Raw Breast Research Articles

Effects of Different CMV-Heat-Inactivation-Methods on Growth Factors in Human Breast Milk

Preterm infants can inoculate virulent cytomegalovirus (CMV) through their mothers' raw breast milk. Complete virus inactivation is achieved only by heat treatment, but the effect on growth factors has never been assessed systematically. Insulin-like-growth-factor-1-, IGF-2-, insulin-like-growth-factor-binding-protein-2-, and IGFBP-3-concentrations were measured, before and after heating, in 51 breast-milk-samples from 28 mothers, and epidermal-growth-factor-concentrations in a subgroup of 35 samples from 22 mothers. Two heating methods were applied: Short-term (5 s) pasteurisation at 62, 65, and 72 degrees C, and long-term Holder-Pasteurisation (30 min) at 63 degrees C. IGF-1, IGF-2, IGFBP-2, and IGFBP-3 were measured by RIA, and EGF by ELISA. Heating for 30 min decreased significantly IGF-1 by 39.4%, IGF-2 by 9.9%, IGFBP-2 by 19.1%, and IGFBP-3 by 7.0%. In contrast, IGF-1, IGF-2, IGFBP-2, and IGFBP-3 were not altered significantly when using a short heating duration of 5 s, irrespective of the level of temperature, except for IGF-2 at 62 degrees C for 5 s (p = 0.041) and IGFBP-2 at 72 degrees C for 5 s (p = 0.025). Neither long- nor short-time heating methods changed the concentration of EGF. Only short heating methods (5 s, 62-72 degrees C) can preserve, almost completely, the concentrations of IGFs in human milk, whereas Holder-Pasteurization does not.

Meta-analysis of gene expression profiles related to relapse-free survival in 1,079 breast cancer patients

The transcriptome of breast cancers have been extensively screened with microarrays and large sets of genes associated with clinical features have been established. The aim of this study was to validate original gene sets on a large cohort of raw breast cancer microarray data with known clinical follow-up. We recovered 20 publications and matched them to Affymetrix HGU133A annotations. Raw Affymetrix HGU133A microarray data were extracted from GEO and MAS5 normalized. For classifying patients using the selected gene sets, we applied prediction analysis of microarrays and constructed Kaplan-Meier plots. A new classification including all patients was generated using supervised principal components analysis. Seven studies including 1,470 patients were downloaded from GEO. Notably, we uncovered 641 microarrays representing 251 individual tumor specimens among them, which were repeatedly described under independent GEO identifiers. We excluded all redundant data and used the remaining 1,079 samples. Eight of the 20 gene sets were able to predict response at a significance of P < 0.05. The discrimination of good and poor prognosis groups exclusively relying on gene expression data resulted in high significance (P = 1.8E-12). A model including genes fitted by both gene expression and clinical covariates (lymph node status and grade) contains 44 genes and can predict response at P = 9.5E-7. The outcome provides a ranking of the gene lists regarding applicability on an independent dataset. We established a consensus predictor combining the available clinical and gene expression data. The database comprising expression profiles of 1,079 breast cancers can be used to classify individual patients.

Antioxidative Potential of Raw Breast Meat from Broiler Chicks Fed a Dietary Medicinal Herb Extract Mix

This study was performed to evaluate the antioxidative potential and quality of the breast meat of broiler chickens fed a dietary medicinal herb extract mix (MHEM, consisting of mulberry leaf, Japanese honeysuckle, and goldthread at a ratio of 48.5:48.5:3.0). A total of 480 one-day-old male Cobb broiler chicks were randomly allotted to 12 pens, with 40 birds per pen (replicate), and reared for 35 d. Dietary treatments consisted of a corn-soybean meal basal diet (control); a basal diet with 0.3% MHEM (T1); and a basal diet with 1% (T2) MHEM. At the end of the feeding trial, breast meat samples were excised and stored in a refrigerator at 4°C to be analyzed at d 0, 3, and 7. The MHEM did not affect proximate composition of the breast meat. Total phenols content of the breast meats in the T1 and T2 diets was approximately 2 times greater than that of the control diet (P < 0.05). 1,1-Diphenyl-2-picrylhy-drazyl radical-scavenging activity and 2,2-azinobis-(3 ethylbenzothiazoline-6-sulfonic acid) cation-reduction activity were greater in the T2 diet at d 0 and in the T1 diet at d 3 compared with the control diet (P < 0.05). 2-Thiobarbituric acid-reactive substance values in the T1 and T2 diets were lower than in the control diet at d 3 and 7 and did not increase during storage, whereas the value in the control diet increased significantly. The pH of the T1 diet was significantly greater than that of the control diet at d 0 and 3. In a sensory test, panelists preferred the T1 breast meat throughout the 7-d storage period. This research indicates that dietary MHEM could increase the antioxidative potential and overall preference of breast meat during cold storage.

