Marination pressure and phosphate effects on broiler breast fillet yield, tenderness, and color.

In the United States a large percentage of raw poultry meat is marinated prior to cooking. Many products are marinated by vacuum tumbling meat with a mixture of water, salt, and phosphates to increase cook yield and perceived tenderness. This study was designed to determine the effect of 3 pressure treatments (ambient, vacuum, or positive) and phosphate on yield, tenderness, and color on broiler breast meat. In each of 3 replicate trials, 60 broiler breast fillets were randomly assigned to a tumble marination treatment of 1) ambient tumble pressure (101 kPa); 2) vacuum tumble pressure (50 kPa); or 3) positive tumble pressure (204 kPa). Each pressure treatment was conducted with and without phosphate in the marination solution. Marination tumblers were operated at 15 rpm for 20 min at a temperature of 3 degrees C. Broiler breast fillets were weighed (raw, immediately after marination, 1 h postmarination, and after cooking), sheared after cooking with a Warner-Bratzler device, and evaluated for color (CIE L, a, and b) before marination and after cooking. Pressure and phosphate treatment combinations did not significantly (P < 0.05) affect marinated or drip weights, Warner-Bratzler shear values, cooked b, or percent drip loss. There was no effect of pressure treatment except for marinade uptake, where ambient tumble uptake was 12.7%, which was significantly higher than positive tumble (11.4%); vacuum tumble uptake (12.0%) was not different from either. Phosphate significantly increased cook weight (from 94.9 to 106.1 g) and cook yield (from 76.6 to 86.1%); L and a values were slightly but significantly decreased. Type of pressure during tumble marination had no effect except on marinade uptake, but the effect disappeared with 1 h holding time and cooking. Phosphate improved cook weight and yield. These data show that vacuum pressure during tumbling is not necessary, but phosphate is important to cook yields.

Moisture retention by water- and air-chilled chicken broilers during processing and cutup operations.

The objective of this study was to evaluate effects of storage and cutting on moisture retention by air- and water-chilled broiler chickens. Sixty-four broilers were slaughtered, chilled by cold air or immersion in water, stored over night, cut into fore- and hindquarters, and then stored an additional 24 h. Air chilling conditions were 4 degrees C with air velocity of 2.2 m3/min. Water chilling conditions were 1 degree C with mechanical agitation. Moisture absorption and retention were observed as weight changes throughout the process. Air-chilled carcasses lost an average of 0.68% of their postslaughter weight in storage prior to cutting but lost no more during cutting or postcutting storage. The water-chilled carcasses absorbed 11.7% moisture in chilling but retained 6.98% through precutting storage, 6.00% through cutting and 3.90% through postcutting storage. These data offer baseline values for use in complying with new USDA processing standards.

Effect of vacuum on moisture absorption and retention by marinated broiler fillets.

Effects of vacuum on moisture retention and quality characteristics of aged chicken breast fillets were evaluated. One hundred twenty-eight broilers (2 replicates of 64 birds each) were manually slaughtered, chilled in ice water, placed in unsealed plastic bags, and then aged overnight at 4 degrees C. Both pectoralis major muscles were harvested from each carcass. Left muscles were marinated for 30 min en vacuo with 20% (vol/wt) of a 10% NaCl (wt/vol) solution containing 4% (wt/vol) commercial food-grade polyphosphate. Right fillets were marinated similarly but without vacuum. Moisture absorption, cooked yield, pH change during marination, and shear values of vacuum-marinated fillets were compared to those on fillets marinated without vacuum. Use of vacuum during marination increased moisture absorption during marination, but after cooking, yields were similar. Nor did vacuum effect pH or shear values. Under the conditions of this study, use of vacuum during marination appeared to offer no significant advantage over marination at atmospheric pressure.

Influence of age and postchill carcass aging duration on chicken breast fillet quality.

