Post-rigor Beef Research Articles

Application of gamma radiation in the beef texture development during accelerated aging.

This study aimed to evaluate the effects of gamma radiation (3kGy) on the quality of post-rigor beef (M. longissimus lumborum) aged for up to 21 days at different temperatures (1, 7, and 15°C). Irradiation reduced the mesophilic and lactic acid bacteria counts, which were higher in the non-irradiated samples aged at 7 and 15°C. The water retention capacity was lower in the irradiated beef, resulting in higher values of exudation and cooking losses. High aging temperatures increased the exudation loss and myofibrillar proteolysis (lower fragmentation index; FI) and reduced the total and insoluble collagen contents and the beef Warner-Bratzler square Shear Force (WBsSF). However, irradiated beef had higher FI and SF than non-irradiated ones, increasing the time required for the beef tenderizing. Gamma irradiation (3kGy) can be used to ensure the microbiological safety during short storage at high temperatures (up to 15°C) in order to accelerate the process of beef tenderizing.

Technological characteristics of pre- and post-rigor deboned beef mixtures from Holstein steers and quality attributes of cooked beef sausage

The objective of this study was to determine the effects of deboning time (pre- and post-rigor), processing steps (grinding - GB; salting - SB; batter formulation - BB), and storage time on the quality of raw beef mixtures and vacuum-packaged cooked sausage, produced using a commercial formulation with 0.25% phosphate. The pH was greater in pre-rigor GB and SB than in post-rigor GB and SB (P < .001). However, deboning time had no effect on metmyoglobin reducing activity, cooking loss, and color of raw beef mixtures. Protein solubility of pre-rigor beef mixtures (124.26 mg/kg) was greater than that of post-rigor beef (113.93 mg/kg; P = .071). TBARS were increased in BB but decreased during vacuum storage of cooked sausage (P ≤ .018). Except for chewiness and saltiness being 52.9 N-mm and 0.3 points greater in post-rigor sausage (P = .040 and 0.054, respectively), texture profile analysis and trained panelists detected no difference in texture between pre- and post-rigor sausage.

Consumer Acceptability and Willingness-To-Pay of Cooked Beef Bratwurst Sausage Formulated With Pre- or Post-Rigor Beef

ObjectivesThe current study was designed to determine consumer acceptability and willingness-to-pay (WTP) of 2 products, pre- and post-rigor beef Bratwurst sausages. Materials and MethodsFrom five 24-mo-old Holstein steers, the left chucks were deboned, ground (1.27-cm particle size), and salted (1.5% w/w) within 2 h post-mortem (pre-rigor treatment); whereas the right chucks were deboned at 72 h post-mortem (post-rigor treatment). On the day of sausage production (d 6 post-mortem), post-rigor trimmings were ground to 1.27-cm particle size and salted with 1.5% sodium chloride (w/w). Both pre- and post-rigor ground beef was processed into sausage batter by grinding the lean and fat trimmings separately through a 0.16-cm plate and mixing them with ingredients (beef bratwurst spice mix, water/ice slurry, corn syrup, erythorbate, nitrite, salt, and 0.25% w/w sodium tripolyphosphate). Sausages were cooked to 74°C by a generic smoked sausage cycle, including pre-drying, smoking, steaming, and cold shower, vacuum-packaged, and stored for 30 d at 2°C. Sausage links were warmed to 74°C and cut to 2.54-cm thickness. A total of 100 consumers evaluated appearance, aroma, flavor, texture, and overall acceptability on a 9-point hedonic scale. Each consumer was served with both pre- and post-rigor sausage from the same steer during each session. Immediately after the sensory evaluation, subjects were asked to formulate a WTP for each product using the information recorded on the evaluation sheets. A Becker–DeGroot–Marshak auction mechanism was used to solicit truthful WTPs. An aggregate unit-demand curve was constructed from the entire subject pool’s bidding data. Cluster analysis was conducted by the Agglomerative Hierarchical Clustering procedure in XLSTAT 2018.2.50198 using Ward’s method. Consumer acceptability was subsequently analyzed in each cluster by the GLIMMIX procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) at 0.05 level of significance. ResultsCluster analysis revealed 5 consumer clusters based on overall acceptability. Cluster 1 (7.9 and 8.1 overall acceptability unit for pre- and post-rigor, respectively; P = 0.130) and 5 (3.9 and 3.4 for pre- and post-rigor, respectively; P = 0.340) consisted of 40 consumers and had no difference in any sensory attribute between pre- and post-rigor treatments (P ≥ 0.091). However, panelists in cluster 3 (37 consumers) preferred the aroma, flavor, and texture of pre-rigor than post-rigor sausage (P ≤ 0.011). Similarly, 8 consumers in cluster 4 preferred the flavor, texture, and overall acceptability of pre-rigor than post-rigor sausage (P ≤ 0.020). However, 15 consumers in cluster 2 liked the texture of post-rigor sausage better (P = 0.004). Average predicted demand was 0.7 lb greater for pre-rigor than post-rigor sausage (P ≤ 0.001). In a scenario with a realistic market price of $6/lb, demand for pre-rigor sausage was 5% greater than post-rigor sausage. This greater demand for pre-rigor sausage might be driven by the greater acceptability of flavor and texture found in cluster 3 and 4. ConclusionPre-rigor processing yields sausage with greater consumer acceptability and demand. However, scalable production costs should be considered before finalizing the decision to implement pre-rigor processing in an industrial setting.

