Browsing by Subject "LACTIC-ACID BACTERIA"

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  • Ahlberg, Sara; Randolph, Delia; Okoth, Sheila; Lindahl, Johanna (2019)
    Aflatoxins continue to be a food safety problem globally, especially in developing regions. A significant amount of effort and resources have been invested in an attempt to control aflatoxins. However, these efforts have not substantially decreased the prevalence nor the dietary exposure to aflatoxins in developing countries. One approach to aflatoxin control is the use of binding agents in foods, and lactic acid bacteria (LAB) have been studied extensively for this purpose. However, when assessing the results comprehensively and reviewing the practicality and ethics of use, risks are evident, and concerns arise. In conclusion, our review suggests that there are too many issues with using LAB for aflatoxin binding for it to be safely promoted. Arguably, using binders in human food might even worsen food safety in the longer term.
  • Kant, Ravi; Palva, Airi; von Ossowski, Ingemar (2017)
    As an ecological niche, the mammalian intestine provides the ideal habitat for a variety of bacterial microorganisms. Purportedly, some commensal genera and species offer a beneficial mix of metabolic, protective, and structural processes that help sustain the natural digestive health of the host. Among these sort of gut inhabitants is the Gram-positive lactic acid bacterium Lactobacillus ruminis, a strict anaerobe with both pili and flagella on its cell surface, but also known for being autochthonous (indigenous) to the intestinal environment. Given that the molecular basis of gut autochthony for this species is largely unexplored and unknown, we undertook a study at the genome level to pinpoint some of the adaptive traits behind its colonization behavior. In our pan-genomic probe of L. ruminis, the genomes of nine different strains isolated from human, bovine, porcine, and equine host guts were compiled and compared for in silico analysis. For this, we conducted a geno-phenotypic assessment of protein-coding genes, with an emphasis on those products involved with cell-surface morphology and anaerobic fermentation and respiration. We also categorized and examined the core and accessory genes that define the L. ruminis species and its strains. Here, we made an attempt to identify those genes having ecologically relevant phenotypes that might support or bring about intestinal indigenousness.
  • Nionelli, Luana; Wang, Yaqin; Pontonio, Erica; Immonen, Mikko; Rizzello, Carlo; Maina, Ndegwa; Katina, Kati; Coda, Rossana (2020)
    Bread is one of the most consumed food products in the world and one of the most discarded, due to its intrinsic short shelf-life and susceptibility to mold spoilage. Additionally, bread waste is generated during production and distribution, leading to the disposal of bread otherwise still fit for consumption. To avoid generating huge amount of bread waste, strategies to enable its reutilization should be sought. In this study, surplus bread, still suitable for consumption, was bioprocessed with enzymes and fermented by selected lactic acid bacteria generating an ingredient with antifungal properties. Bread hydrolysate fermented by Lactobacillus brevis AM7 showed broad inhibitory spectrum against the fungal species tested and antifungal activity ranging from 20 to 70%. Nine antifungal peptides were identified via Liquid Chromatography-Electrospray Ionisation-Mass Spectra/ Mass Spectra (nano-LC-ESI-MS/MS), having 10-17 amino acid residues and mass ranging from 1083.6 to 1980.7 Da, all of them encrypted in wheat proteins sequences. Bread hydrolysate fermented by Lb. brevis AM7, non fermented bread hydrolysate and a slurry consisting of water-bread mixture were used as ingredients in bread making and compared to regular wheat bread. Breads containing the fermented hydrolysate (18 and 22% of the dough weight) showed the longest mold-free shelf-life compared to the other breads, lasting up to 10 days before mold appearance. Additionally, the fermented hydrolysate was the least detrimental on bread quality, emphasizing the positive impact and potential of the studied biotechnology.
  • Verni, Michela; Pontonio, Erica; Krona, Annika; Jacob, Sera; Pinto, Daniela; Verardo, Vito; Díaz-de-Cerio, Elixabet; Coda, Rossana; Rizzello, Carlo (2020)
    Brewers' spent grain (BSG) is the major by-product of the brewing industry which remain largely unutilized despite its nutritional quality. In this study, the effects of fermentation on BSG antioxidant potential were analyzed. A biotechnological protocol including the use of xylanase followed by fermentation withLactiplantibacillus plantarum (Lactobacillus plantarum)PU1, PRO17, and H46 was used. Bioprocessed BSG exhibited enhanced antioxidant potential, characterized by high radical scavenging activity, long-term inhibition of linoleic acid oxidation and protective effect toward oxidative stress on human keratinocytes NCTC 2544. Immunolabelling and confocal laser microscopy showed that xylanase caused an extensive cell wall arabinoxylan disruption, contributing to the release of bound phenols molecules, thus available to further conversion through lactic acid bacteria metabolism. To clarify the role of fermentation on the antioxidant BSG potential, phenols were selectively extracted and characterized through HPLC-MS techniques. Novel antioxidant peptides were purified and identified in the most active bioprocessed BSG.
