Effects of L- or D-lactate-enhancement on the internal cooked colour development and biochemical characteristics of beef steaks in high-oxygen modified atmosphere

The effects of L- or D-lactate on internal cooked colour development of steaks packaged in high-oxygen (80% O₂/20% CO₂) modified atmosphere packaging (MAP) was investigated. Ten USDA Select beef strip loins were divided individually into 4 equal-width sections, and one of four treatments (control, 0.3% sodium tripolyphosphate, 2.5% L-lactate + 0.3% sodium tripolyphosphate, and 2.5% D-lactate + 0.3% sodium tripolyphosphate) was assigned randomly to the loin sections. Loin sections were injected to approximately 10% of their raw weight. Steaks packaged in high-oxygen MAP were stored in the dark at 1 °C for 10 days. Instrumental internal colour of raw and cooked steaks (70 °C), total reducing activity (TRA), NADH concentration, and percent myoglobin denaturation (PMD) were measured. Cooked steaks enhanced with 2.5% L-lactate/phosphate maintained higher a*/b* ratios, lower hue values, higher TRA and NADH concentration, and lower PMD than the control and D-lactate-injected steaks, whereas enhancement with 2.5% D-lactate did not affect cooked colour, TRA, NADH, or PMD. Thus, inclusion of an L-lactate/alkaline phosphate blend increased the reducing activity of muscle tissues by replenishing NADH and subsequently decreased the thermal denaturation of myoglobin by maintaining the reduced state of myoglobin in the high-oxygen package.     

Role of lactate dehydrogenase in metmyoglobin reduction and color stability of different bovine muscles

The role of lactate dehydrogenase (LDH) in metmyoglobin reducing activity (MRA) and color stability of different bovine muscles was studied in two consecutive experiments. In experiment 1, three different bovine muscles – M. longissimus lumborum (LL), M. semimembranosus (SM), and M. psoas major (PM) – were obtained (n = 7, respectively), cut into steaks, PVC packaged, and then displayed for 7 days at 1 °C. The LL was the most red over display time and had more (P < 0.05) LDH-B activity (catalyzing toward NADH generation), LDH1 isoform expression, NADH, and higher (P < 0.05) MRA than the other two muscles studied. The PM had the least color stability and lowest MRA. In experiment 2, LL steaks (n = 8) were cut in half, one side syringe-injected with oxamate, and the other injected with distilled water. Inclusion of oxamate decreased (P < 0.05) LDH-B activity, NADH, and a* values after 10 days display at 1 °C. These results suggest that variation in color stability of physiologically different muscles is regulated by different replenishment rates of NADH via different LDH isozymes.     

Potential mechanisms of carbon monoxide and high oxygen packaging in maintaining color stability of different bovine muscles

The objectives were to compare the effects of packaging methods on color stability, metmyoglobin-reducing-activity (MRA), total-reducing-activity and NADH concentration of different bovine muscles and to explore potential mechanisms in the enhanced color stability by carbon monoxide modified atmosphere packaging (CO-MAP, 0.4% CO/30% CO₂/69.6% N₂). Steaks from longissimus lumborum (LL), psoas major (PM) and longissimus thoracis (LT) packaged in CO-MAP, high-oxygen modified atmosphere packaging (HiOx-MAP, 80% O₂/20% CO₂) or vacuum packaging were stored for 0 day, 4 days, 9 days, and 14 days or stored for 9 days then displayed in air for 0 day, 1 day, or 3 days. The CO-MAP significantly increased red color stability of all muscles, and especially for PM. The PM and LT were more red than LL in CO-MAP, whereas PM had lowest redness in HiOx-MAP. The content of MetMb in CO-MAP was lower than in HiOx-MAP. Steaks in CO-MAP maintained a higher MRA compared with those in HiOx-MAP during storage. After opening packages, the red color of steaks in CO-MAP deteriorated more slowly compared with that of steaks in HiOx-MAP.     