Quality properties of pre- and post-rigor beef muscle after interventions with high frequency ultrasound

The delivery of a consistent quality product to the consumer is vitally important for the food industry. The aim of this study was to investigate the potential for using high frequency ultrasound applied to pre- and post-rigor beef muscle on the metabolism and subsequent quality. High frequency ultrasound (600kHz at 48kPa and 65kPa acoustic pressure) applied to post-rigor beef striploin steaks resulted in no significant effect on the texture (peak force value) of cooked steaks as measured by a Tenderometer. There was no added benefit of ultrasound treatment above that of the normal ageing process after ageing of the steaks for 7days at 4°C. Ultrasound treatment of post-rigor beef steaks resulted in a darkening of fresh steaks but after ageing for 7days at 4°C, the ultrasound-treated steaks were similar in colour to that of the aged, untreated steaks. High frequency ultrasound (2MHz at 48kPa acoustic pressure) applied to pre-rigor beef neck muscle had no effect on the pH, but the calculated exhaustion factor suggested that there was some effect on metabolism and actin-myosin interaction. However, the resultant texture of cooked, ultrasound-treated muscle was lower in tenderness compared to the control sample. After ageing for 3weeks at 0°C, the ultrasound-treated samples had the same peak force value as the control. High frequency ultrasound had no significant effect on the colour parameters of pre-rigor beef neck muscle. This proof-of-concept study showed no effect of ultrasound on quality but did indicate that the application of high frequency ultrasound to pre-rigor beef muscle shows potential for modifying ATP turnover and further investigation is warranted.

A proposed mechanism of tenderising post-rigor beef using high pressure–heat treatment

Tenderness of beef M. Sternomandibularis was tough when cooked from both raw, and when previously heated (60 degrees C, 20 min), whereas a significant improvement in tenderness was achieved when pressure-heat (P-H) treated muscle (200 MPa, 60 degrees C, 20 min) was cooked. In order to determine the mechanism for this improvement, connective tissue, myofibrillar and sarcoplasmic proteins, were separated into three fractions and studied with regard to their solubilisation, denaturation and aggregation, degradation and strengthening of protein structures for the three treatments (raw, heated and H-P treated). Measurements included DSC, SDS-PAGE, surface hydrophobicity, and the appearance, length and width of myofibres (light microscopy). For the connective tissue fraction, heat solubility was determined. It is suggested that the mechanism for this improvement in tenderness is the formation of a strengthened myofibrillar structure that, when sheared by mastication, allows the crack to pass through the meat rather than dissipate into a more visco-elastic structure. In this way a more brittle fracture is achieved and the meat is perceived as more tender. The pre-requisite is that adequate enzymatic activity has occurred. It is suggested that cathepsins are responsible.

