Impact of muscle type and sodium chloride concentration on the quality, sensory, and instrumental color characteristics of solution enhanced whole-muscle beef

Beef biceps femoris (n = 10; muscle sections, n = 20; BF), infraspinatus (n = 10; muscle sections, n = 20; IS), and longissimus (n = 10; muscle sections, n = 20; LM) muscles were utilized to evaluate the effect of enhancement with phosphate and varying levels of sodium chloride in beef muscles differing in composition and palatability. Muscles were untreated or solution enhanced to 112% of raw product weight with sodium tripolyphosphate at 0.4% of product weight (STPP), or STPP and sodium chloride (NaCl) at 0.5%, 1.0% or 1.5% of product weight. There was a quadratic relationship (P = 0.04) for percent free water to decrease and a linear relationship (P < 0.01) for cook yield to increase as the level of NaCl increased. The IS steaks required less (P < 0.05) shear force than either the BF or LM, with the BF and LM having similar (P > 0.05) shear force values. There was a linear relationship (P < 0.01) for shear force values to decrease with increasing salt concentration. Steaks from all four enhancement treatments had lower (P < 0.05) shear force values than untreated steaks. Sensory overall tenderness ratings revealed that the IS and LM were similar (P > 0.05) and superior (P < 0.05) to the BF in tenderness. Steaks enhanced with STPP and 0.5%, 1.0%, or 1.5% NaCl all were rated more tender (P < 0.05) than untreated or STPP-only treated steaks. The BF exhibited the lowest (P < 0.05) L* (lightness) and a* (redness) values, as well as decreased (P < 0.05) vividness. The LM generally exhibited superior color to the other two muscle types. There was a linear relationship (P < 0.01) for L*, a*, b* (yellowness) values, and vividness to decline with increasing salt concentration, but steaks enhanced with STPP and 0.5% NaCl were similar (P > 0.05) in a* values and vividness to untreated steaks. These results suggest that across three different muscles varying in composition and palatability, enhancement with 0.4% STPP and 0.5% NaCl allowed for improvements in palatability while minimizing the color deterioration associated with phosphate/salt enhancement.     

The effect of production system and age on concentrations of fatty acids in intramuscular fat of the longissimus and triceps brachii muscles of Angus-cross heifers

The concentrations of fatty acids were measured in intramuscular fat from the longissimus lumborum (LL) and triceps brachii (TB) muscles of Angus-cross heifers finished either on a high-concentrate ration in Washington, USA, (US cattle, n = 15) or on pasture in New Zealand (NZ cattle, n = 16). Half of the NZ cattle were of a similar age to the US cattle (NZAge) and half were of a similar weight (NZWt). Intramuscular fat levels were higher for the LL muscle and for the US cattle but only within the LL muscle (P < 0.05). Aspects of the fatty-acid patterns that are of relevance to human nutrition tended to favour the pasture-finished NZ cattle with lower n − 6/n − 3 fatty acid ratios (P < 0.001), higher concentrations of an anticarcinogenic conjugated linoleic acid (C18:2 c9,t11) (P < 0.05) and its precursor (trans-vaccenic acid, TVA) (P < 0.01), and lower levels of the 18-carbon trans monounsaturated fatty acids other than TVA (P < 0.01). Concentrations of 20 of the 22 fatty acids analysed differed significantly between the two muscles. When values were adjusted to a common intramuscular fat level by covariance, most of the group differences remained, but a number of the muscle differences became non-significant. For almost half the fatty acids considered, there was a significant interaction between treatment group and muscle, which indicates that the results for one muscle do not necessarily apply to other muscles, although the ranking of the groups was usually the same for both muscles.     

Fatty acids and tocopherol levels in M. Longissimus dorsi of beef cattle in Sweden - A comparison between seasonal diets

This study investigated the influence of Swedish outdoor feeding systems on the fatty acid composition and tocopherol content of M. Longissimus dorsi from beef. Dietary effects of pasture (PA), silage, and silage supplemented with grain (SIG) were compared. Each dietary group consisted of six animals. Higher levels (P < 0.05) of polyunsaturated fatty acids (PUFA) were found in the PA treatment. The n − 6/n − 3 fatty acid ratio of total lipids in the muscle tissue was in the range 1.2–1.5. The SIG treatment increased the n − 6/n − 3 ratio and decreased the total PUFA content of muscle tissue. The lipid class composition and the content of -tocopherol in the meat showed no differences among treatments.     

