6,242 research outputs found
Spectral characterisation of red pigment in Italian-type dry-cured ham. Increasing lipophilicity druing processing and maturation
Spectroscopic studies of Parma ham during processing revealed a gradual transformation of muscle myoglobin, initiated by salting and continuing during ageing. Electron spin resonance spectra did, however, conclusively show that the pigment in dry-cured Parma ham at no stage is a nitrosyl complex of ferrous myoglobin as found in brine-cured ham and Spanish Serrano hams. Both near-infra red reflectance spectra of sliced ham and UV/visible absorption spectra of extract of hams, obtained with aqueous buffer or acetone, showed the presence of different red pigments at varying processing stages for both solvents. Especially, the pigment extracted with aqueous buffer exhibited unique spectral features different from those of well-known myoglobin derivatives. At the end of processing, the pigment(s) becomes less water extractable, while the fraction of red pigment(s) extractable with acetone/water (75%/25%) increases throughout the processing time up to full maturation at 18 months. The chemical identity of the 6th ligand of myoglobin could not be conclusively established, but possible candidates are discussed. The partition of the pigment(s) between pentane and acetone/water showed a strong preference for pentane, suggesting that only the heme moiety is present in the acetone/water extract, and that Parma ham pigment is gradually transformed from a myoglobin derivative into a non-protein heme complex, which was found to be thermally stable in acetone/water solutio
Thermal and photochemical degradation of myoglobin pigments in relation to colour stability of sliced dry-cured Parma ham and sliced dry-cured ham produced with nitrite salt
Lipophilic and hydrophilic extracts of the red pigments from Parma ham and nitrosylated pigment of dry-cured ham produced with nitrite salt were prepared with acetone/water (75/25 v/v %) solution and aqueous phosphate buffer, respectively. The spectral characteristics differed for both the lipophilic and the hydrophilic Parma ham pigment compared with the dry-cured ham produced with nitrite salt. The red lipophilic pigment(s) extractable from Parma ham was(were) found to be very stable towards thermal degradation in acetone/water (75/25 v/v %) solution for temperatures up to 70 °C in contrast to the lipophilic pigment(s) extractable from dry-cured ham produced with nitrite salt, which was(were) found to have an energy of activation of 99 kJ/mol for thermal degradation. In contrast, quantum yields for photodegradation of the lipophilic ham pigments exposed to 366 nm (420 nm) monochromatic light were larger for Parma ham than for nitrite-cured ham [1.6×10–5 (6.9×10–6) versus 1.6×10–6 (2×10–6) mol einstein–1] as determined for acetone/water (75/25 v/v %) solution. In agreement with these findings for the extracted lipophilic pigments, sliced Parma ham showed better colour stability than sliced dry-cured ham produced with nitrite salt, when stored in the dark at low oxygen concentration, in contrast to a faster initial discolouration for Parma ham when exposed to light, as shown for chilled storage for 35 days under retail conditions for the two products each packed at two oxygen levels (0.4 and 21%)
Studies on the antioxidative activity of red pigments in Italian-type dry-cured ham
Aqueous phosphate buffer extracts and acetone/water extracts of pigments from Parma ham were assessed as antioxidants by (1) electron spin resonance spectroscopy using a spin probing technique to evaluate their efficiencies as scavengers of free radicals, and (2) by electrochemical measurement of oxygen depletion rate in an aqueous methyl linoleate emulsion to evaluate their efficiencies as chain-breaking antioxidant, and using both methods, compared with the effect of apomyoglobin and nitrosylmyoglobin. Aqueous phosphate extracts and acetone/water extracts of Parma ham pigment both scavenged a semi-stable nitroxide radical (Fremy's salt), and both extracts reduced the rate of oxygen consumption for lipid peroxidation (initiated by metmyoglobin) very efficiently. For apomyoglobin no antioxidative capacity was observed, and the heme moiety of the pigment(s) of Parma ham were concluded to have antioxidative properties. The more lipophilic pigment, as extracted by acetone/water, had the most significant effect, and its ability to inhibit lipid oxidation was further tested in a model food system based on cooked pork. The lipid oxidation was increasingly inhibited by increasing additions from 0.12 ppm to 0.24 ppm Parma ham pigment, and the pigment protected a-tocopherol against degradation in a concentration dependent manner
Mineral X, a new thalcusite homologue from the Ilimaussaq complex, South Greenland Contribution to the mineralogy of Ilimaussaq, no. 144
Calcareous nannofossil and foraminifer biostratigraphy of the Campanian–Maastrichtian chalk of the Femern Bælt (Denmark–Germany).