Changes in lysosomal enzyme activities and shear values of high pressure treated meat during ageing

The effects of pressure treatment (520 MPa for 260 s at 10°C) on lysosomal enzyme activities, Warner–Bratzler (WB) shear values and physico-chemical parameters of post-rigor (day 2) beef ( Biceps femoris and Longissimus dorsi muscles) were investigated immediately after treatment and during ageing. Activities of cathepsin D and acid phosphatase in pressurised meat samples were higher than in controls at 2 days post-mortem and throughout storage. This increase in activities was related to the breakdown of the lysosomal membrane and/or to enzyme activation. The WB peak forces were higher for pressurised samples of both muscles at 2 days than in the control and remained higher throughout ageing. The WB shear force deformation curves from pressurised samples showed that the increase in toughness was due to the increase in shear force of the myofibrillar component and not the collagen component. Pressurised muscle led to a significant decrease in sarcomere length and higher cooking loss. Post-rigor application of high pressure induced higher catheptic activity but no conclusive effect on the post-mortem rate of tenderization or tenderness of meat was observed.

Modifications of Ultrastructure and Myofibrillar Proteins of Post-rigor Beef Treated by High Pressure

This study was conducted in order to determine the effects of high pressure treatment on several parameters that contribute to beef tenderness. Isolated myofibrils and post-rigor steaks of Biceps femoris muscles (2 d post-mortem) were pressurized from 100 to 600 MPa for 260 s at 10 °C. Electron micrographs showed modifications on both cross and longitudinal sections depending on the intensity of pressure applied. After treatment at 130 MPa, the ultrastructure of longitudinal and cross sections was similar to the control. The changes occurred from 325 MPa pressure. Ultrastructural changes included a heterogeneous aspect on the intermyofibrillar space attributed to the aggregation or coagulation of proteins, and the disappearance of the M-line in the H-zone and loss of integrity of I-band filament. The intensification of costameres and intermediate filament bundles could also be observed. A significant increase in the area of myofibrils and in myofibrillar solubility was observed in pressurized samples. Moreover, electrophoretic analysis revealed increased solubilization of two myosin light chains (LC1 and LC2) after treatment at 300, 400 and 600 MPa.

Proteolytic activity of four strains of Pseudomonas on crude extracts of contractile proteins

Hydrolytic activities of exogenous proteases obtained from Pseudomonas upon crude extracts of contractile proteins were studied. Four strains were used: C61 and C20, isolated from beef samples, and P. fragi (ATCC-4973) and P. fluorescens (NRRL-B-1244). Proteolytic activity was tested on crude extracts of actomyosin, myosin+ actin+regulatory proteins, actin and high molecular weight proteins obtained from postrigor beef by differential precipitation according to their solubility in salt solutions of various ion strengths. Electrophoresis analysis showed considerable degradation of actomyosin in samples treated with a C61 enzymatic extract. Myosin degradation was similar for treatments with proteases obtained from C61 and P. fragi. Actin degradation was similar for all enzymatic extracts. The most active protease was a 46.8 kDa enzyme produced by C60. P. fragi produced two proteases of 49.2 kDa and 34.2 kDa, P. fluorescens one of 46.1 kDa, and C20 one of 49.2 kDa.

The effects of hot water pasteurizing treatments on the appearances of pork and beef

Portions of post- and pre-rigor pork and beef were treated by immersion in water of 75 or 85 °C for 5, 10, 15 or 20 s. The appearances of untreated and treated cut muscle, fat, membrane covered and cut bone surfaces, and the overall appearances of treated and untreated meat pieces, were assessed by a 5-member panel 2 hr and 24 hr after each treatment. At those times, CIE L ∗a ∗b ∗ values were obtained for cut-muscle surfaces. The appearances of surfaces covered by membrane, of fat and cut bone surfaces of pre-rigor pork and beef, and of fat and cut bone surfaces of post-rigor pork, were not persistently degraded by any treatment. However, the appearances of fat and cut bone surfaces of post-rigor beef were persistently degraded by the harsher treatments, apparently because of pre-treatment staining of fat and changes in the bone marrow. Panel scores for the overall appearance and for the appearance of cut muscle surfaces were generally the same for each meat piece. All treatments caused patchy bleaching of cut muscle. The degraded appearances of pre- and post-rigor pork and post-rigor beef muscle persisted at 24 hr, but the appearances of beef muscle treated pre-rigor improved between 2 and 24 hr. Most treated muscle gave increased CIE L ∗ values and decreased a ∗ and b ∗ values as compared with untreated portions from the same primal cut. However, CIE b ∗ values for pre-rigor beef muscle were higher than for untreated muscle 2hr after treatment, but lower than for untreated muscle 24 hr after treatment. It appears that pasteurizing treatments cannot be applied to meat without some degradation of the appearances of cut muscle surfaces, which will persist in pork treated pre- or post-rigor and in beef treated post-rigor, but which will partially resolve during the storage of beef treated pre-rigor.