Lipid oxidation in lamb meat: Effect of the weight, handling previous slaughter and modified atmospheres

This study examined the effect of pre-slaughter handling (electrical, gas (CO₂) or non-stunning) on lipid oxidation (as thiobarbituric acid reactive substances, TBARS; in the unit of mg malondialdehyde/kg⁻¹ of meat) of Spanish Manchega breed lamb meat, at 24 h and at 7 days post-mortem. Lambs were slaughtered at two different weights (light (L), 25 kg, vs. suckling (S), 12.8 kg). In general gas-stunned lambs had lower lipid oxidation (P < 0.001), and it was higher (P < 0.001) in light lambs compared to suckling lambs. In both groups (S and L), malondialdehyde level increased with time (P < 0.001), although this increase was lower (P < 0.05) in gas-stunned suckling lambs.

In addition, we evaluated the effect of stunning methods (TS: electrical vs. gas) and the weight (L vs. S) on lipid oxidation values in samples packed in different types of modified atmosphere (MA: A: 70%O₂ + 30%CO₂; B: 69.3%N₂ + 30%CO₂ + 0.7%CO; C: 60%N₂ + 40%CO₂) at 7, 14 and 21 days post-packing. Values were higher in samples with MA-type A and lower in B and C types (P < 0.05). A significant interaction (P < 0.001) weight × TS was observed and the lowest rates of TBARS were found in the samples of light lambs stunned with gas and packed under anaerobic conditions (MA-B and C).     

Chemical, physical and sensory properties of meat from pure and crossbred Podolian bulls at different ageing times

The present study aimed to investigate the effect of crossbreeding with Limousine sires on fatty acid profile, physical and sensory properties of meat produced by Podolian young bulls. Polyunsaturated fatty acid content was influenced by crossbreeding (P < 0.01) with Podolian bulls (P) producing beef characterised by a higher level of unsaturation in comparison with crossbred animals (LP). As a consequence, P/S ratio was significantly higher in meat produced by P animals than LP (P < 0.01). P animals had higher linoleic (P < 0.05), linolenic (P < 0.05), EPA (P < 0.05) and DHA acids (P < 0.001) levels than LP subjects. No breed effect was observed for the ratio n − 6/n − 3 (P > 0.05). WBS force of LD was significantly lower in meat from crossbred subjects (P < 0.05). Both crossbreeding with Limousine and extension of ageing from 2 to 7 days improved LD tenderness as assessed by panel taste (P < 0.001).     

The influence of early post-mortem enhancement and accelerated chilling on pork quality

To improve pork quality, the effectiveness of early post-mortem enhancement and accelerated chilling were investigated. The four treatments evaluated were: Enhancement with Accelerated Chilling (ENAC), Accelerated Chilling Only (ACO), Enhancement with Conventional Chilling (ENCC), and Conventional Chilling Only (CCO). ENAC had a higher (P < 0.05) pH than all other treatments. CCO resulted in the highest (lightest; P < 0.05) L^*, while ENAC had the lowest L^* value (darkest; P < 0.05). Subjective color and striping did not differ (P > 0.05) between ENAC and ENCC, although ENAC was numerically higher for both parameters. Sensory analysis for juiciness and tenderness were not different (P > 0.05) between ENAC and ENCC, but both were higher (P < 0.05) than ACO and CCO. Enhancement early post-mortem coupled with accelerated chilling may be used to improve instrumental color and pH over conventional processing methods.     

