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Non-conventional yeasts (NCYs) (i.e., non-Saccharomyces) are used as alternative starters to promote aroma complexity of fermented foods (e.g., bakery products). A total of 66 yeasts isolated from artisanal food matrices (bread and pizza sourdoughs and milk whey) from different geographical areas of the Campania region (Italy) were screened for physiological and technological characteristics such as leavening ability, resistance to NaCl and pH, exopolysaccharide and phytase activity production, and carbohydrate assimilation. Selected and isolated microorganisms were also used to study the leavening kinetics in experimental doughs as mixed inocula of two different strains. Volatile organic compounds (VOCs) of the inoculated doughs were analyzed with solid-phase microextraction/gas chromatography–mass spectrometry (SPME/GC-MS). Most of the strains belonged to non-Saccharomyces species (Pichia kudriavzevii, Kluyveromyces marxianus) and Saccharomyces (S. cerevisiae). Several strains produced exopolysaccharides (EPSs), that are important for dough rheological properties. Moreover, yeasts isolated from whey showed extracellular phytase activity. The mixed starter culture of the S. cerevisiae and NCY strains showed a synergic effect that enhanced the doughs' aroma complexity. The use of non-conventional yeasts mixed with S. cerevisiae strains can be advantageous in the bakery industry because they improve the bread aroma profiles and nutritional properties by bioactive molecule production. [ABSTRACT FROM AUTHOR]

Background: Non-conventional yeasts (NCY) (i.e., non-Saccharomyces) may be used as alternative starters to promote biodiversity and quality of fermented foods and beverages (e.g., wine, beer, bakery products). Methods: A total of 32 wine-associated yeasts (Campania region, Italy) were genetically identified and screened for decarboxylase activity and leavening ability. The best selected strains were used to study the leavening kinetics in model doughs (MDs). A commercial strain of Saccharomyces cerevisiae was used as the control. The volatile organic profiles of the inoculated MDs were analyzed by solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS). Results: Most of strains belonged to the NCY species Hanseniaspora uvarum, Metschnikowia pulcherrima, Pichia kudriavzevii, Torulaspora delbruekii, and Zygotorulaspora florentina, while a few strains were S. cerevisiae. Most strains of H. uvarum lacked decarboxylase activity and showed a high leaving activity after 24 h of incubation that was comparable to the S. cerevisiae strains. The selected H. uvarum strains generated a different flavor profile of the doughs compared to the S. cerevisiae strains. In particular, NCY reduced the fraction of aldehydes that were potentially involved in oxidative phenomena. Conclusions: The use of NCY could be advantageous in the bakery industry, as they can provide greater diversity than S. cerevisiae-based products, and may be useful in reducing and avoiding yeast intolerance. [ABSTRACT FROM AUTHOR]

A method is developed based on selective immunoaffinity capture enrichment that can be performed in a single-tube experiment for selective isolation of the protein toxin. The application of this method to complex biological matrices is shown by selective detection of Staphylococcal enterotoxin B (SEB) seen in different matrices like the cultivation media of Staphylococcus aureus and raw milk samples.

Several lines of evidence suggest that adherent-invasive Escherichia coli (AIEC) strains play an important role in Crohn's disease (CD). The objective of this study was to investigate the pathogenic role of two AIEC strains, LF82 and O83:H1, in CD patients. Organ cultures of colonic biopsies from patients were set up to assess the effects of LF82 and O83:H1 on the expression of CEACAM6, LAMP1, HLA-DR, ICAM1 by immunohistochemistry and of IL-8, IFNʏ, and TNF-α genes by RT-PCR. Moreover, on Caco2 cells, we analyzed the cell cycle, the expression of MGMT and DNMT1 genes, and DNA damage induced by LF82 and O83:H1, by FACS, RT-PCR, and DAPI staining, respectively. Epithelial and lamina propria mononuclear cells (LPMNC) expression of CEACAM6 and LAMP1 were higher in biopsies cultured in the presence of both O83:H1 and LF82 than in biopsies cultured with non-pathogenic E. coli. Both AIEC strains induced increased expression of ICAM-1 on blood vessels and HLA-DR on LPMNC. We observed higher levels of TNF-α, IFN-γ, and IL-8 transcripts in biopsies cultured with both AIEC strains than in those cultured with NP. Both LF82 and O83:H1, block the cell cycle into S phase, inducing DNA damage, and modulate the expression of DNMT1 and MGMT genes. Our data suggest that LF82 and 083:H1 strains of E. coli are able to increase in CD colonic biopsies the expression of all the pro-inflammatory cytokines and all the mucosal immune markers investigated. J. Cell. Physiol. 232: 2860-2868, 2017. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The supplementation of chestnut cream in a new muffin formulation was investigated to evaluate the use of chestnut derivatives in baked goods. To assess the muffins qualities, with and without potassium sorbate, were evaluated the physical-chemical properties, fatty acids and volatile organic compounds (VOCs) profiles and shelf life (30 days). The fatty acid composition showed that the highest concentrations were evidenced for linoleic acid (47.3%), oleic acid (30.4%) and palmitic acid (14.2%). The total microbial count (TMC), yeasts and molds loads increased during the storage but remained under limit imposed by law. The VOCs detected are produced during baking process as a result of thermally induced reactions while phenolic compounds could derive from the chestnut cream. The electronic nose results showed that the 'fingerprints' of VOCs are not overlapping, confirming the HS-SPME-GC/MS data. According to the results, the formulation of new muffin could expand the array of commodities and further enlarge, the market for chestnut derivatives. Practical Application The introduction of the new sweet chestnut cream muffin formulation could represent a chance to increase the use of chestnut derivatives and could be alternative ingredients in baked goods. In fact, the supplementation of chestnut cream may give interesting properties as better physico-chemical properties, fatty acids, volatile organic compounds and a good shelf life. Moreover, they preserve the nutritional characteristics of the starting fruit. [ABSTRACT FROM AUTHOR]