  • Douillard, Francois P.; de Vos, Willem M. (2019)
    Over the last decade, there has been an increasing scientific and public interest in bacteria that may positively contribute to human gut health and well-being. This interest is reflected by the ever-increasing number of developed functional food products containing health-promoting bacteria and reaching the market place as well as by the growing revenue and profits of notably bacterial supplements worldwide. Traditionally, the origin of probiotic-marketed bacteria was limited to a rather small number of bacterial species that mostly belong to lactic acid bacteria and bifidobacteria. Intensifying research efforts on the human gut microbiome offered novel insights into the role of human gut microbiota in health and disease, while also providing a deep and increasingly comprehensive understanding of the bacterial communities present in this complex ecosystem and their interactions with the gut-liver-brain axis. This resulted in rational and systematic approaches to select novel health promoting bacteria or to engineer existing bacteria with enhanced probiotic properties. In parallel, the field of gut microbiomics developed into a fertile framework for the identification, isolation and characterization of a phylogenetically diverse array of health-promoting bacterial species, also called next-generation therapeutic bacteria. The present review will address these developments with specific attention for the selection and improvement of a selected number of health-promoting bacterial species and strains that are extensively studied or hold promise for future food or pharma product development.
  • Rizzello, Carlo G.; Coda, Rossana; Wang, Yaqin; Verni, Michela; Kajala, Ilkka; Katina, Kati; Laitila, Arja (2019)
    The interest towards legumes in food applications has risen over the past decades. However, the presence of antinutritional factors (ANF) and the poor technological performances still restricts their application in food fortification. In this study, four lactic acid bacteria (LAB) isolated from faba bean were applied as starter cultures for faba bean bioprocessing. None of the strains employed produced exopolysaccharides from raffinose, on the contrary, they did with sucrose as substrate. The fermented doughs were characterized and the strains were compared for their adaptation capacity and metabolic performance including the formation of dextrans, the degradation of ANF and the ability to improve antioxidant activity and in vitro protein digestibility (IVPD). A contribution to the proteolysis was given by the presence of endogenous enzymes, responsible for the increase of peptides and amino acids in dough from irradiated flour. However, the LAB strains further enhanced proteolysis. Weissella cibaria VTT E-153485 led to the highest peptide release and consequentially to the highest IVPD. In doughs fermented with Pediococcus pentosaceus VTT E-153483 and Leuconostoc kimchi VTT E-153484, phytic acid was reduced to more than half the initial concentration. Inoculated doughs had significantly lower content of oligosaccharides after 24 h of incubation compared to the controls. The most efficient raffinose consumption was found for Leuc. kimchi and W. cibaria. Doughs inoculated with weissellas contained > 1% of dextrans. Weissella confusa VTT E-143403 induced a significant increment in viscosity (ca. 7 times higher than the controls). This study revealed that well-characterized, indigenous LAB provided beneficial biotechnological features in faba bean dough processing and contributed to its implementation in the food production.
  • Banić, Martina; Uroić, Ksenija; Leboš Pavunc, Andreja; Novak, Jasna; Zorić, Katarina; Durgo, Ksenija; Petković, Hrvoje; Jamnik, Polona; Kazazić, Saša; Kazazić, Snježana; Radović, Slobodanka; Scalabrin, Simone; Hynönen, Ulla; Šušković, Jagoda; Kos, Blaženka (2018)
    Abstract S-layers represent the simplest biological membranes developed during the evolution and are one of the most abundant biopolymers on Earth. Current fundamental and applied research aim to reveal the chemical structure, morphogenesis and function of S-layer proteins (Slps). This is the first paper that describes the Slps of certain Lactobacillus brevis strain isolated from sauerkraut. The whole genome sequence (WGS) analysis of the L. brevis SF9B strain uncovered three genes encoding the putative Slps, but merely one, identified as similar to the SlpB of L. brevis ATCC 14869, was expressed. Slp-expressing SF9B cells exhibited increased survival in simulated gastrointestinal (GI) conditions and during freeze-drying. Their survival in stress conditions was additionally enhanced by microencapsulation, especially when using alginate with gelatine as a matrix. Thus prepared cells were subjected to simulated GI conditions and their mortality was only 0.28 ± 0.45 log CFU/mL. Furthermore, a correlation between the high surface hydrophobicity and the remarkable aggregative capacity of SF9B strain was established. The results indicate a prominent role of Slps in adhesion to mucin, extracellular matrix (ECM) proteins, and particularly to Caco-2 cells, where the removal of Slps utterly abolished the adhesiveness of SF9B cells for 7.78 ± 0.25 log CFU/mL.