A Novel Laser Air Puff and Shape Profile Method for Predicting Tenderness of Broiler Breast Meat

The potential application of a new laser air puff system to assess poultry meat tenderness was investigated. Ninety broilers were deboned at either 1.25, 4, or 24 h postmortem. The raw breast fillets were scanned on a conveyor belt longitudinally by a laser distance sensor to obtain overall shape profiles and scanned again with a pressurized source of air (206.8 kPa). The 2 resulting profiles were superimposed to quantify the amount of deformation caused by the application of pressurized air. Five parameters including a height and length of each fillet were calculated and used to establish a model to predict tenderness. Tenderness of cooked fillets was determined instrumentally with the Meullenet-Owens razor shear, Blunt-Meullenet-Owens razor shear, and with sensory analysis. Hardness, Meullenet-Owens razor shear energy, and Blunt-Meullenet-Owens razor shear energy were modeled with the parameters extracted from the air puff system. Predicted values obtained from the models and observed values of individual fillets were subjected to logistic regression to classify fillets into tenderness levels. Tender fillets in the air puff predicted tender group represented 82, 81, and 88% based on hardness, Meullenet-Owens razor shear energy, and Blunt-Meullenet-Owens razor shear energy, respectively. The use of this tool resulted in more than a 20% improvement in the number of tender fillets after classification. The results suggested that this new system could potentially be implemented as an online tool for sorting poultry breast fillets by tenderness levels.

Nutritional and sensory qualities of raw meat and cooked brine‐injected turkey breast as affected by dietary enrichment with docosahexaenoic acid (DHA) and vitamin E

AbstractBACKGROUND: This aim of this study was to evaluate the effects of feeding turkeys with docosahexaenoic acid (DHA) and vitamin E on the fatty acid profile, proteolytic enzyme activities and oxidative status of raw breast meat and cooked brine‐injected breast meat. Four treatments were investigated: T1, basal diet (control); T2, basal diet plus 15 g kg−1 DHA; T3, basal diet plus 100 mg kg−1 vitamin E; T4, basal diet plus 5.4 g kg−1 DHA plus 100 mg kg−1 vitamin E. A sensory analysis of cooked brine‐injected breasts was conducted in order to assess the sensory characteristics of these products and relate them to the expected nutritional benefits.RESULTS: Among the four treatments tested, no differences were observed in enzyme activities. No activities of cathepsin B, cathepsins B + L and catalase were detected in cooked brine‐injected breast meat. Glutathione peroxidase activity was reduced and superoxide dismutase activity was similar to that measured in raw meat. The diets supplemented with DHA increased eicosapentaenoic acid and DHA levels in comparison with the control in both raw and cooked products. The increase in n‐3 polyunsaturated fatty acids (PUFAs) led to a reduction in n‐6/n‐3 PUFA ratio to values between 1.01 ± 0.11 and 2.94 ± 0.47. In cooked brine‐injected breast, treatment with 15 g kg−1 DHA (T2) induced a considerable fishy flavour, while treatment with 5.4 g kg−1 DHA plus 100 mg kg−1 vitamin E (T4) induced a slight fishy flavour. However, fishy odour in T4 did not differ significantly from that of the control.CONCLUSION: By feeding turkeys with 5.4 g kg−1 pure DHA plus 100 mg kg−1 vitamin E, the nutritional quality is improved through the introduction of a natural antioxidant and the reduction in n‐6/n‐3 PUFA ratio. With this treatment the sensory characteristics were similar to those of control samples, except for the fishy flavour, which could probably be masked by modifying the technological process. Copyright © 2008 Society of Chemical Industry

