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Frontiers in Nutrition 2022There is a growing need for gluten-free bakery products with an improved nutritional profile. Currently, gluten-free baked goods deliver low protein, fiber, and mineral...
There is a growing need for gluten-free bakery products with an improved nutritional profile. Currently, gluten-free baked goods deliver low protein, fiber, and mineral content and elevated predicted glycaemic index (pGI). Olive cake (OC), a by-product from virgin olive oil extraction, is an excellent natural source of unsaturated fatty acids, dietary fiber and bioactive molecules, including polyphenols and tocopherols. In this framework, this study aimed at using two selected lactic acid bacteria and a yeast for increasing the antioxidant features and the phenol profile of the gluten-free breadsticks fortified with OC with the perspective of producing a functional food. Control (CTR) samples were prepared and compared with fermented ones (fCTR). Samples were added with either non-fermented OC (nfOC) or fermented for 12 and 20 h (fOC-12 and fOC-20). Our results showed that the predicted glycemic index (pGI) was influenced by both OC addition and sourdough fermentation. In fact, the lowest value of pGI was found in fOC-12, and hydrolysis index and pGI values of samples with OC (fOC-12 and nfOC) were statistically lower than fCTR. Both OC addition and fermentation improved the total phenol content and antioxidant activity of breadsticks. The most pronounced increase in hardness values was observed in the samples subjected to sourdough fermentation as evidenced both from texture profile analysis and sensory evaluation. Moreover, in most cases, the concentration of the detected volatile compounds was reduced by fermentation. Our work highlights the potential of OC to be upcycled in combination with fermentation to produce gluten-free breadsticks with improved nutritional profile, although additional trials are required to enhance textural and sensory profile.
PubMed: 35223958
DOI: 10.3389/fnut.2022.830932 -
BioMed Research International 2013Two strains (B7 and Z8) of the Leuconostoc mesenteroides subspecies mesenteroides that were isolated from Algerian camel milk from an initial pool of 13 strains and...
Two strains (B7 and Z8) of the Leuconostoc mesenteroides subspecies mesenteroides that were isolated from Algerian camel milk from an initial pool of 13 strains and demonstrated a high ability to inhibit the growth of Listeria spp. were selected and characterised at the phenotypic and genotypic levels. Probiotic profiling and inhibition spectra against food borne pathogens in mixed cultures were also investigated. The bacteriocin produced by L. mesenteroides strain B7 was identified as leucocin B by specific PCR. In vitro studies demonstrated that both Leuconostoc mesenteroides strains exhibited a marked probiotic profile, showing high survival at low pH (2-3 and 4) in the presence of 0.5%, 1%, and 2% of bile salts and at pH 3 in the presence of 3 mg/mL pepsin. Susceptibility testing against antimicrobial agents was also performed for both strains. When tested in a mixed culture with Listeria innocua, Listeria ivanovii, or Staphylococcus aureus, strain B7 reduced the numbers of these species by 1.87, 1.78, and 1.38 log units, respectively. Consequently, these two strains were found to possess good probiotic properties in vitro and a high capacity for Listeria spp. inhibition in mixed cultures. Therefore, these strains have a favourable technological aptitude and a potential application as novel probiotic starters.
Topics: Animals; Bacteriocins; Camelus; Food Microbiology; Humans; Lactobacillaceae; Listeria; Milk; Probiotics; Staphylococcus aureus
PubMed: 24392451
DOI: 10.1155/2013/418132 -
BioMed Research International 2019Tomatoes and tomato based-foods contain beneficial microorganisms and various organic acids that have important nutritional values for human. The objective of this study...