Effects of early maternal separation of lambs and rearing with minimal and maximal human contact on meat quality

The present study aims to assess the effect of gentling on behaviour and meat quality of lambs. Thirty-two Comisana lambs were divided into four groups of eight animals: ER (ewe reared), AR (artificially reared) and the corresponding gentled groups ERG and ARG. The provision of human contacts stimulated gentled subjects to explore, whereas the proportion of idling subjects was reduced (P < 0.10). At increasing age the number of subjects contacting the person increased in the gentled groups (P < 0.05). Lambs left with their dams showed higher warm and cold carcass yields compared to artificially reared animals, although animals benefiting from both maternal care and gentling, had the highest dressing percentage (P < 0.05). Values of pH declined more rapidly in meat from gentled animals than from ungentled subjects (P < 0.05), b* and h values were higher in ARG than in AR group (P < 0.05), whereas Warner-Bratzler shear force and hardness tended to be lower in gentled lambs (P < 0.15). We conclude that human–animal relationship can play an important role in affecting welfare, productive performances and meat quality of lambs, in particular when young subjects are prematurely separated from mothers.     

Irradiation effect on fatty acid composition and conjugated linoleic acid isomers in frozen lamb meat

The effect of gamma radiation processing on the lipid content, fatty acid composition and conjugated linoleic acid (CLA) profile in frozen lamb meat was investigated. Samples of longissimus thoracis muscle from lambs fed lucerne basal diets either unsupplemented or supplemented with polyunsaturated vegetable oils were irradiated (7 kGy) and analysed. CLA contents in lamb meat did not affect (P > 0.05) the levels of lipid oxidation induced by the irradiation. No significant differences (P > 0.05) were observed for fatty acid composition, related nutritional indexes (n − 6/n − 3 and PUFA/SFA), as well as for total lipid and CLA contents, between non-irradiated (control) and irradiated meat samples. In contrast, meat irradiation affected the relative proportions of total trans, trans and cis/trans CLA isomers (P < 0.001), in addition to the percentage of some minor individual CLA isomers (t11, t13 and t9, t11, with P < 0.05 and P < 0.001, respectively). The percentage of total cis/trans CLA isomers slightly decreased in irradiated samples, while the relative proportion of total trans, trans isomers slightly increased. This observation may be explained by the higher susceptibility to autoxidation of the cis double bond relative to the trans configuration.     

Intramuscular fatty acid composition of lambs given a tanniniferous diet with or without polyethylene glycol supplementation

The aim of this trial was to investigate the effects that dietary tannins have on lamb intramuscular fatty acids. Twenty-seven lambs were divided into three homogeneous groups: control group, receiving commercial concentrate based on maize; tannin group, fed a diet based on carob pulp (45% as fed basis); PEG group, receiving the same diet as the latter with addition of 42 g/kg of polyethylene glycol (PEG, a binding agent that eliminates the effects of condensed tannins). The duration of the trial was 45 d. Intramuscular fatty acids were measured in the longissimus dorsi muscle. The isomer cis-9 trans-11 of linoleic acid (conjugated linoleic acid or CLA) and linolenic acid were higher in the longissimus muscle fat from animals fed the control diet compared to the other groups (P < 0.0005); these fatty acids were higher in the fat from animals fed the carob diet supplemented with PEG compared to those fed the same diet without PEG (P < 0.05). trans-Vaccenic acid (C18:1 trans-11) was found at higher concentration in fat from control and PEG lambs compared to tannin lambs (P < 0.01); the CLA/C18:1 trans-11 ratio was lower in lambs fed control and PEG diets than in tannin-fed animals (P < 0.05).     

Nutritional profile of restructured beef steak with added walnuts

Amino acid, fatty acid profile, cholesterol, vitamin E and mineral contents were assessed in restructured beef steak with 20% added walnut (20W). Compared with control restructured beef steak (0% added walnut), the product with added walnut presented a lower (P < 0.05) lysine/arginine ratio, larger (P < 0.05) quantities (mg/100 g product) of monounsaturated (MUFA) and n3 polyunsaturated (PUFA) fatty acids (mainly -linolenic acid), a lower (P < 0.05) n6/n3 PUFA ratio and a higher (P < 0.05) polyunsaturated/saturated fatty acid ratio. The replacement of raw meat material by walnut reduced (P < 0.05) the cholesterol content and increased (more than 400 times) the amount of γ-tocopherol. Iron, calcium, magnesium and manganese contents of 20W sample were greater (P < 0.05) than in the control. Some changes induced by added walnut in the nutritional quality of the restructured product may present health benefits.     

