Search results for "Glycerol"
showing 10 items of 283 documents
Contribution to the study of the alteration of lipase activity ofCandida rugosa by ions and buffers
1994
A semipurified C. rugosa lipase (LS) has been prepared from commercial lipase (LC) using an economical procedure. The presence of sugars and glycopeptides has been detected in LS and LC. Pure lipase only has covalently bonded sugars. The hydrolysis of olive oil catalyzed by LS and commercial lipase (LC) is sensitive to the presence of cations Na(I), Mg(II), Ca(II), and Ba(II) and to the nature of buffer. Highest enzyme activity is obtained with 0.1M Tris/HCl buffers and the combination of NaCl 0.11M and CaCl2 0.11M. Fluorescence spectroscopy analysis of LC, LS, and both pure isoenzymes lipases A and B, was used to analyze the interaction of the lipase with these effectors. Inorganic cations…
A free plate model can predict guided modes propagating in tubular bone-mimicking phantoms
2014
The goal of this work was to show that a non-absorbing free plate model can predict with a reasonable accuracy guided modes measured in bone-mimicking phantoms that have circular cross-section. Experiments were carried out on uncoated and coated phantoms using a clinical axial transmission setup. Adjustment of the plate model to the experimental data yielded estimates for the waveguide characteristics (thickness, bulk wave velocities). Fair agreement was achieved over a frequency range of 0.4 to 1.6 MHz. A lower accuracy observed for the thinnest bone-mimicking phantoms was caused by limitations in the wave number measurements rather than by the model itself.
Study of glycerol and respiro-fermentative metabolism diversity among Saccharomyces yeasts
2016
Introducción Las levaduras son responsables de numerosos procesos biotecnológicos tales como la producción de bebidas y alimentos fermentados. Las levaduras de interés biotecnológico son organismos muy especializados que han evolucionado bajo restrictivas condiciones ambientales en distintos ambientes manipulados por el hombre. Durante el proceso de adaptación a estos ambientes manipulados por el hombre, distintas cepas y especies del género Saccharomyces se han visto sometidas a procesos selectivos generados por su uso inconsciente en la fermentación alcohólica (Querol et al., 2003), lo que también ha generado diferencias adaptativas entre ellas (Barrio et al., 2006). Aunque la especie más…
Phase equilibria for the ternary systems ethanol, water+ethylene glycol or+glycerol at 101.3kPa
2013
Abstract Two solvents, ethylene glycol and glycerol, are proposed as possible entrainers for the extractive distillation of the binary azeotropic mixture formed by ethanol and water. In this way, consistent isobaric vapour–liquid equilibrium data at 101.3 kPa were measured for the ternary systems ethanol + water + ethylene glycol and ethanol + water + glycerol. The data were correlated by local compositions models Wilson, NRTL and UNIQUAC. Parameters of these models were later employed to evaluate ability of the candidates to break the original azeotrope. The obtained results led to consider the ethylene glycol and the glycerol as valid entrainers for the extractive distillation process of …
PHA Latex Composite Films: Mechanical Properties and Surface Visualization
2013
Homopolymer PHB and copolymer PHB/HV containing granules were isolated from Azotobacter chroococcum cells and used for latexes formation. Composite latex films were formed from the PHB and PHB/HV latexes with different content of poly (vinyl alcohol) and glycerol and a hydrophobic fluorescent benzanthrone derivated dye 3-piperidinobenzanthrone, possessed high fluorescence intensity in a system with PHA granules. Fluorescence based methods were used for characterization of the elaborated latex film by their stability at high temperature and for visualization of the film surfaces PHA granules distribution. Film stability in phosphate buffered saline was evaluated by dye migration activity in …
Synergistic and Antagonistic Effects of Combined Subzero Temperature and High Pressure on Inactivation of Escherichia coli
2006
ABSTRACT The combined effects of subzero temperature and high pressure on the inactivation of Escherichia coli K12TG1 were investigated. Cells of this bacterial strain were exposed to high pressure (50 to 450 MPa, 10-min holding time) at two temperatures (−20°C without freezing and 25°C) and three water activity levels (a w ) (0.850, 0.992, and ca. 1.000) achieved with the addition of glycerol. There was a synergistic interaction between subzero temperature and high pressure in their effects on microbial inactivation. Indeed, to achieve the same inactivation rate, the pressures required at −20°C (in the liquid state) were more than 100 MPa less than those required at 25°C, at pressures in t…
Water vapour permeability, thermal and wetting properties of whey protein isolate based edible films
2010
Abstract This study deals with the effect of whey protein isolate (WPI) and glycerol (GLY) used as a plasticizer on some physical properties of cast whey protein isolate (WPI) films. Films were prepared from heated (80 °C for 30 min) aqueous solutions of WPI at 7, 8, 9 and 10% (w/w), GLY (40%, w/w, of WPI) and WPI at 8% (w/w), GLY (30, 40, and 60%, w/w, of WPI). For all types of films, water vapour permeability for four relative humidity differentials (30–100%, 30–84%, 30–75%, and 30–53%), surface and thermal properties were measured. Varying the proportion of WPI and GLY in edible films had some effect on water vapour permeability, wetting and thermal properties of WPI films. A cumulative …
Hochleistungsfl�ssigchromatographische Bestimmung von organischen S�uren, Zuckern, Glycerin und Alkohol im Wein an einer Kationenaustauschers�ule
1985
Mit der HPLC ist es moglich, die wichtigsten Bestandteile von Wein (Ethanol, Glycerin, Glucose, Fructose, Tartrat, Malat, Lactat, Succinat, Acetat und Citrat) in einem Lauf innerhalb von 25 min zu trennen und quantitativ zu bestimmen. Als stationare Phase dient der Kationenaustauscher HPX 87 H und als mobile Phase verdunnte Schwefelsaure. Die Untersuchungsergebnisse an einigen Weinen werden dargestellt. Es besteht eine gute Ubereinstimmung zwischen den Analysenergebnissen der HPLC und herkommlichen Methoden.[/p]
Measurements and correlation at different temperatures of liquid–liquid equilibria of 2-butanol or 2-methyl-2-butanol+1,2,3-propanetriol+water ternar…
2014
Abstract In this work, the experimental liquid–liquid equilibria (LLE) data of 2-methyl-2-butanol + 1,2,3-propanetriol (glycerol) + water and 2-butanol + 1,2,3-propanetriol (glycerol) + water systems at different temperatures are presented. The LLE of the systems has been measured between 283 and 323 K. The NRTL and UNIQUAC models were applied to the ternary systems. The interaction parameters obtained from both models successfully correlated the equilibrium compositions. The experimental tie lines were compared to the values predicted by the UNIFAC method. Finally, the solvent capability of both alcohols was checked in order to separate the mixture formed by glycerol and water.
Protein and glycerol contents affect physico-chemical properties of soy protein isolate-based edible films
2010
Abstract This study was conducted to determine the effect of both soy protein and glycerol contents on physico-chemical properties of soy protein isolate-based edible (SPI) films. The aim of this study was to better understand the influence of SPI and GLY contents on the behavior of the physico-chemical properties of soy protein isolate-based films. Films were casted from heated (70 °C for 20 min) alkaline (pH 10) aqueous solutions of SPI at 6, 7, 8, and 9 (w/w %), glycerol (50%, w/w, of SPI) and SPI at 7 (w/w %), glycerol (40, 60, 70 %, w/w of SPI). Water vapor permeability (WVP), was measured at 25 °C and for four different relative humidities (30–100%, 30–84%, 30–75%, 30–53%). Surface pr…