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101.
ABSTRACT: Effects of carbon monoxide in modified-atmosphere packaging (MAP-CO) for pork were investigated. Eighty pork loins (40 injected, 40 uninjected) were used to evaluate color, microbial growth, rancidity, purge, and sensory quality of pork chops in 4 packaging environments (aerobic-overwrap, vacuum, MAP without CO, and MAP-CO). Treatments were evaluated during 36 d of refrigerated storage. Overall Hunter a values were significantly ( P < 0.001) greater in MAP-CO (11.25) than aerobic (6.93) packages. Sensory color values (100 point scale) were also greater for chops in MAP-CO (85.91) than aerobic (62.47) packages. However, MAP-CO did not reduce purge loss. Results showed that CO significantly improved color stability and sensory panel scores for both injected and noninjected pork chops. 相似文献
102.
Jochen Kirschbaum Corina Krause Hans Brückner 《European Food Research and Technology》2006,222(5-6):572-579
According to the directive 94/36/EC of the European Union (EU), quantities of synthetic colorants added to foods are restricted
by upper limits and, therefore, reliable methods for their quantification have to be established. Approved colorants, defined
by so-called E numbers, are permitted for dying fish roe (commonly named caviar). We developed a chromatographic method for
the quantitation of colorants in roe. The recovery rates of 14 synthetic food colorants from solid materials (Al2O3, XAD-2, anion exchangers, and polyamide-6) were tested, and polyamide powder was selected as adsorbent for quantitative determination
of colorants in fish roe. The most effective sample preparation comprises extraction of colorants from roe with 1 M aqueous
ammonia, defatting of the solution with n-hexane, adjustment of pH 2 of the extract, adsorption of dyes on the polyamide and desorption with a mixture of aqueous ammonia
(25%) and methanol (1:9 v/v). The isolated colorants were analyzed by RP-HPLC with diode-array detection. In several caviars,
the maximum of individual colorants regulated by EU were exceeded or colorants declared on food labels were not detected.
Presented at 25th International Symposium on Chromatography, Paris, France, October 4–8, 2004. 相似文献
103.
Several dietary and host related factors potentially influencing carotenoid (beta-carotene, lutein and zeaxanthin) bioaccessibility from spinach, including different concentrations of sodium, calcium and magnesium, were systematically investigated by means of an in vitro digestion model. Bioaccessibility was highest when milk (4% fat) and lowest when skimmed milk or more complex food matrices such as sausage were added to the meal. Micellarisation significantly depended on the presence and concentration of bile salts and pancreatin (p < 0.001, Bonferroni) but was unaffected by pepsin. Micellarisation significantly decreased to 61.4 ± 3.0% of control (p < 0.001, Dunnett’s) at high cholesterol (114 mg/test meal) but not at similar stigmasterol concentrations. Calcium and magnesium ?13.8 mM individually inhibited micelle formation ( >40% on average), presumably due to the generation of insoluble soaps with fatty acids and bile salts. Increased sodium concentrations (280 and 460 mM) altered carotenoid micellarisation patterns, favoring beta-carotene isomers (p < 0.001, Bonferroni) but decreasing lutein and zeaxanthin (p < 0.001 and p < 0.05, respectively, Bonferroni). This study suggests that minerals may impact carotenoid bioavailability. 相似文献
104.
The present study examined the effects of morphine in pigeons responding under a progressive-ratio 25 schedule of food delivery. Morphine initially reduced response rates and breaking points. With chronic exposure, tolerance developed to these effects. The magnitude of the observed tolerance was not obviously different from that previously reported under a PR 5 schedule of food delivery. In addition, when drug effects were compared under the fixed-ratio 25 and fixed-ratio 100 components comprised by the progressive-ratio schedule, comparable tolerance was observed. Although prior studies using other procedures have shown that ratio size modulates the development of tolerance to morphine and other drugs, the present data suggest that this relation is constrained, and is not easily observed under progressive-ratio schedules. 相似文献
105.
