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101.
The Different Physical and Chemical Composition of Grape Juice and Marc Influence Saccharomyces cerevisiae Strains Distribution During Fermentation
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102.
Elisabetta Delibato Fabrizio Anniballi Paola Sinibaldi Vallebona Giuseppe Palleschi Giulia Volpe Marina Nadia Losio Dario De Medici 《Food Analytical Methods》2013,6(4):996-1003
Foodborne disease caused by Salmonella represents a worldwide public health problem. In Europe, salmonellosis is still the second most commonly recorded zoonosis. Since the standard culture method for detecting Salmonella (ISO 6579:2002) requires up to 5 days to produce results, the need to develop rapid methods represents an important issue for the authorities and the producers. The aim of the present study was the in-house validation, according to ISO 16140, of an open-formula diagnostic real-time PCR for the detection of Salmonella in all the different meat categories reported in the EU Regulations relative to microbiological criteria for food safety. The assay employed specific primers and a probe target within the ttrRSBCA locus, which allows the tetrathionate respiration in Salmonella. Selectivity, relative accuracy, relative sensitivity and relative specificity were established by testing 110 bacterial strains and 175 various edible meat samples. Results showed 100 % selectivity, 100 % relative accuracy, 100 % relative sensitivity and 100 % relative specificity of the real-time PCR when compared to the standard culture method used as reference. In addition, in order to minimize the effect of the competitive micro-flora naturally present on meat samples, a highly nutritious and selective commercial medium (ONE Broth Salmonella, Oxoid) was evaluated in comparison with the classical non-selective pre-enrichment broth (buffered peptone water). Results demonstrated that the ONE Broth Salmonella medium increases the growth of Salmonella in the presence of competitive micro-flora. 相似文献
103.
104.
Paola Roccia Pablo D. Ribotta Cristina Ferrero Gabriela T. Pérez Alberto E. León 《Food and Bioprocess Technology》2012,5(4):1255-1264
High levels of soy flour added to wheat bread produce negative effects on gluten network formation, dough properties, and
on bread final quality. The objective of this study was to assess the influence of three enzymes, transglutaminase (TG), glucose
oxidase (GOX), and endoxylanase (XYL), on dough properties and final quality of high-protein breads. The addition of TG and
GOX increased the mixing stability and maximum resistance of dough, decreased its extensibility, and produced stronger and
more consistent dough samples. XYL incorporation produced opposite results. XYL addition and the lowest GOX dose increased
bread volume significantly and decreased initial crumb firmness, while high doses of TG (0.3%) produced detrimental effects
on bread volume and crumb firmness. In conclusion, XYL and GOX 0.001% addition improved the final quality of soy-fortified
breads, but XYL was the best additive to improve dough properties, bread volume, and quality. 相似文献
105.
In this study the satiating capacity of three beverages containing 3 g barley β-glucan, or 2.5 g dietary fibre (DF) from fruit, or without DF (control) was evaluated. Fourteen healthy volunteers were randomized to have isocaloric breakfasts including one of the beverages in different occasions. Appetite ratings over 3 h post-breakfast and energy intakes at ad libitum lunch, blood glucose, insulin, ghrelin, PYY, GLP-1, GIP, and PP concentrations, and 24 h food intake, were assessed. The bevaerages containing DF increased fullness and satiety over 3 h post-breakfast, but only the β-glucan-enriched vs. the control significantly reduced energy intakes by 18% at lunch and 40% over the rest of the day. Blood ghrelin and PP responses were differently modulated by beverages. The fruit-based and the β-glucan-enriched beverage suppressed by 8.9% and 8.1% ghrelin response over the 3 h and the first hour post-breakfast, respectively, while only the latter increased PP response by 34.6%, compared to the control. A sucrose-sweetened beverage providing 3 g barley β-glucans can control food intake by modulating PP response and it can even reduce 24 h energy intake. Ghrelin suppression by fruit dietary fibre and mixed sugars was not sufficient to significantly reduce food intake compared to the control. 相似文献
106.
107.
