279 research outputs found
Contribution of diet to the composition of the human gut microbiota
This paper is part of the Proceedings from the 2013 ENGIHR Conference in Valencia, Spain. More papers from this supplement can be found at http://www.microbecolhealthdis.net Microbial Ecology in Health & Disease 2015. © 2015 Daniela Graf et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported License (http://creativecommons.org/licenses/by-nc/3.0/), permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ACKNOWLEDGEMENTS The authors acknowledge the support of the European Science Foundation (ESF), in the framework of the Research Networking Programe, The European Network for Gastrointestinal Health Research.Peer reviewedPublisher PD
Microbial cell-free extracts as sources of enzyme activities to be used for enhancement flavor development of ewe milk cheese
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Technological, functional and safety aspects of enterococci in fermented vegetable products: a mini-review
Bacteria belonging to the genus Enterococcus spp.âa member of the lactic acid bacteria groupâare natural inhabitants of various environments, including vegetable products. Although some strains show pathogenic determinants, overall these bacteria may have some pro-technological features. Some enterococci have been described as potential starter or protective cultures in the dairy industry, since they contribute to the organoleptic and quality characteristics of dairy products. Although several fermented vegetable products have a long history in human nutrition, studies regarding autochthonous enterococci and their application to fermented vegetable foods are much less numerous than those concerning dairy foods. In this review, after a general overview of enterococci, their presence and role in fermented vegetable foods (including table olives, sauerkraut, kimchi, tomato juice, French beans, caper berries and cereal-based products) will be covered
Thirty years of knowledge on sourdough fermentation: A systematic review
Abstract Background Sourdough is one of the oldest examples of natural starters, mostly used for making fermented baked goods as an alternative to baker's yeast and chemical leavening. Almost 30 years of research have accumulated showing its performance. Time is mature to elaborate collectively these data and to draw conclusions, which would represent milestones for scientists, industries and consumers. Scope and approach With the scope of highlighting its microbiological, biochemical, technological and nutritional potential, we used "sourdough" as the only keyword and the PRISMA flow diagram to retrieve, select and systematically review 1230 peer reviewed research articles from four databases (Google Scholar, Scopus, PubMed and ScienceDirect). Key findings and conclusions The literature states that sourdough baked goods underwent characterization in almost 50 countries and all continents, mainly dealing with salty (breads and substitutes) and sweet products. Converging data defined optimal use conditions, most common microbiological and biochemical characteristics, criteria for selecting and re-using starters, and versatility of sourdough for making baked goods with a relevant number of flour species/varieties and agro-food by-products. Because of the unique microbial composition and functionality, sourdough has claimed as an irreplaceable starter for improving the sensory, rheology and shelf life attributes of baked goods. The most recent literature showed how the sourdough fermentation mainly increased mineral bioavailability, enabled fortification with dietary fibers, lowered glycemic index, improved protein digestibility and decreased the content of anti-nutritional factors. This knowledge is solid for delivering to industries and consumers, and to face new research challenges starting from a consolidated state of the art
Volatilome and Bioaccessible Phenolics Profiles in Lab-Scale Fermented Bee Pollen
Bee-collected pollen (BCP) is currently receiving increasing attention as a dietary supplement
for humans. In order to increase the accessibility of nutrients for intestinal absorption, several
biotechnological solutions have been proposed for BCP processing, with fermentation as one of the
most attractive. The present study used an integrated metabolomic approach to investigate how the
use of starter cultures may affect the volatilome and the profile of bioaccessible phenolics of fermented
BCP. BCP fermented with selected microbial starters (Started-BCP) was compared to spontaneously
fermented BCP (Unstarted-BCP) and to unprocessed raw BCP (Raw-BCP). Fermentation significantly
increased the amount of volatile compounds (VOC) in both Unstarted- and Started-BCP, as well as
modifying the relative proportions among the chemical groups. Volatile free fatty acids were the
predominant VOC in Unstarted-BCP. Started-BCP was differentiated by the highest levels of esters
and alcohols, although volatile free fatty acids were always prevailing. The profile of the VOC was
dependent on the type of fermentation, which was attributable to the selected Apilactobacillus kunkeei
and Hanseniaspora uvarum strains used as starters, or to the variety of yeasts and bacteria naturally
associated to the BCP. Started-BCP and, to a lesser extent, Unstarted-BCP resulted in increased
bioaccessible phenolics, which included microbial derivatives of phenolic acids metabolism
