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Objective: This study was aimed to investigate the muscle-specific beef color stability at normal and high ultimate pHs. Methods: The impact of muscle (Longissimus lumborum [LL] vs psoas major [PM]) and pH (normal ultimate pH [Np] vs high pH dark cutting beef [Hp]) on color stability, indicated by basic color traits, metmyoglobin reducing activity (MRA) and oxygen consumption (OC), as well as the lipid oxidation, were determined over 7 days of display at 4°C. Results: Hp-LL had the highest pH (6.92), followed by Hp-PM (6.01), Np-PM (5.76), and Np-LL (5.52). Hp-LL had increased (p<0.05) a*, chroma and % oxymyoglobin during display. Hp-LL also had the highest metmyoglobin (MMb) reducing activity and OC among all the samples, thus, the greatest color stability, although very dark throughout storage, with lowest values for lightness (L*) and yellowness (b*). Np-LL also exhibited relatively high color stability, as a result of its lower % MMb and OC and higher MRA than psoas muscle samples. The 0.2 unit difference of the pH between Hp and Np psoas muscle, resulted in the difference of the color intensity, not the color stability. Interestingly, high pH psoas muscle (Hp-PM) did not have better color stability than Np-PM, and in fact had lower color stability than even Np-LL. The similar level of OC and lipid oxidation cannot explain the difference in color stability between Hp-PM and Np-LL. Conclusion: The Hp does not always show better color stability compared with Np beef, which depends on the muscle type. The balance of MRA and OC is important to keep the color in great intensity and stability in the meantime. [ABSTRACT FROM AUTHOR]

In this study, the relationship between sensory evaluation and several objective metrics of beef tenderness was tested. Objective metrics included shear force, sarcomere length, collagen content, myofibrillar, and sarcoplasmic protein solubility and particle size analysis. These results were compared to consumer panel scores of tenderness for the same aged beef striploin (longissimus lumborum muscle) samples. There was found to be a significant relationship between sarcomere length, shear force, and particle size with tenderness scores. Collagen content and protein solubilities were not associated to tenderness scores (p > 0.05). Sarcomere length contributions for explaining tenderness variation were overlapped by the contributions of shear force (collinearity). Independent models demonstrated that the lower 95% confidence interval of the fitted regression line exceeded 50% acceptance of tenderness when shear force values <42.6 N and when particle size values <198 μm. We can recommend these as thresholds for consumer acceptance of beef tenderness, although considerations of sample type, analytical methodology, and consumer demographics should be made prior to their adoption. This provision was based on the variation in tenderness scores evident between individual panelists and experimental striploins. [ABSTRACT FROM AUTHOR]

The potential of spatially offset Raman spectroscopy (SORS) for distinguishing different beef cuts was investigated. Six different retail beef cuts (rump, Scotch fillet, round, chuck, tenderloin, and T‐bone) were analysed spectroscopically using SORS. This technique makes it possible to measure the Raman signal 5 mm below the surface of meat muscles, allowing non‐invasive analysis of meat samples that are not readily feasible using conventional Raman spectroscopy. This study has shown for the first time that monitoring of the changes in glycogen, fat, and protein content of muscles can be investigated directly and, most importantly, non‐invasively within various meat cuts. The spectral results reveal differences in structure‐sensitive bands from the amide I and III regions as well as from cysteine, glutamic acid, and phenylalanine vibrations. Statistical analysis confirms these observations based on strong clustering of SORS bands (this was derived from principal component analysis scores of the SORS data) measured for the different cuts. Highlights: Deep Raman spectroscopy was employed to investigate the subsurface composition of meatNon‐invasive differentiation of dissimilar meat cutsIdentification of biomarker bands for each individual meat cutsStatistical analysis clustering of each meat cut confirmed the spectroscopic results [ABSTRACT FROM AUTHOR]

Summary: The global population is becoming older, and still, this cohort considers red meat (beef and sheep meat) as an important staple in their diet. It is understood that the requirements from these red meats will vary as a person ages, often because of associated physiological changes; nutrition and health concerns; and reduced sensorial capacities. This creates an imperative to develop red meat products that appeal and satisfy the demands of elderly people. Here, we have reviewed current literature with the aim to comprehend the elderly consumer market, their demands for nutritive and quality traits, and their requirements for safe and convenient red meat (beef and sheep) products. Based on these studies, it was apparent that these specifications may be delivered using available knowledge of intrinsic and extrinsic influences on red meat if considered within the context of elderly customers, that is, to deliver upon elderly people's requirements for conventional red meat products which are inexpensive, of consistent and perceivable high quality, and quell any associated health concerns for the consumer. [ABSTRACT FROM AUTHOR]