  • Douillard, Francois P.; Kant, Ravi; Ritari, Jarmo; Paulin, Lars; Palva, Airi; de Vos, Willem M. (2013)
  • Sun, Zhihong; Harris, Hugh M. B.; McCann, Angela; Guo, Chenyi; Argimon, Silvia; Zhang, Wenyi; Yang, Xianwei; Jeffery, Ian B.; Cooney, Jakki C.; Kagawa, Todd F.; Liu, Wenjun; Song, Yuqin; Salvetti, Elisa; Wrobel, Agnieszka; Rasinkangas, Pia; Parkhill, Julian; Rea, Mary C.; O'Sullivan, Orla; Ritari, Jarmo; Douillard, Francois P.; Ross, R. Paul; Yang, Ruifu; Briner, Alexandra E.; Felis, Giovanna E.; de Vos, Willem M.; Barrangou, Rodolphe; Klaenhammer, Todd R.; Caufield, Page W.; Cui, Yujun; Zhang, Heping; O'Toole, Paul W. (2015)
    Lactobacilli are a diverse group of species that occupy diverse nutrient-rich niches associated with humans, animals, plants and food. They are used widely in biotechnology and food preservation, and are being explored as therapeutics. Exploiting lactobacilli has been complicated by metabolic diversity, unclear species identity and uncertain relationships between them and other commercially important lactic acid bacteria. The capacity for biotransformations catalysed by lactobacilli is an untapped biotechnology resource. Here we report the genome sequences of 213 Lactobacillus strains and associated genera, and their encoded genetic catalogue for modifying carbohydrates and proteins. In addition, we describe broad and diverse presence of novel CRISPR-Cas immune systems in lactobacilli that may be exploited for genome editing. We rationalize the phylogenomic distribution of host interaction factors and bacteriocins that affect their natural and industrial environments, and mechanisms to withstand stress during technological processes. We present a robust phylogenomic framework of existing species and for classifying new species.
  • Andreevskaya, Margarita; Jääskelainen, Elina; Johansson, Per; Ylinen, Anne; Paulin, Lars; Björkroth, Johanna; Auvinen, Petri (2018)
    Psychrotrophic lactic acid bacteria (LAB) are the prevailing spoilage organisms in packaged cold-stored meat products. Species composition and metabolic activities of such LAB spoilage communities are determined by the nature of the meat product, storage conditions, and interspecies interactions. Our knowledge of system level responses of LAB during such interactions is very limited. To expand it, we studied interactions between three common psychrotrophic spoilage LAB (Leuconostoc gelidum, Lactococcus piscium, and Lactobacillus oligofermentans) by comparing their time course transcriptome profiles obtained during their growth in individual, pairwise, and triple cultures. The study revealed how these LAB employed different strategies to cope with the consequences of interspecies competition. The fastest-growing bacterium, Le. gelidum, attempted to enhance its nutrient-scavenging and growth capabilities in the presence of other LAB through upregulation of carbohydrate catabolic pathways, pyruvate fermentation enzymes, and ribosomal proteins, whereas the slower-growing Lc. piscium and Lb. oligofermentans downregulated these functions. These findings may explain the competitive success and predominance of Le. gelidum in a variety of spoiled foods. Peculiarly, interspecies interactions induced overexpression of prophage genes and restriction modification systems (mechanisms of DNA exchange and protection against it) in Lc. piscium and Lb. oligofermentans but not in Le. gelidum. Cocultivation induced also overexpression of the numerous putative adhesins in Lb. oligofermentans. These adhesins might contribute to the survival of this slowly growing bacterium in actively growing meat spoilage communities. IMPORTANCE Despite the apparent relevance of LAB for biotechnology and human health, interactions between members of LAB communities are not well known. Knowledge of such interactions is crucial for understanding how these communities function and, consequently, whether there is any possibility to develop new strategies to interfere with their growth and to postpone spoilage of packaged and refrigerated foods. With the help of controlled experiments, detailed regulation events can be observed. This study gives an insight into the system level interactions and the different competition-induced survival strategies related to enhanced uptake and catabolism of carbon sources, overexpression of adhesins and putative bacteriocins, and the induction of exchange of genetic material. Even though this experiment dealt with only three LAB strains in vitro, these findings agreed well with the relative abundance patterns typically reported for these species in natural food microbial communities.