Reductions of Listeria innocuaand Brochothrix thermosphactaon beef following nisin spray treatments and vacuum packaging

Sections of UV sterilized lean and adipose tissues from the surfaces of post-rigor (24 h post-mortem) beef carcasses were inoculated withBrochothrix thermosphacta orListeria innocua to obtain approximately 4.50 log 8cfu cm −2and subjected to spray treatments with sterile water or nisin (5000 AU ml −1). Untreated and spray treated samples were vacuum-packaged, and incubated at 4°C for up to 4 weeks. Bacterial populations from untreated vacuum-packaged tissues and spray treated, vacuum-packaged tissues were enumerated on non-selective and selective media at 0, 7, 14, 21 or 28 days. Nisin spray treatments of lean and adipose vacuum-packaged tissues reduced the numbers of L. innocua up to 2.83 log 8cfu cm −2. Additionally, nisin sprays and vacuum packaging effectively suppressed L. innocua during the 4-week incubation such that the remaining bacteria did not grow to the same level as untreated or water-treated, vacuum-packaged tissues. Nisin spray treatments and vacuum packaging of lean and adipose tissues reducedB. thermosphacta to undetectable levels. Data from this study demonstrate that nisin spray treatments followed by vacuum packaging under refrigerated conditions could increase the shelf life by suppressing or inhibiting the growth of undesirable bacteria present on fresh beef.

Effect of heating rate on palatability and associated properties of pre- and postrigor muscle.

Precooked, uncured meat is not widely available to consumers, partially because of associated palatability problems and lack of published information on heat uptake under different industrial conditions. The objectives of this study were to determine the tenderness, extent of lipid oxidation, and total cooking losses in pre- and posterior beef and pork roasts heated at different rates. The muscles were cooked in stainless-steel, perforated heating chambers at oven temperatures of 150, 200, or 250 degrees C and the temperature rise during and after heating was monitored with a digital temperature recorder. Samples were vacuum-packaged, frozen at -20 degrees C for 45 d, thawed at 4 degrees C for 24 h, and reheated in 60 degrees C water for 1 h. Cooking losses, Warner-Bratzler shear force values, thiobarbituric acid values, and pH were determined. The results provide heating curves for pre- and postrigor beef and pork roasts at three oven temperatures. Prerigor samples of both species were less tender than postrigor samples (P < .05). Cooking losses were generally low in prerigor samples of both species compared with postrigor samples (P < .05). All beef samples had relatively low thiobarbituric acid (TBA) values before and after storage, whereas pork samples had relatively high TBA values before and after storage. Results indicate that prerigor cooked roasts shrink less, are equivalent or better in oxidative stability, and are less tender than postrigor cooked roasts under the conditions of this experiment.

Microbiological Condition of Restructured Steaks Prepared From Pre- and Postrigor Beef