A new study based on calcareous nannofossil and benthic
and planktonic foraminifer biostratigraphy is presented for
the upper Campanian – Maastrichtian chalk of the Femern
Bælt (Denmark and Germany; Fig.1). The results are consistent
with recent studies of the Danish chalk for this interval,
allowing correlation across the Danish Basin and forming the
basis for correlation further afield within the Boreal Realm.
Numerous studies have been carried out recently on the upper
Campanian – Maastrichtian chalk of the Danish Basin,
covering aspects such as sedimentology, depositional environment,
macrofossil biostratigraphy, carbon isotope stratigraphy
as well as nannofossil and dinoflagellate biostratigraphy.
However, very few published studies on foraminifers
exist across this interval in this area. The 09.A.006, 09.A.007
and 09.A.008 boreholes (Fig. 2) were drilled in 2009 in preparation
for construction of a fixed link across the Femern
Bælt, which will connect Denmark to Germany (Rambøll
Arup JV 2011). The boreholes penetrated glacial till, Paleocene–
Eocene clay and chalk (Sheldon et al. 2012). Here, for
the first time, the Boreal foraminifer biostratigraphy of the
late Campanian – Maastrichtian interval is investigated and
presented alongside nannofossil biostratigraphy
The evolution of field early-type galaxies to z~0.7
We have measured the Fundamental Plane (FP) parameters for a sample of 30
field early-type galaxies (E/S0) in the redshift range 0.1<z<0.66. We find
that: i) the FP is defined and tight out to the highest redshift bin; ii) the
intercept \gamma evolves as d\gamma/dz=0.58+0.09-0.13 (for \Omega=0.3,
\Omega_{\Lambda}=0.7), or, in terms of average effective mass to light ratio,
as d\log(M/L_B)/dz=-0.72+0.11-0.16, i.e. faster than is observed for cluster
E/S0 -0.49+-0.05. In addition, we detect [OII] emission >5\AA in 22% of an
enlarged sample of 42 massive E/S0 in the range 0.1<z<0.73, in contrast with
the quiescent population observed in clusters at similar z. We interpret these
findings as evidence that a significant fraction of massive field E/S0
experiences secondary episodes of star-formation at z<1.Comment: ApJ Letters, in pres
The Minkowski metric in non-inertial observer radar coordinates
We give a closed expression for the Minkowski (1+1)-dimensional metric in the
radar coordinates of an arbitrary non-inertial observer O in terms of O's
proper acceleration. Knowledge of the metric allows the non-inertial observer
to perform experiments in spacetime without making reference to inertial
frames. To clarify the relation between inertial and non-inertial observers the
coordinate transformation between radar and inertial coordinates, also is
given. We show that every conformally flat coordinate system can be regarded as
the radar coordinate system of a suitable observer for a suitable
parametrization of the observer worldline. Therefore, the coordinate
transformation between arbitrarily moving observers is a conformal
transformation and conformally invariant (1+1)-dimensional theories lead to the
same physics for all observers, independently of their relative motion.Comment: Revtex4, 6 pages, 1 figur
A New Kind of Uniformly Accelerated Reference Frames
A new kind of uniformly accelerated reference frames with a line-element
different from the M{\o}ller and Rindler ones is presented, in which every
observer at consts. has the same constant acceleration. The laws of
mechanics are checked in the new kind of frames. Its thermal property is
studied. The comparison with the M{\o}ller and Rindler uniform accelerated
reference frames is also made.Comment: 10 pages, 2 figures. to appear in Int. J. Mod. Phys.
Spherically Symmetric Solutions in M\o ller's Tetrad Theory of Gravitation
The general solution of M\o ller's field equations in case of spherical
symmetry is derived. The previously obtained solutions are verified as special
cases of the general solution.Comment: LaTeX2e with AMS-LaTeX 1.2, 8 page
Approximate Bayesian inference for a spatial point process model exhibiting regularity and random aggregation
In this paper, we propose a doubly stochastic spatial point process model
with both aggregation and repulsion. This model combines the ideas behind
Strauss processes and log Gaussian Cox processes. The likelihood for this model
is not expressible in closed form but it is easy to simulate realisations under
the model. We therefore explain how to use approximate Bayesian computation
(ABC) to carry out statistical inference for this model. We suggest a method
for model validation based on posterior predictions and global envelopes. We
illustrate the ABC procedure and model validation approach using both simulated
point patterns and a real data example.Comment: 37 pages, 10 figures; one line was adde
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