Postmortem Aging Time Research Articles

Evaluation of Fresh and Frozen Beef Strip Loins of Equal Aging Periods for Palatability Traits

Although studies evaluating freezing are prevalent, most have used varied postmortem aging times to facilitate study design. The lack of a comprehensive study evaluating equally aged fresh and frozen steaks prevents a true under-standing of the impact of freezing. Therefore, the objective of this study was to determine the eating quality and consumer perception differences between fresh and frozen beef steaks of 3 equal aging periods. Beef carcasses were selected from a processing plant on 2 kill dates 1 wk apart to allow for a 1-wk freezing period, fabricated, and aged for 21, 28, or 35 d. On the same day, all samples of equal aging periods were fed to consumer and trained sensory panelists, sheared for shear force, and powdered for lab assays. For consumer panels, the first 4 steaks were given with no additional information, whereas the last 4 steaks were served with the labels “previously frozen” or “fresh, never frozen.” The consumer panelists rated the frozen samples as more tender (P<0.05) than the fresh samples but found no other differences (P>0.05). Even when given additional information, the perception of quality was not impacted (P>0.05). Similarly, the trained panelists rated the frozen samples higher (P<0.05) than the fresh counterparts for overall tenderness, but the fresh samples scored higher (P<0.05) for initial and sustained juiciness. Supporting the sensory data, the frozen steaks had lower (P<0.05) shear force values regardless of the aging period. However, the fresh samples resulted in lower (P<0.05) purge and cook loss. Although some meat quality factors were impacted by freezing, the overall eating quality and perception of quality were not negatively impacted. Therefore, frozen meat should not be discounted due to the eating quality or perception of the quality of beef steaks.

The effect of modified atmosphere packaging at an early postmortem stage on lamb meat quality during subsequent aging.

This study explores the influence of modified atmosphere packaging (MAP) on fresh lamb meat quality with respect to gas concentration, rigor state, and post-mortem aging time. A comparison was done for the quality characteristics of lamb Longissimus thoracis lumborum chops that had been packaged separately in air, 75%O2 +25%CO2 MAP or 50%O2 +50%CO2 MAP at 1, 6, and 24h post-mortem and then stored for 6, 12, 24, 72, and 144h post-mortem, and the quality of lamb chops had been evaluated at each post-mortem period separately. Chops packaged at 1 and 6h post-mortem in MAP had reduced pH decline, less purge loss, and enhanced redness at early post-mortem storage times. Lamb color stability was evidently greater in 75%O2 +25%CO2 MAP than in 50%O2 +50%CO2 MAP during the early storage period when a* and R630/R580 were taken into account. Shear force values were lowest in lambs packaged at 1h post-mortem with 75%O2 +25%CO2 MAP at 12h post-mortem and then increased until 72h post-mortem, suggesting that rigor has been delayed by such a high O2 MAP. Thus, fresh lamb quality was maintained most effectively when packaged at 1h post-mortem in 75%O2 +25%CO2 MAP for consumption at 12h post-mortem. The exact mechanisms and optimization of MAP based on Chinese retail conditions should be considered in future studies. PRACTICAL APPLICATION: In this study, three slaughter patterns in the meat industry involving boning immediately after dressing (hot-boning) and chilling for a short period (warm-boning) or overnight (cold-boning) are considered, as well as the behavior of non-immediate consumption after purchase. Modified atmosphere packaging provides an effective preservation of early post-mortem muscles with enhanced color stability, water holding capacity, and texture during refrigerated storage. This could provide new insights into how to process lamb muscles in the early post-mortem period to improve and stabilize lamb quality.

Morphological changes of mitochondria-related to apoptosis during postmortem aging of beef muscles.

This study aimed to investigate how postmortem muscle cells' mitochondria changed in morphology from three aspects: the outer membrane, cristae, and fission/fusion. Atomic force microscopy (AFM) results showed that mitochondria underwent a morphology transformation from normal to swelling and collapse. Meanwhile, the cleavage of OPA1, upregulation of OMA1, downregulation of Mic60 and transmission electron microscope micrographs revealed that mitochondrial cristae ruptured with an aging time extended. Additionally, the increased expressions of Fis1 and Drp1, and the AFM topographic images mutually confirmed mitochondrial fission. These results further proved from the perspective of mitochondrial morphology that the degree of mitochondrial damage increased with the postmortem aging time extended, which was consistent with the results of the release of cytochrome c caused by the increase of mitochondrial permeability transition pore opening and the decrease of mitochondrial membrane permeability, and further induced the apoptosis of postmortem muscle cells.

