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.     

A response surface investigation of the effects of sodium chloride and tripolyphosphate on the thermal properties of beef muscle

A response surface investigation, utilizing a central composite rotatable design, measured the thermal response of beef muscle samples treated with sodium chloride (NaCl, 0·5-2%) and sodium tripolyphosphate (TPP, 0·2-0·6%). Low temperature transitions were reduced in enthalpy and transition temperature by increased salt concentration. Enthalpy was raised by increased TPP levels. Total enthalpy, over the temperature range 45-90°C, demonstrated the strong stabilizing effect of TPP at salt levels below 1%, and the lack of effect of TPP concentrations over 0·5% with salt levels greater than 1·25%. NaCl and TPP concentrations in excess of 1·5 and 0·4%, respectively, show little additional effect on thermal response.     

Antioxidant activity of carnosine in cooked ground pork

Carnosine (0·5-1·5%) reduced (P < 0·05) the formation of thiobarbituric acid reactive substances (TBARS) in cooked unsalted ground pork after 7 days of storage at 4°C. The antioxidant activity of carnosine was less in cooked salted ground pork, with only 1·5% carnosine inhibiting (P < 0·05) TBARS formation during refrigerated storage. The antioxidant activity of carnosine in cooked salted and unsalted ground pork was greater than those of the lipid-soluble free radical scavengers, butylated hydroxytoluene and α-tocopherol (P < 0·05) but less than that of sodium tripolyphosphate (P < 0·05). These data suggest that carnosine could be used to reduce the oxidative deterioration of cooked salted and unsalted ground pork.     

Effects of potassium lactate, sodium chloride, sodium tripolyphosphate, and sodium acetate on colour, colour stability, and oxidative properties of injection-enhanced beef rib steaks

This study determined the effects of potassium lactate (KL), sodium chloride, sodium tripolyphosphate, and sodium acetate on colour, colour stability, and oxidative properties of injection-enhanced beef rib steaks. Enhancement solutions (8.5% pump) contained combinations of KL (0% or 1.5%), sodium chloride (0.3% or 0.6%), sodium tripolyphosphate (0% or 0.3%), and sodium acetate (0% or 0.1%). Steaks were packaged in a high-oxygen modified atmosphere (80% O(2)/20% CO(2)). Steaks with KL or KL and sodium acetate were darker but more colour stable (P<0.05) than control steaks. Steaks had less glossy surfaces when they contained acetate (P<0.05) and KL (P<0.11). Increasing sodium chloride content resulted in darker, less colour-stable steaks (P<0.05). Removing phosphate had little impact on colour (P>0.05). Both KL and sodium acetate improved visual appearance of injection-enhanced beef rib steaks, whereas the greater salt level were detrimental.     

Effect of α-Tocopherol, β-Carotene, and Sodium Tripolyphosphate on Lipid Oxidation of Refrigerated, Cooked Ground Turkey and Ground Pork

ABSTRACT α-Tocopherol and β-carotene at 0.03% levels and sodium tripolyphosphate (STP) at 0.2% and 0.3% levels, alone and in combination, were added to ground turkey and ground pork. Hexanal was measured after cooking and storage at 4 °C for 2, 4, or 6 d. α-Tocopherol alone significantly reduced hexanal of stored, cooked, turkey but had no effect in pork. STP was more effective than α-tocopherol and a combination of α-tocopherol with STP resulted in enhanced antioxidant activity. Hexanal of pork with 0.03%α-tocopherol plus 0.3% STP did not increase significantly during storage, and that of turkey increased only slightly. β-Carotene and salt (1% NaCl) had no effect on hexanal.     

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

Calcium chloride (250, 500 ppm) was examined for its ability to reduce the pink color defect induced by sodium nitrite (10 ppm) 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.     

Color and Color Stability of Frozen Restructured Beef Steaks: Effect of Sodium Chloride, Tripolyphosphate, Nitrogen Atmosphere, and Processing Procedures

This study investigated the effect of mixing and grinding, tempering, addition of sodium chloride and sodium tripolyphosphate and processing under a nitrogen atmosphere on the color of restructured beef steaks initially and at 1-month intervals for 3 months of frozen storage. Mixing and grinding and manufacture under a nitrogen atmosphere had the greatest detrimental effect on the extent of discoloration initially; this was probably due to low oxygen concentration. Tempering and the addition of sodium chloride without sodium tripolyphosphate produced the most rapid increase in rate of discoloration during frozen storage. Tripolyphosphate partially counteracted the detrimental effect of sodium chloride, however, this effect did not appear to be due to the higher pH produced by the phosphate or the chelating ability of the phosphate. Surface discoloration and overall color were highly correlated with surface metmyoglobin (r= -0.87) and overall met-myoglobin (r= -0.94).     