  • Deptula, Paulina; Chamlagain, Bhawani; Edelmann, Minnamari; Sangsuwan, Panchanit; Nyman, Tuula A.; Savijoki, Kirsi; Piironen, Vieno; Varmanen, Pekka (2017)
    Propionibacterium freudenreichii is a traditional dairy bacterium and a producer of short chain fatty acids (propionic and acetic acids) as well as vitamin B12. In food applications, it is a promising organism for in situ fortification with B12 vitamin since it is generally recognized as safe (GRAS) and it is able to synthesize biologically active form of the vitamin. In the present study, vitamin B12 and pseudovitamin biosynthesis by P. freudenreichii was monitored by UHPLC as a function of growth in food-like conditions using a medium mimicking cheese environment, without cobalt or 5,6-dimethylbenzimidazole (DMBI) supplementation. Parallel growth experiments were performed in industrial-type medium known to support the biosynthesis of vitamin B12. The production of other key metabolites in the two media were determined by HPLC, while the global protein production was compared by gel-based proteomics to assess the effect of growth conditions on the physiological status of the strain and on the synthesis of different forms of vitamin. The results revealed distinct protein andmetabolite production, which reflected the growth conditions and the potential of P. freudenreichii for synthesizing nutritionally relevant amounts of active vitamin B12 regardless of the metabolic state of the cells.
  • Nissila, Eija; Douillard, Francois P.; Ritari, Jarmo; Paulin, Lars; Jarvinen, Hanna M.; Rasinkangas, Pia; Haapasalo, Karita; Meri, Seppo; Jarva, Hanna; de Vos, Willem M. (2017)
    Lactobacillus rhamnosus strains are ubiquitous in fermented foods, and in the human body where they are commensals naturally present in the normal microbiota composition of gut, vagina and skin. However, in some cases, Lactobacillus spp. have been implicated in bacteremia. The aim of the study was to examine the genomic and immunological properties of 16 clinical blood isolates of L. rhamnosus and to compare them to the well- studied L. rhamnosus probiotic strain GG. Blood cultures from bacteremic patients were collected at the Helsinki University Hospital laboratory in 2005-2011 and L. rhamnosus strains were isolated and characterized by genomic sequencing. The capacity of the L. rhamnosus strains to activate serum complement was studied using immunological assays for complement factor C3a and the terminal pathway complement complex (TCC). Binding of complement regulators factor H and C4bp was also determined using radioligand assays. Furthermore, the isolated strains were evaluated for their ability to aggregate platelets and to form biofilms in vitro. Genomic comparison between the clinical L. rhamnosus strains showed them to be clearly different from L. rhamnosus GG and to cluster in two distinct lineages. All L. rhamnosus strains activated complement in serum and none of them bound complement regulators. Four out of 16 clinical blood isolates induced platelet aggregation and/or formed more biofilms than L. rhamnosus GG, which did not display platelet aggregation activity nor showed strong biofilm formation. These findings suggest that clinical L. rhamnosus isolates show considerable heterogeneity but are clearly different from L. rhamnosus GG at the genomic level. All L. rhamnosus strains are still normally recognized by the human complement system.
  • Ran, Li; Wan, Xing; Takala, Timo; Saris, Per (2021)
    The yeastSaccharomyces boulardiiis well known for its probiotic effects such as treating or preventing gastrointestinal diseases. Due to its ability to survive in stomach and intestine,S. boulardiicould be applied as a vehicle for producing and delivering bioactive substances of interest to human gut. In this study, we cloned the genelecCencoding the antilisterial peptide leucocin C from lactic acid bacteriumLeuconostoc carnosuminS. boulardii. The constructedS. boulardiistrain secreted a peptide, which had molecular weight corresponding to leucocin C in SDS-PAGE. The peptide band inhibitedListeria monocytogenesin gel overlay assay. Likewise, concentratedS. boulardiiculture supernatant inhibited the growth ofL. monocytogenes. The growth profile and acid tolerance of the leucocin C secretingS. boulardiiwere similar as those of the strain carrying the empty vector. We further demonstrated that the cells of the leucocin C producingS. boulardiiefficiently killedL. monocytogenes, also without antibiotic selection pressure. These results showed that antilisterial activity could be added to the arsenal of probiotic activities ofS. boulardii, demonstrating its potential as a carrier for therapeutics delivery.
