Identifying constituents of whey protein concentrates that reduce the pink color defect in cooked ground turkey

Whey protein concentrate constituents were tested for their ability to reduce naturally occurring pink color defect and pink cooked color induced by sodium nitrite (10 ppm) and nicotinamide (1.0%) in ground turkey. β-lactoglobulin (1.8%), -lactalbumin (0.8%), bovine serum albumin (0.15–0.3%), lactose (1.0–3.0%), potassium chloride (500–1500 ppm), and ferrous iron chloride (0.3–30 ppm) had no effects on cooked pink color. Lactoferrin (30–5000 ppm) increased or decreased pink color depending on its concentration in samples without added sodium nitrite or nicotinamide. Annatto (0.1–1.0 ppm) reduced pink color whereas the higher concentration of magnesium chloride (22–88 ppm) and ferric iron chloride (0.3–30 ppm) increased pink color in samples with added nicotinamide. Calcium chloride (160–480 ppm) was the only tested constituent that consistently reduced pink cooked color in samples with and without added nitrite and nicotinamide. Due to the variability of whey protein concentrates and the number of constituents that do not reduce pink cooked color, the addition of calcium alone or dried milk minerals containing calcium, phosphate, and citrate, represents a better means to regularly prevent the pink color defect in cooked ground turkey.     

Investigation of mechanisms by which sodium citrate reduces the pink color defect in cooked ground turkey

The principal mechanism by which sodium citrate reduces the pink color defect in cooked ground turkey was investigated. Sodium citrate (SC; 0, 0.125, 0.25, 0.5, 1.0, 2.0 M), sodium nitrite (0.01, 0.1 M), and nicotinamide (0.5, 0.75 M) were combined in solutions of bovine hemin to determine SCs ability to bind heme iron and competitively inhibit pink-color-generating ligands from binding. Additionally, the effects of sodium erythorbate (0, 275, 550 ppm), ferrous iron chloride (0, 0.3, 3.0, 30 ppm), and ferric iron chloride (0, 0.3, 3.0, 30 ppm) on SCs ability to reduce pink cooked color was examined. Absorbance curves of hemin + nitrite and hemin + nicotinamide were relatively unaffected by SC, therefore whether or not SC bound heme iron, that did not appear to be a mechanism for inhibiting the pink color defect. Both ferrous and ferric iron chloride had minimal effects on color values, possibly due to sodium tripolyphosphate chelation ability in the meat system and thus their presence did not enhance SCs ability to reduce the pink color defect. However, sodium erythorbate, a reducing agent, inhibited SCs ability to decrease the pink color defect in samples induced pink with sodium nitrite and nicotinamide. Therefore, it appears SC requires the presence of oxygen and may participate in oxidative processes to reduce the pink color defect.     

Citric Acid and Sodium Citrate Effects on Reducing Pink Color Defect of Cooked Intact Turkey Breasts and Ground Turkey Rolls

ABSTRACT The ability of citric acid (0.1%, 0.2%, 0.3%) and sodium citrate (1.0%) to reduce the pink color defect induced with sodium nitrite (1 ppm, 5 ppm, 10 ppm) and nicotinamide (0.5%, 1.0%) in cooked, intact turkey breasts and ground turkey rolls was examined. Citric acid at 0.2% and 0.3% and sodium citrate consistently reduced natural or induced pink color in ground turkey rolls but had no effect on pink color of intact turkey breasts. Citric acid reduced pH and cooking yields, whereas sodium citrate did not. Therefore, sodium citrate may represent a viable option for use by poultry processors in reducing the occurrence of undesirable pink color in cooked, uncured, ground turkey.     

Citric acid and sodium citrate effects on pink color development of cooked ground turkey irradiated pre- and post-cooking

The effects of citric acid (0.15%, 0.3%) and sodium citrate (0.5%, 1.0%) on pink color development in ground turkey following irradiation (0, 2.5, 5.0kGy) were examined. Citric acid and sodium citrate had little effect on pink color when samples were irradiated prior to cooking. In contrast, when samples were cooked prior to irradiation, citric acid (0.3%) and sodium citrate (1.0%) reduced redness as indicated by eliminating a reflectance minimum at approximately 571nm, lessening greater reflectance in the red wavelength region, and preventing greater reducing conditions caused by irradiation. Citric acid significantly reduced pH and yields whereas sodium citrate reduced pH and yields to a lesser extent. Both citric acid and sodium citrate are potential ingredients that can be added during processing to prevent undesirable pink color in precooked irradiated ground turkey and therefore can result in greater acceptance of irradiated products by consumers.     