Evaluation of antioxidant capacity and colour stability of calcium lactate enhancement on fresh beef under highly oxidising conditions

Fifteen USDA Select beef strip loins were divided individually into four equal width sections, and one of six treatments containing phosphate and/or calcium lactate (CAL) enhancement solutions were assigned randomly to each loin section (n = 10). Steaks from each loin section were packaged with high-oxygen (80% O₂) modified-atmosphere packaging, and/or irradiated at 2.4 kGy, stored 10 days and then displayed for 5 days at 1 °C. Instrumental colour, total reducing activity (TRA), 2-thiobarbituric acid value (TBARS), and NADH concentration were measured. Loins with CAL and phosphate maintained the most stable red colour, increased NADH (p < 0.05), and were the least oxidised. Among irradiated steaks, CAL with phosphate treatment significantly minimised lipid oxidation, increased NADH and TRA, and consequently had a higher a^∗ value. These results suggest that lactate inclusion improves colour stability of fresh beef by providing superior antioxidant capacity and increased reducing activity of myoglobin by elevating NADH concentration.     

Effects of lactate and modified atmospheric packaging on premature browning in cooked ground beef patties

Our objectives were to determine the effects of lactate and modified atmosphere packaging on raw surface color, lipid oxidation, and internal cooked color of ground beef patties. Eight chubs (85% lean) were divided in half and each half was either assigned to the control (no lactate) or mixed with 2.5% lactate (w/w). Following treatment, patties were prepared and packaged in either vacuum, PVC (atmospheric oxygen level), high-oxygen (80% O₂ + 20% CO₂), or 0.4% CO (30% CO₂ + 69.6% N₂) and stored for 0, 2, or 4 days at 2 °C. After storage, raw surface color and lipid oxidation were measured and patties were cooked to either 66 °C or 71 °C. Lactate improved (p < 0.05) color stability of PVC, high-oxygen, and vacuum packaged raw patties, but had no effect (p > 0.05) on the a∗ values and visual color scores of patties in 0.4% CO. Lactate decreased (p < 0.05) lipid oxidation in all packaging atmospheres. Nevertheless, high-oxygen and PVC-packaged patties had more (p < 0.05) lipid oxidation than patties in CO and vacuum. Lactate had no effect (p > 0.05) on premature browning, whereas patties packaged in high-oxygen demonstrated premature browning. Conversely, cooked patties in 0.4% CO and vacuum were more red (p < 0.05) than both high-oxygen and PVC-packaged patties. Although lactate improved raw color stability, it did not minimize premature browning in cooked ground beef patties.     

High-oxygen modified atmosphere packaging system induces lipid and myoglobin oxidation and protein polymerization

Beef steaks from longissimus lumborum, semimembranosus, and adductor muscles (n = 10; respectively) were cut at 24 h postmortem, randomly assigned to either high-oxygen modified atmosphere packaging (HiOx-MAP; 80% O₂, 20% CO₂) or vacuum (VAC), and displayed for 9 days at 1 °C. HiOx-MAP packaged beef steaks had a rapid increase in lipid oxidation and a decrease in color stability during display. The steaks in HiOx-MAP had significantly lower tenderness and juiciness scores, and higher off-flavor scores compared to steaks in VAC. HiOx-MAP condition did not affect the postmortem degradation of troponin-T or desmin. Furthermore, autolysis of μ-calpain was not influenced by packaging. SDS–PAGE, immunoblotting, and diagonal-PAGE revealed oxidative cross-linking of myosin heavy chain in meat packaged in HiOx-MAP. These results suggest that the HiOx-MAP system may negatively affect meat quality characteristics by inducing lipid and myoglobin oxidation and cross-linking/aggregation of myosin by protein oxidation.     

