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51.
Relationship between collagen characteristics,lipid content and raw and cooked texture of meat from young bulls of fifteen European breeds 总被引:1,自引:0,他引:1
Mette Christensen Per Ertbjerg Sebastiana Failla Carlos Sañudo R. Ian Richardson Geoff R. Nute José L. Olleta Begoña Panea Pere Albertí Manuel Juárez Jean-François Hocquette John L. Williams 《Meat science》2011
Variations in texture were determined for 10 day aged raw and cooked Longissimus thoracis (LT) muscle from 436 bulls of 15 European cattle breeds slaughtered at an age of 13–16 months. Variations in texture were related to differences in pH 24 h post-mortem, sarcomere length, collagen characteristics and lipid content. The shear force of cooked meat samples varied from 43.8 to 67.4 N/cm2. Simmental, Highland and Marchigiana cattle had the highest shear force values and Avileña-Negra Ibérica, Charolais, Casina and Pirenaica cattle had the lowest values. Cooked meat toughness showed a weak negative correlation to lipid content (P < 0.001) but no correlation to collagen characteristics. Raw meat texture measured by compression correlated positively (P < 0.001) with total and insoluble collagen. In conclusion, collagen characteristics showed correlation to raw meat texture but not to cooked meat toughness of LT muscle in European young bulls. 相似文献
52.
Ian D. Fisk Konstantinos Gkatzionis Mita Lad Christine E. R. Dodd David A. Gray 《European Food Research and Technology》2009,228(4):613-621
The effect of irradiation (0–20 kGy) on hemp and sunflower seeds was assessed, with specific reference to the oxidatively
labile lipid component (unsaturated fatty acids and tocochromanols). Total protein, lipid, and solids content of the seeds
did not vary with irradiation dose. Lipid hydroperoxide concentration increased significantly in the sunflower seeds (48 mmol kg−1 lipid) and a significant increase in volatile secondary oxidation products was measured in both seeds (e.g. hexanal, heptanal,
1-penten-3-ol) with increasing irradiation dose. Irradiation at 5 kGy sterilised the seeds of all microbial contamination
and irradiation doses of 20 kGy prevented germination. A loss of the antioxidant tocopherol was shown with increasing irradiation
doses, although this was selective for specific tocopherol isoforms (α-tocopherol, β-tocopherol and γ-tocopherol). 相似文献
53.
Reactive dyes containing a sulphonylazide group can undergo fixation on nylon substrates by two different mechanisms. Under aqueous dyeing conditions, at or below 120d? C, the free amino end-groups of the polymer attack the sulphonylazide group with displacement of azide ion, and results in attachment of the dye to the substrate by a sulphonamide linkage. In contrast, if the dyed substrate is subjected to dry heat fixation at 170d? C, the azide group decomposes to a sulphonylnitrene species which undergoes insertion into C-H bonds of the polymer. The dye is again attached by a sulphonamide bridge, but in this case the amount of dye that can be fixed is independent of the amino end-group content of the polymer. 相似文献
54.
A range of 18 diesel fuels and 21 kerosene fuels from mainly Australian petroleum and synthetic fuel sources, including coal, shale and peat, was investigated. Compositional details were defined as the weight per cent abundances of n-alkanes, branched plus cyclic saturates, single-ring aromatics, doublering aromatics and polynuclear aromatics, using both h.p.l.c. and 13C n.m.r. techniques. Relationships between fuel composition and a range of fuel properties were sought. Simple linear relationships between property values and compositional data were used. Explicit correlative expressions were derived using multiple linear regression analysis, with the coefficient of multiple determination, R2, indicating the quality of the fit between observed and calculated property values. In most cases good correlations were achieved. For diesels the properties investigated, with R2 values in parentheses, were: inverse specific gravity (0.99); 13C n.m.r. aromaticity (0.99); 1H n.m.r. aromaticity (0.88); cetane index (0.97); aniline point (0.96); diesel index (0.98); and FIA-measured aromatics content (0.77). For kerosenes the properties, with R2 values in parentheses, were: 13C n.m.r. aromaticity (0.98); 1H n.m.r. aromaticity (0.97); smoke point (0.88); and FIA-measured aromatics content (0.94). The results are shown to be of value in assessing the potential and limitations of hydrotreating as a process for upgrading synfuels. 相似文献
55.
Cellulose can be totally liquefied by heating to 350 °C in the presence of an aqueous phenolic solvent containing a catalyst. The main products are light aromatic hydrocarbons, benzofurans, heavier aromatic hydrocarbons such as substituted indanes and tetralin, and xanthenes. The variation of product distribution with catalyst was examined and it was found that in aqueous phenol, xanthene formation was enhanced by acidity. By substituting guaiacol for phenol, it was determined that most benzofuran formation involved the phenol solvent molecules, although a small proportion did not. This benzofuran may have arises from phenol generated from cellulose, the incorporation of phenol in the products being enhanced through a cage effect. 相似文献
56.
Anthony D. Caunt John A. Licchelli Ian W. Parsons Robert N. Haward Malik R.Y. Al-Hillo 《Polymer》1983,24(1):121-125
Reduction of TiCl4 with organomagnesiums either in the presence of preformed MgCl2, or concurrently with the formation of MgCl2 from chlorocarbons, yields materials which are active catalysts for the polymerization of propene and ethene. Transformation of these materials to a violet allotrope by heating with TiCl4 gives materials much more active for propene polymerization, albeit stereoregulation is still not good. interestingly, these transformed materials show little advantage for ethene polymerization except at high temperatures. Use of a Lewis base does not give high stereoregulation with propene; although some advantage is gained activity is greatly diminished by this. 相似文献
57.
Ian G. Richardson Adrian R. Brough Rik Brydson Geoffrey W. Groves Christopher M. Dobson 《Journal of the American Ceramic Society》1993,76(9):2285-2288
Solid-state 27 Al and 29 Si magic angle spinning NMR spectroscopy has been combined with electron energy loss spectroscopy carried out in the transmission electron microscope to determine the location of Al substituting in a semicrystalline C-S-H gel present in a hydrated synthetic slag glass. The gel is found to contain mainly pentameric silicate chains in which the central silicon is substituted by aluminum. 相似文献
58.
The results are presented of an investigation into the instability induced in dye-fibre bonds by peroxide treatments. The nature of the reactions involved are discussed. 相似文献
59.
Investigation of the lipid extract of the Australian chrysomelid beetle,Monolepta australis, has revealed a novel homologous series of long-chain, unsaturated-saturated dialkyl ethers in the cuticular wax. Gas chromatography-mass spectrometry, proton magnetic resonance, infrared spectroscopy, and chemical degradation have shown that ethers of formula CH3(CH2)9CH=CH(CH2)6O(CH2)12–16CH3 predominate. 相似文献
60.
By changing from the usual solvent-fixed frame of reference for flows to one based upon a fixed anion, electro-osmotic transference numbers are defined for any electrolyte, for which transport numbers are known. For sulphonate membranes, chloride electrolyte analogues were chosen. Agreement between observed transference numbers and those of the model electrolytes are shown to be excellent for both polystyrene based and perfluoro-sulphonic acid membranes.From irreversible thermodynamics it is shown that the transference number for any membrane will have a maximum value equal to the molar ratio of water to fixed charge in the membrane and independent of ionic form. The observed value is in addition, proportional to the fraction of the total water friction, which is due to water interaction with counterion. It is the latter which is estimated successfully from model electrolytes. The ionic forms used were Li+, Na+, K+, Rb+, Cs+ and H+ at 25°C in membranes in which electrolyte exclusion was almost complete. 相似文献