AMP-activated protein kinase is negatively associated with intramuscular fat content in longissimus dorsi muscle of beef cattle

Marbling, or intramuscular fat, is an important factor in meat quality. As a key regulator of lipid metabolism, AMP activated protein kinase (AMPK) may be associated with intramuscular fat accumulation. Our objective was to evaluate the relationship among AMPK and its associated signaling mediators, with marbling and lean growth in beef cattle. Steers with high intramuscular fat content (High IMF, 5.71 ± 0.36%, n = 5) and low intramuscular fat content (Low IMF, 2.09 ± 0.19%, n = 5) were selected. High IMF was associated with increased tenderness (P < 0.05) and backfat thickness (P < 0.01). Muscle weights were higher in Low compared to High IMF (P < 0.05). High IMF steers had a reduced AMPK activity (P < 0.01), reduced acetyl-CoA carboxylase phosphorylation (P < 0.05), and reduced total mTOR (P = 0.02) content. Data provide evidence that AMPK is involved in IMF deposition in beef cattle.     

Effect of different stunning systems on meat quality of light lamb

The present study was proposed to compare the effect that different types of stunning (TS) had on the quality of refrigerated meat from light lambs of the Spanish Manchega breed at 24 h and 7 days post-mortem. Lambs were electrically stunned (ESL; n = 10), using CO₂ (GSL; n = 10) or slaughtered without previous stunning (USL; n = 10). Measurements on meat quality were carried out by evaluating pH, colour coordinates (L^*, a^*, b^*), water holding capacity (WHC), cooking loss (CL), shear force (SF) and drip loss (DL). At 24 h post-mortem, no significant differences were found in any of the variables studied. However, at 7 days post-mortem, meat quality was affected by the different TS: pH, CL and DL were lower (P < 0.001) in the USL group and GSL obtained the lowest a^* (redness) and b^* (yellowness) values (P < 0.01) than in the other groups. Ageing of meat affected SF in the ESL group (P < 0.01), although there were no significant differences due to treatments at any of the ageing times.     

The effects of antioxidant combinations on color and lipid oxidation in n-3 oil fortified ground beef patties

This study was carried out to determine an effective combination of chelators, reductants and free radical scavengers for enhancing color stability and minimizing lipid oxidation in muscle foods fortified with n − 3 fatty acids. Chelators (sodium tripolyphosphate, STPP; sodium citrate, CIT), reductants (sodium erythorbate, ERY) and radical scavengers (butylhydroxyanisole, BHA; mixed tocopherols from two different sources, 30 or 95TOC; rosemary extract, ROSE) were incorporated in various combinations into ground beef (15% fat) with or without n − 3 oil fortification (n = 8). Individually, STPP and CIT had no significant effect on a* values except day 4, but showed higher a* values when combined with ERY (STPP + ERY and CIT + ERY) (P < 0.05). CIT had lower hue angle values than STPP on days 4 and 6, but CIT + ERY showed more discoloration than STPP + ERY (P < 0.05). CIT + ERY showed less lipid oxidation than CIT alone (P < 0.05), whereas there was no difference between STPP and STPP + ERY. CIT + ERY + ROSE demonstrated higher a* values than CIT + ERY + 95TOC on days 4 and 6 (P < 0.05); there was no difference between ROSE and 95TOC groups when n − 3 oil was incorporated into ground beef patties (P > 0.05). The combination of ROSE and ERY appeared to be effective in slowing the decline of a* values. All antioxidant combinations were effective at delaying lipid oxidation when compared to CON or n − 3. A combination of CIT, ERY and ROSE was most effective for stabilizing color and delaying lipid oxidation.     