In two experiments the microbiological quality of restructured steaks prepared from hot and cold boned beef was investigated. Half of each electrically stimulated carcass was hot boned (ca. 45 min postmortem), and the other side was deboned after 20–24 h chilling. For both experiments, defatted desinewed neck and flank muscles were flaked, and 1 % NaCl was added to half of the meat batches. In experiment 1, meat batches were stored at −40°C for ca. 1 month, then tempered, restructured into steaks and refrozen. In experiment 2, restructuring of the hot boned meat followed the flaking process, then steaks were stored at −40°C. After thawing, steaks were stored at 1±1°C until sampled. Sampling occurred after 1, 4, 8, 11 and 15 d in experiment 1 and after 1 and 7 d in experiment 2, and included assays for aerobic mesophilic and psychrotrophic colony counts and Enterobacteriaceae. Results of experiment 1 indicated that deboning treatment did not affect bacterial numbers significantly. Initial contamination levels were low (ca. 4 log10 CFU/g) and spoilage occurred after ≥8 d of storage. In experiment 2, deboning treatment had a significant effect on bacterial growth. Initial (mesophilic and psychrotrophic) contamination was lower on hot processed steaks, yet after 7 d of refrigerated storage, bacterial numbers were higher (p<0.95) on hot vs. cold boned steaks.Experiments 1 and 2 showed that salt did not affect bacterial growth.

Effect of salt on myoglobin derivatives in the sarcoplasmic extract from pre- and post-rigor beef in the presence or absence of mitochondria and microsomes

The effect of salt and pH on the colour stability (oxymyoglobin) in the sarcoplasmic extract (SPE) prepared from pre- and post-rigor beef muscle was studied in the presence or absence of mitochondria and microsomes during 96 h at 4°C. The sarcoplasmic extract from the post-rigor meat (pH 5·4) or from the pre-rigor meat adjusted to pH 5·4 contained more oxymyoglobin (MbO 2) than the pre- or post-rigor SPE maintained at pH 7·4. The presence or absence of mitochondria and microsomes in the SPE at pH 5·4 had little effect on the percentage of MbO 2. At pH 7·4, however, the percentage of MbO 2 decreased in the SPE in the presence of mitochondria, whereas the percentage of MetMb was lower in the presence of microsomes. The relative proportion of MbO 2 decreased and that of metmyoglobin (MetMb) increased with increasing salt concentration at low pH (more so in the absence of subcellular organelles) and with storage period in the SPE from both pre- and post-rigor meat. However, at pH 7·4, high levels of salt (2–4%) helped to maintain a high percentage of MbO 2 in SPE in the absence of subcellular organelles, especially the mitochondria. The first-order interactions of pH value × subcellular organelles ( P < 0·01) and pH value × salt concentration ( P < 0·01) accounted for about 55% of the total variation in the percentage of MbO 2 in the SPE. It is suggested that depressing microbial growth may be the operative mechanism by which added salt stabilizes the colour in pre-rigor minced meat rather than by enzymic effects of subcellular organelles.

MECHANICAL PROPERTIES OF FISH AND BEEF GELS PREPARED WITH AND WITHOUT WASHING AND SODIUM CHLORIDE

ABSTRACTExcellent gels, as measured by fold test, were prepared from three species of fish without first washing the minced tissue. Dependent on species (red hake, cod, or winter flounder), excellent to adequate gels, as determined by the fold test, could be prepared from fish muscle without NaCl provided that the minced tissue was washed prior to gel formation. Postrigor beef formed inadequate gels while excellent to good gels could be produced from prerigor beef although salt was a requirement. The concentration of contractile proteins in fish gels was estimated and they did not appear to be a major factor determining gel quality. Soluble muscle protein did not appear to interfere with gel formation either. Percent expressible moisture, percent recovery, and modulus of deformability did not relate well to fold test scores.

Effect of salt on oxidative changes in pre- and post-rigor ground beef

Pre- and post-rigor beef was ground and salt was added to give 0·0, 0·5, 2·0 and 4·0% NaCl (w/w). Samples were removed after 0, 24, 48, 72 and 96 h at 4°C and analyzed for pH, TBA numbers and percentages of reduced myoglobin (Mb), metmyoglobin (MMb) and oxymyoglobin (MbO 2). After holding for 96 h the samples were cooked in a boiling water bath to an internal temperature of 80°C and held at 4°C for 48 h before TBA analysis. Pre-rigor grinding and salting reduced the post-mortem pH decline and the extent of meat discoloration as shown by the differences in the amount of MMb. The extent of lipid oxidation as measured by TBA numbers was not significantly different for the pre- and post-rigor ground salted meat samples, although salt accelerated oxidation during storage. Results demonstrated that pre-rigor grinding and salting of beef produces a more stable bright red color, which appears to be associated with a lower percentage of MMb and a higher ultimate pH in the pre-rigor salted meat.

