465 research outputs found
The influence of extraction and precipitation pH on the dry matter yield of broiler dark meat
Abstract In recent years, demand for white meat products has resulted in excess supplies and depressed prices of leg meat in the United States. One approach to increasing the utilization of dark meat is to extract the pigments and fat to make the resulting product more acceptable for the production of further-processed meat products. To date, such technologies have been inefficient (low yields) or have resulted in products of limited use. Three replicate trials were conducted to determine the effects of extraction pH and precipitation pH on the wet and dry extract yields of boneless, skinless broiler leg meat. Broiler leg meat was chopped with added water and extracted by adjusting the pH to 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, and 12.0 while mixing. After determination of extraction yields, each extraction was adjusted to pH 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, 5.0, and 5.2 to determine the effect of precipitate pH on total wet and dry yields. Dry yield increased with extraction pH and precipitation pH. However, the greatest yields, over 70%, were at extraction pH values above 10.5, which have been associated with the production of potentially harmful by-products. Combinations of extraction pH values between 9 and 10.5 and precipitation pH values above 4.4 resulted in dry yields of approximately 65%. These results indicate that pH extraction and precipitation may result in economically viable yields. Further research is needed to determine the optimal conditions of yield, composition, and functionality
Physical and Functional Properties of Intact and Ground Pale Broiler Breast Meat
The functional and physical properties of intact and ground meat were determined during 4 replicate trials on a total of 180 pale [lightness (L*) > 53] and normal (46 < L* < 53) boneless, skinless breast fillets collected from 2 commercial processing plants. At 24 h postmortem, L*, redness (a*), yellowness (b*), and pH were determined on each fillet. The left fillet from each breast was ground and used to determine cook loss (CL) and Allo-Kramer (AK) shear on meat patties as well as moisture uptake (MU) and CL on meat slurries before and after adjustment to the normal meat pH of 5.9. The right fillet from each breast was kept intact and used to determine expressible moisture (EM), CL, and AK shear on the intact meat. Compared with normal fillets, pale fillets exhibited significantly higher L* values, lower ultimate pH (5.67 vs. 5.94), higher AK (3.5 vs. 2.9 kg/g), higher EM, lower MU, and higher CL measured on the intact fillets, ground meat patties, and meat slurries. Adjustment of the pH of the pale meat slurries to normal meat pH (5.9) resulted in a higher MU (11.05 vs. 3.69%), indicating a partial restoration of protein functionality. These results indicate that wide differences in raw broiler breast meat color, mainly due to differences in the muscle pH, are related to important variations in the water-holding and binding capacities of the meat. The effect of low meat pH can be partially ameliorated in ground meat by pH adjustment
The Effect of Holding Temperature on Live Shrink, Processing Yield, and Breast Meat Quality of Broiler Chickens
The effects of antemortem holding temperatures on live shrink, processing yields, and breast meat quality of broiler chickens were evaluated. A total of 462 broilers was reared to 45 d of age using conventional husbandry practices, removed from feed and water, and cooped 12 h prior to slaughter. During the 12-h feed withdrawal and holding time, the birds were held at 25, 29.5, or 34 C. Birds were individually weighed at cooping, prior to slaughter, and during processing to determine live shrink and processed carcass yields. The breast meat was removed at 2 or 24 h postmortem and was used to determine hot and cold boned meat pH, R-value, sarcomere length, meat color (lightness, redness, and yellowness), cooked yield, and shear value. The birds held at 34 C showed the significantly greatest live shrink, 5.7%, compared to those held at 29.5 or 25 C with 3.9 and 3.2% shrink, respectively. Birds held at 34 C exhibited significantly lower processed carcass yields based on initial catch weight, but when calculated using postshrink weights, there were no significant differences between treatment groups. For breast meat harvested at 2 h postmortem, the birds held at 25 C had higher R-values, redness, and yellowness values and lower cooked meat yield and shear values. For breast meat harvested at 24 h postmortem, the birds held at 25 C had higher pH, R-values, and redness. These results support earlier reports that holding conditions may dramatically effect live bird shrink and apparent yields (based on calculation denominator) but have relatively little effect on subsequent breast meat quality, regardless of postmortem deboning time
Least Squares and Shrinkage Estimation under Bimonotonicity Constraints
In this paper we describe active set type algorithms for minimization of a
smooth function under general order constraints, an important case being
functions on the set of bimonotone r-by-s matrices. These algorithms can be
used, for instance, to estimate a bimonotone regression function via least