Effects of lactate/phosphate injection enhancement on oxidation stability and protein degradation in early postmortem beef cuts packaged in high oxygen modified atmosphere

The influence of lactate/phosphate enhancement on meat color and lipid oxidation stability, tenderness, protein degradation, and protein aggregation of early postmortem beef muscles packaged in a high oxygen modified atmosphere packaging (HiOx-MAP; 80% O₂, 20% CO₂) were studied. At 24 hr postmortem, three bovine muscles (longissimus, semimembranosus, and adductor; n = 10, respectively) were enhanced (10% injection rate) with either lactate (2.5%)/phosphate (0.3%) solution or water, packaged in HiOx-MAP, stored 9 days at 1 °C, and then displayed for 7 days at 1 °C. The lactate/phosphate injection significantly improved color stability (higher a* values) of all three bovine muscles throughout display period. Accumulation of lipid oxidation determined by 2-thiobarbituric acid-reactive substances values was also decreased (P < 0.05) in the lactate/phosphate injection compared to the water treatment during storage and display periods. The objective tenderness values of longissimus and semimembranosus were also improved (P < 0.05) by the lactate/phosphate enhancement treatment compared to the water treatment based on star probe measurement. There were no significant differences found in desmin and troponin-T degradation, or oxidative cross-linking of myosin between treatments. The results suggest that lactate/phosphate enhancement has beneficial effects on color and lipid oxidation stability, and tenderness development of beef cuts under HiOx-MAP conditions.     

Influence of muscle type on physicochemical and sensory properties of foal meat

The effect of muscle type on physico-chemical properties and sensory characteristics of foal meat was investigated. Six muscles: longissimus dorsi (LD), semimembranosus (SM), semitendinosus (ST), biceps femoris (BF), triceps brachii (TB) and psoas major & minor (PM) from twelve foals slaughtered at 15 months from an extensive production system in freedom regimen were extracted for this study. Regarding chemical composition, intramuscular fat content showed significant differences among muscle where PM presented higher values (0.7%) than the other ones. The heme-iron content also presented significant differences ranging between 1.5 and 2.4 mg/100 g fresh meat. ST was the lightest, while TB and PM presented a more intense redness. The muscles that had a greater capacity to hold water were ST and BF, which presented lower drip loss (2 and 2.2%) and cooking loss (17.3 and 17.2%), respectively. Textural traits established the following scale in response to the tenderness: LD > PM > ST > TB > BF > SM. Finally, sensory analyses revealed that color and texture traits (hardness, juiciness and fibrousness) were significantly influenced by muscle type.     

Effects of pelvic suspension of beef carcasses on quality and physical traits of five muscles from four gender-age groups

Pelvic and Achilles suspension methods for beef carcasses were compared for four gender-age groups (24 month bulls, 34 month bulls, heifers, and cows) and five muscles [M. longissimus dorsi (LD), M. semimembranosus (SM), M. adductor (AD), M. psoas major (PM), and M. gluteus medius (GM)]. Pelvic suspension increased muscle and sarcomere lengths in the SM, LD, GM, and AD muscles. The following effects were significant (p < 0.05). Peak force was reduced by pelvic suspension in the LD and GM of bulls-24 and bulls-34, but not heifers and cows. Furthermore, peak forces decreased for the SM after pelvic suspension in bulls-24, bulls-34, and heifers. For the AD, the only decrease in peak force was for bulls-34. Water-holding capacity increased and purge in vacuum bags decreased for pelvic suspension of all muscles except the PM. Although the effects of pelvic suspension varied somewhat between gender-age groups and muscles, this method of hanging carcasses merits industrial consideration because it improves muscle yields, tenderness, and reduces variation within muscles.     