Use of Cryoprotectants to Stabilize Functional Properties of Prerigor Salted Beef During Frozen Storage

ABSTRACTChanges in functional properties (gelforming ability, water‐holding capacity, and protein solubility) of salted prerigor beef and postrigor beef were measured over 6 months frozen storage at −28°C, as affected by addition of 5.6% cryoprotectants [Polydextrose® or a mixture (1:1) of sucrose and sorbitol]. Addition of NaCl to comminuted muscle prior to freezing accelerated destabilization of muscle proteins with respect to functional properties. This effect was reduced by cryoprotectants; most effectively by sucrose/sorbitol and only slightly less effectively by polydextrose. As evidenced by the parameters investigated, quality of prerigor salted muscle treated with cryoprotectants and stored 6 months was approximately equal to that of untreated postrigor meat prior to freezing.

Effects of Rigor State, Salt Level and Storage Time on Chemical and Sensory Traits of Frozen and Freeze-Dried Ground Beef

Both pre- and post-rigor beef semimembranosus muscles were ground with salt (0, 2 and 4%) and then subdivided into two treatment groups (freezing and freeze drying) and evaluated during storage of 0, 5, 10 and 15 wk for chemical and sensory traits. Rehydration ratios of pre-rigor freeze-dried beef (salted or unsalted) were not significantly changed during a 15-wk storage period at 25°C. With the addition of 2 and 4% salt, pre-rigor freeze-dried beef was less susceptible (P<0.05) to lipid oxidation (lower TBA values) than post-rigor, freeze-dried beef. Pre-rigor, freeze-dried beef was superior to post-rigor, freeze-dried meat in all sensory traits studied. Differences in TBA values were not significant between pre-rigor and post-rigor, frozen beef treatments at any salt level (0, 2 and 4%). Pre-rigor, frozen beef samples were superior (P<0.05) to conventional post-rigor, frozen meat in panel tenderness and acceptability scores. The TBA values of pre- and post-rigor beef (frozen or freeze dried), in general, increased with increased salt level (0, 2 and 4%). Freeze-dried beef samples (pre- or post-rigor) were less (P<0.05) tender, cohesive, acceptable and more rancid and/or off-flavor than frozen meat (pre- or post-rigor).

Hydrophobicity and water holding parameters of pre- and post-rigor beef neck muscle

Hydrophobicity and water holding parameters of pre- and post-rigor beef neck muscle

Effects of Rigor, Salt, Freezing, Lyophilization and Storage Time on pH, Water-Holding Capacity and Soluble Protein Nitrogen in Beef Muscle

The water-holding capacity (WHC) of frozen and reconstituted lyophilized (freeze-dried) beef (both pre- and post-rigor) increased (P<0.05) with the increase in salt levels (0, 2 and 4%). Freeze-dried and reconstituted beef had lower (P<0.05) WHC than the frozen control at all salt levels tested. The freeze-drying process may damage some of the beef muscle proteins. The WHC of the freeze-dried beef (both pre- and post-rigor) decreased (P<0.05) with the increase of storage time (10 weeks). Salt (2 and 4%) retarded the glycolysis process in the pre-rigor frozen and freeze-dried beef as indicated by higher (P<0.05) pH values than the post-rigor frozen and freeze-dried beef. The addition of salt (0, 2 and 4%) increased (P<0.05) the extractable soluble protein nitrogen content in the prerigor frozen beef and decreased (P<0.05) the soluble protein nitrogen content in the post-rigor frozen beef. The pre-rigor freeze-dried beef with 2% salt contained (P<0.05) more extractable soluble protein nitrogen than the other two pre-rigor freeze-dried groups (0 and 4% salt). The pre-rigor beef contained more (P<0.05) extractable soluble protein nitrogen than the post-rigor beef at the three different salt levels (0, 2 and 4%) during the 15 weeks of storage.

Effects of Mechanical Tenderization and Cooking Treatments upon Product Attributes of pre-and post-Rigor Beef Roasts

Effects of Mechanical Tenderization and Cooking Treatments upon Product Attributes of pre-and post-Rigor Beef Roasts