Microbial and metabolic characterization of organic artisanal sauerkraut fermentation and study of gut health-promoting properties of sauerkraut brine

Giulia Gaudioso; Tobias Weil; Giulia Marzorati; Pavel Solovyev; Luana Bontempo; Elena Franciosi; Luigi Bertoldi; Carlo Pedrolli; Kieran Michael Tuohy; Francesca Fava

doi:10.3389/fmicb.2022.929738

Microbial and metabolic characterization of organic artisanal sauerkraut fermentation and study of gut health-promoting properties of sauerkraut brine

Front Microbiol. 2022 Oct 13:13:929738. doi: 10.3389/fmicb.2022.929738. eCollection 2022.

Authors

Affiliations

¹ Nutrition and Nutrigenomics Unit, Research and Innovation Center, Fondazione Edmund Mach, San Michele all'Adige, Italy.
² Centre for Integrative Biology (CIBIO) - Department of Cellular, Computational and Integrative Biology, University of Trento, Trento, Italy.
³ Traceability Unit, Research and Innovation Center, Fondazione Edmund Mach, San Michele all'Adige, Italy.
⁴ Organic Agriculture Unit, Environmental Department, Technology Transfer Center, Fondazione Edmund Mach, San Michele all'Adige, Italy.
⁵ Dietetics and Clinical Nutrition, Nutrition Department, S. Chiara Hospital, Azienda Provinciale per I Servizi Sanitari, Trento, Italy.
⁶ School of Food Science and Nutrition, University of Leeds, Leeds, United Kingdom.

Abstract

Sauerkraut is a traditionally fermented cabbage, and recent evidence suggests that it has beneficial properties for human health. In this work, a multi-disciplinary approach was employed to characterize the fermentation process and gut health-promoting properties of locally produced, organic sauerkraut from two distinct producers, SK1 and SK2. 16S rRNA metataxonomics showed that bacterial diversity gradually decreased as fermentation progressed. Differences in sauerkraut microbiota composition were observed between the two producers, especially at the start of fermentation. Lactic acid bacteria (LAB) dominated the microbiota after 35 days, with Lactiplantibacillus being the dominant genus in both sauerkraut products, together with Leuconostoc and Paucilactobacillus in SK1, and with Pediococcus, Levilactibacillus, and Leuconostoc in SK2. LAB reached between 7 and 8 Log CFU/mL brine at the end of fermentation (35 days), while pH lowering happened within the first week of fermentation. A total of 220 LAB strains, corresponding to 133 RAPD-PCR biotypes, were successfully isolated. Lactiplantibacillus plantarum and Lactiplantibacillus pentosus accounted for 67% of all SK1 isolates, and Lactiplantibacillus plantarum/paraplantarum and Leuconostoc mesenteroides represented 72% of all the isolates from SK2. ¹H-NMR analysis revealed significant changes in microbial metabolite profiles during the fermentation process, with lactic and acetic acids, as well as amino acids, amines, and uracil, being the dominant metabolites quantified. Sauerkraut brine did not affect trans-epithelial electrical resistance through a Caco-2 cell monolayer as a measure of gut barrier function. However, significant modulation of inflammatory response after LPS stimulation was observed in PBMCs-Caco-2 co-culture. Sauerkraut brine supported a robust inflammatory response to endotoxin, by increasing TNF-α and IL-6 production while also stimulating the anti-inflammatory IL-10, therefore suggesting positive resolution of inflammation after 24 h and supporting the potential of sauerkraut brine to regulate intestinal immune function.

Keywords: fermented food; food microbiota; gut barrier; lactic acid bacteria; microbial metabolites; sauerkraut.