Fermentation of African kale (Brassica carinata) using L. plantarum BFE 5092 and L. fermentum BFE 6620 starter strains.
Vegetables produced in Africa are sources of much needed micronutrients and fermentation is one way to enhance the shelf life of these perishable products. To prevent post-harvest losses and preserve African leafy vegetables, Lactobacillus plantarum BFE 5092 and Lactobacillus fermentum BFE 6620 starter strains were investigated for their application in fermentation of African kale (Brassica carinata) leaves. They were inoculated at 1×107cfu/ml and grew to a maximum level of 108cfu/ml during 24h submerged fermentation. The strains utilized simple sugars (i.e., glucose, fructose, and sucrose) in the kale to quickly reduce the pH from pH6.0 to pH3.6 within 24h. The strains continued to produce both d and l lactic acid up to 144h, reaching a maximum concentration of 4.0g/l. Fermentations with pathogens inoculated at 104cfu/ml showed that the quick growth of the starters inhibited the growth of Listeria monocytogenes and Salmonella Enteritidis, as well as other enterobacteria. Denaturing gradient gel electrophoresis and 16S rRNA gene (V3-V4-region) amplicon sequencing showed that in the spontaneous fermentations a microbial succession took place, though with marked differences in biodiversity from fermentation to fermentation. The fermentations inoculated with starters however were clearly dominated by both the inoculated strains throughout the fermentations. RAPD-PCR fingerprinting showed that the strains established themselves at approx. equal proportions. Although vitamins C, B1and B2decreased during the fermentation, the final level of vitamin C in the product was an appreciable concentration of 35mg/100g. In conclusion, controlled fermentation of kale offers a promising avenue to prevent spoilage and improve the shelf life and safety.
Department of Microbiology and Biotechnology, Max Rubner-Institut, Hermann-Weigmann-Straße 1, 24103 Kiel, Germany; Department of Microbiology, Faculty of Science, University of Lagos, Akoka, Lagos, Nigeria.
Folarin A
FA
Oguntoyinbo
Department of Microbiology and Biotechnology, Max Rubner-Institut, Hermann-Weigmann-Straße 1, 24103 Kiel, Germany.
Gyu-Sung
GS
Cho
Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut, Haid-und-Neu-Straße 9, 76131 Karlsruhe, Germany.
Bernhard
B
Trierweiler
Department of Microbiology and Biotechnology, Max Rubner-Institut, Hermann-Weigmann-Straße 1, 24103 Kiel, Germany.
Jan
J
Kabisch
Department of Microbiology and Biotechnology, Max Rubner-Institut, Hermann-Weigmann-Straße 1, 24103 Kiel, Germany.
Niels
N
Rösch
Department of Microbiology and Biotechnology, Max Rubner-Institut, Hermann-Weigmann-Straße 1, 24103 Kiel, Germany.
Horst
H
Neve
Department of Microbiology and Biotechnology, Max Rubner-Institut, Hermann-Weigmann-Straße 1, 24103 Kiel, Germany.
Wilhelm
W
Bockelmann
Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut, Haid-und-Neu-Straße 9, 76131 Karlsruhe, Germany.
Lara
L
Frommherz
Department of Food Science, University of Copenhagen, Denmark.
Dennis S
DS
Nielsen
Department of Food Science, University of Copenhagen, Denmark.
Lukasz
L
Krych
Department of Microbiology and Biotechnology, Max Rubner-Institut, Hermann-Weigmann-Straße 1, 24103 Kiel, Germany. Electronic address: Charles.Franz@mri.bund.de.
Charles M A P
CM
Franz
D000349:Africa; D001205:Ascorbic Acid / Q000737:chemistry; D001937:Brassica / Q000382:microbiology*; D004755:Enterobacteriaceae / Q000254:growth & development; D005285:Fermentation; D005516:Food Microbiology; D005838:Genotype; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000737:chemistry; D052197:Limosilactobacillus fermentum / Q000254:growth & development*; D048191:Lactiplantibacillus plantarum / Q000254:growth & development*; D064307:Microbiota; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique; D012995:Solubility; D014675:Vegetables / Q000382:microbiology; D014815:Vitamins / Q000737:chemistry
D012336:RNA, Ribosomal, 16S; D014815:Vitamins; D019344:Lactic Acid; D001205:Ascorbic Acid
Fermentation; Kale; Lactic acid bacteria; Metagenomics indigenous food