Tomatoes and tomato based-foods contain beneficial microorganisms and various organic acids that have important nutritional values for human. The objective of this study was to access the physiochemical properties of fermented tomatoes juices and to evaluate the competitiveness of lactic acid bacteria (LAB) against , , and spp., in artificially contaminated tomato juice. Microbial counting (LAB, fungi spp., and spp.) was performed after fermentation and weekly during storage. Different organic acids (Lactic, succinic, and acetic) and ethanol were also monitored using HPLC method. Color parameters were also determined. The results showed an increase of lactic and acetic acid content, during fermentation and storage of juices inoculated with and at 25°C. Besides, citric acid and ethanol revealed higher content at the end of storage compared to that registered at 4°C. The pH from tomatoes juices decreased from an initial value of 4.5 to below 3.2. Alongside, foodborne pathogen population was significantly suppressed in tomatoes juices when the samples were coinoculated with LAB strains. Moreover, the inhibition of species was faster compared to that of . After four weeks of storage at 4°C, and showed high survival rate, while pathogenic bacteria, yeasts, and molds cell numbers decreased drastically in all the contaminated vials. This work highlights the efficiency of and as potential starters for developing nutritious and safe fermented tomato juice products.
Topics: Bioreactors; Colony Count, Microbial; Fermentation; Food Microbiology; Foodborne Diseases; Fruit and Vegetable Juices; Humans; Lactobacillus plantarum; Leuconostoc mesenteroides
PubMed: 30931330
DOI: 10.1155/2019/6937837 -
Microorganisms Jan 2021SBC001, isolated from chive, produces glucansucrase and synthesizes oligosaccharides through its enzymatic activity. This study was conducted to optimize...
SBC001, isolated from chive, produces glucansucrase and synthesizes oligosaccharides through its enzymatic activity. This study was conducted to optimize oligosaccharide production using response surface methodology, analyze the structure of purified oligosaccharides, and investigate the prebiotic effect on 24 bacterial and yeast strains and the anti-inflammatory activity using RAW 264.7 macrophage cells. The optimal conditions for oligosaccharide production were a culture temperature of 30 °C and sucrose and maltose concentrations of 9.6% and 7.4%, respectively. Based on H-NMR spectroscopic study, the oligosaccharides were identified as gluco-oligosaccharides that consisted of 23.63% α-1,4 glycosidic linkages and 76.37% α-1,6 glycosidic linkages with an average molecular weight of 1137 Da. The oligosaccharides promoted the growth of bacterial and yeast strains, including , , , , , and . When lipopolysaccharide-stimulated RAW 264.7 cells were treated with the oligosaccharides, the production of nitric oxide was decreased; the expression of inducible nitric oxide synthase, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-10 was suppressed; and the nuclear factor-kappa B signaling pathway was inhibited. In conclusion, the gluco-oligosaccharides obtained from SBC001 exhibited a prebiotic effect on six bacterial and yeast strains and anti-inflammatory activity in RAW 264.7 macrophage cells.
PubMed: 33477973
DOI: 10.3390/microorganisms9010200 -
Isolation of antifungal activity of TA from kimchi and characterization of its antifungal compounds.Food Science and Biotechnology 2016Strain TA harboring antifungal activity was isolated from kimchi and identified based on Gram-staining, biochemical properties using an API 50 CHL, determination of rRNA...
Strain TA harboring antifungal activity was isolated from kimchi and identified based on Gram-staining, biochemical properties using an API 50 CHL, determination of rRNA gene sequences, and RAPD analysis. The determined gene sequences and RAPD pattern showed 100% homology with those of ATCC 8293. However, their properties were slightly different from each other. Especially, TA could not utilize lactose while strain ATCC 8293 could use lactose. ATCC 8293 showed higher antibacterial activity against than TA, whereas the antifungal activities of these 2 LAB against were the same. TA showed broad antimicrobial activities against Gram-positive and - negative bacteria as well as molds. We determined that the responsible antifungal compounds from TA are lactic acid, acetic acid and unidentified hydrophobic compound(s). Additionally, synergistic interactions involving acetic acid, lactic acid, phenyllactic acid, and unidentified hydrophobic compound(s) contribute to the overall inhibitory activity of TA.
PubMed: 30263260
DOI: 10.1007/s10068-016-0032-8 -
Microorganisms Nov 2021It is urgent to expand the market of biodegradable alternatives to oil-derived plastics owing to (i) increasingly limited oil availability/accessibility, and (ii) the...