Use of ionic liquids based on phosphonium salts for preparing biocomposites by in situ polymerization
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A sodium montmorillonite, Dellite HPS, was modified with ionic liquids based on phosphonium salts, such as octadecyltriphenylphosphonium tetrafluoroborate and octadecyltriphenylphosphonium bromide. Thanks to their high thermal stability, these salts can be used during in situ polymerization, a method that favors the achievement of a good dispersion of the clay. Poly(1,4‐dimethylcyclohexane adipate) (PCHA), was chosen as an example of aliphatic polyester which can be a suitable matrix for new biocomposites with organo‐clays. The organo modified clays prepared were characterized by X‐ray diffraction (XRD), ATR‐FTIR spectroscopy, and thermal gravimetric analysis (TGA) while biocomposites were analyzed in terms of molecular structure, thermal and thermomechanical properties. The degree of dispersion of the clays in the polymer matrix was studied by XRD. The results show that the clays are well dispersed in the biocomposites, despite an intercalated structure highlighted by XRD analysis. Moreover, the clays confer a certain improvement in mechanical properties to the final materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42467. 相似文献
108.
Calorimetric results obtained by differential scanning calorimetry (DSC) have been used to develop a kinetic model for the crystallization behavior of PCL/starch and their composites with sisal fibers. The model takes into account the effects of nucleation and crystal growth, and it is able to describe the isothermal and non‐isothermal conditions, especially for the low cooling rates. The effect of the sisal fiber has also been analyzed. The Avrami exponent was 2.0 for the crystallization of PCL/starch and sisal fiber reinforced composite. The activation energy of the crystallization process was 4.3 and 4.0 kJ/mol for PCL/starch and sisal composite, respectively. The induction time of the crystallization and the crystallization rate was not influenced by the presence of sisal fiber. 相似文献
109.
Víctor M. Ovando‐Medina Paola E. Díaz‐Flores René D. Peralta Eduardo Mendizábal Gladis Y. Cortez‐Mazatan 《应用聚合物科学杂志》2013,127(4):2458-2464
Vinyl acetate (VAc) and butyl acrylate (BuA) were copolymerized in heterophase by a semicontinuous process (unseeded) and compared with the seeded semicontinuous microemulsion polymerization of the same monomers. A mixture of sodium dodecyl sulfate (SDS) and poly(ethylene oxide) dodecyl ether (Brij‐35®) were used as surfactants. The effects of monomer addition rate (Ra) and surfactants concentrations (4 or 1 wt % with respect to the initial mixture of reaction) on polymer and latex properties were studied. High copolymer content latexes (24–36 wt %) with average particle diameters (Dp) from 38 to 55 nm and relatively narrow particle size distributions, high polymerization rates, weight ratios of polymer to surfactant (P/S) from 13.3 to 32.8 were obtained. The number‐average molecular weights (Mn) were between 96,000 and 188,000 g/mol. Homogeneous copolymer compositions were obtained throughout the reaction for both, seeded and unseeded processes, which is not possible by the usual batch microemulsion process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
110.
Fausto Puntoriero Giacomo Bergamini Paola Ceroni Vincenzo Balzani Fritz Vögtle 《Journal of Inorganic and Organometallic Polymers and Materials》2008,18(1):189-194
Starting from 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane, we have prepared two compounds by replacing the amine hydrogens
with naphthyl or 3,5-bis(2′-oxymethylnaphthyl)benzyl units. The absorption and emission spectra of compounds 2 (N,N′-bis(2-naphthylmethyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) and 3 (N,N′-bis[3,5-bis(2′-oxymethylnaphthyl)benzyl]-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) have been studied in CH3CN:CH2Cl2 1:1 (v/v) solution. For comparison purposes, the spectroscopic properties of N-methyl(2-methylnaphthalene)ethylamine (1) have also been investigated. For each compound, the absorption spectra are qualitatively very similar to that of naphthalene,
with molar absorption coefficients as expected for the presence of one (1), two (2), and four (3) naphthyl chromophoric groups. The fluorescence spectra, however, are quite different from that of naphthalene. The naphthalene-type
fluorescence (λmax = 337 nm) is strongly quenched, particularly for compounds 1 and 2 which also exhibit a broad emission band in the visible region (λmax ≈ 480 nm) assigned to a low lying charge-transfer excited state. In the case of compound 3, a quenched naphthalene-type band is accompanied by weak exciplex and excimer emissions. Upon titration with CF3SO3H, the charge transfer bands of 1 and 2 and the exciplex emission of 3 disappear and the naphthalene-type bands regain intensity. Titration plots show that in compounds 2 and 3 the protonation of the two nitrogens occurs stoichiometrically in two distinct steps. Titration with Zn2+ gives rise to 2.Zn2+ and 3.Zn2+ complexes.
This article is dedicated to Professor Dedier Astruc. 相似文献