  • Xu, Yan; Coda, Rossana; Holopainen-Mantila, Ulla; Laitila, Arja; Katina, Kati; Tenkanen, Maija (2019)
    The aim of this study was to investigate the impact of in situ produced exopolysaccharides (EPS) on the rheological and textural properties of fava bean protein concentrate (FPC). EPS (dextrans) were produced from sucrose by two lactic acid bacteria (LAB). The acidification, rheology, and texture of FPC pastes fermented with Leuconostoc pseudomesenteroides DSM 20193 and Weissella confusa VTT E-143403 (E3403) were compared. A clear improvement in rheological and textural parameters was observed in sucrose-added pastes after fermentation, especially with W. confusa VTT E3403. Only moderate proteolysis of fava bean protein during fermentation was observed. The microstructure of the protein in FPC pastes, as observed by confocal laser scanning microscopy, revealed a less continuous and denser structure in EPS-abundant pastes. The beneficial structure formed during EPS-producing fermentation could not be mimicked by simply mixing FPC, isolated dextran, lactic acid, and acetic acid with water. These results emphasize the benefits of in situ produced EPS in connection with the LAB fermentation of legume protein-rich foods. Fermentation with EPS-producing LAB is a cost-effective and clean-labeled technology to obtain tailored textures, and it can further enhance the usability of legumes in novel foods.
  • Fernandez, Maria; Hudson, John Andrew; Korpela, Riitta; de los Reyes-Gavilsn, Clara G. (2015)
  • Xu, Yan; Wang, Yaqin; Coda, Rossana; Säde, Elina; Tuomainen, Päivi; Tenkanen, Maija; Katina, Kati (2017)
    Fava bean flour is regarded as a potential plant-based protein source, but the addition of it at high concentration is restricted by its poor texture-improving ability and by anti-nutritional factors (ANF). Exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) are regarded as good texture modifiers. In this study, fava bean flour was fermented with Leuconostoc spp. and Weissella spp. with or without sucrose addition, in order to evaluate their potential in EPS production. The contents of free sugars, organic acids, mannitol and EPS in all fermented fava bean doughs were measured. Rheological properties of sucrose-enriched doughs, including viscosity flow curves, hysteresis loop and dynamic oscillatory sweep curves, were measured after fermentation. As one of the ANF, the degradation of raffinose family oligosaccharides (RFO) was also studied by analyzing RFO profiles of different doughs. Quantification of EPS revealed the potential of Leuconostoc pseudomesenteroides DSM 20193 in EPS production, and the rheological analysis showed that the polymers produced by this strain has the highest thickening and gelling capability. Furthermore, the viscous fava bean doughs containing plant proteins and synthesized in situ EPS may have a potential application in the food industry and fulfill consumers' increasing demands for "clean labels" and plant-originated food materials. (C) 2017 Elsevier B.V. All rights reserved.
  • Rizzello, Carlo Giuseppe; Hernandez-Ledesma, Blanca; Fernandez-Tome, Samuel; Curiel, Jose Antonio; Pinto, Daniela; Marzani, Barbara; Coda, Rossana; Gobbetti, Marco (2015)
    Background: There is an increasing interest toward the use of legumes in food industry, mainly due to the quality of their protein fraction. Many legumes are cultivated and consumed around the world, but few data is available regarding the chemical or technological characteristics, and especially on their suitability to be fermented. Nevertheless, sourdough fermentation with selected lactic acid bacteria has been recognized as the most efficient tool to improve some nutritional and functional properties. This study investigated the presence of lunasin-like polypeptides in nineteen traditional Italian legumes, exploiting the potential of the fermentation with selected lactic acid bacteria to increase the native concentration. An integrated approach based on chemical, immunological and ex vivo (human adenocarcinoma Caco-2 cell cultures) analyses was used to show the physiological potential of the lunasin-like polypeptides. Results: Italian legume varieties, belonging to Phaseulus vulgaris, Cicer arietinum, Lathyrus sativus, Lens culinaris and Pisum sativum species, were milled and flours were chemically characterized and subjected to sourdough fermentation with selected Lactobacillus plantarum C48 and Lactobacillus brevis AM7, expressing different peptidase activities. Extracts from legume doughs (unfermented) and sourdoughs were subjected to western blot analysis, using an anti-lunasin primary antibody. Despite the absence of lunasin, different immunoreactive polypeptide bands were found. The number and the intensity of lunasin-like polypeptides increased during sourdough fermentation, as the consequence of the proteolysis of the native proteins carried out by the selected lactic acid bacteria. A marked inhibitory effect on the proliferation of human adenocarcinoma Caco-2 cells was observed using extracts from legume sourdoughs. In particular, sourdoughs from Fagiolo di Lamon, Cece dell'Alta Valle di Misa, and Pisello riccio di Sannicola flours were the most active, showing a decrease of Caco-2 cells viability up to 70 %. The over-expression of Caco-2 filaggrin and involucrin genes was also induced. Nine lunasin-like polypeptides, having similarity to lunasin, were identified. Conclusions: The features of the sourdough fermented legume flours suggested the use for the manufacture of novel functional foods and/or pharmaceuticals preparations.
