Selection of Wild Lactic Acid Bacteria Strains as Promoters of Postbiotics in Gluten-Free Sourdoughs

Abstract

The occurrence of inflammatory responses in humans is frequently associated with food intolerances and is likely to give rise to irritable bowel disease. The use of conventional or unconventional flours to produce gluten-free baking doughs brings important technological and nutritional challenges, and the use of the sourdough biotechnology has the potential to overcome such limitations. In addition, the typical metabolic transformations carried out by Lactic Acid Bacteria (LAB) can become an important biotechnological process for the nutritional fortification and functionalization of sourdoughs due to the resulting postbiotics. In such a context, this research work aimed at isolating and selecting new LAB strains that resort to a wide range of natural environments and food matrices to be ultimately employed as starter cultures in gluten-free sourdough fermentations. Nineteen LAB strains belonging to the genera of Lactobacillus, Leuconostoc, Pediococcus, and Streptococcus were isolated, and the selection criteria encompassed their acidification capacity in fermentations carried out on chickpea, quinoa, and buckwheat flour extracts; the capacity to produce exopolysaccharides (EPS); and the antimicrobial activity against food spoilage molds and bacteria. Moreover, the stability of the LAB metabolites after the fermentation of the gluten-free flour extracts submitted to thermal and acidic treatments was also assessed.

Bioconversion of Milk Permeate with Selected Lactic Acid Bacteria Strains and Apple By-Products into Beverages with Antimicrobial Properties and Enriched with Galactooligosaccharides

“…In addition, LAB take a leading role in food fermentation as they not only improve sensory properties of foods, but also increase its biosafety [7]. Most of the LAB strains possess antimicrobial properties, because of various metabolic processes-for example lactose metabolism, bacteriocin and bacteriocin-like inhibitory substance (BLIS) production, organic acids (mainly lactic and acetic acids), polysaccharide biosynthesis, proteolytic enzymes, bacteriophage resistance, metal-ion and antibiotic resistance, and citrate uptake [8][9][10][11][12][13][14][15][16][17]. Incorporation of fermented foods is very important towards a healthy and balanced diet, since fermented foods offer numerous benefits to human health [18].…”

“…There these prebiotics become selectively metabolized by some beneficial intestinal bacteria population, such as bifidobacteria and lactobacilli (probiotics), thus promoting their growth and multiplication and their bioactivity results in the production of beneficial microbial metabolites (postbiotics) not only to humans but also to animals and fishes. GOSs may protect against intestinal pathogens via their antiadhesive activity of enteric pathogens on the surface of gastrointestinal epithelial cells [11,22,23].…”

Monitoring and Optimization of Cupuaçu Seed Fermentation, Drying and Storage Processes

“…Instead of following composting, these by-products—rich in lignocellulose, polysaccharides and other carbohydrates compounds, among others—may be used to yield high-added value products such as bioethanol, biobutanol, biogas, biopolymers, and biofertilizers, among other possibilities. The microbial processing [anaerobic or solid-state fermentations (STF)] or pyrolysis to release fermentable sugars are promising solutions to further produce single cell proteins (SCP) and oils (SCO) [ 13 , 15 , 20 , 33 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ]. Cupuaçu endocarp (placenta) could be used to produce vinegar (acetic acid) or as an ingredient in sweets.…”

“…Simultaneously, food fermentation enables the growth and exponential multiplication of the competitive and desirable regular non-spore-forming Gram-positive rods and the catalase-negative Gram-positive cocci—for example, lactic acid bacteria (LAB)—such as lactobacilli, pediococci, lactococci, leuconostoc, micrococci, streptococci and group D-enterococci—, and the production by the latter of desirable bioactive, antimicrobial, and antioxidant metabolites, such as small peptides, exopolysaccharides (EPS), organic acids, ethanol, CO 2 , bacteriocins, etc. [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. These desirable microorganisms and resulting compounds from their metabolic activity are generally non-toxic and food-grade microorganisms, being classified as Generally Regarded as Safe (GRAS) and Qualified Presumption of Safety (QPS) [ 15 ].…”

“…[ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. These desirable microorganisms and resulting compounds from their metabolic activity are generally non-toxic and food-grade microorganisms, being classified as Generally Regarded as Safe (GRAS) and Qualified Presumption of Safety (QPS) [ 15 ].…”