Home About us Contact
|
Home About us Contact | ||
|
|
||
Instrumental Analyses (instrumental + analysis)
Selected AbstractsEFFECT OF THAWING METHODS ON TEXTURAL QUALITY OF SOUS-VIDE STEWED BEEF ASSESSED BY SENSORY AND INSTRUMENTAL ANALYSESJOURNAL OF FOOD QUALITY, Issue 5 2001N.J.N. YAU ABSTRACT This study compared four different thawing methods using sensory test with magnitude estimation, preference test with hedonic scale and physical analyses. The four methods were tap-water, refrigeration, microwave reheating, and boiling-water reheating. For physical analyses, there were differences (p,0.001) among treatments in drip loss and expressible juice. For drip loss, the microwave reheated samples were the highest and the refrigeration and tap-water treated samples were the lowest. For expressible juice, tap-water and refrigerated samples were higher (p,0.01) than the microwave and boiling-water reheated samples. Microwave and boiling-water reheated samples had higher hardness and cheviness and lower juiciness and fiber-looseness. The refrigerated and tap-water thawed samples had reverse sensory properties. Naive panelists preferred the refrigerated and tap-water treated samples to the microwave and boiling-water reheated samples for juiciness, tenderness, and overall preference. Physical parameters from textural profile analysis were not different among the thawing methods. Expressible juice was the best indicator for sensory hardness, juiciness, fiber-looseness and chewiness among the physical parameters. Usually a quadratic regression model fit best when expressible juice was used to predict sensory textural properties. [source] CONSUMER ACCEPTABILITY, SENSORY AND INSTRUMENTAL ANALYSIS OF PEANUT SOY SPREADSJOURNAL OF FOOD QUALITY, Issue 1 2003N.J. DUBOST ABSTRACT Textural properties of commercial peanut butter, commercial soy nut spread and three formulated peanut soy spreads with 8, 14, and 20% isolated soy protein were characterized using the Texture Analyser TA.TX2® Significant differences were found between the textural parameters of the treatments (,=0.05). Testing of color, aroma and textural attributes by a descriptive analysis panel indicated significant differences existed between the treatments. Based on consumer acceptability testing using a three-point acceptability scale, the three peanut soy spreads were acceptable products. A mathematical relationship (R2= 0.5) existed between the sensory descriptor aroma and consumer acceptability, and between superior quality (tastes great) and aroma and mouthcoating. No significant relationships were observed between instrumental and consumer acceptability testing. [source] Novel Palladium-on-Carbon/Diphenyl Sulfide Complex for Chemoselective Hydrogenation: Preparation, Characterization, and ApplicationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2008Akinori Mori Abstract A diphenyl sulfide immobilized on palladium-on-carbon system, Pd/C[Ph2S], was developed to achieve the highly chemoselective hydrogenation of alkenes, acetylenes, azides, and nitro groups in the presence of aromatic ketones, halides, benzyl esters, and N-Cbz protective groups. Instrumental analyses of the heterogeneous catalyst demonstrated that diphenyl sulfide was embedded on Pd/C via coordination of its sulfur atom to palladium metal or physical interaction with graphite layers of the activated carbon. The catalyst could be recovered and reused at least five times without any significant loss of the reactivity. [source] EVALUATION OF MICROBIOLOGICAL, PHYSICOCHEMICAL AND SENSORY QUALITIES OF CHITOSAN TOFU DURING STORAGEJOURNAL OF FOOD QUALITY, Issue 1 2004MEERA KIM ABSTRACT Tofu containing both low and high viscosity chitosan was prepared and changes in the microbiological, physicochemical and sensory properties of the tofu during storage were investigated. The colony forming units of mesophilic and psychrotrophic microorganisms in tofu containing high viscosity chitosan were markedly lower during storage than those in the control tofu as well as the tofu containing low viscosity chitosan. The pH of the tofu samples increased during storage. The L and a values of the tofu, especially the control tofu, increased during storage. In the sensory test, the roasted nutty and beany aromas of the tofu decreased during storage. Instrumental analysis of hardness and chewiness of the tofu decreased during storage. Overall preference for the tofu gradually decreased during storage, but overall preference for the tofu containing high viscosity chitosan scored higher than the other tofu samples. [source] Reduction of Oil Absorption in Deep-Fried, Battered, and Breaded Chicken Patties Using Whey Protein Isolate as a Postbreading Dip: Effect on Flavor, Color, and TextureJOURNAL OF FOOD SCIENCE, Issue 1 2009E. Mah ABSTRACT:, The effect of the application of whey protein isolate (WPI) solution as a postbreading dip to reduce oil absorption in deep-fried, battered, and breaded chicken patties on sensory properties was investigated. Chicken patties were battered, breaded with either crackermeal (CMP) or Japanese breadcrumbs (JBP), and dipped into WPI solutions at varying protein concentrations (0%, 2.5%, 5%, and 10%[w/w] WPI) and pH levels (pH 2, 3, and 8). A trained descriptive sensory panel evaluated the patties for 16 attributes relating to appearance, texture, and flavor. Instrumental analysis on the color and texture of the patties was also performed. The only perceivable changes in treated patties were related to color, hardness, and crunchiness. Increasing WPI concentration caused darkening of JBP