Pink discoloration in cooked white meat

Effects of different types of xanthophyll extracted from marigold on pigmentation of yellow-feathered chickens

OBJECTIVE

This study aimed to explore the effects of different types of xanthophyll extracted from marigold on the growth performance, skin color, and carcass pigmentation.

METHODS

A total of 192 healthy 60-day-old yellow-feathered broilers weighing an average of 1,279±81 g were randomly allocated to 4 groups, each with 6 replicates and 8 broilers. The 4 treatments were as follows: i) CON group, fed with basal diet; ii) LTN group, supplemented with lutein; iii) MDP group, supplemented with monohydroxyl pigment including dehydrated lutein, β-cryptoxanthin, and α-cryptoxanthin; iv) LTN+MDP group, supplemented with lutein and monohydroxyl pigment in proportion to 1:1. The supplementary content of LTN, MDP, and LTN+MDP was 2 g/kg. Skin color was measured after 7, 14, 21, and 28 days of feeding the dietary treatments. The breast, thigh, and abdominal fat of slaughtered chickens were stored in cold storage at 4°C for 24 hours and then the meat color of lightness (L*), redness (a*), and yellowness (b*) values was determined.

RESULTS

The results showed that all treatments enhanced the yellow scores of subwing skin on day 14, 21, and 28 (p<0.05), and the mixture of lutein and monohydroxyl pigment promoted the yellow scores of shanks on day 14, 21, and 28 (p<0.05). The mixture of lutein and monohydroxyl pigment increased the yellow scores of beaks and all treatments enhanced the yellow of shanks on day 28 (p<0.05). In addition, all treatments improved the yellow (b*) values of breast and thigh muscle, moreover, the monohydroxyl pigment and the mixture of lutein and monohydroxyl pigment enhanced the values of redness (a*) and yellow (b*) of abdominal fat (p<0.05).

CONCLUSION

In summary, different types of xanthophyll extracted from marigold significantly increased the yellow scores of skin color and the yellow (b*) values of carcass pigmentation. Especially, the mixture of lutein and monohydroxyl pigment was more efficient on skin color.

Presalting Condition Effects on the Development of Pink Color in Cooked Ground Chicken Breasts

The effects of presalting conditions (storage temperature and duration) with/without sodium tripolyphosphate (STPP) on the color and pigment characteristics of cooked ground chicken breast were investigated. Meat mixtures containing 2% NaCl (control) or 2% NaCl and 0.5% STPP (STPP treatment) were stored for 0, 3, 5, 7, and 10 d at 2°C or 7°C, followed by cooking to 75°C, and cooling and storage at 2°C-3°C until further analysis. The treatment was the most effective on the pink color defect of all independent variables. The effect of storage temperature was only observed on CIE L* values and percentage myoglobin denaturation (PMD). The control was redder than the STPP treated samples and the CIE a* values increased (p<0.05) from 0 to 5 d in the control and STPP treated samples. Compared to the STPP treatment, the control exhibited increased reducing conditions (more negative oxidation reduction potential), lower undenatured myoglobin, and greater PMD. No differences in the cooking yields of the control and STPP-treated samples were observed for various storage durations. Products with STPP showed higher (p<0.05) pH values than those without STPP, but no differences (p>0.05) in PMD were observed over the storage period in the control and STPP treated samples, except for day 0. Thus, STPP is effective at reducing the pink color in cooked chicken breasts. In addition, presalting for longer than 5 d resulted in increased pink color of the cooked chicken breasts.

Effects of Different Grain Sources in Both Maternal and Offspring Diets on Pigmentation and Growth Performance in Yellow-Skinned Chickens

This study aims at investigating the effects of different grain sources during pre-hatch (from diet of the breeders) and post-hatch (from the diet of broilers) on coloration (Roche color fan scores; L*, lightness; a*, redness; and b*, yellowness) as well as the growth performance in yellow-skinned chickens at market age (42 days old). In this experiment, six thousand yellow-skinned broiler breeders at 27 weeks were fed with a corn or sorghum and barley-based diet in which contained high (+) or low (-) xanthophyll levels, respectively. After the beginning of the trial, from day 41 to 42, eggs from two treatments were collected to artificial incubation. In this trial, 2×2 factorial designs were used and male chicks hatched from breeders fed with a corn or sorghum-based diet. According to the results, it demonstrated that hens fed with a corn-base diet were observed an elevated coloration both in the eggs and newly-hatched chicks (p<0.05). The dietary pigments improved pigment deposition in the egg yolk and the tissue of newly-hatched chicks. Besides, there was no difference in growth performance attributed to dietary grain sources both from hens or chicks. There showed no difference of coloration in abdominal fat, shank or breast skin (or kept at 4°C for 24 hours and 7 days) between two breeder grain sources (p>0.05). However, abdominal fat, shank and breast skin from the broiler chicks fed with the corn-based diet had a significantly higher RFC scores, a* and b* value than that fed with the sorghum and barley-based diet. The current results indicated that the broiler dietary grain sources (different xanthophyll contents), other than the breeder dietary grain sources influenced the pigmentation in abdominal fat, shank and breast skin, and the skins stored at 4°C in broiler. Therefore, it can be suggested that a low xanthophyll-containing diet (sorghum and barley-based diet) might be applied in yellow-skinned broiler breeders without causing negative effects of coloration or growth performance on their offspring at market age.