Color Characteristics of Irradiated Vacuum-Packaged Pork, Beef, and Turkey

Changes in color of irradiated meat were observed to be species-dependent. Irradiated pork and turkey became redder due to irradiation but irradiated beef a* values decreased and yellowness increased with dose and storage time. The extent of color change was irradiation dose-dependent and was not related to myoglobin concentration. Visual evaluation indicated pork and turkey increased in red ness whereas beef decreased in redness as dose levels increased. Reflectance spectra showed that irradiation induced an oxymyoglobin-like pigment in pork and that both oxymyoglobin and metmyoglobin developed in beef as a result of irradiation.     

Model System Studies on N-Nitrosamine Formation in Cured Meats: The Effect of Curing Solution Ingredients

Solutes commonly employed in curing solutions were evaluated for their effect on nitrosamine formation utilizing a ground pork model system. Sodium erythorbate and sodium ascorbate were found to be equally effective in reducing nitrosopyrrolidine levels. The incorporation of sodium tripolyphosphate or sucrose had no detectable effect on nitrosamine formation. However, sodium chloride, the solute present at the highest concentration in bacon curing solutions, exhibited a concentration dependent inhibition of nitrosopyrrolidine formation. Nitrosopyrrolidine levels in samples containing no added sodium chloride were found to be 50% higher than samples processed with 1.5% added salt.     

Influence of sodium chloride and sodium tripolyphosphate on the quality of UK-style grillsteaks: relationship to freezing point depression

Grillsteaks were prepared from lean beef flaked at –4°C and subsequently mixed at nominal temperatures of either –3°C or +1°C with each combination of five sodium chloride levels (0, 0.5, 1.0, 2.0 and 4.0%) and three levels of sodium tripolyphosphate (Na5P3O10) (0, 0.25 and 0.50%).
Sodium chloride was more effective than sodium tripolyphosphate in lowering the initial freezing point (ifp) of meat, as measured by differential scanning calorimetry which also showed that the freezing point depression was proportional to the solute concentration.
Cooking losses generally were lower with higher levels of sodium chloride and sodium tripolyphosphate, and when the meat was mixed at +1°C. It is argued that localized salt concentrations can influence product quality, as can the relative proportions of ice and water when meat is processed below the ifp.     

Metmyoglobin and inorganic metals as pro-oxidants in raw and cooked muscle systems

The pro-oxidant activities of metmyoglobin (Mb) and metal ions on the induction of lipid oxidation in raw and heated water-washed muscle systems from fish, turkey, chicken, pork, beef and lamb and during storage of these systems at 4°C, were investigated. Lipid oxidation was invariably faster in heated than in raw systems. In raw Mb-catalyzed systems, oxidation was slow over a 5-day period, except in fish, where significant (P < 0·05) increases in TBA values occurred; in contrast, significant (P < 0·05) increases in TBA values occurred in cooked fish, turkey, chicken and pork after 3 days of storage. Cooked beef and lamb, however, showed significant lipid oxidation only after 5 days of storage. Fe(2+) was found to be highly catalytic in cooked muscle. Cu(2+) and Co(2+) were less effective catalysts than Fe(2+); the overall pro-oxidant activity was in the order Fe(2+) > Cu(2+) > Co(2+) > Mb, and the susceptibility to lipid oxidation of the muscle systems was in the order: fish > turkey > chicken > pork > beef > lamb, probably reflecting the degree of unsaturation of the constituent triglyceride fractions.     