Breast fillet quality was evaluated from 37-, 39-, 42-, 44-, 46-, 49-, and 51-d-old broilers after post-chill (PC) aging of the carcass 0, 2, 4, or 6 h and deboning. Fillets were vacuum sealed in cooking bags and heated to an internal temperature of 72 C by submersion in a 95 C water bath. Cook yield was determined as the weight percentage of the fillet remaining after cooking. Texture of the cooked fillets was measured using a Warner-Bratzler (W-B) shear device. Fillet cook yield and shear force values were significantly affected by bird age at slaughter, and PC carcass aging duration before deboning. Bird gender significantly affected cook yield, whereas the interaction between age and PC aging duration significantly affected W-B shear. Fluid lost during cooking was greater for fillets aged 0 h PC and decreased when PC aging was 2 h or greater. Overall, W-B shear values decreased (more tender) when fillets were aged on the carcass at least 2 h PC, with the exception of fillets from 51-d-old broilers. After 2 h of PC aging on the carcass, shear force values for fillets from older broilers (49- and 51-d-old) were in the "very tough" portion of a texture scale (>12.60 kg), whereas textures of fillets from 42- and 44-d-old broilers were in the "slightly tough to slightly tender" portion of the scale (8.5 and 7.2 kg, respectively). These data show that if poultry processors harvest fillets earlier than usual (<2 h PC aging), the fillet texture will be more tender if it originates from younger broilers (42- or 44-d-old) instead of older broilers (49- or 51-d-old).

Effects of age, sex, and duration of postmortem aging on percentage yield of parts from broiler chicken carcasses.

The objective of this study was to evaluate effects of age, sex, and postmortem carcass aging duration on parts yield from broiler chickens. Two hundred twenty-four mixed-sex broilers were reared under commercial-like conditions for various periods between 37 and 51 d, slaughtered, packed in ice, and then aged for 0, 2, 4, or 6 h. Mean percentage yield of thighs, drumsticks, forequarters, wings, breasts, and filets were evaluated for each rearing period, sex, and postmortem aging duration. Yield of meatier parts such as thighs, forequarters, breasts, and filets increased with birds' ages. Female carcasses produced higher percentage yields of forequarters, breasts, and filets but lower yields of drumsticks. Carcasses aged 2 h or more postmortem tended to have lower yields of forequarters, breasts, and drumsticks than did carcasses aged for shorter durations. No statistically significant interactions among age, sex, or postmortem aging duration that affected yield of parts were detected. This information is useful to integrated poultry firms wishing to optimize yield of the most commercially valuable parts.

Quantitative analysis of cumulative trauma risk factors and risk factor interactions.

This study identifies the strongest occupational risk factors and risk factor interactions in the development of indicators associated with cumulative trauma disorders (CTD). Suggestions for minimizing the occurrence of indicators associated with onset of CTD are presented. Five Occupational risk factors and six risk factor interactions were evaluated to determine their contribution to accepted indicators of the onset of CTD, including exertion, discomfort, difficulty, and fatigue. Taguchi's level-analysis procedure was used to design a 16-trial hammering experiment and to analyze the results. From the hypothesized occupational risk factors, repetition was found to have the strongest effect on the values of the physiological and subjective indicators of the onset of CTD.

LEA.135 expression: its comparison with other prognostic biomarkers for patients with primary breast carcinoma.

