Meat quality and chemical assessment of porcine longissimus dorsi within different muscle pH

This study was carried out to investigate the influence of pH on the Berkshire’s pork longissimus dorsi muscle, by comparing physicochemical characteristics in a high pH group (5.92 ± 0.02) and a low pH group (5.55 ± 0.03) on the basis of muscle pH24 h post-mortem. Fifteen pigs were assigned to each group (n = 15). The low pH group showed higher filter-paper fluid uptake, cooking loss and National Pork Producers Council marbling scores but did not significantly differ from the high pH group (P > 0.05). The low pH group also showed higher Commission International de l’Eclairage L* and b*, drip loss, and shearing forces were significantly different from the high pH group. However, Commission International de l’Eclairage meat colour value (a*) and National Pork Producers Council colour were higher in the high pH group. The content of glutamic acid, threonine, and serine amino acids associated with a good flavour was higher in the high pH group. Also, amino acids associated with a bitter or poor flavour, such as valine, isoleucine, leucine, tyrosine, and histidine, was higher in the high pH group as well. The taste of umami was significantly (P < 0.01) higher in the high pH group. Levels of the nucleotide compounds hypoxanthine and inosine tended to be higher (P < 0.05) in the high pH group, whereas adenosine diphosphate levels were increased in the low pH group (P < 0.05). It is concluded that pH of pork could be a good indicator of pork quality and related to factors influencing pork eating quality. As pH of pork is not only positively associated with physical traits of pork but also closely related to chemical traits of which higher free amino acids and nucleotides enhance pork quality.

Effect of kosher salt application on microbial profiles of poultry carcasses

The effect of conventionally applied kosher salt on the microbiological profile of posteviscerated chicken carcasses obtained from a local commercial processing facility was evaluated. The broiler carcasses were divided into treatments 1 through 8. Standard sampling methods were used to evaluate Salmonella prevalence, aerobic plate counts, coliforms, generic Escherichia coli, and psychrotroph counts. Results indicate significant reductions in microbial populations in all the salted groups compared with controls. Significant reductions (1.45, 2.31, 2.81, and 1.48 log cfu/mL of rinse) were obtained for aerobic plate count (APC), coliforms, generic E. coli, and psychrotroph counts, respectively, on prechill salt-treated carcasses compared with controls. Salt-treated carcasses sampled after chilling had lower microbial populations compared with control chilled samples with significant reductions in coliforms and generic E. coli (1.25 and 1.77 log, respectively). Salt-treated samples had lower counts on APC and psychrotrophs after 10 d of refrigerated storage compared with controls. Finally, drip loss of salt-treated carcasses was lower after 24 h compared with nontreated controls. Based on the results, it can be concluded that salting process is an effective contributor to microbial reductions during processing that needs further investigation as a possible intervention in commercial poultry processing settings.

Molecular variation in pigmentation genes contributing to coat colour in native Korean Hanwoo cattle

Pigmentation genes such as TYR (tyrosinase), TYRP1 (tyrosinase-related protein 1), DCT (previously TYRP2, or tyrosinase-related protein 2), ASIP (agouti) and MC1R (melanocortin receptor 1) play a major role in cattle coat colour. To understand the genotypic profile underlying coat colour in native Korean Hanwoo cattle and Angus black cattle, portions of the above-mentioned genes were amplified. Sequence analysis revealed variation in the TYRP1 (exon 5) and MC1R genes. Restriction enzyme analysis of these two genes could distinguish between different colours of Hanwoo cattle. Quantitative estimates of melanin and eumelanin in hair from three different-coloured Hanwoo phenotypes and Angus black showed significant differences at the breed and phenotypic levels. Finally, sequence variants in MC1R were associated with total melanin and eumelanin in breeds as well as in Hanwoo phenotypes.