  • Tamene, Aynadis; Baye, Kaleab; Kariluoto, Susanna; Edelmann, Minnamari; Bationo, Fabrice; Leconte, Nicolas; Humblot, Christele (2019)
    Folate deficiencies are widespread around the world. Promoting consumption of folate-rich foods could be a sustainable option to alleviate this problem. However, these foods are not always available. Cereals, being a staple food, could contribute to folate intake. They are fermented prior to consumption in many African countries, and fermentation can modify the folate content. In Ethiopia, injera is a widely consumed fermented flat bread. The main drivers of its fermentation are lactic acid bacteria (LAB). The aim of this work was to isolate and identify folate-producing LAB from injera fermented dough and to evaluate their ability to increase folate status after depletion in a rat model. Among the 162 strains isolated from 60 different fermentations, 19 were able to grow on a folate-free culture medium and produced 1 to 43 mu g/L (24 h, 30 degrees C incubation). The four highest folate producers belonged to the Lactobacillus plantarum species. The most productive strain was able to enhance folate status after depletion in a rat model, despite the relatively low folate content of the feed supplemented with the strain. Folate-producing L. plantarum strain has potential use as a commercial starter in injera production.
  • van den Nieuwboer, Maurits; van Hemert, Saskia; Claassen, Eric; de Vos, Willem M. (2016)
    Lactobacillus plantarum WCFS1 is one of the best studied Lactobacilli, notably as its genome was unravelled over 12years ago. L.plantarum WCFS1 can be grown to high densities, is amenable to genetic transformation and highly robust with a relatively high survival rate during the gastrointestinal passage. In this review, we present and discuss the main insights provided by the functional genomics research on L.plantarum WCFS1 with specific attention for the molecular mechanisms related to its interaction with the human host and its potential to modify the immune system, and induce other health-related benefits. Whereas most insight has been gained in mouse and other model studies, onlyfive human studies have been reported with L.plantarum WCFS1. Hence NCIMB 8826 (the parental strain of L.plantarum WCFS1) in human trials as to capitalize on the wealth of knowledge that is summarized here.
  • Koistinen, Ville M.; Mattila, Outi; Katina, Kati; Poutanen, Kaisa; Aura, Anna-Marja; Hanhineva, Kati (2018)
    Sourdough fermentation by lactic acid bacteria is commonly used in bread baking, affecting several attributes of the final product. We analyzed whole-grain wheat and rye breads and doughs prepared with baker's yeast or a sourdough starter including Candida milleri, Lactobacillus brevis and Lactobacillus plantarum using non-targeted metabolic profiling utilizing LC-QTOF-MS. The aim was to determine the fermentation-induced changes in metabolites potentially contributing to the health-promoting properties of whole-grain wheat and rye. Overall, we identified 118 compounds with significantly increased levels in sourdough, including branched-chain amino acids (BCAAs) and their metabolites, small peptides with high proportion of BCAAs, microbial metabolites of phenolic acids and several other potentially bioactive compounds. We also identified 69 compounds with significantly decreased levels, including phenolic acid precursors, nucleosides, and nucleobases. Intensive sourdough fermentation had a higher impact on the metabolite profile of whole-grain rye compared to milder whole-grain wheat sourdough fermentation. We hypothesize that the increased amount of BCAAs and potentially bioactive small peptides may contribute to the insulin response of rye bread, and in more general, the overall protective effect against T2DM and CVD.