The purpose of this retrospective study was to examine the prognostic value of expression of luminal epithelial antigen (LEA.135) for recurrence and overall survival of patients with primary invasive breast carcinoma by both univariate and multivariate analyses. The possible prognostic value of LEA.135 was also compared with some widely utilized prognostic biomarkers such as c-erbB 2, topoisomerase II.alpha (TPII.alpha), MIB 1, estrogen receptor (ER) and progesterone receptor (PR), as well as age of the patients and clinicopathologic parameters. The study was carried out by immunohistochemical methods on formalin-fixed/paraffin-embedded tissue sections in a series of 225 patients with median follow-up of 8.5 years. Prognostic significance of the biomarkers was determined by two-sided p value. In this series of patients, among the age and clinicopathologic parameters, only age, was significantly associated with a decreased overall survival (logrank p = 0.027). Among the prognostic biomarkers, TPII a expression at high (> 50% positive cells) or moderate (6-50% positive cells) level was associated with an increased rate of recurrence (logrank p < 0.001). However, the association of TPII.alpha expression with a decreased overall survival failed to reach a statistically significance. Expression of c-erbB 2 showed a trend of being associated with an increased probability of recurrence, but the association did not reach statistical significance. The remaining biomarkers were not associated with either the probability of recurrence or overall survival. LEA.135 expression was observed in 163 (72.4%) of the 225 patients. The patients with high (> 50% positive cells) or moderate (6-50% positive cells) level of LEA.135-positive cancer cells showed a significantly decreased probability of recurrence (logrank p < 0.001) and an increased overall survival (logrank p < 0.001) compared with those with LEA.135-negative cancer cells. The association remained significant by multivariate analysis for recurrence (likelihood ratio test p < 0.001) and overall survival (likelihood ratio test p < 0.001) when assessed with other prognostic parameters. Furthermore, the combination of LEA.135 with other prognostic biomarkers stratified four subgroups of patients with distinct clinical outcome. The subgroup of patients who were LEA.135+/TPII.alpha- showed the lowest probability of recurrence and the longest overall survival compared with those who were LEA.135-/TPII.alpha+ (logrank p < 0.001). Interestingly, the patients whose cancer cells were LEA.135+/TPII.alpha+, LEA.135+ MIB.1+ or LEA.135+/c-erbB 2+ experienced a decreased probability of recurrence and an increased overall survival compared with those with LEA.135-/TPII.alpha+, LEA.135- MIB.1+ or LEA.135-/c-erbB 2+ (logrank p < 0.001). The results demonstrated that LEA.135 is an independent and favorable prognostic biomarker for patients with primary invasive breast carcinoma, that the loss of LEA.135 expression is associated with aggressive phenotype of cancer cells during the breast cancer progression, and that its continued expression seems to override the adverse effects of expression of an oncogene or cell proliferation-associated molecules.

Effect of electrical stimulation and polyphosphate marination on drip from early-harvested, individually quick-frozen chicken breast fillets.

Individual and combined effects of electrical stimulation and polyphosphate marination on drip and other quality attributes of early-harvested, individually quick-frozen chicken breast fillets were evaluated. Broiler chickens were slaughtered, half conventionally processed and half with electrical stimulation. Fillets were harvested 1 h postmortem and marinated in either NaCl solution or NaCl plus polyphosphate solution. Marinade absorption, pH, drip, cooking loss, and shear values were observed. Electrical stimulation had no direct effect on pH, cooking loss, or shear values, whereas polyphosphate increased pH and decreased cooking loss. Polyphosphate treatment caused fillets from unstimulated carcasses to absorb more marinade and yielded more drip that those from stimulated carcasses. Fillets from stimulated carcasses marinated in NaCl solution without polyphosphate yielded less drip than those from unstimulated carcasses. Polyphosphate reduced drip of fillets from unstimulated carcasses but not of those from stimulated carcasses. Results support previous reports indicating interactions between polyphosphates and processing parameters that can affect ultimate quality of poultry meat products.

Immunohistochemical identification of androgen receptors in human lacrimal glands.