Dietary polyphenols are bioactive molecules that beneficially affect human health, due to their anti-oxidant, anti-inflammatory, cardio-protective and chemopreventive properties. They are absorbed in a very low percentage in the small intestine and reach intact the colon, where they are metabolized by the gut microbiota. Although it is well documented a key role of microbial metabolism in the absorption of polyphenols and modulation of their biological activity, molecular mechanisms at the basis of the bacteria-polyphenols interplay are still poorly understood. In this context, differential proteomics was applied to reveal adaptive response mechanisms that enabled a potential probiotic Lactobacillus acidophilus strain to survive in the presence of the dietary polyphenol rutin. The response to rutin mainly modulated the expression level of proteins involved in general stress response mechanisms and, in particular, induced the activation of protein quality control systems, and affected carbohydrate and amino acid metabolism, protein synthesis and cell wall integrity. Moreover, rutin triggered the expression of proteins involved in oxidation-reduction processes.This study provides a first general view of the impact of dietary polyphenols on metabolic and biological processes of L. acidophilus. [ABSTRACT FROM AUTHOR]

Non-Saccharomyces yeasts are microorganisms that play a prominent role in the fermentation dynamics, composition and flavour of wine. The principal aromatic compounds responsible for varietal aroma in wine are terpenes; of these, the monoterpenes represent the oenologically most important group in terms of volatility and odour, if they are present in a free form. The glycosidically bound forms can be converted into compounds with free odours by hydrolysis with the glycosidases produced by yeasts. We performed a screening of non-Saccharomyces yeasts present in the grapes and must of Aglianico and Fiano cultivars typical of South Italy (Irpinia), which have a high extra-cellular glycosidase activity. Among the species analysed was a strain belonging to Rhodotorula spp. that showed the highest glycosidase activity, an increased free terpene fraction and, simultaneously, little modification of the bouquet. The isolated yeast was subsequently utilized for experimental winemaking processes of Aglianico and Fiano wines. The results demonstrated that the obtained wines had a more intense floral aroma and some sweet and ripened fruit notes. [ABSTRACT FROM AUTHOR]

A methodology based on matrix-assisted laser desorption ionization-time of flight mass spectrometry of intact bacterial cells was used for rapid discrimination of 24 bacterial species, and detailed analyses to identify Escherichia coli O157:H7 were carried out. Highly specific mass spectrometric profiles of pathogenic and nonpathogenic bacteria that are well-known major food contaminants were obtained, uploaded in a specific database, and made available on the Web. In order to standardize the analytical protocol, several experimental, sample preparation, and mass spectrometry parameters that can affect the reproducibility and accuracy of data were evaluated. Our results confirm the conclusion that this strategy is a powerful tool for rapid and accurate identification of bacterial species and that mass spectrometric methodologies could play an essential role in polyphasic approaches to the identification of pathogenic bacteria. [ABSTRACT FROM AUTHOR]

Fresh figs are very sensitive to microbial spoilage, even in cold storage conditions. Thus, fresh figs are high perishable products during postharvest with microbiological decay that induces an unpleasant taste and smell due to rot, and suitable conservation methods must therefore be applied. The fruit usually is consumed fresh locally, dried, or preserved longer term in other transformed forms. A sustainable approach to extend the shelf-life of figs can be constituted by application of an edible coating able to maintain the quality of the fruit during storage. A comparison between fresh figs in a commercial preservation system, with the figs preserved in an edible coating, and an active edible coating to preserve their quality characteristics was carried out. The coating efficacy was enhanced with the addition of pomegranate peel extract at two different concentrations. The inclusion of a component with high antioxidant activity in an edible coating proved to be an excellent method for preserving the quality of this highly perishable fruit. The application of natural products, obtained from renewable sources, represents a simple and economic strategy, but also a tool capable of preserving the quality of the fruit during the postharvest storage, which is often consumed in production areas due to shelf-life problems. [ABSTRACT FROM AUTHOR]

The growing importance of mass spectrometry for the identification and characterization of bacterial protein toxins is a consequence of the improved sensitivity and specificity of mass spectrometry-based techniques, especially when these techniques are combined with affinity methods. Here we describe a novel method based on the use of immunoaffinity capture and matrix-assisted laser desorption ionization—time of flight mass spectrometry for selective purification and detection of staphylococcal enterotoxin B (SEB). SEB is a potent bacterial protein toxin responsible for food poisoning, as well as a potential biological warfare agent. Unambiguous detection of SEB at low-nanogram levels in complex matrices is thus an important objective. In this work, an affinity molecular probe was prepared by immobilizing anti-SEB antibody on the surface of paratoluene-sulfonyl-functionalized monodisperse magnetic particles and used to selectively isolate SEB. Immobilization and affinity capture procedures were optimized to maximize the density of anti-SEB immunoglobulin G and the amount of captured SEB, respectively, on the surface of magnetic beads. SEB could be detected directly ‘on beads’ by placing the molecular probe on the matrix-assisted laser desorption ionization target plate or, alternatively, ‘off beads’ after its acidic elution. Application of this method to complex biological matrices was demonstrated by selective detection of SEB present in different matrices, such as cultivation media of Staphylococcus aureus strains and raw milk samples. [ABSTRACT FROM AUTHOR]