Effects of feeding strategy during a short finishing period on performance, carcass and meat quality in previously-grazed young bulls

Twenty-one Brown Swiss × Limousin young bulls reared on pasture were housed for a short finishing period (60 days). CA group (concentrate-ad libitum group) received concentrate and straw ad libitum for the whole finishing period. CR group (concentrate-restricted group) received 4 kg of concentrate/animal per day and ad libitum alfalfa hay throughout the 60 days. CRA group (concentrate-restricted/ad libitum group) received the same diet as CR group for the first 30 days and the same diet as CA group for the last 30 days. CA and CRA groups presented higher fatness values. Myoglobin concentration in muscle was highest in CA group (P < 0.05) and carotene content in subcutaneous fat was highest in CR group (P < 0.01), while Warner–Bratzler shear force and sensory traits were unaffected (P > 0.05). It is concluded that, in this type of young animal, 4 kg concentrate plus ad libitum alfalfa hay for a 60-day finishing period, despite lower fatness, provides carcasses and meat with acceptable quality characteristics, similar to those obtained from ad libitum fed animals for the same period.     

Influence of dietary inclusion level of manganese on pork quality during retail display

Boneless pork loins (n = 112) were used to test the influence of dietary manganese (Mn) inclusion level on pork quality traits during retail display. Crossbred barrows and gilts were fed diets formulated with 0, 20, 40, 80, 160, or 320 ppm Mn from Availa^®Mn (AvMn; a Mn–amino acid complex) from 23.8 to 106.8 kg live weight. At approximately 48 h postmortem, boneless pork loins were fabricated into longissimus thoracis et lumborum (LM) chops, which were subsequently placed in open-topped, coffin-chest display cases (2.6 °C) under continuous warm-white, fluorescent lighting (1600 lx) for 7 days. Dietary Mn level had no effect on LM pH (P = 0.47), purge volume (P = 0.60) and loss (P = 0.53), or moisture loss (P = 0.95) during retail display. Chops from pigs fed 80 ppm Mn received higher (P < 0.05) American and Japanese color scores than pigs fed 0 and 40 ppm Mn. Even though the LM from pigs fed 80, 160, and 320 ppm Mn tended to be darker (lower L^* values; P = 0.07) than chops from pigs fed 40 ppm Mn, a^* (redness) and b^* (yellowness) values, as well as hue angle and chroma, were not (P  0.19) affected by dietary Mn. On days 0 and 1, the reflectance ratio of 630 nm/580 nm was similar (P > 0.05) among dietary Mn supplementation levels; yet, by day 4 of retail display, chops from pigs fed 80 ppm Mn had higher (P < 0.05) reflectance ratios than chops from pigs fed 0, 20, 40, and 160 ppm, whereas LM chops from pigs fed 40 ppm Mn had lower (P < 0.05) reflectance ratios than all other dietary treatments on day 7 (Mn supplementation level × display day; P = 0.04). Although TBARS were greater (P < 0.001) on day 7 than 0 of retail display, TBARS values did not (P = 0.43) differ among dietary Mn levels. Results indicate that supplementing swine diets with 80 ppm Mn may improve pork color during retail display without increasing the likelihood of lipid oxidation.     

The effect of grazing saltbush with a barley supplement on the carcass and eating quality of sheepmeat

The carcass and eating quality of sheep grazing a saltbush dominant saline pasture system or on a ‘control’ dry pasture, stubble plot both supplemented with barley for 14 weeks was investigated (Experiment 1, 50 (2 × 25) 6 month merino lamb wethers and Experiment 2, 50 (2 × 25) 18 month old merino hogget wethers). Treatment had no significant effect on eating quality attributes (P > 0.05). Saltbush grazed sheep in both experiments had a significantly (P < 0.01) lower carcass fat and significantly higher lean (P < 0.01) content than the control grazed sheep. This is a positive finding as fat denudation is a significant cost to processors. The long term consumption of saltbush and barley prior to slaughter did increase muscle fluid content (P < 0.05) but did not result in a decreased carcass weight loss at slaughter due to confounding changes in body composition. Grazing saltbush resulted in increased urine weight (P < 0.001) and decreased urine concentration (P < 0.05) at slaughter indicating an improved hydration status at slaughter. However both experiments demonstrated sub-optimal liveweight gains indicating that saltbush with a barley supplement can still be effectively used as a maintenance ration without compromising carcass and eating quality.     