Functional Exploitation of Carob, Oat Flour, and Whey Permeate as Substrates for a Novel Kefir-Like Fermented Beverage: An Optimized Formulation
This study investigated the fortification of a carob-based kefir-like beverage (KLB) with
whey permeate (WP) and oat flour (OF). The response surface method was used to show the effect of
WP and OF concentrations on lactic acid bacteria and yeast cell densities, pH, total titratable acidity
(TTA), total phenolics content (TCP), DPPH radical scavenging activity, and overall acceptability
(OA) in KLB. The statistical design provided thirteen formulations where OF concentration varied
from 3% to 5% and WP from 10% to 15%. The enrichment of carob pods decoction with WP and OF
had a positive effect on biomass production. Overall fermentation was shown to increase TPC of
KLB. Furthermore, OF supplementation led to the higher levels of TPC and antiradical activity. WP
negatively affected OA at linear and quadratic levels, whereas no effect of OF was observed at the
linear level. The optimum point was found by using WP at 11.51% and OF at 4.77%. Optimized KLB
resulted in an enrichment of bioavailable phenolics derivatives and highly digestible proteins
Date Seeds Flour Used as Value-Added Ingredient for Wheat Sourdough Bread: An Example of Sustainable Bio-Recycling
Our study proposed date seeds flour (DSF) as an innovative ingredient for sourdough
bread production through sustainable bio-recycling. We isolated autochthonous lactic
acid bacteria and yeasts from DSF and DSF-derived doughs to build up a reservoir
of strains from which to select starters ensuring rapid adaptation and high ecological
fitness. The screening based on pro-technological criteria led to the formulation of a
mixed starter consisting of Leuconostoc mesenteroides, Lactiplantibacillus plantarum,
and Saccharomyces cerevisiae strains, which allowed obtaining a mature type I
sourdough after consecutive refreshments, in which an aliquot of the durum wheat
flour (DWF) was replaced by DSF. The resulting DSF sourdough and bread underwent
an integrated characterization. Sourdough biotechnology was confirmed as a suitable
procedure to improve some functional and sensory properties of DWF/DSF mixture
formulation. The radical scavenging activity increased due to the consistent release
of free phenolics. Perceived bitterness and astringency were considerably diminished,
likely because of tannin degradation
How water-soluble saccharides drive the metabolism of lactic acid bacteria during fermentation of brewers' spent grain
We proposed a novel phenomic approach to track the effect of short-term exposures of Lactiplantibacillus plantarum and Leuconostoc pseudomesenteroides to environmental pressure induced by brewers' spent grain (BSG)-derived saccharides. Water-soluble BSG-based medium (WS-BSG) was chosen as model system. The environmental pressure exerted by WS-BSG shifted the phenotypes of bacteria in species- and strains-dependent way. The metabolic drift was growth phase-dependent and likely underlay the diauxic profile of organic acids production by bacteria in response to the low availability of energy sources. Among pentosans, metabolism of arabinose was preferred by L. plantarum and xylose by Leuc. pseudomesenteroides as confirmed by the overexpression of related genes. Bayesian variance analysis showed that phenotype switching towards galactose metabolism suffered the greatest fluctuation in L. plantarum. All lactic acid bacteria strains utilized more intensively sucrose and its plant-derived isomers. Sucrose-6-phosphate activity in Leuc. pseudomesenteroides likely mediated the increased consumption of raffinose. The increased levels of some phenolic compounds suggested the involvement of 6-phospho-beta-glucosidases in beta-glucosides degradation. Expression of genes encoding beta-glucoside/cellobiose-specific EII complexes and phenotyping highlighted an increased metabolism for cellobiose. Our reconstructed metabolic network will improve the understanding of how lactic acid bacteria may transform BSG into suitable food ingredients.Peer reviewe
Nutrients Bioaccessibility and Anti-inflammatory Features of Fermented Bee Pollen: A Comprehensive Investigation
We compared raw bee-collected pollen (Raw-BCP), spontaneously fermented BCP (Unstarted-BCP), and BCP fermented with selected microbial starters (Started-BCP) to deepen whether fermentation may favorably affect the nutrients bioaccessibility and functional features of BCP. Under in vitro gastrointestinal batches, the highest serum-availability of phenolic compounds was found in Started-BCP, highlighting the positive effect exerted by selected microbial starters. The same effect was not found in spontaneously fermented BCP. In colon adenocarcinoma cell line-2 (Caco-2) cells stressed by a pro-inflammatory stimulus, the treatment with Started-BCP halted the increase of pro-inflammatory mediatorâs level. Started-BCP counteracted efficiently the deleterious effects of inflammatory stimuli on the integrity of the Caco-2 cells monolayer and its barrier function. Started-BCP successfully counteracted the H2O2-induced intracellular accumulation of reactive oxygen species (ROS) in Caco-2 cells. A protective role against lipopolysaccharide (LPS)-induced inflammation was exerted by Started-BCP in human keratinocytes. The same protective effects on Caco-2 and keratinocyte cell lines were negligible after treatments with Raw-BCP or Unstarted-BCP
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