Development of LiF:Mg,Cu,Si TL material (new KLT-300) with a low-residual signal and high-thermal stability

LiF-based thermoluminescence (TL) materials have been widely used for radiation dosimetry due to their attractive features. LiF:Mg,Cu,P is one of the most sensitive tissue-equivalent TL materials, approximately 40 times more sensitive than LiF:Mg,Ti (TLD-100), but it has two main drawbacks: a thermal loss of the TL sensitivity when annealed at temperatures>240 degrees C, and a relatively high-residual signal. Recently, LiF:Mg,Cu,Na,Si TL material was developed to overcome these drawbacks at the Korea Atomic Energy Research Institute, but it provided only marginal improvements in reducing the residual signal. The newly developed LiF:Mg,Cu,Si TL material has a significantly lower residual signal and a better stability to thermal treatments. In this article, the preparation method and some dosimetric properties (sensitivity and residual signal) of the new LiF:Mg,Cu,Si TL material are presented. At the end of the preparation procedures, a dual-step annealing method is introduced and this has proved as a very efficient method to reduce the high-temperature peak and is the cause of residual signal. Therefore, the high-temperature peak in the glow curve was significantly reduced. The sensitivity is approximately 20 times higher than that of TLD-100 and the residual signal was estimated to be approximately 0.04%.

Dosimetric properties of the newly developed KLT-300 (LiF:Mg,Cu,Na,Si) TL detector

The dosimetric properties of the newly developed KLT-300 (KAERI LiF:Mg,Cu,Na,Si TL detector) in KAERI (Korea Atomic Energy Research Institute) were investigated. The sensitivity of the TL detector was about 30 times higher than that of the TLD-100 by light integration. In the study of the dose linearity of the detector, the dose response was very linear up to 10 Gy and a sublinear response was observed at higher doses. The energy response of the detector was studied for photon energies from 20 to 662 keV. The results show that a maximum response of 1.004 at 53 keV and a minimum response of 0.825 at 20 keV were observed. The reproducibility study for the TL detector was also carried out. The coefficients of variation for each detector separately did not exceed 0.016, and for all the 10 detectors collectively it was 0.0054. IEC Standard requires that the coefficient of variation shall not exceed 0.075. So, the reproducibility of this new TL detector sufficiently satisfied the IEC requirements. A detection threshold of the detector was investigated and found to be 70 nGy by Harshaw 4500 TLD Reader.

On the roles of the dopants in LiF: Mg,Cu,Na,Si thermoluminescent material

In this paper, some results of the study on the roles of the dopants in the LiF:Mg,Cu,Na,Si thermoluminescent (TL) material that was developed at the Korea Atomic Energy Research Institute for radiation protection are presented. Although there have been many studies to investigate the roles of the dopants in LiF:Mg,Cu,P TL material in the TL process, there are some discrepancies in the understanding of the roles of Cu and P between various researchers. In case of LiF:Mg,Cu,Na,Si TL material, there are a few studies on the roles of the dopants. Three kinds of samples in each of which one dopant is excluded, and the optimised sample, were prepared for this study. The measurements and analysis of the three-dimensional TL spectra, based on the temperature, wavelength and intensity, and the glow curves for those samples are used in this study. The results show that Mg plays a role in the trapping of the charge carriers and Cu plays a role in the luminescence recombination process; however, the effect of Na and Si on the glow curve structure and the TL emission spectra is much less than that of Mg and Cu. It is considered that Na and Si each plays a role in the improvement of the luminescence efficiency.

A computer program for the deconvolution of thermoluminescence glow curves

A quick and efficient computer program was developed in order to resolve the peaks from the thermoluminescence (TL) glow curve. The program was designed to be easily used on any MS Windows-based computer with a graphical user interface. In this program, a new method based on the general one-trap TL equation was adopted to analyse the TL glow curve with the traditional first-order, second-order and general-order kinetics model. The method described here, general approximation, generates TL glow peaks and interpolates the relevant TL parameters from the glow data. The program was tested with simulated and experimental TL glow data and the results were found to be adequate and reliable.

Effects of ribose supplementation on selected metabolic measurements and performance in maximally exercising Thoroughbreds

The objective of this study was to investigate the effects of ribose supplementation on blood ammonia-N, plasma lactic acid, plasma glucose, volume of oxygen consumption (VO2), heart rate, and performance in Thoroughbred geldings performing a maximal treadmill standardized exercise test (SET). The hypothesis tested was that ribose supplementation would decrease ammonia-N and lactic acid accumulation during exercise, and improve performance. Eight Thoroughbred geldings were assigned randomly to one of two groups: glucose or ribose. The glucose group received 0.15 g glucose/kg of BW, and the ribose group received 0.15 g of ribose/kg BW top-dressed on the feed twice daily. After 2 wk of glucose or ribose supplementation, a SET was performed. Blood was analyzed for blood ammonia-N, plasma lactic acid, and plasma glucose before exercise (0 min), every minute during SET, and at 15 and 30 min after exercise. Heart rate and VO2 were recorded for the duration of SET. After a 10-d washout period, geldings switched groups. Following another 2 wk of supplementation, a second SET was performed, and same data recorded. Blood ammonia-N and plasma lactic acid increased as duration of SET increased and reached a peak at 15 min after exercise. Peak plasma glucose was observed at 15 min after exercise, and peak heart rate and VO2 were recorded at highest speed during SET. Geldings supplemented with ribose had blood ammonia-N, plasma lactic acid, plasma glucose, VO2, heart rate, and performance similar to those of geldings supplemented with glucose. Results from this study show that supplementation with 0.15 g ribose/kg BW twice daily in the diet of conditioned Thoroughbred geldings for 2 wk does not influence blood ammonia-N, plasma lactic acid, plasma glucose, VO2, heart rate, or performance during SET or the first 30 min of recovery.

