermentation were analysed by quantitative real-time PCR (qRT-PCR) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The result showed that inoculation with L.casei 11MZ-5-1 lowered the pH of the fermentation system more rapidly than in the control model (CK). The content of vitamin C (V-C) (44.64 +/- 2.12mgkg(-1)) was higher and nitrite (under 0.76mgkg(-1)) was lower than CK (P<0.05). The numbers of 16S rRNA gene copies in the experimental model (BA) were lower than in CK at the end fermentation time. According to the PCR-DGGE analyses, 22 and 17 specific bands were detected in CK and BA, respectively. L.paracasei and L.casei were predominant during the fermentation in BA. The relative abundance and diversity indices of bacteria in BA were 8.23 +/- 0.25 and 2.01 +/- 0.06, respectively, lower than in the CK (P<0.05). So, the L.casei 11MZ-5-1 inoculations could effectively inhibit the microbial diversity in the fermentation system. The fermented cabbage with L.casei 11MZ-5-1 was more favourably estimated by consumers in terms of colour, crispness, sourness, aroma, bitterness, stink, stale flavour and overall acceptability.