A factorial analysis of water-binding properties and firmness of heated, comminuted pork liver and pork loin products as influenced by addition of sodium chloride and pH regulators

Canned, pasteurized, comminuted pork liver and pork loin were used for a factorial study to evaluate the effects of the addition of sodium chloride (0 and 1·8%), acid and alkaline mono- and diphosphates (0 and 0·3% P(2)O(5)), acetic acid (0 and 0·25%), sodium acetate (0 and 0·63%) and glucono-delta-lactone (0 and 0·5%) on their water-binding properties and firmness. The water-binding properties were evaluated by measuring cooking losses (for both types of product) and by moisture release by centrifugation (for the liver products only). The liver products had much better water-binding abilities and were softer than the loin products. The interaction of salt and pH regulators also differed greatly from the interaction for the comminuted loins, resulting in a barely perceptible effect of the pH regulating compounds on the water-binding abilities of the salt-containing comminuted liver. The firmness of the salt-containing liver products was greatly reduced by the addition of acidulants. The loin products were normally affected by the compounds tested, with the exception of Na(4)P(2)O(7). The added amount of this diphosphate caused a considerable rise in the product pH, which resulted in a large reduction in cooking loss, thus leaving no possibility of an extra reduction by the combination of salt and Na(4)P(2)O(7).     

Antioxidative effects of encapsulated sodium tripolyphosphate and encapsulated sodium acid pyrophosphate in ground beef patties cooked immediately after antioxidant incorporation and stored

Ground beef with 1% NaCl was incorporated with 0.5% unencapsulated sodium tripolyphosphate (uSTP), 0.5% encapsulated sodium tripolyphosphate (eSTP), 0.5% unencapsulated sodium acid pyrophosphate (uSAPP), or 0.5% encapsulated sodium acid pyrophosphate (eSAPP) prior to being cooked and stored (0 or 6 d, 3 °C). The pH was higher (P < 0.05) for sodium tripolyphosphate samples (6 d: uSTP 5.98; eSTP 5.89) and lower (P < 0.05) for sodium acid pyrophosphate (6 d: uSAPP 5.31, eSAPP 5.33) samples than control sample (6 d, 5.50). Overall, samples with uSTP had the least cooking loss and lowest TBARS values. TBARS (mg/kg) for the phosphate treatments were lower (P < 0.05; ave. 1.78, 0 d; 3.49, 6 d) than for the control samples (3.07, 0 d; 22.85, 6 d). Therefore, phosphate incorporation into ground beef prior to cooking aids in the reduction of oxidation in the cooked, stored product, although a longer period of time before thermal processing may be necessary for the encapsulated phosphate to have significant benefits.     

Metmyoglobin Formation in Beef Stored in Carbon Dioxide Enriched and Oxygen Depleted Atmospheres

SUMMARY: A spectroreflectometric technique was used to determine the relative percentages of three myoglobin pigments, reduced myoglobin, oxymyoglobin and metmyoglobin at the surface of fresh beef. It was shown that, at constant humidity, the formation of metmyoglobin in beef was maximal at 6 + 3 mm Hg of oxygen at 0°C and 7.5 ± 3 mm Hg at 7°C for semitendinosus muscles. Carbon dioxide concentrations of 10% and higher had negligible effect on the formation of metmyoglobin, provided the oxygen pressure was above about 5%. At high partial pressures of carbon dioxide, absorption of carbon dioxide increased and the pH of the surface decreased. In air, the formation of metmyoglobin varied widely from muscle to muscle.     

The effect of calcium carbonate and sodium alginate on the color and bind strength of restructured beef steaks

This study investigated the effect of calcium carbonate concentration (0·00-0·26%) and sodium alginate concentration (0·0-1·4%) on the amount of discoloration and the raw and cooked bind-strength of restructured beef steaks. Alginate slightly increased and calcium carbonate markedly decreased the amount of discoloration in the restructured steaks. The protective effect of the calcium carbonate did not increase with increasing concentration and did not appear to be due to increased pH. The amount of discoloration in restructured steaks prepared with alginate was similar to that in conventionally prepared restructured steaks. The optimum concentration of calcium carbonate and alginate required for minimum discoloration and maximum raw and cooked bind-strength was 0·13% and 0·7%, respectively.     

The effect of phytic acid on oxidative stability of raw and cooked meat

The effects of phytic acid addition (0.1, 1 and 5 mM) to pork and beef homogenates on TBARS and metmyoglobin levels in raw meat, and TBARS and heme iron contents in cooked meat during 3 days of storage at 4 °C were investigated. Also, the role of inositol as a potential synergist of IP₆ (phytic acid) was examined. IP₆ effectively decreased the TBARS accumulation in raw and cooked meat homogenates. The metmyoglobin formation was inhibited in raw beef by phytic acid in a dose-dependent manner. The effect of IP₆ was more pronounced in cooked meat than in raw and in cooked beef homogenates more than pork. Inositol did not enhance antioxidant action of phytic acid in minced meat.     