Developments in the synthesis of LiF:Mg,Cu,Na,Si TL material

A procedure for synthesis of the highly sensitive pellet-type LiF:Mg,Cu,Na,Si thermoluminescent (TL) detector has been newly developed. It was found that the optimum concentrations of dopants for a pellet-type LiF:Mg,Cu,Na,Si TL detector were found to be Mg: 0.2 mol %, Cu: 0.05 mol %, Na: 0.9 mol%, and Si: 0.9 mol%. The TL sensitivity of this new detector was about 30 times higher than that of the TLD-100 by light integration measurements. Reusability study of the detector was carried out for 10 cycles. The results show that the coefficients of variation for each detector separately did not exceed 0.016, and that for all 10 detectors collectively was 0.0054.

Analysis of the glow curves obtained from LiF:Mg,Cu,Na,Si TL material using the general order kinetics model

Three-dimensional thermoluminescence (TL) spectra based on temperature, wavelength and intensity for newly developed LiF:Mg,Cu,Na,Si TL material at the Korea Atomic Energy Research Institute (KAERI) were measured and analysed. The glow curves were obtained by integration of luminescence intensity over all wavelengths at each temperature, and various trapping parameters related to the traps were determined by analysing these curves. A computerised glow curve deconvolution (CGCD) method which was based on the general order kinetics (GOK) model was used for the glow curve analysis. The glow curves of LiF:Mg,Cu,Na,Si TL material were deconvoluted to six isolated glow curves which have peak temperatures at 333, 374, 426, 466, 483 and 516 K. The main glow peak of peak temperature at 466 K had activation energy of 2.06 eV and a kinetic order of 1.05. This TL material was also found to have three recombination centres, 1.80 eV, 2.88 eV and 3.27 eV by analysis of the TL spectra.

Differential antioxidant enzyme activities and glutathione content between rat and rabbit conceptuses

Redox status regulates numerous cellular processes like transcription factor activation and binding, protein folding, and calcium sequestration. Because the most abundant reducing equivalent in the cell is glutathione (GSH), it could play a role for teratogens that cause oxidative stress and disrupt pathways involved in differentiation and proliferation. Investigation of the redox status of two species that have demonstrated differential sensitivity to teratogens represents a novel approach for determining the role of redox alteration in teratogenesis. Furthermore, examining specific regions of the embryo may also help to explain why certain tissues are uniquely sensitive, while others are resistant to oxidative insult. In the presented study, New Zealand White rabbit (GD 12) and Sprague Dawley rat embryos (GD 13) were removed from the uterus on days of similar development. Each embryo was dissected into three portions-the limbs, the head, and the trunk. Samples were placed in the appropriate buffers for the measurement of both direct and indirect redox status contributors-GSH, cysteine, thioredoxin, glutathione disulfide, protein-glutathione mixed disulfides, superoxide dismutase, glutathione peroxidase, and glutathione disulfide reductase. Species comparison of whole embryos indicated that the rabbit embryo possesses a higher redox potential (more oxidative) than the rat embryo. Findings, in general, show that the rabbit may be more sensitive to redox-altering teratogens because it is inherently more pro-oxidizing and may be more easily perturbed resulting in misregulation of cellular processes. Differences were most apparent in the limb as compared to the embryonic head and trunk, where the rabbit limb has a significantly more pro-oxidizing redox environment than the rat limb. Species comparisons like these may help in the understanding of how redox shifts affect cellular processes and would contribute to regulation of biochemical and molecular events that may be associated with mechanisms of teratogenesis. These may contribute to a more complete rationale for choosing a species for study and provide a better correlation with human developmental toxicants.