PURPOSE: Androgens are thought to play a role in the regulation of the human lacrimal gland. Androgen receptor mRNA has been isolated from human lacrimal tissue; however, it is not known which cell(s) in human lacrimal tissue may contain androgen receptors. This study is an immunohistochemical investigation of the location and distribution of androgen receptors in human lacrimal tissue. METHODS: Formalin-fixed, paraffin-embedded human lacrimal gland tissues were subjected to established antigen retrieval techniques. This was followed by routine immunohistochemical staining, employing one of two anti-human androgen receptor monoclonal antibodies, each specific for a different antigenic epitope within the receptor molecule. RESULTS: The two anti-human androgen receptor monoclonal antibodies demonstrated similar staining patterns in adjacent tissue sections from the same human lacrimal gland specimens. Specific staining for androgen receptors was observed in the nucleus and cytoplasm of lacrimal acinar cells, as well as in lacrimal duct cells. Both the intensity of staining and the number of cells demonstrating staining varied among specimens. We also observed staining for androgen receptors in interstitial and inflammatory cells distributed between lacrimal acinar units in some specimens. CONCLUSIONS: Androgen receptors are located in human lacrimal gland acinar cell nuclei as observed in other animals. However, the detection of androgen receptors in lacrimal interacinar interstitial and inflammatory cells suggests that androgens may play a role in modulating the activities of cells other than lacrimal cells within the human lacrimal gland.

Effect of polyphosphate treatment and electrical stimulation on postchill changes in quality of broiler breast meat.

The objective of this study was to assess effects of treating electrically stimulated broiler forequarters with polyphosphates after various aging periods on quality. Ninety-six mixed sex broilers were electrically stunned and slaughtered. Half the carcasses were electrically stimulated during bleeding and half were not. Forequarters were harvested immediately after chilling and after 2, 4, and 6 h postchill. Left forequarters were marinated in salt solution and right forequarters in salt solution plus sodium tripolyphosphate. After marination, the quarters were cooked. Yield and meat pH were evaluated immediately after marinating; and color, yield, and cooking loss were evaluated after cooking. Electrical stimulation resulted in a decline in muscle pH for the 0 postchill group. The pH of muscles from unstimulated and stimulated carcasses from the remainder of the postchill times were equivalent. Phosphate treatment increased pH at all postchill times. Electrical stimulation of the marinated quarters increased cooking loss and decreased yield regardless of marinade composition. Both cooking loss and yield were superior for forequarters harvested at 0 or 2 h postchill compared to those harvested at 4 or 6 h postchill. The phosphate improved moisture binding regardless of electrical treatment or time of harvest. Color values of cooked muscles were unaffected by marination time, but the phosphate-treated muscles had higher b* (yellowness) values than controls. Shear values of unstimulated carcasses that received phosphate treatment were 35% greater than those that received no phosphate treatment. When the carcasses were electrically stimulated, the toughening effect of the phosphate was eliminated.

Calcium-induced modification of protein conformation demonstrated by immunohistochemistry: What is the signal?

A recent study by Morgan et al. on the mechanism of the heating antigen retrieval (AR) has raised an interesting issue concerning calcium-induced modification of protein conformation demonstrated by immunohistochemistry (IHC). The current study is based on calcium-induced modification of thrombospondin (TSP) and Ki-67, as demonstrated by IHC using seven monoclonal antibodies (MAbs) to TSP and an MAb MIB1. Experiments were carried out on frozen tissue sections of bladder carcinoma and lymph node. Frozen sections were incubated with solutions of 50 mM CaCl2 and/or 10 mM EDTA at 4C overnight before formalin or acetone fixation for TSP and Ki-67, respectively. Sections were then fixed in 10% neutral buffered formalin or acetone before immunostaining. Seven MAbs to TSP, named Ab1 to 7 representing clone numbers of A4.1, D4.6, C6.7, A6.1, B5.2, A2.5, and HB8432, respectively, and MIB1 were utilized as primary antibodies. ABC was used as the detection system and AEC as the chromogen for immunohistochemical staining. An extracellular immunostaining pattern represented a positive result for TSP, and nuclear staining for MIB1. Frozen sections preincubated in 50 mM CaCl2 overnight at 4C showed significant loss of staining and/or altered staining pattern for six of the seven antibodies to TSP and MIB1 compared to positive controls not exposed to CaCl2. Lack of immunostaining of TSP and MIB1 attributable to exposure to CaCl2 could be partially recovered by incubating the frozen sections in EDTA. Calcium-induced modification of protein structure was demonstrated more than 10 years ago on the basis of immunochemical techniques. In this study, similar calcium-induced modification of protein was detectable by IHC in frozen tissue sections, suggesting that calcium-induced modification of protein structure may occur independently of fixation-induced modification. The fact that calcium binding may affect IHC staining is not surprising in view of the fact that antibody/antigen interactions are protein structure-dependent. However, in this experiment the change occurred before and independent of formalin fixation and does not necessarily imply a role for calcium in AR. There may be a valuable role for the use of chemical modification in visualization of protein structure changes in tissue sections by IHC. (J Histochem Cytochem 47:463-469, 1999)