Response Surface Methodology for Reduction of Pinking in Cooked Turkey Breast Mince by Various Dairy Protein Combinations

Nonfat dry milk (NFDM), sodium caseinate (SC), whey protein concentrate (WPC), and combinations of each were evaluated for abilities to reduce pink color development in cooked, ground, uncured turkey breast. Protein treatments were also evaluated in the presence of pink-color-generating ligands (nicotinamide, 1%, sodium nitrite, 10 ppm, and sodium nitrate, 50 ppm) with and without ethylenedinitrilo-tetraacetic acid disodium salt (200 ppm). NFDM and WPC at levels as low as 1.5% were effective in reducing CIE a* values (P < 0.05) regardless of ligand treatment; SC was not. EDTA reduced pink color within all protein and ligand treatments. Poultry producers can reduce pink color development in further-processed products by selective addition of dairy proteins.     

Whey protein concentrates effects on pink color development in a cooked ground turkey breast model system

The ability of whey protein concentrates (WPCs) to reduce pink color in cooked ground turkey was investigated. Ground turkey was formulated with no ligand and nitrite and nicotinamide to induce pinking. Five WPCs with 34 or 80% protein were tested and turkey samples were cooked to 80 and 85 °C and stored for 1 and 7 days. Three WPCs reduced a* values in turkey without added nitrite or nicotinamide and one WPC reduced nitrite induced pinking. In nicotinamide-induced pink turkey, two WPCs reduced a* values and two WPCs increased pink color. Nitrosylhemochrome was reduced by two WPCs and nicotinamide hemochrome was reduced by one WPC and increased by two WPCs. Increased cooking temperatures enhanced inhibitory effects or reduced reddening effects of two WPCs. Storage time and protein content had minimal effects on pink color. Whey protein concentrates have the potential to reduce the pink defect in cooked uncured turkey, although the mechanism is unclear.     

Injection order effects on efficacy of calcium chloride and sodium tripolyphosphate in controlling the pink color defect in uncured,intact turkey breast

An experiment was conducted to test sequential injection of sodium tripolyphosphate (STP; 0.5% meat weight basis, mwb) followed by injection with or without addition of calcium chloride (CaCl₂, 500 ppm mwb), and to test the effect of post-injection delay prior to cooking. A second experiment evaluated the impact of injection order and delay time between independent addition of CaCl₂ (500 ppm mwb) and STP (0.5% mwb). Turkey was formulated without an added pink generating ligand (NONE), with nicotinamide (NIC; 0.1% mwb), or with sodium nitrite (NIT; 10 ppm mwb). A white colloid was observed in the extracellular space of treatments containing both STP and CaCl_2. Addition of CaCl₂ decreased nitrosylhemochrome but did not reduce levels of nicotinamide hemochrome or CIE a^∗ values. Injection order or delay between injections did not contribute to controlling the pink defect in cooked, intact turkey breast.     

Ability of Various Dairy Proteins to Reduce Pink Color Development in Cooked Ground Turkey Breast

Dairy proteins were evaluated for their ability to reduce pink color in ground turkey samples. Sodium nitrite and nicotinamide were added to induce pink color formation. Nonfat dry milk (NFDM) and 1 of the whey protein concentrates (WPC) reduced CIE a* values in samples containing 10 ppm sodium nitrite. All of the dairy proteins tested reduced CIE a* values in nicotinamide-treated samples. In samples prepared without nicotinamide or nitrite, only WPC reduced CIE a* values, while the other proteins tested had no effect or increased redness. NFDM or specific WPC proteins could be used to reduce the pink color defect and increase yield.     

INHIBITION OF PINK COLOR DEVELOPMENT IN COOKED, UNCURED GROUND TURKEY BY THE ADDITION OF CITRIC ACID

Citric acid (CIT, 0.3%) was assessed for its ability to reduce the pink color defect in ground, cooked (80C) turkey breast associated with nicotinamide hemochrome (NICHEME) and nitrosyl hemochrome (NITHEME). CIT incorporation in nicotinamide-treated (NIC, 1.0%) samples (CIT plus NIC) reduced (P<0.05) redness by 51% compared to the control and 63% compared to the NIC-only treatment. CIT addition in sodium nitrite-treated (NIT, 10 ppm) samples (CIT plus NIT) was similar (P>0.05) in redness to the control and reduced (P<0.05) the redness by 43% compared to the NIT- only treatment. All treatments containing citric acid lowered the pH and increased (P<0.05) cooking loss compared to samples without citric acid. At the level tested, addition of citric acid would provide poultry processors a means to eliminate or significantly reduce the pink defect. However, the use of citric acid may require the addition of nonacid     