but made CMP lighter. Patties treated at pH 8 were significantly darker across all WPI concentrations. The presence of WPI increased hardness and crust fracture for CMP but not JBP. Variations in pH levels did not affect texture. Thus, JBP that showed the highest lipid reduction (10% WPI at pH 2) were observed to be darker, less yellow, but did not produce any perceivable changes in hardness or crunchiness, while CMP with the lowest lipid content (5% WPI at pH 2) were lighter, more yellow, harder, and crunchier. [source] Instrumental analysis of gas hydrates propertiesASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2010Y. Rojas Abstract Gas hydrates attracted intense research interest when it was first recognised some 70 years ago that they were responsible for the blockage of flow lines, valves and well heads, thereby causing great loss of production and other severe safety hazards to the oil and gas industry. After many decades, these compounds are still the topic of research activities in various multi-disciplinary fields, including chemical and petroleum engineering, earth and geophysics, chemistry and environmental sciences. This is not only due to the great impact that these compounds have on the oil and gas industry, but also to the potential applications they have in many evolving areas, including, but not only, natural gas storage and transportation, carbon dioxide sequestration, and sea-water desalination. It is generally accepted that gas hydrates represent the largest source of hydrocarbons on earth, something which has not been appreciated until only recently. Management, either prevention or application or both, of gas hydrates requires a complete knowledge and understanding of the formation, decomposition and inhibition mechanisms of gas hydrates, which in turn demands advanced experimental methods and instrumental techniques for gas hydrate characterisation. This paper reviews a broad range of techniques that have been used for natural gas hydrate characterisation. It includes the basic physical science principles of each method and the gas hydrate properties that each method is capable of detecting, including some modern instrumental analyses that enable direct determination of gas hydrate phases and possible measurement of molecular interactions within the fluid phases. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Polychlorinated naphthalenes and other dioxin-like compounds in Elbe River sedimentsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2008Werner Brack Abstract Contamination of Elbe River (Germany) sediments with dioxin-like toxicants was investigated following the 500-year flood (flood that statistically occurs once in 500 years) of 2002. It was hypothesized that large amounts of particulate matter from river beds and associated dioxin-like toxicants were mobilized and transported during this flood event. The investigation focused on polychlorinated naphthalenes (PCNs) that have not been determined previously in the Elbe River. The in vitro H4IIE- luc assay was used as an overall measure for toxicants capable of binding to the aryl hydrocarbon receptor (AhR). The assay was combined with congener-specific instrumental analyses and fractionation to quantify PCN contributions to total AhR-mediated activity relative to polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). Penta- to octachloron-aphthalene concentrations of 30 ng/kg dry weight up to 13 ,g/kg dry weight were found in Elbe River sediments downstream of Bitterfeld. Concentrations of penta- to octachloronaphthalenes, however, were only approximately 3 ,g/kg dry weight at a site in the vicinity of Bitterfeld, where a level of approximately 3 mg/kg dry weight was reported before the flood. Also, the congener pattern of PCNs at this site changed after the flood, and PCN patterns reported previously for Bitterfeld and assigned to chlor-alkali electrolysis with graphite electrodes could now be observed at the sites from downstream of Bitterfeld and Magdeburg. Whereas PCDD/Fs dominated the dioxin-like activity in the middle and lower Elbe River, PCNs contributed as much as 10% of the total AhR-mediated activity. The contribution of PCBs was less significant (maximum, 0.2%). Thus, in Elbe River sediments, PCNs should be considered as relevant contaminants and be included in future monitoring and risk assessment programs. [source] Kinetics of graft copolymerization of poly(hexanedioic acid ethylene glycol) and methyl acrylate initiated by potassium diperiodatocuprate(III)JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007Libin Bai Abstract A redox system, potassium diperiodatocuprate(III) [DPC]/poly(hexanedioic acid ethylene glycol) (PEA) system, was employed to initiate graft copolymers of methyl acrylate (MA) and PEA in alkaline medium. The results indicate that the equation of the polymerization rate (Rp) is as follows: Rp = k [MA]1.62[Cu(III)]0.69, and that the overall activation energy of graft polymerization is 42.5 kJ/mol. The total conversion at different conditions (concentration of reactants, temperature, concentration of the DPC, and reaction time) was also investigated. The infrared spectra proved that the graft copolymers were synthesized successfully. Some basic properties of the graft copolymer were studied by instrumental analyses, including thermogravimetry and scanning electron microscope. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2376,2381, 2007 [source] Effects of silicone rubber on properties of dielectric acrylate elastomer actuatorPOLYMER ENGINEERING & SCIENCE, Issue 10 2006G. Mathew This article describes the effects of silicone rubber (SR) networks on the actuating behavior of acrylate rubber (AR)-based dielectric actuators. SR chains were diffused into a swollen AR networks in the presence of a co-solvent, and then the silicone chains were chemically crosslinked in an attempt to form an interpenetrating polymer network. The presence of SR in the AR network was confirmed by various instrumental analyses including attenuated total reflectance-Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The total crosslink density based on a swelling method and tensile properties increased with modification time. The Maxwell stresses were also determined using a pure-shear specimen. They increased in a parabolic fashion with the applied voltage, and depended on the type of compliant electrode and SR used. POLYM. ENG. SCI. 46:1455,1460, 2006. © 2006 Society of Plastics Engineers. [source] Instrumental analysis of gas hydrates propertiesASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2010Y. Rojas Abstract Gas hydrates attracted intense research interest when it was first recognised some 70 years ago that they were responsible for the blockage of flow lines, valves and well heads, thereby causing great loss of production and other severe safety hazards to the oil and gas industry. After many decades, these compounds are still the topic of research activities in various multi-disciplinary fields, including chemical and petroleum engineering, earth and geophysics, chemistry and environmental sciences. This is not only due to the great impact that these compounds have on the oil and gas industry, but also to the potential applications they have in many evolving areas, including, but not only, natural gas storage and transportation, carbon dioxide sequestration, and sea-water desalination. It is generally accepted that gas hydrates represent the largest source of hydrocarbons on earth, something which has not been appreciated until only recently. Management, either prevention or application or both, of gas hydrates requires a complete knowledge and understanding of the formation, decomposition and inhibition mechanisms of gas hydrates, which in turn demands advanced experimental methods and instrumental techniques for gas hydrate characterisation. This paper reviews a broad range of techniques that have been used for natural gas hydrate characterisation. It includes the basic physical science principles of each method and the gas hydrate properties that each method is capable of detecting, including some modern instrumental analyses that enable direct determination of gas hydrate phases and possible measurement of molecular interactions within the fluid phases. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Complete elimination of carbonates: A critical step in the accurate measurement of organic and black carbon in sedimentsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2005Marta T. Lukasewycz Abstract Accurate measurement of organic carbon (OC) and black carbon (BC) in sediments requires the complete removal of coexisting inorganic carbonates from the sample before instrumental analysis. The removal of carbonates from sediments is achieved with acidification, which causes the dissolution and decomposition of carbonates with accompanying effervescence. This effervescence, or the lack of it, is commonly used as an indicator for the presence or absence of carbonates. We have found that the lack of effervescence endpoint used with the direct acidification method (adding aliquots of acid to samples) is not a reliable indicator for complete removal of carbonates from sediment samples. The ineffectiveness of the lack of effervescence endpoint, we believe, is caused by the presence of carbonates with dissolution rates much slower than those of calcite, resulting in much slower rates of visible effervescence. We propose and demonstrate a method for determining the amount of acid required for complete elimination of all carbonates using Lake Michigan (USA) sediment samples. Based on our experiences with the lack of effervescence endpoint, we recommend that in any scheme for analysis of OC and/or BC, a minimum of two samples be treated with three different levels of acidification, with the lowest level being the same as that planned for all the OC and/or BC analyses. There can be no significant differences among the OC and BC contents measured using the three different levels of acidification. [source] CHANGES IN CHEMICAL, SENSORY AND RHEOLOGICAL CHARACTERISTICS OF MANCHEGO CHEESES DURING RIPENINGJOURNAL OF SENSORY STUDIES, Issue 4 2001MIGUEL ANGEL GONZÁLEZ-VIÑAS ABSTRACT Manchego cheese is a high-fat pressed ewe's-milk cheese made in Castilla-La Mancha (Spain) and produced by enzymatic coagulation. The minimum ripening time before marketing required by the Regulatory Board of the Manchego Cheese Appellation of Origin is 60 days. This paper describes the physicochemical, proteolysis, sensory and texture characteristics of Manchego cheese, and the degree of homogeneity of cheeses made under the Manchego Appellation of Origin. The data gathered in this study indicate that sensory and instrumental analysis are useful tools for detecting changes in Manchego cheese during ripening. These changes were first detected by the instrumental analysis (2 months). The panelists detected differences after 4 months' ripening in all the factories. With physicochemical analysis, on the other hand, longer ripening times (6,8 months) are required before such changes become appreciated. [source] | |||||||||||||