Postmortem pH, Muscle, and Refrigerated Storage Effects on Ability of Vacuum-Packaged Pork to Bloom

ABSTRACT: Effects of pH, muscle, and storage time on the ability of vacuum-packaged pork chops to bloom were investigated. Low pH samples exhibited more change in color measures during the 30 min blooming period than did the medium and high pH samples. The low pH sample bloomed more rapidly and to a greater extent than medium and high pH samples. Among the 3 muscles, Longissimus had the highest, while Semimembranosus had the lowest a^* value and hue angle changes. Overall, refrigerated storage of vacuum packaged pork for 7 d or more resulted in more efficient blooming when pH was low. The ability of vacuum-packaged pork to rebloom is necessary for the meat to regain the consumer-expected pink-red color after opening the vacuum bag.     

Excitation control design of local machines in a large-scale power system by using dynamic equivalencing technique

A linear optimal control design for machine excitation is developed to improve the local system stability in a large-scale power system. Dynamic equivalents for the external system are used to provide the controller with information about the original external system. The paper investigates whether external system information helps the controller to stabilize the local system and whether the dynamic equivalents are a reliable source of that information. The validity and accuracy of the proposed method is demonstrated by simulated tests on two sample power systems.     

The case for technology in developing regions

Alongside good governance, technology is considered among the greatest enablers for improved quality of life. However, the majority of its benefits have been concentrated in industrialized nations and therefore limited to a fraction of the world's population. We believe that technology has a large role to play in developing regions, that "First World" technology to date has been a poor fit in these areas, and that there is thus a need for technology research for developing regions. Despite the relative infancy of technology studies in developing regions, anecdotal evidence suggests that access to technology has a beneficial economic impact. Cellular telephony is probably the most visible application, but there are many others, some of which we cover in this article. The World Bank's infoDev site catalogs hundreds of information and communications technologies (ICT) projects, albeit not all successful. Most of these projects use existing off-the-shelf technology designed for the industrialized world. Although it is clear that there are large differences in assumptions related to cost, power, and usage, there has been little work on how technology needs in developing regions differ from those of industrialized nations. We argue that Western market forces continue to meet the needs of developing regions accidentally at best.     

Using interval arithmetic for robust state feedback design

A problem of a modal P-regulator synthesis for a linear multivariable dynamical system with uncertain (interval) parameters in state space is considered. The designed regulator has to place all coefficients of the system characteristic polynomial within assigned intervals. We have developed the approach proposed earlier in Dugarova and Smagina (Avtomat. i Telemech. 11 (1990) 176) and proved a direct correlation between interval system controllability and existence of robust modal P-regulator.     

On the design of feedback control for relative stability

A basic theorem on relative stability is generalized and carefully interpreted. Two new theorems are then presented which simplify the calculation of feedback gains to achieve a prescribed damping ratio.     

Irradiation effects on meat color - a review

Color changes in irradiated fresh meat occur because of the susceptibility of the myoglobin molecule, especially the iron, to alterations in the chemical environment and to energy input. The potential for iron electrons to exist in various states makes the environment adjacent to the iron atom particularly vulnerable to the presence of electron-donating compounds and high energy inputs (irradiation). Initial condition of the myoglobin (Fe(++)O(2), Fe(+++)), modification of oxidation-reduction potential of the tissue, and generation of ligand-forming compounds (CO) from endogenous organic compounds and water are enhanced or suppressed depending on the gas atmosphere, temperature, pH and myoglobin concentration of the system. Generation of stable red pigments or brown pigments which become red over time appears to be due to binding of irradiation-generated reactive oxygen species (()O(2)(-)) or gasses (CO) which become ligands bound by iron under altered reducing conditions. Rapid generation of large amounts of metmyoglobin when irradiation is conducted in an oxygen-containing environment appears to be an acceleration of the normal process by which myoglobin undergoes oxidation. Generation of green pigments appears to be due to breakdown of the porphyrin integrity and/or formation of sulfmyoglobin. Maintenance of ideal meat color during irradiation can be enhanced by various combinations of pre-slaughter feeding of antioxidants to livestock, optimizing the condition of the meat prior to irradiation, addition of antioxidants, gas atmosphere (MAP), packaging, and temperature control.     

Effect of dietary vitamin E supplementation on textural and aroma attributes of enhanced beef clod roasts in a cook/hot-hold situation

The objective of this study was to evaluate the effects of supplementing vitamin E into the diets of finishing cattle on quality characteristics of beef pumped with a phosphate/salt solution (enhanced) the cooked and held in a simulated foodservice situation. Twelve steers were fed either a control (E-) diet or a diet supplemented with dl-α-tocopheryl-acetate (E+). Paired clod roasts were either used as controls (C) or were pumped (P) to 110% of raw weight to contain 0.4% sodium chloride and 0.4% phosphate in the finished product. Following injection, clods were allowed to equilibrate then frozen. A flavor profile panel evaluated texture attributes and aroma characteristics of roasts immediately after cooking and after 1 and 2 h of hot-holding. Pumping improved taste and textural attributes of the hot-held clod roasts. Dietary vitamin E supplementation reduced thiobarbituric acid reactive substances (TBARS) from ～0.61 to ～0.42, but over the 2-h time period, did not significantly improve aroma quality of beef roasts.     

Designing Neural Networks in Culture: Experiments are described for controlled growth, of nerve cells taken from rats, in predesigned geometrical patterns on laboratory culture dishes

Technology has advanced to where it is possible to design and grow-with predefined geometry and surprisingly good fidelity-living networks of neurons in culture dishes. Here we overview the elements of design, emphasizing the lithographic techniques that alter the cell culture surface which in turn influences the attachment and growth of the neural networks. Advanced capability in this area makes it possible to design networks of desired complexity. Other issues addressed include the influence of glial cells and media on activity and the potential for extending the designs into three dimensions. Investigators are advancing the art and science of analyzing and controlling through stimulation the function of the neural networks, including the ability to take advantage of their geometric form in order to influence functional properties.