M. Krause J. M. Hausherr B. Burgeth C. Herrmann W. Krenkel 《Journal of Materials Science》2010,45(4):888-896
Computed tomography is a non-destructive testing technique based on X-ray absorption that permits the 3D-visualisation of
materials at micron-range resolutions. In this article, computed tomography is used to investigate fibre orientation and fibre
position in various fibre-reinforced materials such as ceramic matrix composites, glass fibre-reinforced plastics or reinforced
concrete. The goal of this article is to determine the quantitative orientation of fibres in fibre-reinforced materials. For
this purpose, a mathematical technique based on the structure tensor is used to determine the local orientation of fibres.
The structure tensor is easy to implement and results in a fast algorithm relying solely on local properties of the given
reconstruction. In addition, the local X-ray transform is used to denoise fibres and to segment them from the matrix. 相似文献
106.
A relatively simple method to determine the length distribution of carbon nanotubes (CNTs) before and after melt processing was developed. This involves the selection of a suitable solvent for dispersing pristine CNTs as well as to dissolve the matrix of melt mixed composites and the choice of an appropriate nanotube concentration. The length of suitably individualized CNTs was visualized using transmission electron microscopy and length distributions were measured using image analysis. Examples are shown for Baytubes® C150HP and Nanocyl™ NC7000 and their melt mixed composites with polycarbonate where the same procedure was applied to both, measuring the initial length distribution and the distribution after recovering from the composites. These results indicated a significant shortening after melt processing up to 30% of the initial length. 相似文献
107.
Agnieszka Wróblewska Joanna Wajzberg Anna Fajdek Eugeniusz Milchert 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(9):1344-1349
BACKGROUND: The influence of technological parameters on the epoxidation of 1‐butene‐3‐ol (1B3O) over titanium silicalite TS‐2 catalyst has been investigated. Epoxidations were carried out using 30%(w/w) hydrogen peroxide at atmospheric pressure. The major product from the epoxidation of B3O was 1,2‐epoxybutane‐3‐ol, with many potential applications. RESULTS: The influence of temperature (20–60 °C), 1B3O/H2O2 molar ratio (1:1–5:1), methanol concentration (5–90%(w/w)), TS‐2 catalyst concentration (0.1–6.0%(w/w)) and reaction time (0.5–5.0 h) have been studied. CONCLUSION: The epoxidation process is most effective if conducted at a temperature of 20 °C, 1B3O/H2O2 molar ratio 1:1, methanol concentration (used as the solvent) 80%(w/w), catalyst concentration 5%(w/w) and reaction time 5 h. Copyright © 2009 Society of Chemical Industry 相似文献
108.
This paper presents a new boundary shape representation for 3D boundary value problems based on parametric triangular Bézier surface patches. Formed by the surface patches, the graphical representation of the boundary is directly incorporated into the formula of parametric integral equation system (PIES). This allows us to eliminate the need for both boundary and domain discretizations. The possibility of eliminating the discretization of the boundary and the domain in PIES significantly reduces the number of input data necessary to define the boundary. In this case, the boundary is described by a small set of control points of surface patches. Three numerical examples were used to validate the solutions of PIES with analytical and numerical results available in the literature. 相似文献
109.
110.
Eugeniusz Rusiński Jerzy Czmochowski Artur Iluk Marcin Kowalczyk 《Engineering Failure Analysis》2010,17(1):179-191
A bucket wheel excavator (BWE) collapsed in a brown coal mine. As a result of a tie rod fracture the counterweight boom, the discharge boom and several other components of the other assemblies underwent plastic deformation. This paper presents the results of computer simulations of the collapse. A finite element method analysis of the counterweight boom tie rod showed stress concentrations exceeding the allowable level. Also material tests of the fracture surface were carried out to identify the causes of the collapse. Macroscopic and microscopic images of areas within the fracture were obtained. Measurements of hardness and microhardness in the vicinity of the weld were performed. The FEM analyses and material tests showed that the causes of the collapse were design and welding faults. 相似文献