Proteome changes in Neck-arm restraint and Achilles tendon suspensions during early post-mortem aging in cattle

The aging process of beef is impacted by the suspension method and aging time during the postmortem process. The neck-arm restraint (NR) suspension can accelerate the aging of beef carcasses compared with Achilles tendon (AT) suspension. However, the muscle protein changes between these two suspension methods in early postmortem aging are still unclear. This study aimed to investigate the proteomes of longissimus thoracis (LT) muscles between AT and NR suspension methods at 1 h and 72 h postmortem by the multiplexed isobaric tagging technology for relative quantitation (iTRAQ) technique and uncover the critical protein biomarkers of beef quality. A total of 59 proteins were differentially expressed between different suspension methods or postmortem aging times, which were mainly involved in actin cytoskeleton reorganization, actomyosin structure organization, response to calcium ions, and muscle contraction. Through the analysis of protein-protein interaction (PPI), we detected that ALB, APOA1, FGA, and TTN could be served as the hub proteins. Integration with the reported quantitative trait loci (QTL) of beef quality revealed that 30 differentially expressed proteins (DEPs) were involved in 46 QTL, in which, 11 proteins were differentially expressed in both the suspension method and time point comparison groups. We inferred these 11 proteins (MYL6B, MYO1A, COL3A1, AFP, CLN6, FGB, GLS2, BAG4, FGG, A2M, and WNT10A) as the most promising markers for the beef quality during the aging process.

Effect of slaughter age and postmortem aging time on tenderness and water-holding capacity of yak (Bos grunniens) longissimus thoracis muscle

The present study investigated the effect of slaughter age (2.43 ± 0.20, 4.15 ± 0.19, 6.62 ± 0.18, 10.59 ± 0.74 years) and postmortem aging time (1, 24, and 72 h) on the tenderness and water-holding capacity (WHC) of yak longissimus thoracis muscles to determine the most suitable age for slaughter to ensure product consistency. Under conventional postmortem aging conditions (4 °C), muscles of each age group exhibited the effect of cold shortening. Once the cold shortening occurred, the age effect on thickening muscle fiber and developing cross-links of collagen, considered to intensify the meat toughness, became less important. Owing to greater carcass weight and intramuscular fat, muscles of the older carcass (over 6-year-old) were less influenced by the cold shortening effect during the chilling process and showed lessened sarcomere contraction, delayed formation of drip loss channels, and increased level of myofibril fragmentation index (MFI) and myofiber structural disintegration, resulting in greater tenderness and WHC, especially 6–7 years group. Aging of 72 h structurally disintegrated the collagen cross-linking and integrity of muscle fibers and elevated the MFI, improving the meat tenderness. Therefore, the suitable slaughter age for yak is 6–7 years old and after 72 h aging, improved quality of yak meat can be obtained.

Effects of dietary supplementation with selenium yeast and jujube powder on mitochondrial oxidative damage and apoptosis of chicken

The main objective of this study was to explore the effects of dietary selenium yeast and jujube powder on mitochondrial oxidative damage and cell apoptosis of broilers during postmortem aging, chicken breasts of broilers fed diets supplemented with different concentrations of selenium yeast and jujube powder were used as research subjects. With the prolongation of postmortem aging time, the levels of reactive oxygen species (ROS), carbonyl content, mitochondrial permeability transition pore (MPTP) openness, and mitochondrial membrane permeability increased significantly (P < 0.05). The contents of the sulfhydryl, mitochondrial membrane potential, shear force, and cytochrome C (Cyt-c) reduction level decreased significantly (P < 0.05). The activity of Caspase-3 and Caspase-9 increased from 0 to 24 h postmortem but fell from 24 to 72 h postmortem. Compared with the control group, dietary selenium yeast and jujube powder significantly reduced mitochondrial oxidative damage. They greatly increased the shear force, mitochondrial membrane potential, and Cyt-c reduction levels (P < 0.05). Among them, the combination group of high-dose selenium yeast and jujube powder had more significant effects on ROS scavenging, reducing cell membrane permeability, protecting cell membrane integrity, and increasing Cyt-c reduction level (P < 0.05). In conclusion, cell apoptosis intensifies during the chicken breast's aging time, and muscle tenderness continues. Still, different doses of dietary selenium yeast and jujube powder can inhibit mitochondrial oxidation to various degrees. The combined group of selenium yeast and jujube powder with 0.6 mg·kg−1 has the best effect. This study is of great significance for applying natural antioxidant ingredients such as selenium yeast and jujube powder in the development and utilization of poultry feed.