Influence of preslaughter stunning on turkey breast muscle quality.

Pectoralis muscle quality was evaluated from 18-wk-old tom turkeys after electrical stun, carbon dioxide stun, or no stun methods were applied. Color was measured on raw muscle and cooked meat using a colorimeter. Muscle pH was measured 15 min post-mortem (initial), 24 h post-mortem (final), and after cooking. The right Pectoralis muscle of each carcass was excised for m-calpain analysis within 4 min post-mortem. After 24 h of storage at 4 C, the left Pectoralis muscle was excised to determine cook loss and shear force measurements. No significant difference was found in initial muscle pH (15 min) from turkeys receiving electrical or carbon dioxide stunning, 6.36+/-0.15 and 6.20+/-0.14, respectively. However, initial muscle pH for birds that were not stunned (5.99+/-0.08) was lower (P < 0.05) than the muscle pH of birds stunned using either of the two stunning methods. Stunning method had no effect on the final muscle pH, raw muscle color, cooked meat pH, cooked meat color, cook loss, or shear force. Cook loss was found to positively correlate with initial muscle lightness (r = 0.53), and cooked meat lightness (r = 0.48), but to negatively correlate with cooked meat yellowness (r = -0.48) and shear strength (r = -0.43). m-Calpain activity declined with the stunning methods in the following order: electrical > carbon dioxide > no stun. In addition, m-calpain activity was found to correlate with initial muscle pH (r = 0.95) and with cooked meat shear force (r = -0.43). The results of this study show that electrical stunning, carbon dioxide stunning, and no stunning methods provide comparable cooked turkey breast meat quality with no consistent differences after aging on the carcass for 24 h.

Effects of age and tissue type on the calpain proteolytic system in turkey skeletal muscle.

A study was conducted to examine the effects of bird age and muscle tissue type on calpain and calpastatin activities in turkey skeletal muscle. Enzymatic activities of calpains and calpastatin were found to vary with bird age and muscle type. Breast muscle from younger birds (age 5 wk) had higher mu-calpain, m-calpain, and calpastatin activities (P < 0.05) than breast muscle from older birds (9, 13, and 17 wk of age). Thigh muscle calpain activities were not affected by bird age, but thigh calpastatin activity was found to increase with age, with muscle from 17-wk-old birds having 35% higher activity than muscle from 13-wk-old birds. When extracted from 9-wk-old turkeys, breast muscle mu-calpain activity was 30% higher than thigh muscle mu-calpain. By 13 wk of age, breast muscle mu-calpain activity was 20% less than thigh mu-calpain. Thigh muscle m-calpain and calpastatin activities were found to be significantly higher (P < 0.05) than that found in breast muscle, with some values more than double in older birds (17 wk of age).

Effect of postchill aging and sodium tripolyphosphate on moisture binding properties, color, and Warner-Bratzler shear values of chicken breast meat.