Effects of stocking density on growth performance, carcass yield, and immune status of a local chicken breed

An experiment was conducted to evaluate the effect of stocking density on growth performance, carcass yield, and immune status of a local chicken breed. In total, 840 one-day-old male Suqin yellow chickens were placed into 4-m(2) cages in groups of 50 (low), 70 (medium), or 90 (high) birds. Each treatment was represented by 4 replicates (cages). The cages measured 2.84 × 1.42 m; half of the area of the cage (2 m(2)) was used from 1 to 28 d and the whole cage was used from 29 to 42 d. Stocking densities were 25, 35, and 45 birds/m(2) from 1 to 28 d and 12.5, 17.5, and 22.5 birds/m(2) from 29 to 42 d (low, medium, and high, respectively). Final production (live bird mass after fasting) per unit area was 14.46, 19.46, and 24.23 kg/m(2), respectively, at 42 d of age. Several immune parameters were evaluated, and the growth performance, carcass yield, and meat quality were determined. Body weight at 28 and 42 d of age was significantly reduced as the stocking density increased (P < 0.05). A depression in daily weight gain was noticed from 1 to 28 d and 1 to 42 d of age, and daily feed intake decreased significantly in each period as density increased (P < 0.05). The feed/gain from 29 to 42 d and from 1 to 42 d of age decreased as density increased (P < 0.05). At 42 d, there was no effect of the stocking density on carcass, eviscerated carcass, breast, and abdominal fat yields (P > 0.05). The thigh yield of chickens in the medium-density group improved significantly (P < 0.05) compared with those of the other 2 groups. The water-loss rate, shear force, and meat color of the muscle were unaffected (P > 0.05) by the stocking density, but pH values increased slightly as density increased. No significant difference was noted in the immunological parameters, but the blood total protein and potassium were significantly affected by stocking density (P < 0.05). The findings of this study suggest that increasing the stocking density advantageously affected feed/gain and decreased the final BW, whereas no evidence was found that stocking density caused changes in any of the measured immune parameters.

Calcium chloride and tricalcium phosphate effects on the pink color defect in cooked ground and intact turkey breast

Calcium chloride (250, 500ppm) was examined for its ability to reduce the pink color defect induced by sodium nitrite (10ppm) and nicotinamide (1.0%) in cooked ground turkey in the presence and absence of sodium tripolyphosphate (0.25, 0.5%) and sodium citrate (0.5, 1.0%). The ability of tricalcium phosphate (0.1-0.5%) to reduce pink cooked color also was evaluated in ground turkey and both calcium chloride and tricalcium phosphate were tested for their effects on pink cooked color in whole breast muscle. The combination of calcium chloride and sodium tripolyphosphate, not calcium chloride alone, was necessary for a reduction in pink cooked color induced by nicotinamide. Subsequently, in the presence of phosphate, both calcium chloride and sodium citrate reduced pink cooked color and were most effective in combination. Tricalcium phosphate also was capable of reducing pink cooked color in ground turkey, however substituting tricalcium phosphate for sodium tripolyphosphate resulted in lower pH and cooking yields. Neither calcium chloride nor tricalcium phosphate was capable of reducing pink cooked color in whole turkey breast. Currently, a combination of sodium tripolyphosphate, calcium chloride, and sodium citrate represents the most suitable means for reducing or preventing the pink color defect in uncured ground turkey.

The effect of age, dietary carbohydrate source, and feed withdrawal on broiler breast fillet color

An experiment was conducted to determine the effect of bird age, diet (feeds formulated with 69.5% corn, 69.7% milo, or 73.6% wheat), and feed withdrawal times (0 or 8 hours) on color (CIE L*, lightness; a*, redness; and b*, yellowness) of raw broiler breast fillets. Broilers were placed on diets at 28 d of age. Replicate groups of 24 birds (eight each from different diet and four each either full fed or feed withdrawn) were processed (slaughtered and eviscerated under simulated commercial conditions) each day from 42 to 45 and 49 to 52 d of age (n = 192). Carcasses were chilled and deboned 4 h postmortem, and triplicate color measurements taken from the medial (bone) side of the fillet. Bird age did not significantly affect fillet color values. Fillets from the birds fed the wheat diet were significantly lighter than fillets from the corn or milo fed birds (48.9 vs. 46.9 and 46.7, respectively). The milo diet resulted in significantly redder fillets than corn or wheat (3.9 vs. 3.5 and 3.3, respectively). The corn diet produced significantly more yellow fillets than milo or wheat (4.8 vs. 2.4 and 2.6, respectively). Feed withdrawal significantly increased fillet lightness from an average of 46.1 to 48.9, decreased redness from 4.1 to 3.1, and increased yellowness from 2.8 to 3.7. Raw broiler breast fillet color is significantly affected by both diet and feed withdrawal, but not by age.

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.

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.