Determining the longissimus lumborum and psoas major beef steak color life threshold and effect of post-mortem aging time using meta-analysis

longissimuslumborum (LL) and psoas major (PM) steaks duringretail display and the effect of postmortem aging time (PMT) on the displaycolor life of LL and PM steaks using meta-analysis was determined. In phaseone, data were retrieved from 13 and 3 referred journal articles, for LL andPM, respectively, that included a* and subjective visual scores. The total display dayobservations for LL and PM were 148 and 27, respectively. Lower bound estimatesusing a 95% confidence interval for a* as a borderline for the display colorlife of LL and PM steaks were 20.24 and 20.99, respectively. For phase two, datawere retrieved from 26 and 10 referred journal articles, for LL and PM,respectively, that included a* and PMT. The total display dayobservations for LL and PM in phase two were 255 and 71, respectively. For LLsteaks, the actual PMT was grouped into five categories: 0-7 d; 8-14 d; 15-21d; 22-28 d; and 29-65 d. Additionally, the PMT of PM steaks was grouped intotwo categories: 0-7 d and 8-21 d. The first 21 d PMT for LL steaks had thelongest color life with 7 d of color life. Additionally, 22-28 and 29-65 d ofPMT had 5 and 4 d, respectively, of color life for LL steaks. The borderlineacceptability estimated for PM steaks with 0-7 d and 8-21 of PMT was 3 and 2 dof color life, respectively. Estimations from this meta-analysis demonstrate that usingLL and PM subprimals having a PMT of 21 d or less and 7 d or less, respectively,would optimize retail display color life of aerobically packaged steaks.&amp;nbsp;

Exploration of flavor and taste of soft-boiled chicken at different post-mortem aging time: Based on GC-IMS and multivariate statistical analysis

As a well-known yellow-feathered broiler, Qingyuan partridge chicken was famous for its phenotype with developed subcutaneous and intermuscular fat, thin skin and soft bones. However, the formation mechanism of deeply preferred flavor for traditional low-temperature marinated Qingyuan partridge chicken has yet to be revealed. Post-mortem aging was a momentous process affecting the flavor. In order to explore the optimal post-mortem aging time, the primary physical and chemical characteristics including pH, texture, taste and flavor substances were investigated and analyzed by multivariate methods. The results demonstrated the characteristic taste of umami and sweetness, pH, hardness and cohesiveness were crucial indicators contributed to the sensory scores of different samples. Four free amino acids, three nucleotides, seven low-molecular weight water-soluble peptides and eight volatile aromas were identified as the main ingredients affecting the flavor. The result of partial least squares discriminant analysis (PLS-DA) indicated that the samples corresponding to1 and 2 h had obvious advantage in taste, but the sample produced at 1 h had a higher value of bitterness. It was determined that the soft-boiled chicken corresponding to post-mortem aging at 2 h was the most outstanding comprehensively, which could provide a theoretical basis for the further processing of yellow-feathered chicken.