Breastfeeding and HCMV-Infection in the Preterm Infant

According to numerous national, international and WHO guidelines, breast milk feeding is recommended for all newborns, especially preterm infants irrespective of birthweight or gestational age. However, preterm and also term infants are at risk of acquiring Cytomegalovirus (CMV) infection in their first weeks of life through their mother's raw breast milk, because nearly all CMV-IgG-positive mothers (carriers) will reactivate the virus during lactation and excrete it into their breast milk [23] [24] [25] [26] [27] [40].

Effect of carbohydrate supplementation provided through drinking water during feed withdrawal on meat and liver colours in broilers

BACKGROUND:The effect of saccarose supplementation provided through drinking water during feed withdrawal on meat and liver colour was investigated in a total of 50 broilers (five floor pens with 10 broilers) at 43 days. Treatments consisted of: (1) full-fed control broilers fed the standard broiler diet and water for the full 10 h (control); (2) fasted broilers receiving only water (FW); (3) 1 g (0.01SW); (4) 2 g (0.02SW); and (5) 3 g (0.03SW) saccarose L−1 supplemented water for the 10 h. The CIE colour values representing lightness (L*), redness (a*), and yellowness (b*) were measured on raw livers, breast and thigh meats. RESULTS:Full-fed broilers had lower dressing percentage, higher abdominal fat and liver yield and lighter thigh meat coloration than the FW birds (P < 0.05). The 0.02SW and 0.03SW resulted in live shrinks that were lower (P < 0.05) than those found in FW broilers. The 0.02SW and 0.03SW resulted in liver colours that were lighter than those found in FW and 0.01SW birds but darker than from control birds (P < 0.05). CONCLUSION:It was concluded that saccarose supplementation during feed withdrawal appears to have a measurable impact on live shrink, and lightness of liver and thigh meat colour in broilers. Copyright © 2007 Society of Chemical Industry

Effect of Chilling Method and Deboning Time on Broiler Breast Fillet Quality

A study was conducted to determine the effects of chilling method and postmortem aging time on broiler breast fillet quality. One hundred fifty eviscerated broiler carcasses were removed from a commercial processing line before chilling and transported to the laboratory. Half of the carcasses were chilled by dry air, whereas the other half were chilled by water immersion. Immersion-chilled (IC) carcasses were divided into 3 groups (0, 1.67, and 24 h) based on postchill fillet aging time on the carcass. Air-chilled (AC) carcasses were divided into 2 groups based on fillet aging time (0 and 24 h postchill). Because AC requires more time to reach the same temperature, fillets removed immediately after chilling (0 h) were the same postmortem age as the 1.67 h IC fillets. Average pH values of IC and AC fillets were similar when fillets were aged for the same length of time postmortem. Method of chilling had no effect on raw breast fillet color; however, postmortem aging time had a slight but significant effect on fillet lightness. Shear values of IC fillets removed 0 and 1.67 h after chilling were similar and corresponded to sensory panel categories of slightly tough to tough (>8 kg/g). Shear values of AC fillets deboned at 0 h (8.4 kg/g) were slightly lower but not significantly different than the shear values for IC fillets (10.3 kg/g) aged for the same length of time (1.67 h). After 24 h of aging, shear values for IC and AC fillets were <8 kg/g and corresponded to sensory panel categories of tender to very tender. Cook yield (%) of AC fillets was significantly higher than cook yield (%) of IC fillets for all deboning times. Results show that air chilling has an accelerating effect on rigor mortis onset, but postchill aging time is required to maximize the proportion of tender meat.