The objective of this study was to assess the effects of treating chicken breast forequarters with sodium tripolyphosphate (STPP) after various postchill storage times on meat quality. Sixty-four commercially reared broilers (two replicates of 32 birds each) were slaughtered and chilled, and then the forequarters (split breasts with spine and ribs) were harvested and aged for 0, 120, 180, or 240 min postchill. After each aging period, one forequarter from each of 16 birds was marinated with a NaCl solution and the opposite forequarter was marinated with the same NaCl solution containing STPP. The quarters were then cooked and the following traits measured: marinade absorption, cooking loss, objective color values, and Warner-Bratzler shear values. As aging time prior to marination increased, cooking loss and redness of the cooked meat decreased, but marinade absorption and the color values were unaffected. The STPP treatment increased marinade absorption, decreased cooking losses, and decreased cooked meat redness (P < 0.05). Shear values decreased with aging time for both the control and STPP-treated breast meat. When the STPP treatment was applied immediately after carcass chilling, the STPP-treated meat exhibited shear values more than 60% greater than those of the controls (9.14 and 5.69 kg, respectively). Results indicate that time postchill at which further processed products are treated with STPP can have a significant effect on quality, especially cooked product texture.

Effect of electrical stimulation in combination with calcium chloride or sodium chloride treatments at constant ionic strength on moisture binding and textural quality of early-harvested breast fillets.

The objective of this study was to assess the effects of a CaCl2 or NaCl treatment combined with electrical stimulation (ES) on textural and moisture binding of early-harvested chicken breast fillets. During exsanguination, half the birds were subjected to ES, and then all carcasses were aged for 30, 60, 90, or 120 min before excising both Pectoralis major muscles. Half the muscles were chilled with a NaCl solution and half with a CaCl2 solution. Effects of ES and chill medium composition on meat pH, moisture absorption, cooking loss, and shear value of the fillets were assessed. The ES reduced meat pH for the NaCl-treated muscles, but had no effect on those treated with CaCl2 of on moisture absorbed during chilling. Cooking loss was greater for the CaCl2-treated than NaCl-treated muscles and for muscles from stimulated birds that were excised more than 30 min post-mortem. Shear values were unaffected by chilling medium composition. However, even though shear values for both ES and unstimulated birds declined as aging time increased, the rate of decline was greater, and ultimate shear value lower, for muscles from ES birds. Results indicate that, although ES might offer some advantage in improving the tenderness of early-harvested breast fillets, combining ES with CaCl2 treatment offers no real advantage. Moreover, reductions in moisture binding properties by these technologies might limit applicability in some commercial environments.

Effects of stunning duration on quality characteristics of early deboned chicken fillets.

The objective of this study was to determine effects of electrical stunning duration on quality of broiler chicken fillets. Seventy-two broiler chickens were electrically stunned for 0, 2, 4, 6, 8, or 10 s, slaughtered, and chilled. After 1 h post-mortem, both pectoral muscles were excised and cooked. Cooking loss, pH, cooked color values, and shear values were measured. As stunning time increased, pH and shear values significantly increased. Except for a small but significant increase in yellowness, color values were unaffected by stunning duration. Cooking loss was unaffected by stunning duration. These data indicate that stunning duration can affect post-mortem muscle metabolism as measured by pH change. Therefore, control of the process of slaughtering broilers requires careful regulation of stunning duration.

Informed consent and parental choice of anesthesia and sedation for the repair of small lacerations in children.

This study investigated the issue of informed consent by surveying parent preferences for local anesthesia and sedation in the repair of small lacerations in their children in the emergency department (ED). Of the 45 ED patients with actual lacerations receiving a suture repair, 11 requested tetracaine-adrenaline-cocaine (TAC), 25 requested infiltrated lidocaine, and 9 were not given a choice (lidocaine administered because of wound proximity to a mucous membrane site). All 45 patients preferred nonsedation over sedation. In 44 of 45 patient cases, parents preferred to be included in the medical decision-making for their children. Of the 94 non-ED cases (interviewed in private offices) with a hypothetical chin laceration, 16 preferred TAC and 78 preferred infiltrated lidocaine. Sixty-seven of 94 preferred nonsedation over sedation. In 89 of 94 patient cases, parents preferred to be included in the medical decision-making for their children. Favorable points of continuous informed consent were presented, with risks, benefits, and alternatives disclosed. From the data presented, the following conclusions were drawn: (1) parents preferred infiltrated local anesthesia more commonly than topical local anesthesia; (2) parents preferred nonsedation over sedation under the clinical circumstances described; (3) parents overwhelmingly preferred to be included in the medical decisions affecting their children.