Correlation of Bioelectrical Impedance With Freshness Quality Attributes of Beef Longissimus Lumborum Steaks

The quality attributes of beef longissimus lumborum during 15 d of retail display were assessed using surface bioelectrical impedance analysis (S-BIA) and internal bioelectrical impedance analysis (I-BIA). Beef loins (N = 18) were obtained from 3 commercial processors with 3 postmortem (PM) ages (27, 34, and 37 d). Loins were fabricated into twelve 2.54-cm-thick steaks, subdivided into 6 consecutively cut pairs, and randomly assigned to one of 6 display days (DD): 0, 3, 6, 9, 12, or 15. Steaks were assessed for S-BIA and I-BIA. Three locations were analyzed within each steak: top, middle, and bottom. Microbiological analysis, BIA, pH, instrumental color, proximate composition, and lipid oxidation were measured. There was a location × PM day × DD interaction (P &amp;lt; 0.05) for longissimus lumborum steaks for S-BIA. Among all 3 locations, steaks aged 27 d had higher (P &amp;lt; 0.05) S-BIA values on day 9 and 12 than steaks aged 34 and 37 d. There were no location × PM day × DD or two-way interactions (P &amp;gt; 0.05) for I-BIA. Display day affected (P &amp;lt; 0.05) all instrumental color data regardless of PM aging times. Among all PM aging times, steaks aged 27 d were 13% and 7% higher for a* and b* , respectively, compared with 34 and 37 d PM. There was a PM day × DD interaction (P &amp;lt; 0.05) for aerobic plate counts (APC). From day 0 and 9 of display, APC of steaks aged 27 d PM were 1 to 2.0 log colony-forming units/cm 2 lower than steaks aged 34 and 37 d. Quality attributes, including a*, b* , APC, and thiobarbituric acid reactive substances, were correlated (r = 0.70, − 0.64, − 0.56, and 0.69, respectively) with S-BIA. Overall, BIA values increased on aerobically packaged longissimus lumborum steaks and were correlated with various freshness quality parameters.

Postmortem Aging Time and Marbling Class Effects on Flavor of Three Muscles From Beef Top Loin and Top Sirloin Subprimals

This study evaluated postmortem aging time and marbling class effects on flavor attributes of longissimus lumborum, gluteus medius, and biceps femoris steaks. Carcasses selected to have Lower Small (Small00 to Small49; n = 50) or Upper Slight (Slight50 to Slight99; n = 50) marbling were assigned to aging treatments (14, 21, 28, or 35 d) in an incomplete block arrangement. A trained sensory panel evaluated longissimus lumborum, gluteus medius, and biceps femoris steaks for tenderness, juiciness, and 31 flavor notes. Tenderness increases with aging time were linear (P &amp;lt; 0.001) in longissimus lumborum and gluteus medius steaks and quadratic (P = 0.001) in biceps femoris steaks. Aging response of rancid flavor in longissimus lumborum steaks was cubic (P = 0.01), whereas the aging response of bloody/serumy flavor in biceps femoris steaks was quadratic (P = 0.03). Compared with Upper Slight marbling, carcasses with Lower Small marbling produced longissimus lumborum steaks with greater (P &amp;lt; 0.01) beef flavor and lesser (P = 0.001) bitter flavor, gluteus medius steaks with greater (P = 0.05) brown/roasted flavor, and biceps femoris steaks with greater (P = 0.02) fat-like flavor, although differences were small. Principal component analysis indicated that bloody/serumy, sour, metallic, and bitter flavor attributes were the strongest contributors to a factor explaining 38% of longissimus lumborum flavor variation. Barnyard, bitter, sour, rancid, and bloody/serumy were the greatest contributors to a principal component explaining 41% of gluteus medius flavor. Barnyard, rancid, sour, bloody/serumy, and bitter were contributors to a component explaining 63% of biceps femoris sirloin cap flavor variance. Sample score plots indicated that neither aging time nor marbling class was associated with principal components and identified production lot as contributing to principal components explaining flavor variation in all 3 muscles. Results indicate that, in strip loin and top sirloin subprimals from carcasses with Upper Slight and Lower Small marbling scores, aging time and marbling class had little impact on beef flavor. Thus, increased aging times could be used to enhance tenderness with no adverse effects on other important palatability attributes.