Influence of muscle type on rheological properties of porcine myofibrillar protein during heat-induced gelation

The gelation characteristics of myofibrillar proteins are indicative of meat product texture. Defining the performance of myofibrillar proteins during gelation is beneficial in maintaining quality and developing processed meat products and processes. This study investigates the impact of pH on viscoelastic properties of porcine myofibrillar proteins prepared from different muscles (semimembranosus (SM), longissimus dorsi (LD) and psoas major (PM)) during heat-induced gelation. Dynamic rheological properties were measured while heating at 1 °C/min from 20 to 85 °C, followed by a holding phase at 85 °C for 3 min and a cooling phase from 85 to 5 °C at a rate of 5 °C/min. Storage modulus (G′, the elastic response of the gelling material) increased as gel formation occurred, but decreased after reaching the temperature of myosin denaturation (52 °C) until approximately 60 °C when the gel strength increased again. This resulted in a peak and depression in the thermogram. Following 60 °C, the treatments maintained observed trends in gel strength, showing SM myofibrils produced the strongest gels. Myofibrillar protein from SM and PM formed stronger gels at pH 6.0 than at pH 6.5. Differences may be attributed to subtle variations in their protein profile related to muscle type or postmortem metabolism. Significant correlations were determined between G′ at 57, 72, 85 and 5 °C, indicating that changes affecting gel strength took effect prior to 57 °C. Muscle type was found to influence water-holding capacity to a greater degree than pH.     

Effect of ohmic heating and vacuum impregnation on the quality and microbial stability of osmotically dehydrated strawberries (cv. Camarosa)

The combined effect of osmotic dehydration/ohmic heating (OD–OH) and vacuum impregnation/ohmic heating (VI–OH) on physicochemical and quality parameters of strawberry (a_w, color, firmness and microstructure), as well as on microbial stability of storage samples at 5 and 10 °C, was analyzed. Treatments were carried out with a 65% (w/w) sucrose solution at 30 °C, and ohmic heating at 9.2, 13, and 17 V/cm electric field strengths, corresponding to applied voltages of 70, 100, and 130 V. Dehydrated samples showed that water loss was greater in OD–OH treatments at 17 V/cm. The greatest solute gain, least firmness loss and least color loss were obtained in the VI–OH treatment at 13 V/cm. The shelf-life of strawberries treated with VI–OH at 13 V/cm and stored at 5 °C was extended from 12 d (control samples) to 25 d. Furthermore, the VI–OH treatment at 13 V/cm was the best processing condition for dehydrating strawberries.     

Evaluation of freshness decay of minced beef stored in high-oxygen modified atmosphere packaged at different temperatures using NIR and MIR spectroscopy

Meat freshness has been monitored by various microbiological, chemical and sensorial indices. However, these methods are slow and not suited to automation. Infrared spectroscopy is one of the most convenient analytical tools which could be used to monitor the evolution of food quality. The aim of this work was to investigate the ability of both NIR (Near Infrared) and MIR (Mid Infrared) spectroscopy to follow meat freshness decay. The minced beef was packaged in high-oxygen modified atmosphere (30% CO₂ and 70% O₂) and stored at three temperatures. Spectra were collected by Fourier-Transformation (FT)-NIR and FT-IR instruments. PCA, applied to the data, was able to discriminate samples on the basis of storage time and temperature. The modelling of PC scores versus time allowed the setting of the time of initial freshness decay for the samples (6–7 days at 4.3 °C, 2–3 days at 8.1 °C and less than 1 day at 15.5 °C).     

Influence of lamb age and high-oxygen modified atmosphere packaging on protein polymerization of long-term aged lamb loins

The objective of this study was to determine the influence of lamb age and high-oxygen modified atmosphere (HiOx-MAP) on tenderness of loins during display. Loins from 36 carcasses of two different age groups [4-month-old (New season; NS) and 11-month-old lambs (Old season; OS)] were vacuum-packaged and stored for 8 weeks at −1.5 °C. After storage, the loins were cut into 6-cm thick chops, assigned to either HiOx-MAP or oxygen-permeable overwrap-PVC, and then displayed for 8 days at 3 °C. Initially, packaging methods did not influence shear force (P > 0.05). However, at the end of display, a significant increase in shear force and lipid oxidation was found in OS loins under HiOx-MAP. SDS–PAGE and Western blot results found a greater extent of cross-linked myosin products from OS loins in HiOx-MAP compared to NS loins. These results suggest that HiOx-MAP can adversely influence meat quality of fully-tenderized loins, and meat from older lamb may be more susceptible to an oxidizing environment of HiOx-MAP.     