It is urgent to expand the market of biodegradable alternatives to oil-derived plastics owing to (i) increasingly limited oil availability/accessibility, and (ii) the dramatic impact of traditional plastics on aquatic life, the food chain, all Earth ecosystems, and ultimately, human health. Polyhydroxyalkanoates (PHAs) are promising biodegradable polymers that can be obtained through microbial fermentation of agro-industrial byproducts, e.g., milk and cheese whey. Here, the PHA-accumulating efficiency of a mixed microbial culture (MMC, derived from activated sludges) grown on dairy byproducts (cheese and scotta whey) was measured. Bioreactor tests featuring temperature and pH control showed that both scotta and pre-treated Toma cheese whey could be used for PHA production by MMC, although scotta cheese whey supported higher PHA yield and productivity. The advantages of open MMCs include their plasticity and versatility to fast changing conditions; furthermore, no growth-medium sterilization is needed prior to fermentation. However, the use of pure cultures of efficient PHA producers may support better metabolic performances. Therefore, PHA-producing strains were isolated from a MMC, leading to the satisfactory identification of two bacterial strains, and spp., whose ability to accumulate PHAs in synthetic media was confirmed. A more detailed investigation by mass spectrometry revealed that the strain was . Although the validation of potential to produce PHA through fermentation of agro-industrial byproducts requires further investigations, this is the first study reporting PHA production with the genus.
PubMed: 34946028
DOI: 10.3390/microorganisms9122426 -
Frontiers in Veterinary Science 2021Lactic acid bacteria (LAB) convert carbohydrates into organic acids [mainly lactic acid (LA)], which reportedly have bactericidal activities. is a Gram-negative...
Lactic acid bacteria (LAB) convert carbohydrates into organic acids [mainly lactic acid (LA)], which reportedly have bactericidal activities. is a Gram-negative bacteria which infects birds, and causes significant economic losses. In this study, we investigated the antibacterial activity of the LA producing, QZ1178 from Qula (fermented food), against , using the Oxford cup method. Our data showed that QZ1178 inhibited isolates from different origins; however, QZ1178 antibacterial activity dropped dramatically at pH 5.5-pH 6. The LA concentration and pH of the liquid broth containing QZ1178 after 24 h culture was 29 mg/mL and 3.6, respectively. This concentration (29 mg/mL at pH 3.6) and the antibiotic, cefotaxime (minimum inhibitory concentration (MIC) 2.5 μg/mL) effectively inhibited (GAC026) growth as observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). treated with LA exhibited extensive cell surface collapse, increased cell damage, cell membrane disruption, and cytoplasmic leakage, indicative of cell lysis. We suggest QZ1178 exerts potential antibacterial effects against the poultry pathogen, via LA.
PubMed: 33969032
DOI: 10.3389/fvets.2021.630294 -
Gut Microbes 2023Fermented foods demonstrate remarkable health benefits owing to probiotic bacteria or microproducts produced via bacterial fermentation. Fermented foods are produced by...
Fermented foods demonstrate remarkable health benefits owing to probiotic bacteria or microproducts produced via bacterial fermentation. Fermented foods are produced by the fermentative action of several lactic acid bacteria, including ; however, the exact mechanism of action of these foods remains unclear. Here, we observed that prebiotics associated with -produced exopolysaccharides (EPS) demonstrate substantial host metabolic benefits. -produced EPS is an indigestible α-glucan, and intake of the purified form of EPS improved glucose metabolism and energy homeostasis through EPS-derived gut microbial short-chain fatty acids, and changed gut microbial composition. Our findings reveal an important mechanism that accounts for the effects of diet, prebiotics, and probiotics on energy homeostasis and suggests an approach for preventing lifestyle-related diseases by targeting bacterial EPS.
Topics: Prebiotics; Leuconostoc mesenteroides; Gastrointestinal Microbiome; Probiotics; Lactobacillales; Bacteria; Fermentation
PubMed: 36604628
DOI: 10.1080/19490976.2022.2161271 -
Food Microbiology Sep 2019Lactococcus lactis subsp. lactis biovar diacetylactis and Leuconostoc mesenteroides are considered to be the main aroma producers in Dutch-type cheeses. Both species of...