Flavor Characterization of Grass- and Grain-Fed Australian Beef Longissimus Lumborum Wet-Aged 45 to 135 Days

The study objective was to evaluate the effects of extended postmortem wet aging of Australian beef, cattle diet, and their interaction on objective and subjective measures of beef flavor of the longissimus lumborum. Beef strip loins were collected from grass- and grain-fed cattle (n = 50 total) at a commercial abattoir near Brisbane, Australia. Beef longissimus lumborum were portioned and assigned randomly to one of 3 postmortem aging periods (45, 70, or 135 d). As each section reached its respective postmortem aging designation, that section was fabricated into 2.5-cm steaks, individually vacuum packaged, and frozen (−21°C). Trained panelists evaluated cooked steaks for numerous flavor attributes, tenderness, and juiciness; volatile compounds were also evaluated. Sensory scores differed (P &amp;lt; 0.05) due to diet, whereby grain-fed samples were rated more intense (P &amp;lt; 0.05) for beef flavor identity, fat-like, liver-like, and sweet but grass-fed samples were more intense (P &amp;lt; 0.05) for green-hay and bitter. Juiciness, tenderness, and 4 flavor attributes (bloody/serumy, metallic, umami, and rancid) were similar (P &amp;gt; 0.05) between diets. Extending postmortem aging from 45 to 135 d resulted in decreased beef and umami flavors (P &amp;lt; 0.05), along with concurrent increased detection of off-flavors, such as liver-like, rancid, bitter, and sour (P &amp;lt; 0.05). Volatile flavor compounds were more influenced by postmortem aging than diet. Increased postmortem aging time increased concentration for both lipid oxidation and Maillard-reaction–derived volatiles, resulting in the concentration of negative flavor volatile compounds rather than the absence of positive flavor compounds. Based on these results, differences existed in the flavor profile of longissimus lumborum from grass- and grain-fed beef, regardless of postmortem aging. However, aging beef strip loins 135 d is not recommended based on reduced beef flavor and increased off-flavor detection compared to samples aged 45 or 70 d postmortem.

Evaluation of Beef Steak Exudate Differing in Quality Grade and Post-Mortem Aging Time

ObjectivesEvaluate absorbance and metabolite differences of beef exudate from raw beef steaks differing in quality grade and post-mortem aging time.Materials and MethodsUSDA Select (SE; n = 18) and USDA Choice (CH; n = 18) beef strip loins were aged for 7d, cut into 2.54 cm thick steaks, and randomly assigned a post-mortem aging duration of either 10 or 20d post-mortem (n = 72 total). Steaks were individually packaged on d7 and frozen on the assigned day at –20°C until time for analysis. Steaks were thawed for 24h at 4°C before 2 mL of exudate was collected from each bag on removal of the steak. The exudate was frozen at –80°C until further analysis. For analysis of absorbance, 0.5 mL of thawed exudate was diluted with 4.5 mL ultra-pure water and centrifuged. Then, 200 μL of the dilution was pipetted in triplicated onto a 96 well plate. Absorbance was read at a range of 350–700nm wavelengths. A dilution of 1:20 beef exudate: ultra-pure water was filtered and used for metabolite analysis. Using a HILIC column, 5 μL were injected into an organic mobile phase gradient and analyzed using an Agilent 6545 LC/MS-QTOF in positive mode. Data were analyzed using a two-factorial design with quality grade and post-mortem day of aging as fixed effects with an α of 0.05. Loin was included as a random effect. Least squares means, correlations, and principal component analysis were used to discriminate data.ResultsCH exudate had greater (P &lt; 0.05) absorbance than SE at wavelength ranges of 350–404, 423–467, and 491–508 nm. For the range of 350–598nm, CH exudate tended (P &lt; 0.10) to have a greater absorbance than SE exudate. No differences (P &gt; 0.05) were detected at all other wavelengths analyzed between quality grade. Post-mortem aging had no effect (P &gt; 0.05) on wavelength absorbance. Of the total metabolites present (n = 33) in the samples, no differences (P &gt; 0.05) were observed among fixed effects. Only three metabolites exhibited a twofold change in expression, observed as a downregulation from SE to CH exudate. With age, nearly two-thirds of the metabolites (n = 19) tended to increase in intensity. Tritriacontyl octacosanoate was unique to SE exudates.ConclusionBeef exudate tends to be influenced by quality grade more than post-mortem aging duration. Accordingly, exudate samples from raw steaks may be classified by quality grade no matter the duration of aging time.