Germicidal Ultraviolet Light to Lower Numbers of Listeria monocytogenes on Broiler Breast Fillets

Raw broiler breast fillets were subjected to germicidal ultraviolet (UV) light (dose of 1,000 μW/cm2 for 5 min at a wavelength of 254 nm) to evaluate its potential to reduce Listeria monocytogenes numbers on raw product before shipment to a poultry further-processing plant. Boneless, skinless breast fillets were inoculated with 4 different strains of L. monocytogenes 5 min before treatment. After the UV treatment, breast fillets were stored at 4°C for 24 h. Enumeration of remaining L. monocytogenes was performed using the spread plate method on modified Oxford agar. An approximate 2-log reduction in viable L. monocytogenes was observed with all 4 strains on UV-treated breast fillets as compared with the nontreated breast fillets. The UV treatment caused only slight changes in meat color (lightness, redness, and yellowness) on day of treatment or after 7 d of storage. This study suggests that UV treatment of raw breast fillets at a slaughter plant can significantly reduce L. monocytogenes without negatively affecting meat color. This process could be used to reduce the negative effect of raw poultry as a transmission vector of L. monocytogenes into a poultry further-processing plant.

The Influence of the Season and Market Class of Broiler Chickens on Breast Meat Quality Traits

The influence of the season and market class of broiler chickens on breast meat quality traits was determined on a total of 18 flocks reared and processed under commercial conditions. According to the Italian poultry production system the following classes of birds were considered: light size (1.2 kg of carcass weight; n = 90) and medium size (1.8 kg of carcass weight; n = 90), represented by females slaughtered at 40 and 52 d old, respectively, whereas heavy size were 57-d-old male broilers (2.4 kg of carcass weight; n = 90). After slaughter, 15 carcasses per flock (n = 270) were randomly collected during winter (n = 135) and summer (n = 135) seasons and used at 24 h postmortem to determine breast (pectoralis major) meat color (lightness, redness, and yellowness), pH, drip and cook loss, as well as Allo-Kramer (AK) shear values. Furthermore, pectoralis minor muscles were used to determine lipid, protein, moisture, and ash content. Finally, because the flocks included white- and yellow-skinned broilers, the color of the carcass skin was measured to assess the relationship between skin and raw breast meat color. With regard to the season, breast meat from birds slaughtered during summer exhibited a paler and less red color, lower pH, higher drip and cook losses, lower AK-shear, and a higher content of moisture and a lower content of protein and ash. In respect to medium and heavy birds, light broilers produced breast meat with higher values of redness, lower pH and cook loss, higher AK-shear values, and a higher content of moisture and ash. Finally, a positive correlation (r = +0.92; P ≤ 0.001) between skin and breast meat yellowness was found. These results indicate that during summer, broiler breast meat undergoes a depression of its functionality and quality. Moreover, the market class of birds also determined some differences in breast meat quality attributes.

Effects of α-tocopheryl acetate and β-carotene dietary supplementation on the antioxidant enzymes, TBARS and sensory attributes of turkey meat

1. The aim of the study was to evaluate the effects of α-tocopheryl acetate (50 mg/kg) and β-carotene (15 mg/kg) dietary supplementation on the oxidative status of raw turkey breast and leg muscles assessed by thiobarbituric acid test values, the vitamin E levels and the antioxidant enzyme activities. In parallel, a quantitative descriptive sensory analysis was carried out on cooked, stored and reheated samples. 2. Vitamin E was present in sufficient quantity to reduce oxidation, since iron-induced reactive substances (TBARS) were significantly lower in antioxidant-supplemented treatments. The results suggested that the presence of β-carotene in the diet limits the accumulation of α-tocopherol in turkey muscles. 3. In the present study, there was no conclusive relationship between dietary antioxidant supplementation and endogenous antioxidant enzyme activities. 4. Sensory evaluation showed that a longer supplementation time and dose may be necessary in turkeys to prevent meat from rancidity and warmed-over flavour (WOF). Leg pastiness and stringiness were modified by dietary antioxidant supplementation, indicating the possible synergism between antioxidants and cysteine proteinases in the perception of meat quality. 5. Given the modern trends that lead consumers to increase their consumption of poultry meat, it would be interesting to evaluate the commercial potential and cost effectiveness of routine dietary antioxidant supplementation.