Abstract The bolar blade, striploin and topside cuts from dark cutting (DC) and normal (nDC) beef carcasses were compared in terms of their eating quality, oxidation and colour traits. Carcass grades were assigned so that striploins assessed to have pH > 5.7 were classified DC. Cuts were aged (14 and 28 d) before their shear force, sarcomere length, ultimate pH, particle size, TBARS, drip and cooking losses, and colour stability traits were analysed. DC effects on tenderness traits were not uniform across all cuts. Only TBARS was influenced by grade and ageing period interactions. Colorimetric variation due to grade was more evident in the striploin than the other cuts, although this was independent to ageing or display. Cuts themselves differed and were impacted by ageing and display periods. It was concluded that unlike the topside and striploin, the bolar blade from DC carcasses had comparable quality to nDC and could therefore retain its value if priced independent to the entire carcasses. [ABSTRACT FROM AUTHOR]

Abstract We compared the capacity for the Nix Colour Sensor Pro™ (NIX) and HunterLab MiniScan™ (HUNTER) to detect colour variation using aged (0, 3 and 5 weeks) and then displayed (0, 1, 2 and 3 d) beef M. longissimus lumborum samples (n = 8). NIX L* and hue values were found to be respectively higher and lower than for the HUNTER. No significant interactions between instrument and display or ageing periods were identified for a* – unlike for b* and chroma where NIX measures were observed to be lower than those from the HUNTER. Both instruments identified ageing and display period effects on colorimetric traits. Based on these results, the NIX cannot be considered comparable to the HUNTER when measuring beef colour – albeit captured similar colorimetric trends over display and ageing periods which suggest its independent usefulness to beef colour assessment. [ABSTRACT FROM AUTHOR]

This study evaluated a microwave (Mw) cooking method for determining beef toughness using the Warner–Bratzler slice shear force (WBsSF) protocol. Longissimus thoracis muscles were aged for 1, 10, 19, and 28 days at 4C. They were then either cooked on a clam‐shell grill until reaching an internal temperature of 72C, in a Mw for 100 s at maximum power (Mw100) or for 140 s at 60% of maximum power (Mw60). Cooking loss and shear force (SF) values were higher in Mw samples than in grilled ones. SF assessment by grill and Mw100 were able to discriminate tenderness by aging times in the same way as the sensory panel. The SF measured in a grilled sample had higher repeatability (R = .74) and correlation with sensory scores (r = −.79) than Mw100 (R = .61; r = −.62) and Mw60 (R = .51; r = −.53). Mw100 can be considered as an appropriate alternative for the WBsSF protocol. Practical applications: Tenderness is the most important attribute for consumers. Many studies have evaluated tenderness in meat and different protocols for cooking. This work was intended to optimize and evaluate the use of the microwave as a cooking method for shear force determination, against a standard protocol and establish the correlation to sensory tenderness. [ABSTRACT FROM AUTHOR]

Dark cutting in beef and sheep meat has been the subject of extensive research with numerous associations established between it and various production practices. Despite these associations, dark cutting still occurs and causes significant financial losses globally in the fresh meat market. Consumers tend to reject dark meat as it is perceived to be from old or poorly-handled animals and is described as being tough, having an undesirable flavor, and having a short shelf-life. There is no universal system to categorize dark cutting carcasses and meat across countries, although various methods are used to determine the phenomenon. Classifying carcasses as dark cutters on the basis of ultimate pH or color using one muscle, such as the m. longissimus thoracis can lead to mis-description of other muscles within the same carcass and loss of income across the supply chain. The purpose of this review was to identify the factors predisposing animals to dark cutting and to provide recommendations and directions for future research. The review revealed no single production factor causing dark cutting, but that a range of factors or a combination of factors and interactions lead to its occurrence. Dark cutting is a complex condition that can be resolved through comprehensive management of animals, and management of human involvement, and clear guidelines to minimize the incidence of 'dark cutting' meat and to improve the profitability of all sectors in the supply chain are provided here. [ABSTRACT FROM AUTHOR]

Intramuscular fat (IMF) is an important trait for beef eating quality. The mechanism of how IMF is deposited in beef cattle muscle is not clear at the molecular level. The muscle ( M. longissimus lumborum : LL) of a group of Xiangxi yellow × Angus cattle with high fat levels (HF), was compared to the muscle of a low fat group (LF). The meat quality and the expressed protein patterns were compared. It was shown that LL from the HF animals had a greater fat content (P < 0.05) and lower moisture content (P < 0.05) than LL from LF animals. Forty seven sarcoplasmic proteins were differentially expressed and identified between the two groups. These proteins are involved in 6 molecular functions and 16 biological processes, and affect the Mitogen-activated protein kinases pathway, insulin pathway and c-Jun N-terminal kinases leading to greater IMF deposition. Cattle in the HF group had greater oxidative capacity and lower glycolytic levels suggesting a greater energetic efficiency. [ABSTRACT FROM AUTHOR]