Lactococcus lactis subsp. lactis biovar diacetylactis and Leuconostoc mesenteroides are considered to be the main aroma producers in Dutch-type cheeses. Both species of lactic acid bacteria were grown in retentostat mono- and co-cultures to investigate their interaction at near-zero growth rates and to determine if co-cultivation enhances the aroma complexity compared to single species performance. During retentostat mono-cultures, the growth rates of both species decreased to less than 0.001 h and a large fraction of the cells became viable but not culturable. Compared to Lc. mesenteroides, L. lactis reached a 3.4-fold higher biomass concentration caused by i) a higher ATP yield on substrate, ii) a higher biomass yield on ATP and iii) a lower maintenance requirement (m). Dynamic models estimated that the m of both species decreased approximately 7-fold at near-zero growth rates compared to high growth rates. Extension of these models by assuming equal substrate distribution resulted in excellent prediction of the biomass accumulation in retentostat co-cultures with L. lactis dominating (100:1) as observed in ripened cheese. Despite its low abundance (∼1%), Lc. mesenteroides contributed to aroma production in co-cultures as indicated by the presence of all 5 specific Lc. mesenteroides compounds. This study provides insights in the production of cheese aroma compounds outside the cheese matrix by co-cultures of L. lactis and Lc. mesenteroides, which could be used as food supplements in dairy or non-dairy products.
Topics: Animals; Bacteriological Techniques; Cheese; Fermentation; Food Microbiology; Lactococcus lactis; Leuconostoc mesenteroides; Microbial Interactions; Milk; Odorants; Volatile Organic Compounds
PubMed: 31027769
DOI: 10.1016/j.fm.2019.01.016 -
Biotechnology For Biofuels 2016Lactic acid has been approved by the United States Food and Drug Administration as Generally Regarded As Safe (GRAS) and is commonly used in the cosmetics,...
BACKGROUND
Lactic acid has been approved by the United States Food and Drug Administration as Generally Regarded As Safe (GRAS) and is commonly used in the cosmetics, pharmaceutical, and food industries. Applications of lactic acid have also emerged in the plastics industry. Lactic acid bacteria (LAB), such as and , are widely used as lactic acid producers for food-related and biotechnological applications. Nonetheless, industrial mass production of lactic acid in LAB is a challenge mainly because of growth inhibition caused by the end product, lactic acid. Thus, it is important to improve acid tolerance of LAB to achieve balanced cell growth and a high titer of lactic acid. Recently, adaptive evolution has been employed as one of the strategies to improve the fitness and to induce adaptive changes in bacteria under specific growth conditions, such as acid stress.
RESULTS
Wild-type was challenged long term with exogenously supplied lactic acid, whose concentration was increased stepwise (for enhancement of lactic acid tolerance) during 1 year. In the course of the adaptive evolution at 70 g/L lactic acid, three mutants (LMS50, LMS60, and LMS70) showing high specific growth rates and lactic acid production were isolated and characterized. Mutant LMS70, isolated at 70 g/L lactic acid, increased d-lactic acid production up to 76.8 g/L, which was twice that in the wild type (37.8 g/L). Proteomic, genomic, and physiological analyses revealed that several possible factors affected acid tolerance, among which a mutation of ATPase ε subunit (involved in the regulation of intracellular pH) and upregulation of intracellular ammonia, as a buffering system, were confirmed to contribute to the observed enhancement of tolerance and production of d-lactic acid.
CONCLUSIONS
During adaptive evolution under lethal stress conditions, the fitness of gradually increased to accumulate beneficial mutations according to the stress level. The enhancement of acid tolerance in the mutants contributed to increased production of d-lactic acid. The observed genetic and physiological changes may systemically help remove protons and retain viability at high lactic acid concentrations.
PubMed: 27843489
DOI: 10.1186/s13068-016-0662-3