Formation of nisin, plant-derived biomolecules and antimicrobial activity in starter culture fermentations of sauerkraut Original Research Article

The study investigated the formation of glucosinolate breakdown products and other biomolecules in sauerkraut using different starter cultures of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus sakei, Leuconostoc mesenteroides, Pediococcus pentosaceus, Lactococcus lactis N8 and L. lactis LAC67). Moreover, we examined the antimicrobial effects of cabbage juice containing nisin and glucosinolate breakdown products. The major glucosinolates were sinigrin, glucoiberin, and glucobrassicin. Several breakdown products were formed during fermentation. When L. sakei was used as the starter culture, the amount of total breakdown products in sauerkraut was 2–3 times that of other strains. Especially the concentrations of 3-methylsulphinylpropyl-isothiocyanate (ion ratio 195 100 g−1 FW), allyl-isothiocyanate (980 μg 100 g−1 FW), sulphoraphane (ion ratio 60 100 g−1 FW) were significantly higher in the fermented end product of L. sakei than in the other end products. Goitrin was found in relatively high concentrations (480–1090 μg 100 g−1 FW) in all end products. We detected different types of inhibition on indicator strains in the fermented end products: juice fermented with L. sakei strain effectively inhibited the growth of Candida lambica, whereas Listeria monocytogenes was not affected. Escherichia coli was strongly inhibited in all cabbage juices. L. lactis N8 produced up to 1400 IU ml−1 of nisin in cabbage brine within 24 h, and nisin was detectable even after 13 days (250 IU ml−1).