Evaluation of Beef Steak Exudate Differing in Quality Grade and Post-Mortem Aging Time

Evaluation of Beef Steak Exudate Differing in Quality Grade and Post-Mortem Aging Time

Postweaning Exposure to High Concentrates versus Forages Alters Marbling Deposition and Lipid Metabolism in Steers

Angus-cross steers (n = 20; 261 ± 21.5 kg BW) were used to examine how early exposure to high concentrates or high quality forages altered marbling deposition and lipid metabolism. Steers were randomly assigned to high concentrate diet (CONC) or high quality forages (FOR) at 30-d postweaning, fed for 127 d, and slaughtered. Data were analyzed using a mixed model that included fixed effect(s) of dietary treatment (CONC vs. FOR), time (for plasma levels, ultrasound measures, and postmortem aging time) and two-way interaction (when appropriate). Steers fed CONC had greater (P &lt; 0.01) ADG and heavier (P &lt; 0.001) body weight at 127 d. Ultrasound measures over time showed greater (P &lt; 0.001) intramuscular fat deposition at d 98 and 126 for CONC than FOR steers. Steers fed CONC had elevated (P &lt; 0.05) plasma glucose and insulin concentrations from d 57 to 127 compared to FOR. Early exposure to CONC increased (P &lt; 0.01) dressing percent, HCW, LM area, 12th rib fat thickness, and marbling scores compared to FOR. Total lipid content of the LM was greater (P &lt; 0.01) for CONC than FOR; however, moisture, protein, and ash content was lower (P &lt; 0.01) for CONC than FOR. Concentrate fed steers had greater (P &lt; 0.01) MUFA content and lower (P &lt; 0.01) polyunsaturated fatty acids PUFA n-3 content than FOR. The n-6:n-3 ratio was greater (P &lt; 0.01) for CONC due to decreased (P &lt; 0.01) in n-3 fatty acid content with CONC. Gene expression was up-regulated (P &lt; 0.05) for key lipogenic genes and downregulated for glucose transporter 4 in steers fed CONC vs. FOR. Early exposure to CONC diets for 127 d at 30 d postweaning stimulated marbling deposition and resulted in these carcasses grading 80% Choice when slaughtered at 13 mo of age and 248 kg HCW.

Effect of postmortem aging time on flavor profile of stewed pork rib broth

ABSTRACTThe objective of this study was to investigate changes in flavor components in broth prepared by pork ribs that were aged for 1 d, 3 d, and 7 d. The contents of free amino acids (FAAs), nucleic acid-related compounds, organic acids, and volatile compounds in broth were measured. The overall taste and aroma profiles were evaluated by electronic tongue, electronic nose, and sensory panelists. The results showed that the FAAs and succinic acid contents increased, while the 5ʹ-guanosine monophosphate, 5ʹ-inosine monophosphate, and 5ʹ-adenosine monophosphate contents decreased as the aging time increased. These changes led to the taste characteristics of broth being more savory. However, the results of gas chromatography-mass spectrometry, electronic nose, and sensory test all showed that there were no significant differences in aroma among the samples, where the main volatile compounds of broth were aldehydes, including hexanal, nonanal, octanal, heptanal, (Z)-2-heptanal, and (E)-2-decenal. Hence, postmortem aging affected the taste rather than the aroma of pork rib broth, and extending aging time can improve the taste of broth.

Bioactive peptides in beef: Endogenous generation through postmortem aging

The present research was performed to investigate endogenous release of bioactive peptides in beef during postmortem aging times (1, 10 and 20days). Gradually decreased Warner-Bratzler shear force (WBSF) values of longissimus thoracis (LT) and semitendinosus (ST) muscles were observed and the degradation of structural proteins and collagen led to release of low-molecular weight (<3kDa) peptides. These peptides exhibited 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, ACE- and renin-inhibitory activities. The peptide sequences were identified by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). In silico analysis (PeptideRanker and BIOPEP) of their bioactivity potentials demonstrated peptides with the predicted bioactivity scores (>0.8) as well as collagen peptides with bioactivity scores (0.6–0.8). The present findings provide insights on development of healthy beef through postmortem aging at 4°C.

Rapid Discoloration of Aged Beef Muscles after Short-Term/Extreme Temperature Abuse during Retail Display.