The inhibitory potential of feed supplementation with rosemary and/or α-tocopheryl acetate on microbial growth and lipid oxidation of turkey breast during refrigerated storage

Twenty-four 12-week-old female turkeys divided into four equal groups were fed a basal diet (CONT) or basal diet supplemented with 300 mg α-tocopheryl acetate/kg (TOC), or 5 g rosemary/kg (ROS5), or 10 g rosemary/kg (ROS10), for 4 weeks. Following slaughter, fillets from breast were stored at 4 °C in the dark for 12 days, and lipid oxidation was assessed on the basis of the malondialdehyde formed, whereas microbial growth on the basis of total viable counts (TVC), lactic acid bacteria (LAB), Enterobacteriaceae (ENB) and psychrotrophic (PSY) bacteria. Results showed that incorporation of dried rosemary in turkey diets delayed lipid oxidation in raw breast meat during refrigerated storage. Dietary rosemary at the level of 1 g/100 g was significantly ( P < 0.05 ) more effective in delaying lipid oxidation compared to 0.5 g/100 g but inferior to the dietary supplementation of 300 mg α-tocopheryl acetate/kg. TVC, LAB, ENB and PSY bacterial counts were all significantly increased ( P < 0.05 ) in breast samples of all groups throughout the refrigerated storage. The TOC and CONT groups presented TVC, LAB, ENB and PSY counts that did not differ ( P > 0.05 ) among each other, during the whole storage period. However, the rosemary-supplemented groups presented bacterial counts that were significantly lower ( P < 0.05 ) than the CONT and TOC groups, at day 2 of storage period and thereafter. During this period, the ROS5 group presented TVC, LAB, ENB and PSY counts that were significantly higher ( P < 0.05 ) than the ROS10 group.

Induced Red Discoloration of Broiler Breast Meat: i. Effect of Blood, Bone Marrow and Marination

The bloody, undercooked appearance of fully cooked chicken causes complaints and product rejection by consumers. This defect has been described as a persistent problem with bone-in chicken. Many studies have addressed pink meat or bone darkening, but none have studied the red discoloration problem. Therefore, constituents found in the broiler carcass (breast meat, blood and bone marrow) were combined in an external system to determine the effect of blood and marrow on inducing red discoloration. Three replicate trials were conducted where broiler breast meat was combined with: nothing (control); blood; bone marrow; or, both. An identical set of samples was prepared with added marinade (water, salt and phosphate). Duplicates of each treatment were prepared, placed in glass tubes and cooked. CIE L* (lightness) and a* (redness) values were determined on raw preparations and on cooked meat. Blood, marrow and the combination of both produced significantly (P < 0.05) darker and redder raw and cooked breast meat. Blood contributed more to the darkness of raw meat, while marrow contributed more to th e darkness of cooked meat and to the redness of both raw and cooked meat. The blood-marrow combination produced darker raw and cooked meat than either ingredient alone, but the combination did not produce redder meat than marrow alone. Marination resulted in darkened raw breast meat, but had little effect on meat darkness or redness when blood, marrow, or both were added. Marrow was determined to be the most important component for inducing red discoloration of breast meat.

Vitamin E levels, thiobarbituric acid test and sensory evaluation of breast muscles from broilers fed α‐tocopheryl acetate‐ and β‐carotene‐supplemented diets

AbstractThe objective of this study was to investigate the effect of dietary α‐tocopheryl acetate and β‐carotene supplementation on lipid oxidation of breast meat from broilers fed lard as the fat source. Supplementation of broilers with 100 mg kg−1 α‐tocopheryl acetate increased the vitamin E levels in raw breast samples significantly (p &lt; 0.05), whereas the presence of 1.5 mg kg−1 dietary β‐carotene tended to decrease vitamin E deposition. The presence of vitamin E delayed lipid oxidation significantly, but thiobarbituric acid values of samples from broilers fed the β‐carotene‐supplemented diet did not differ from those of control samples. Vitamin E reduced sensory meat rancidity, whilst vitamin E, β‐carotene and their combination modified meat texture. The results show the effectiveness of dietary α‐tocopheryl acetate supplementation in protecting broiler meat against lipid oxidation. Copyright © 2004 Society of Chemical Industry

Effects of Raw Broiler Breast Meat Color Variation on Marination and Cooked Meat Quality