Variation in Myoglobin Denaturation and Color of Cooked Beef, Pork, and Turkey Meat as Influenced by pH, Sodium Chloride, Sodium Tripolyphosphate, and Cooking Temperature

This study investigated the effects of pH (5.50–7.00), sodium chloride concentration (0.0–3.0%), and sodium tripolyphosphate concentration (0.0 and 0.5%) on the percent myoglobin denatured (PMD) in beef, pork and turkey muscle when heated to temperatures between 55 and 83°C. At most temperatures studied, the presence of sodium chloride and sodium tripolyphosphate increased the PMD. In contrast, high pH markedly decreased the PMD (P<0.05). The effect of pH on PMD was similar for all three species studied and, in all cases, was sufficient to produce obvious color differences in the cooked muscles.     

Sodium Tripolyphosphate and Sodium Ascorbate Monophosphate as Inhibitors of Off-flavor Development in Cooked, Vacuum-packaged, Frozen Turkey

Sodium tripolyphosphate (STP) or sodium ascorbate monophosphate (SAsMP) in water solutions (0.3 and 0.5% levels) or water only were added to ground turkey which was cooked, vacuum packaged, and stored frozen. Soapy flavor was higher, but rancid flavor and hexanal and bathophenathroline-chelateable (nonheme) iron contents were lower in samples with phosphate salts. Samples without phosphates contained the greatest amount of bathophenathroline-chelateable iron; samples with 0.5% STP contained the least. The addition of phosphate salts decreased cooking losses and increased moisture but did not affect the fat content. Generally, intensity scores for stale and rancid aroma and flavor attributes were low, < 1 for all samples.     

Shelf-life of Algin/Calcium Restructured Turkey Products Held under Aerobic and Anaerobic Conditions

The shelf-life of restructured products made with ground turkey or turkey breast pieces and formulated with combinations of 0.5–1.0% sodium alginate, 0.1–0.2% calcium carbonate and 0.15–0.30% lactate (ACL) was compared to product containing a combination of 1.4% NaCl and 0.32% sodium tripolyphosphate and to no-additive controls stored at 4°C under aerobic and anaerobic conditions. No significant (p > 0.05) differences were observed between ACL and salt/phosphate restructured turkey products in the rate and extent of growth of psychrotrophs or lactic acid bacteria. The salt/phosphate combination, however, repressed (p<0.05) the growth of pseudomonads. Overall, inclusion of ACL did not influence spoilage of restructured turkey meat products held under aerobic or anaerobic conditions.     

Flavor of Cooked, Ground Turkey Patties with Added Sodium Tripolyphosphate as Perceived by Sensory Panels with Differing Phosphate Sensitivity

The flavor of cooked, ground turkey patties, with and without sodium tripolyphosphate, was profiled by two panels. One panel had a lower threshold for STP in ground turkey. Flavor profiles indicated that turkey patties without phosphate had more intense protein, serumy, brothy, and metallic character and less intense turkey and soapy character than the samples with phosphate. Both panels found similar characteristics for turkey with added phosphate, although the characteristics had a slightly different order of appearance. The panel with a lower threshold for STP found a more intense soapy character that tended to linger in the phosphate-treated samples.     

Sodium Tripolyphosphate Stability and Effect in Ground Turkey Meat

Ground turkey meat, cooked and uncooked, was prepared with and without 0.5% sodium tripolyphosphate (SIP) and stored at 5°C for different periods of time. STP stability was evaluated by determining soluble orthophosphate. Water-holding capacity (WHC), pH, and mi-crobial count were also measured. STP hydrolyzed rapidly in uncooked samples. Refrigerated storage time (up to 6 days) did not affect STP hydrolysis in cooked turkey meat. Heating accelerated the rate of STP hydrolysis. End point temperatures (65, 75, and 85 °C) did not affect the extent of STP hydrolysis. STP increased WHC in both cooked and uncooked samples. STP did not inhibit total microbial growth in cooked or uncooked ground turkey meat.     

Role of Reduced Hemochromes in Pink Color Defect of Cooked Turkey Rolls

Reflectance and absorbance spectrophotometric studies on commercial and laboratory samples showed that the pigments responsible for a pink color defect sometimes observed in freshly cut surfaces of cooked turkey rolls were reduced hemochromes, possibly nicotinamide-denatured globin hemochromes, rather than nitrosyl pigments. Oxidation-reduction potential measurements of meat systems showed that hemochrome formation was promoted by reducing conditions and prevented by oxidizing conditions. All constituents necessary for the production of pink color defect were present in turkey meat. The variable most affecting its appearance was the redox potential of the meat.     