Stool appearance in intussusception: assessing the value of the term "currant jelly".

This study surveyed the stool appearance descriptions of 107 inpatient children with intussusception. Fifty-six patients presented with grossly bloody stools (passed spontaneously), 10 of which were determined on chart review to resemble currant jelly. Of the 51 patients without grossly bloody spontaneously passed stools, 35 patients had rectal examination results charted. Eight of these children had grossly bloody stools noted on rectal examination, 4 of which were determined on chart review to resemble currant jelly. While most of the grossly bloody stools were not consistent with pure currant jelly, the most common terms used in describing the grossly bloody stools were "bloody," "mucus," "red," and "diarrhea." Since stools truly resembling currant jelly account for a minority of the grossly bloody stools in intussusception, the term "currant jelly stools" should be assessed in the teaching of intussusception. Generic terms such as blood, mucus, burgundy, red, etc, are more objective and sensitive at identifying cases of intussusception. Junior physicians who are taught the classic presentation of intussusception with currant jelly stool should also be taught that intussusception should be considered in the differential diagnosis of children passing any type of bloody stool. As a result, physicians with limited experience will be more likely to appropriately consider the diagnosis of intussusception, permitting a more timely diagnosis and a better outcome.

Identification of the rat maternally transmitted minor histocompatibility antigen.

The rat maternally transmitted Ag has been previously described as a minor histocompatibility Ag composed of a mitochondrially transmitted factor (MTF) and the RT1.Aa MHC class I molecule. We compared the DNA sequences of the 13 mitochondrial open reading frames from different rat strains and identified four coding polymorphisms that correlated with this MTF. We used synthetic 17-mer peptides spanning the polymorphisms to sensitize appropriate target cells in lymphocytotoxicity assays and found that the MTF is derived from an internal region of ATPase 6. A tridecameric derivative of the ATPase 6 17 mer (termed 13N3E) could sensitize RT1.Aa-expressing target cells at picomolar concentrations and, when present on such cells, could compete fully with the natural ligand in cold-target competition assays. Comparing the 13N3E peptide with the known peptide-binding requirements of RT1.Aa suggested two possible binding conformations, placing either an internal or a C-terminal arginine in the F pocket of the peptide-binding groove. Arguments favoring a "bulging" conformation, with N- and C-terminal residues bound into their conserved pockets, are discussed.

Effect of calcium marination on biochemical and textural properties of peri-rigor chicken breast meat.

The objective of this study was to evaluate effects of marinades containing varying calcium concentrations on the biochemical and texture characteristics of peri-rigor chicken breast fillets. Breast muscles from 200 broiler chickens were excised immediately post-mortem and marinated in 0, 50, 100, 150, or 200 mM CaCl2. The treatments had no effect on meat pH either before or after cooking, but as calcium concentration increased, the normal post-mortem conversion of adenosine triphosphate (ATP) to inosine monophosphate (IMP) increased, according to the IMP:ATP ratios (R-values). Calcium treatment at all levels tested improved meat tenderness, but both marinade absorption and cooking losses increased as the calcium concentration in the marinades increased. It was concluded that although treating peri-rigor breast muscle with calcium might be useful in reducing or eliminating the conditioning period to assure tender chicken, methods must be developed for restoring the moisture binding properties that are damaged by the calcium.