Impact of <i>Lactobacillus paracasei</i> HD1.7 as a Starter Culture on Characteristics of Fermented Chinese Cabbage (<i>Brassica rapa</i> var. <i>pekinensis</i>)

Abstract

IntroductionChinese cabbage (Brassica rapa var. pekinensis, hereinafter referred to as cabbage) is a kind of very common vegetable, which is widely planted in Asia and Europe. In autumn and winter, fresh but surplus cabbage is usually made into fermented cabbage, i.e. suan cai (sour vegetable in Chinese) which is nutritious and popular. Fermented cabbage is a very traditional and local food in Asia, especially in northeast China. The production process of fermented cabbage is similar to kimchi in Korea or sauerkraut in Germany, which relies on the fermentation by LAB (lactic acid bacteria). During the traditional producing process, cabbage is soaked into salt water at ambient temperature for weeks. Naturally occurring LAB transferred reducing sugar to organic acids, amino acids and other flavor substances (Wu et al. 2012). The sensory quality of fermented vegetable is unstable due to the variety in species and amount of epiphytic LAB. Meanwhile, nitrite produced by nitrate reducing bacteria during vegetable fermentation potentially threat consumers' health (Paik and Lee 2014).The use of LAB as starter cultures has been considered to ferment fresh vegetables into quality uniform and healthy food in decade. Several LAB such as Leuconostoc mesenteroides, Leu. citreum, and Lactobacillus plantarum have been applied in kimchi fermentation for quality development (Leal-Sánchez et al. 2003;Cho et al. 2014;Jo et al. 2014). LAB strain Lb.delbrueckii and Lb.paracasei have been used as mixed starter cultures to improve the characteristics of fermented cabbage (Han, Yi et al. 2014). The D. Zhao et al. 326 LAB inoculated into the vegetable fermentation produces more nutritive metabolites including lactate, acetate, amino acids, mannitol, and so on (Jung et al. 2012;Jo et al. 2014). Moreover, starter LAB generates more acidic conditions which results in inhibition of pathogenic bacteria (Chang and Chang 2011) and decomposition of nitrite Paik and Lee 2014).Though the bacterial succession and metabolites production during kimchi fermentation with LAB starter is relatively well studied by means of high-throughput sequencing and metabolomics techniques (Jung et al. 2012;, the impact of LAB starter on characteristics of fermented cabbage is barely known. In this research, Lb.paracasei HD1.7 was applied in cabbage fermentation as a starter culture. This strain was isolated from the liquid sample during cabbage fermentation which permitted its good compatibility as a starter (Lei et al. 2007). Several studies have been conducted on strain HD1.7, such as the purification and characteristics of bacteriocin (Ge et al. 2009), the optimization of bacteriocin producing medium (Ge et al. 2011a), the establishment of genetic transformation system (Ge et al. 2011b) and the mechanism of quorum sensing (Ge et al. 2011c gene was amplified and copy numbers were calculated based on the method of (Jung et al. 2011). Although the copy numbers determined by this method were not exactly equal to the cell numbers, we employed the PCR method becaus...

Lactobacillus paracasei HD1.7 used as a starter modulates the bacterial community and metabolome profile during fermentation of Chinese cabbage

“…A total of 1·75 l starter culture of L. paracasei HD1.7 cells was inoculated in the tank (Zhao et al . ). Natural fermentation without inoculation was used as a control.…”

“…Ten kg Cabbages were washed, drained, laid tightly into a 30 l plastic tank, and soaked in 17Á5 l 3% sodium chloride solution. A total of 1Á75 l starter culture of L. paracasei HD1.7 cells was inoculated in the tank (Zhao et al 2016). Natural fermentation without inoculation was used as a control.…”

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

“…So, in BA, lower pH value meant more acidic conditions; hence, V C content was consistently higher than that in CK ( P < 0.05). The result confirmed our previous study (Zhao et al ., ,,) and different/higher than Xiao et al . 's () study in which detected V C concentration was 27 mg kg −1 at the end of Chinese sauerkraut fermentation process ( P < 0.05).…”

“…The other probable reason was the lack of space and nutrition for limiting the growth of bacterial cells. The similar results have been found in fermented Chinese cabbage and kimchi with the use of L. paracasei and L. mesenteroides as starter cultures, respectively (Jung et al ., ; Zhao et al ., ,,).…”

“…The result showed that, during the entire fermentation period at each detection time point, the inoculation of strain L. casei 11MZ‐5‐1 resulted in a consistent lower pH and higher acidity ( P < 0.05), which confirmed Zhao et al . results (Zhao et al ., ,,). In addition, the similar results were also obtained in Chinese sauerkraut sample using other LAB starter Lactobacillus (Han et al ., ; Xia et al ., ,).…”