Pink Color Development in Turkey Meat as Affected by Nicotinamide, Cooking Temperature, Chilling Rate, and Storage Time

Consumers associate pink color in cooked turkey with undercooking. “Pinking” has been attributed to several factors, but remains a problem in the poultry industry. Effects of temperature, chilling rate, and storage time were investigated relative to pink color intensity of turkey meat cooked in the presence of 2% nicotinamide. As final cook temperature increased, sensory pinkness increased as did CIE a* values. Slower chilling rate resulted in higher CIE a* values and lower CIE b* values. Increased storage time generally increased CIE a* values and decreased b* values while CIE L* values were not affected.     

Inhibition of Lipid Oxidation in Meats by Inorganic Phosphate and Ascorbate Salts

The sodium salts of tripolyphosphate, tetrapyrophosphate, L-ascorbate monophosphate, and L-ascorbate polyphosphate at 0.3% and L-ascorbic acid and sodium L-ascorbate at 0.1% were added to ground turkey and ground beef. Sensory attributes and hexanal content were evaluated immediately after cooking and after 1 and 3 days storage (4°C). Percentages of moisture and fat and nonheme iron were determined. All samples containing a phosphate salt had more meaty flavor and less stale and rancid flavor and aroma and contained less hexanal after 3 days storage than samples with no additive. The addition of phosphate salts decreased cooking losses but did not affect fat content. Phosphate salts decreased nonheme iron in cooked turkey patties but not in beef patties. The taste panel detected a very slight soapy flavor in patties with the addition of any phosphate salt at 0.3%.     

Minimum sodium nitrite levels for pinking of various cooked meats as related to use of direct or indirect-dried soy isolates in poultry rolls

The relationship between sodium nitrite level and pinking was investigated in cooked meats, as measured by panel color score, acetone extraction of NO-hemochrome, and instrumental redness values. Beef was less susceptible than poultry breast meat to nitrite-induced pinking. Minimum sodium nitrite level for pinking was 14, 4, 2, and 1 ppm for beef round, pork shoulder, turkey breast, and chicken breast, respectively. By regression analysis, minimum ppm nitrite for pinking=0.092 (ppm total pigment)+0.53 (R(2)=0.99). High levels of nitrate (>250 ppm as sodium nitrate) and nitrite (>45 ppm as sodium nitrite) were found in direct-dried (DD) soy isolates. Chicken breast rolls formulated with >2% DD soy were pink, but control rolls with 156 ppm sodium nitrate were not pink. Thus, it was concluded that nitrite was the primary pinking agent in DD soy. Indirect-dried (ID) soy isolates contained <11 ppm sodium nitrite, which was insufficient for pinking in poultry rolls.     

Inhibition of Oxidative Flavor Changes in Meat by α-Tocopherol in Combination with Sodium Tripolyphosphate

The effects of α‐tocopherol at 0.03%, sodium tripolyphosphate (STP) at 0.3%, alone and in combination, and STP alone at 0.5% on hexanal and sensory attributes of refrigerated cooked ground turkey or pork, with and without salt (1% NaCl), were studied. For turkey, a combination of α‐tocopherol with 0.3% STP was nearly as effective as 0.5% STP. Turkey and meaty flavor of samples from these 2 treatments did not decline; hexanal content and staleness scores remained low throughout storage. Slick mouthfeel and metallic aftertaste were less for turkey with the antioxidant combination than with 0.5% STP. In pork, STP alone at 0.3% adequately prevented oxidative flavor changes. α‐Tocopherol, when used with STP, provided no additional effect.     

Evaluation of the Antioxidant Effects of Dried Milk Mineral in Cooked Beef, Pork, and Turkey

ABSTRACT: This study was done to determine the optimum level of dried milk mineral (MM) to inhibit lipid oxidation in various ground meats. Cooked ground beef and pork required 2% MM to maintain thiobarbituric acid (TBA) values < 1.0 after 14 d refrigerated storage, compared to 1% MM for ground turkey. TBA values of cooked ground beef were lower (p < 0.05) when MM was added in water suspension, rather than as a dry powder. Among MM components (phosphate, calcium, and citrate), polyphosphates most effectively maintained low TBA levels during storage. MM probably chelates soluble iron to colloidal calcium phosphate particles, thus removing iron as a catalyst for lipid oxidation.