Effects of chilling methods and hot-boning on quality parameters of M. longissimus lumborum from Bos indicus Nelore steer

To study the effects of chilling methods and hot-boning on quality parameters of M. longissimus lumborum (LL) of Nelore steers, sixteen left-carcass sides were electrically stimulated and the LL muscles were hot-boned and chilled at − 20 °C (HBVFC) or 0 °C (HBO). Eight control left-carcass sides were cold-boned (AT). All muscles were vacuum-packaged and aged at 0 °C for 14 d. Shear force and tenderness of the AT-treated muscles were not different from HBO-treated muscles. The shear force values of the HBVFC muscles were higher after 7 and 14 d post-mortem (pm) compared to those of the AT muscles, but there was no difference from the HBO muscles. Aging did not reduce the shear force values of the HBVFC muscles. The purge losses of the HBVFC muscles were higher than those of the HBO and AT muscles. The HBVFC muscles were less tender than the HBO and AT muscles at 14 d pm.     

Mitochondrial oxygen consumption in permeabilized fibers and its link to colour changes in bovine M. semimembranosus muscle

Animal and muscle characteristics were recorded for 41 cattle. The oxygen consumption rate (OCR) of M. semimembranosus was measured between 3.0–6.4 h post mortem (PM3-6) and after 3 weeks in a vacuum pack at 4 °C. Colour change measurements were performed following the 3 weeks using reflectance spectra (400–1100 nm) and the colour coordinates L*, a* and b*, with the samples being packaged in oxygen permeable film and stored at 4 °C for 167 h.     

Effects of succinate and pH on cooked beef color

Two experiments were conducted to assess the effects of succinate and pH on cooked beef color. In experiment 1, ten strip loins (M. longissimus lumborum) were divided in half and assigned to either non-enhanced control or 2.5% succinate. Each half-loin was cut into steaks, packaged in vacuum or 80% oxygen, and stored at 1 °C for 0, 6, or 12 days. Steaks were cooked to either 66 °C or 71 °C. Succinate increased (P < 0.05) steak pH, raw a* values, and interior cooked redness when packaged in high oxygen. In experiment 2, to assess the role of succinate in raw and cooked color, succinate or ammonium hydroxide was added to ground beef patties to result in a common meat pH (5.9). At a similar pH, succinate had greater metmyoglobin reducing activity and internal cooked redness compared with ammonium hydroxide (P < 0.05). In addition to ingredient-based changes in muscle pH, succinate may influence color by regenerating reducing equivalents.     

Color-stabilizing effect of lactate on ground beef is packaging-dependent

Previous research on lactate-induced color stability in ground beef did not address the potential influence of packaging. The objective of the present study was to examine the effects of lactate on the color stability of ground beef patties stored in different modified atmosphere packaging (MAP) systems. Ground beef patties with either 2.5% potassium lactate or no lactate were packaged in vacuum (VP), high-oxygen MAP (HIOX; 80% O₂ + 20% CO₂), carbon monoxide MAP (CO; 0.4% CO + 19.6% CO₂ + 80% N₂), or aerobic packaging (PVC) and stored for 0, 2, or 4 days at 2 °C. Lactate-treated patties were darker (P < 0.05; lower L∗ values) than control patties. Surface redness (a∗ values) was greater (P < 0.05) for lactate patties than the controls when stored in PVC, HIOX, and VP. However, lactate’s effects on a∗ values were not evident when packaged in CO (P > 0.05). The color-stabilizing effect of CO could have masked lactate’s effect on surface redness. While lactate patties in PVC and VP demonstrated lower (P < 0.05) discoloration than controls, no differences (P > 0.05) existed between controls and lactate samples in CO and HIOX. Our results indicated that the effects of lactate on ground beef color are dependent on packaging.     