Cholesterol oxidation products in irradiated raw meat with different packaging and storage time

The effect of irradiation and packaging conditions on the formation of cholesterol oxidation products (COPs) as well as lipid oxidation products was determined in raw turkey leg, beef, and pork loin meat during 7 days of storage. Ground turkey leg, beef, and pork loin muscles were prepared as patties. The patties were individually packaged either in oxygen-permeable or impermeable bags, irradiated at 0 or 4.5 kGy using a Linear Accelerator, and stored at 4°C. The COPs such as 7-hydroxycholesterol, 7β-hydroxycholesterol, and 7-ketocholesterol were detected in fresh raw meats at 0 day at the level of 10.9 to 49.2 μg/g lipid. After 7 days of storage, other COPs such as epoxides, 20-hyroxycholesterol, and choletanetriol were formed in mainly aerobically packaged and irradiated raw meats. Packaging effect was more crucial on the cholesterol and lipid oxidation than irradiation. In aerobically packaged and irradiated meats, turkey leg muscles had higher COPs value than beef or pork did. COPs and thiobarbituric acid reactive substances (TBARS) values had a strongly positive correlation in turkey leg and pork. But, cholesterol oxidation in beef proceeded in irradiated and aerobically stored samples despite of its low level of TBARS value.     

Tenderising in M. longissimus dorsi of beef, veal, rabbit, lamb and pork

The decrease in toughness of M. longissimus dorsi with storage time at 1°C was effectively described by an exponential decay equation. The average rate constant for beef, veal and rabbit was 0·17 whilst that for lamb was 0·21 and that for pork, 0·40 days(-1). However, the rate constants were not significantly different due to variations both within muscles and between animals. On average, 50% of the tenderising occurred in 2 days for pork and in 4·2 days for beef, veal and rabbit, and 80% in 4·9 and 9·5 days, respectively. At the completion of tenderising, beef and rabbit were the toughest and pork the most tender, whilst the greatest tenderising occurred in beef and lamb.     

A Simple, rapid preparative method for isolating and purifying oxymyoglobin

A simple and rapid procedure was developed to isolate and purify preparative quantities (up to 200 mg) of reduced myoglobin (98% oxy) of high purity (>96%) from beef and pork muscles. This method involved fractional precipitation of a crude myoglobin extract with ammonium sulfate and purification with a single Chromatographic step on a Sephadex G-100 column. The metmyoglobin level of the myoglobin preparation was minimised by using muscle from freshly slaughtered animals (<48h post-mortem), trimming the muscle immediately before use to remove any oxidised myoglobin on the surface and carrying out all procedures at low temperature (0-5 °C) and alkaline pH (8.0-8.5). The purity of the myoglobin preparations was confirmed by ion exchange HPLC and SDS-polyacrylamide gel electrophoresis. The method was effective for skeletal muscle of both low myoglobin content (pork) and high myoglobin content (beef). The resulting purified myoglobin was very stable and there was little change in metmyoglobin level or autoxidation rate during 3 months' storage at 0 °C.     

Sodium Lactate/Sodium Tripolyphosphate Combination Effects on Aerobic Plate Counts, pH and Color of Fresh Pork Longissimus Muscle

The objective of this study was to evaluate the effects of sodium lactate/sodium tripolyphosphate pump combinations on the characteristics of pork loins. The product was manufactured to simulate fresh pumped pork loins currently available in the retail market. Paired fresh pork loins (longissimus muscle), pumped to contain 0, 1 or 2% sodium lactate (SL) and/or 0, 0·2 or 0·4% sodium tripolyphosphate (STP) were vacuum packaged and stored at 4°C for 28 days. In pork containing 0·4% STP, samples with 1 or 2% SL had lower pH values than those with 0% SL. Pork containing 1 or 2% SL generally had lower aerobic plate counts than those with 0% SL. Pork with 0·4% STP was darker (lower L* value) and redder (higher a* value) than that with 0 or 0·2% STP. When aerobic plate counts and color characteristics are used as the criteria, the optimum SL/STP combination for solutions used to pump fresh pork loins that are vacuum packaged and held under refrigeration was 1% SL with 0·2% STP.