Effects of the inclusion of sodium bicarbonate and sugar beet pulp in the concentrate for fattening lambs on acid-base status and meat characteristics

Thirty-six young Merino lambs (15.3 kg live weight) were allocated into four equal groups to study the effects of the inclusion of sodium bicarbonate (‘Bic’, 0 vs. 2%) and sugar beet pulp (‘SBP’, 0 vs. 12%) in the concentrate on meat characteristics. Lambs were fed barley straw and concentrate ad libitum. When they reached 25 kg a blood sample was taken and the animal slaughtered. After 24 h meat characteristics (pH, colour, water holding capacity, Warner–Bratzler shear force, chemical and fatty acid – ‘FA’ – composition) were measured on M. longissimus thoracis et lumborum. SBP replacing 24% of the barley in the concentrate caused an increase in shear force (P < 0.05) and saturated FA (P < 0.05), decreasing meat unsaturated FA (P < 0.05). SB increased blood base excess (P < 0.05) and meat yellowness (P < 0.05) and decreased meat pH (P < 0.05), without altering any other meat characteristics.     

Augmented postmortem glycolysis does not occur early postmortem in AMPKγ3-mutated porcine muscle of halothane positive pigs

The objective of this study was to determine the effects of the halothane (HAL) and Rendement Napole (RN) genes on the rate-limiting reactions of glycolysis and their relationship to pork quality development. Samples were collected from the longissimus muscle at 0, 30, 60, and 120 min and 24 h postmortem from homozygous HAL and RN pigs (NN/rn⁺rn⁺, NN/RN⁻RN⁻, nn/rn⁺rn⁺, nn/RN⁻RN⁻). Muscle pH was recorded at 0, 15, and 45 min, and 24 h postmortem. HAL mutants, compared with HAL normal, had lower (P < 0.05) ATP concentrations at 0 and 30 min, lower (P < 0.05) pH at 45 min, and hastened glycogen degradation and lactate accumulation in the first 120 min postmortem (HAL × time, P < 0.0001). RN mutants had greater (P < 0.0001) glycolytic potentials than RN normal, and lower (P < 0.05) 24 h pH compared with the normal genotype, but not the HAL mutant genotype. The HAL mutation negatively affected (P < 0.05) L*, b* and color scores whereas both HAL and RN mutations independently decreased (P < 0.05) firmness, marbling and water holding capacity. RN mutant genotypes had higher (P < 0.0001) phosphocreatine concentrations than other genotypes at 0 min. Compared with HAL normal, HAL mutants had elevated (P < 0.05) muscle glucose concentrations at 30, 60, and 120 min, and 24 h. RN mutants had higher (P < 0.05) glucose levels than RN normal after 60 min. Glucose-6-phosphate (G6P) concentrations decreased (P < 0.05) during the first hour postmortem except in HAL/RN mutants, which had higher (P < 0.01) G6P concentrations than all other genotypes at 30 min. From 60 min to 24 h postmortem, G6P increased (P < 0.05) in HAL normal genotypes. Altogether, these data show that elevated muscle glycogen content does not further aggravate rapid early postmortem metabolism.     

Meat quality characteristics of springbok (Antidorcas marsupialis). 3: Fatty acid composition as influenced by age, gender and production region

The effects of age, gender and production region on the fatty acid composition of springbok Musculus longissimus dorsi (LD) were investigated. The major fatty acid of the LD muscle was stearic acid (C18:0), which contributed 23.92–27.02%. Oleic acid (C18:1) represented the largest component (16.33–20.45%) of the mono-unsaturated fatty acids (MUFA). The major n − 6 polyunsaturated fatty acid (PUFA) was C18:2n − 6, which formed 18.77–21.62%, whereas C18:3n − 3 (3.33–4.00%) was the most abundant n − 3 PUFA. The n − 6:n − 3 ratio of the meat varied from 3.02 to 3.35, with an average ratio of 3.2. Polyunsaturated to saturated (P:S) ratios varied between 0.96 and 1.18 and averaged at 1.06. Total MUFA was found to be higher (P < 0.05) in males (20.99%) than females (16.67%). The cholesterol content of the meat varied from 54.45 to 59.34 mg/100 g muscle. Linear correlations between the fatty acid and the intramuscular fat (IMF) content indicated a significant increase in certain saturated and mono-unsaturated fatty acids with increasing IMF content of the meat.