Three replicate trials were conducted to determine the effect of raw broiler breast meat color on marinated and cooked meat quality. In each trial, 90 fillets were collected from a commercial processing plant based on lightness (L*) values of breast meat as follows: light, L* > 53; normal, 48 < L* < 51; and, dark, L* < 46. For each fillet the color, pH, and weight were determined, and the fillets were marinated in three lots of 10 fillets from each color group (20% wt:wt of 5% salt and 2.5% sodium tripolyphosphate in a vacuum tumbler). Marination uptake was determined; the samples were held for 24 h at 2 C, and color, pH, and weight again were determined. Next, the samples were cooked, and the meat was subjected to color, pH, cooked yield, shear force, and moisture analyses. Results showed that absolute color values changed with marination and cooking, but that L* and pH differences by color group were maintained through marination and cooking. There were also significant differences in marinade absorption, cooked yield, and shear value, particularly among the extremes of light and dark meats. There was no significant difference in final cooked meat moisture. As expected, there were significant negative correlations between meat lightness and pH; however, raw muscle pH was not correlated to final product moisture or shear but was positively correlated to cooked meat yield and negatively correlated to marinade absorption. These results indicate that the pH variation associated with extreme raw breast meat color variation can affect breast meat marination and cooked meat quality.

Raw-meat packaging and storage affect the color and odor of irradiated broiler breast fillets after cooking

Raw breast fillets were divided into two groups and either vacuum or aerobically packaged. The fillets in each group were subdivided equally into two groups and then irradiated at 0 or 3 kGy using a Linear Accelerator. After 0, 3 and 7 days of storage at 4 °C, fillets were cooked in an 85 °C water bath (cook-in-bag) to an internal temperature of 74 °C. Oxidation-reduction potential (ORP) of raw fillets was measured before cooking, and color and sensory characteristics were analyzed after cooking. Irradiation decreased the ORP of meat, but the potential in aerobically packaged fillets increased during storage. After cooking, color a*-value of irradiated fillets was higher than that of the non-irradiated. Irradiation of raw meat also changed color L* and b* values after cooking. Aerobic storage reduced the redness of cooked meat induced by irradiation. Irradiated raw broiler fillets stored for 0 day and 3 day under aerobic conditions before cooking produced a oxidized chicken-like odor. The odor, however, disappeared after 7 days of storage under aerobic conditions before cooking. For raw broiler samples stored under vacuum conditions, significant differences in color and odor between irradiated and non-irradiated fillets remained throughout the 7-day storage period after cooking. Irradiation had only a minor influence on lipid oxidation of raw breast fillets as indicated by low TBARS values. This study indicates that the effect of irradiation on color and odor of broiler breast fillets after cooking can be reduced significantly through shelf-display of raw fillets under aerobic conditions. Storage under vacuum conditions before cooking is not effective in reducing irradiation-induced changes in the color and odor of breast fillet after cooking.

SENSORY CHARACTERISTICS AND NEAR‐INFRARED SPECTROSCOPY OF BROILER BREAST MEAT FROM VARIOUS CHILL‐STORAGE REGIMES

ABSTRACTThe terms “fresh” and “frozen” often refer to the physical state of the product (i.e., soft, hard) as well as quality state (i.e., good, inferior). This study addressed quality issues of breast meat subjected to chill‐store regimes that simulate possible scenarios at points between processing, distribution by retailers, and final preparation by consumers. Five temperatures (+4,0, −3, −12, and −18C) at storage regimes (2 days, 7 days, and 7 days at the five temperatures followed by an additional 7 days at −18C) were evaluated. The statistical differences in descriptive sensory texture and moisture characteristics among cooked samples could not be predominantly attributed to temperature, storage, or temperature‐storage treatments. Visible and near‐infrared reflectance spectra of stored raw skinless breasts did not discriminate between individual temperature groups. However, a two‐class model (98.5% correct classification) discriminated between unfrozen (+4, 0, and −3C) and frozen (−12 and −18C) samples, partially due to spectra of myoglobin and oxidative states.