squares or (a smooth approximation of) least absolute deviations. Another
application is shrinkage estimation in image denoising or, more generally,
regression problems with two ordinal factors after representing the data in a
suitable basis which is indexed by pairs (i,j) in {1,...,r}x{1,...,s}. Various
numerical examples illustrate our methods
Laser cladding of rail; the effects of depositing material on lower rail grades
This paper presents a study comparing the wear performance of laser clad rails. A grade of martensitic stainless steel (MSS) was deposited on two substrate materials: The European standard grade rail steel R260, and a lower grade rail steel R200. A twin-disc method has been used to simulate the contact of wheel and rail under closely controlled conditions. Although cladding on a lesser grade of rail has an effect on the hardness and wear performance of the clad layer (due to dilution), the resulting wear performance of the clad layer assessed using this approach is still vastly improved over R260 material alone
Current-induced cooling phenomenon in a two-dimensional electron gas under a magnetic field
We investigate the spatial distribution of temperature induced by a dc
current in a two-dimensional electron gas (2DEG) subjected to a perpendicular
magnetic field. We numerically calculate the distributions of the electrostatic
potential phi and the temperature T in a 2DEG enclosed in a square area
surrounded by insulated-adiabatic (top and bottom) and isopotential-isothermal
(left and right) boundaries (with phi_{left} < phi_{right} and T_{left}
=T_{right}), using a pair of nonlinear Poisson equations (for phi and T) that
fully take into account thermoelectric and thermomagnetic phenomena, including
the Hall, Nernst, Ettingshausen, and Righi-Leduc effects. We find that, in the
vicinity of the left-bottom corner, the temperature becomes lower than the
fixed boundary temperature, contrary to the naive expectation that the
temperature is raised by the prevalent Joule heating effect. The cooling is
attributed to the Ettingshausen effect at the bottom adiabatic boundary, which
pumps up the heat away from the bottom boundary. In order to keep the adiabatic
condition, downward temperature gradient, hence the cooled area, is developed
near the boundary, with the resulting thermal diffusion compensating the upward
heat current due to the Ettingshausen effect.Comment: 25 pages, 7 figure
Particle interactions with single or multiple 3D solar reconnecting current sheets
The acceleration of charged particles (electrons and protons) in flaring
solar active regions is analyzed by numerical experiments. The acceleration is
modelled as a stochastic process taking place by the interaction of the
particles with local magnetic reconnection sites via multiple steps. Two types
of local reconnecting topologies are studied: the Harris-type and the X-point.
A formula for the maximum kinetic energy gain in a Harris-type current sheet,
found in a previous work of ours, fits well the numerical data for a single
step of the process. A generalization is then given approximating the kinetic
energy gain through an X-point. In the case of the multiple step process, in
both topologies the particles' kinetic energy distribution is found to acquire
a practically invariant form after a small number of steps. This tendency is
interpreted theoretically. Other characteristics of the acceleration process
are given, such as the mean acceleration time and the pitch angle distributions
of the particles.Comment: 18 pages, 9 figures, Solar Physics, in pres
Quantum Vacuum Experiments Using High Intensity Lasers
The quantum vacuum constitutes a fascinating medium of study, in particular
since near-future laser facilities will be able to probe the nonlinear nature
of this vacuum. There has been a large number of proposed tests of the
low-energy, high intensity regime of quantum electrodynamics (QED) where the
nonlinear aspects of the electromagnetic vacuum comes into play, and we will
here give a short description of some of these. Such studies can shed light,
not only on the validity of QED, but also on certain aspects of nonperturbative
effects, and thus also give insights for quantum field theories in general.Comment: 9 pages, 8 figur
Prospects for asteroseismology
The observational basis for asteroseismology is being dramatically
strengthened, through more than two years of data from the CoRoT satellite, the
flood of data coming from the Kepler mission and, in the slightly longer term,
from dedicated ground-based facilities. Our ability to utilize these data
depends on further development of techniques for basic data analysis, as well
as on an improved understanding of the relation between the observed
frequencies and the underlying properties of the stars. Also, stellar modelling
must be further developed, to match the increasing diagnostic potential of the
data. Here we discuss some aspects of data interpretation and modelling,
focussing on the important case of stars with solar-like oscillations.Comment: Proc. HELAS Workshop on 'Synergies between solar and stellar
modelling', eds M. Marconi, D. Cardini & M. P. Di Mauro, Astrophys. Space
Sci., in the press Revision: correcting abscissa labels on Figs 1 and
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