Protein denaturing conditions in beef deep semimembranosus muscle results in limited μ-calpain activation and protein degradation

The objective was to determine the effect of muscle location on protein solubility and protein degradation in deep (DSM) and superficial (SSM) portion of beef semimembranosus. At 24 h postmortem, the semimembranosus was removed from beef carcasses (n = 10), packaged in high-oxygen modified atmosphere (80% O₂ + 20% CO₂), and displayed for 7 d at 1 °C. DSM had higher (P < 0.05) L*, a*, b*, and hue values than SSM throughout display. DSM had significantly higher protein denaturation and less protein concentration than SSM. Western blotting for μ-calpain autolysis revealed that DSM maintained more (P < 0.05) unautolyzed μ-calpain than SSM. This result coincided with less desmin and troponin-T degradation in samples from the DSM. These results confirm the hypothesis that increased protein denaturation in DSM results in minimal proteolysis by negatively affecting μ-calpain activation. This demonstrates a potential to alter progression of proteolysis and improvement in tenderness associated with postmortem storage.     

Packaging-specific influence of chitosan on color stability and lipid oxidation in refrigerated ground beef

We examined the influence of chitosan on lipid oxidation and color stability of ground beef stored in different modified atmosphere packaging (MAP) systems. Ground beef patties with chitosan (1%) or without chitosan (control) were packaged either in high-oxygen MAP (HIOX; 80% O₂ + 20% CO₂), carbon monoxide MAP (CO; 0.4% CO + 19.6% CO₂ + 80% N₂), vacuum (VP), or aerobic packaging (PVC) and stored at 1 °C. Chitosan increased (P < 0.05) redness of patties stored in PVC and CO, whereas it had no effect (P > 0.05) in HIOX. Chitosan patties demonstrated lower (P < 0.05) lipid oxidation than controls in all packaging. Control patties in PVC and HIOX exhibited greater (P < 0.05) lipid oxidation than those in VP and CO, whereas chitosan patties in different packaging systems were not different (P > 0.05) from each other. Our findings suggested that antioxidant effects of chitosan on ground beef are packaging-specific.     

The effects of different cooking regimes on the cook yield and tenderness of non-injected and injection enhanced forequarter beef muscles

The aim was to investigate the effect of different cooking regimes on the cook yield and tenderness of non-injected and brine injected (0.5% residual NaCl) bovine M. triceps brachii caput longum (TB), M. supraspinatus (SP) and M. pectoralis profundus (PP). Injected and non-injected TB, SP and PP muscle sections (400 g) were (a) conventionally oven cooked to 72 °C or cooked slowly (using a Δ10 programme) to 72 °C or (b) cooked in a water bath to 72 °C or cooked in a water bath to 55 °C and held at this temperature for 2 h before heating to 72 °C. In addition, injected PP muscle sections were oven cooked to 69 °C and held at this temperature for up to 12 h. Slow cooking using a Δ10 programme had no significant (P < 0.05) effect on WBSF values of injected or non-injected SP and TB muscles but significantly (P < 0.05) decreased the WBSF values of injected and non-injected PP muscles when compared to conventional cooking. Slow cooking significantly (P < 0.05) increased % cook yield of injected PP, SP and TB muscles. Staged cooking significantly (P < 0.05) decreased the WBSF values and had no significant effect on sensory tenderness ratings of non-injected TB, SP and PP muscles and injected PP muscles. Staged cooked injected or non-injected PP, SP and TB muscles had lower % cook yield values than those cooked straight to 72 °C. Increasing the cooking time of injected PP muscles at 69 °C to 8 and 12 h decreased % cook yield, decreased WBSF values and increased sensory tenderness ratings. It also alleviated the problem of residual chewiness which was evident in PP muscles cooked using the other regimes.