The Effect of Broiler Breast Meat Color on pH, Moisture, Water-Holding Capacity, and Emulsification Capacity

The relationship between broiler breast meat color and pH, moisture content, water-holding capacity (WHC), and emulsification capacity (EC) was investigated. In each of three replicate trials, fillets were collected from three different commercial processing plants according to breast meat lightness (L*) values as follows: lighter than normal (light, L* > 53), normal (48 < L* < 53), and darker than normal (dark, L* < 46). Color values of lightness (L*), redness (a*), and yellowness (b*) were measured at 0 and 24 h after collection. Fillets were then ground and homogenized prior to determining color, pH, moisture, WHC, and EC of the ground meat. There was a significant difference among the three color groups (light, normal, and dark) in L*, a*, pH, WHC, and EC. The L* values of whole raw breast fillets had significant negative correlation coefficients with ground meat EC (−0.9237), pH (−0.9610), and a* (−0.6540). Emulsification capacity had significant positive correlations with pH (0.9572) and water-holding capacity (0.7080). WHC had significant correlations with a* (0.8143), moisture (−0.7647), and pH (0.7963). Lighter-than-normal meat was associated with low pH, high moisture, low EC, and low WHC. These results indicate that wide differences in raw breast meat color exist and that these differences may be used by poultry further processors as an indicator of fillets with altered functional properties.

The relationship of raw broiler breast meat color and pH to cooked meat color and pH

Three replicate trials were conducted to determine the influence of raw breast meat color and pH on subsequent cooked meat color and pH. In each trial, approximately 50 breast fillets were obtained from a commercial processing plant based on being either normal, lighter than normal, or darker than normal. Color (L* = lightness, a* = redness, and b* = yellowness) of each fillet was determined in triplicate on the underside surface of the fillet (to avoid scalding effects), and the pH was determined on a tissue sample removed from the posterior portion of each fillet. Fillets were then cooked in steam at 98 C for 20 min and cooled to room temperature, and a second sample was removed from the posterior section for cooked meat pH. Cooked meat color was measured on an exposed surface, to avoid cooking-related discoloration. The data were subjected to linear regression analysis to determine the relationship between raw and cooked values. Results indicated a significant linear relationship between raw and cooked values for each color parameter as well as pH. Model R2 values were 0.43, 0.40, 0.64, and 0.78 for L*, a*, b*, and pH, respectively. There were also significant linear relationships between raw meat L* and raw muscle pH (R2 = 0.59) as well as cooked meat L* and raw meat pH (R2 = 0.36). These results indicate that raw breast meat color and pH affect cooked breast meat color and pH but that cooking reduces the degree of color variation. Moreover, cooked meat lightness is more closely associated with raw breast meat pH than with cooked meat pH.

The effects of antemortem electrical stunning and postmortem electrical stimulation on biochemical and textural properties of broiler breast meat

Experiments were conducted to determine the combined effects of antemortem electrical stunning (STUN) and postmortem electrical stimulation (STIM) on breast muscle rigor development and meat quality attributes. Birds were either unstunned, stunned with low voltage (LV), or stunned with high current (HC) prior to conventional killing. Immediately after exsanguination, birds were either unstimulated, or were subjected to electrical stimulation with 12 1s on/1s off pulses of 440 V AC and allowed to bleed for 90 s to determine the effect of treatment on blood loss. Breast fillets (Pectoralis major) were removed from carcasses immediately after evisceration (0.25 h) or after aging in a static ice-water slush for 1 or 2 h, and analyzed for muscle pH, R-value (ratio of inosine to adenosine nucleotides), and sarcomere length. Raw breast meat color (CIELAB), cook loss, and shear values were determined on samples held at 2 C for 24 h. Results showed both STUN and STIM significantly affected blood loss, pH, R-value, sarcomere length, color, and shear, and there were significant STUN by STIM interactions. Blood loss was significantly lower for the HC STUN and all the STIM treatments. STIM at 440 V resulted in accelerated rigor development as measured by pH, R-value, and sarcomere length, similar to the unstunned or LV STUN samples, but different from the HC STUN birds. These results indicate that electrical stimulation may accelerate rigor most effectively following high current stunning, which tends to delay early rigor development.