The objective of this study was to evaluate the effects of a short-term/extreme temperature abuse (STA) on color characteristics and oxidative stability of aged beef muscles during simulated retail display. Two beef muscles (longissimus lumborum, LL and semitendinosus, ST) were aged for 7 (A7), 14 (A14), 21 (A21), and 28 d (A28), and further displayed at 2℃ for 7 d. The STA was induced by placing steak samples at 20℃ for 1 h on the 4th d of display. Instrumental and visual color evaluations, ferric ion reducing capacity (FRC) and 2-thiobarbituric acid reactive substances (TBARS) assay were performed. Initially, redness, yellowness and hue angle of all beef muscles were similar, regardless of aging time before display (p>0.05). An increase in postmortem aging time increased lipid oxidation and caused a rapid discoloration after STA during display (p<0.05). ST muscle was more sharply discolored and oxidized after STA, when compared to LL muscle (p<0.05). The FRC value of beef muscles was decreased after 7 d of display (p<0.05). The results from the current study indicate adverse impacts of postmortem aging on color and oxidative stabilities of beef muscles, particularly under temperature abusing conditions during retail display. Thus, developing a specific post-harvest strategy to control quality attributes in retail levels for different muscle types and aging conditions would be required.

Effects of enriching goat meat with n − 3 polyunsaturated fatty acids on meat quality and stability

The effect of enriching goat meat with n−3 polyunsaturated fatty acids (PUFA) on meat quality, sensory evaluation, and lipid oxidative stability at different postmortem aging times was investigated. Samples from longissimus thoracis muscle of Boer bucks (n=24) fed diets containing 0% (control, L0), 10% (L10), or 20% (L20) whole linseed were collected for analysis. For meat quality and oxidative stability, sub samples were subjected to 1-day or 7-day postmortem aging period. Feeding linseed had successfully increased n−3 PUFA in goat meat. The increments in 18:3 n−3 were 682% and 975% for L10 and L20, respectively, compared to L0. The increments in total n−3 PUFA were 444% and 590%for L10 and L20, respectively, compared with L0. There was no effect on cooking loss, shear force and color at 1-day aging time. However, at 7-day of aging time the color was affected. Subjectively, the tenderness, juiciness and overall acceptability of L20 meat were rated better than those of L0 and L10. However, no differences were detected in color, flavor, and aroma attributes from sensory evaluation. Lipid oxidation was increased with increasing the contents of n−3 PUFA and postmortem aging time.

Freezing Strip Loin and Top Round Steaks Improves Warner-Bratzler Shear Force

Postmortem aging of steaks is a common practice used to improve tenderness of beef steaks. The impact of proteolysis and improvement in tenderness due to aging varies among muscles. When designing research protocols, samples for Warner-Bratzler shear force (WBSF) are often frozen for later analysis because of convenience and time limitations. Freezing stops postmortem aging and allows for storage until meat can be cooked for WBSF and/or sensory analysis. However freezing meat may cause damage to cell membranes resulting in lower Warner-Bratzler shear force (improved mechanical tenderness), lower water holding capacity, and greater moisture loss during cooking. Several researchers have indicated that freezing strip loin (Longissimus muscle) steaks may lower Warner-Bratzler shear force (improve tenderness) compared with those not previously frozen and sheared fresh. However, these results have been inconclusive for steaks from other muscles. Therefore, the objective of this study was to determine the effects of postmortem aging time and freezing on Warner-Bratzler shear force of six muscles from the beef hindquarter.

Effects of post-mortem aging time and type of aging on palatability of low marbled beef loins

The study objective was to evaluate the effect of post-mortem aging period (14 to 49days), dry vs. wet (D vs W) type of aging on the palatability of bone-in (BI) beef short loins (n=96) and boneless (BL) strip loins (n=96) possessing United States Department of Agriculture marbling scores between Slight and Small. Warner-Bratzler shear force (WBSF) scores decreased linearly over time (P=0.0001). WBSF was not influenced by aging method or loin type. Aged flavor was higher for DBL than for DBI with WBL and WBI intermediate. Dry aging strip loins increase aged flavor yet did not improve beefy flavor compared to wet aging. Based on objective data and panelist's scores for tenderness, juiciness and aged flavor, a boneless, 28days wet aged strip steak, cooked to 71°C would provide the best combination of eating satisfaction and value.