Meat scientists often use objective, laboratory-based methods to understand the sensorial properties of red meat. These approaches are advantageous because of their reproducibility, low cost, rapid generation of data and technical ease – comparative to large scale consumer sensory panels. To enhance the value of these methods, effort has been applied to identify specific limits or thresholds that correspond to a consumer's acceptance or satisfaction with the quality of a meat product. From the literature, we observe there to be inconsistencies in these thresholds. This could stem from disparate laboratory methods, consumer panel procedures and demographics, the approach to statistical analysis, sample type and representativeness, and more. This paper aimed to review consumer thresholds, proposed in the literature, to provide insight into their validity and transferability to other studies. Investigations were limited to red meat (beef and sheep meat) and to non-spectroscopic methods that have been used to predict consumer acceptance of colour, tenderness, juiciness, flavour and overall liking. [ABSTRACT FROM AUTHOR]

In this study, pH, meat color analysis, microbial counts and Raman spectroscopic data were obtained from beef steaks stored at 4 °C for up to 21 days using two different packaging methods: vacuum (VP) and modified atmosphere packaging (MAP). Models using partial least square regression (PLSR), indicated that Raman spectroscopy was able to predict total viable counts (TVC) and lactic acid bacteria (LAB) measured at 21d post mortem (TVC in VP: R 2 cv = 0.99, RMSEP = 0.61; TVC in MAP: R 2 cv = 0.90, RMSEP = 0.38; LAB in VP: R 2 cv = 0.99, RMSEP = 0.54; LAB in MAP: R 2 cv = 0.75, RMSEP = 0.60). The results of this study demonstrate that Raman spectroscopy may have potential for the rapid determination of meat spoilage. • Raman spectroscopy has potential for the rapid determination of meat spoilage. • Preliminary investigation suggests total viable counts at 21 d can be predicted. • Models indicated the potential to predict lactic acid bacteria. [ABSTRACT FROM AUTHOR]

Abstract: SmartShape™ is a novel meat processing technology that uses air pressure to compress and elongate whole cold-boned primals and packages them to retain form. A two stage study was conducted. The first stage established the ability of the SmartShape™ treated beef cube roll (m. longissimus lumborum) to retain shape in a commercial setting. Twelve hours chilling time following treatment was found to be adequate for steaks to retain their shape for up to 24h after slicing. Steak shape and size did not change substantially until after cooking, when the steaks looked less formed. In the second stage a survey was conducted of 421 consumers to clarify the response to the shaping of a subset of raw and cooked scotch fillet steaks. There was no difference in preference for shaped or control steaks. A secondary survey found that informed consumers were more amenable to the SmartShape™ scotch fillet steaks presented here, but would not pay a premium for them. [Copyright &y& Elsevier]

In order to explore the effect of sub-freezing storage on water holding capacity and tenderness of beef, four treatments were compared in this study: sub-freezing (−7 °C) fast sub-freezing (−38 °C until the core temperature achieved to −7 °C), superchilling (−1 °C) and fast frozen (−38 °C until the core temperature achieved to −18 °C) with the latter two treatments serving as the controls. The differences in muscle fiber structure, water distribution, protein oxidation and cytoskeletal protein degradation were studied. The results demonstrated that compared with other treatments, the fast sub-freezing treatment resulted in less structural damage to the muscle fibers and had better water holding capacity. Both sub-freezing and fast sub-freezing treatments inhibited protein oxidation compared with superchilling, but the former treatment's level of protein oxidation was higher than that in fast sub-freezing treatment during long-term storage (42 weeks). In addition, the structural proteins in the sub-freezing and fast sub-freezing treatments underwent faster degradation during long-term storage and therefore the meat was more tender compared with the fast frozen treatment. The results indicate that the fast sub-freezing treatment can be potentially applied in beef storage. • Factory fast freezing and home refrigerator slow freezing of beef were simulated. • The differences of beef under sub-freezing and other groups were compared. • Beef of the fast sub-freezing group has better water holding capacity. • The reasons for the better tenderness in the fast sub-freezing group were analyzed. • The advantages of fast sub-freezing in beef storage were demonstrated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Superchilling (SC) caused the earlier activation of μ-calpain and caspase 3. • SC caused an enhancement in the degree of actomyosin dissociation. • Metabolite abundances differed in SC and conventional chilling (CC) samples. • 4-hydroxyproline is a critical metabolite that distinguishes between SC and CC treatments. • The SC affected the arginine and proline metabolism, as well as purine metabolism. To explore the underlying mechanisms by which superchilling (SC, −3 °C within 5 h of slaughter) improves beef tenderness, an untargeted metabolomics strategy was employed. M. Longissimus lumborum (LL) muscles from twelve beef carcasses were assigned to either SC or very fast chilling (VFC, 0 °C within 5 h of slaughter) treatments, with conventional chilling (CC, 0 ∼ 4 °C until 24 h post-mortem) serving as the control (6 per group). Biochemical properties and metabolites were investigated during the early post-mortem period. The results showed that the degradation of μ-calpain and caspase 3 occurred earlier in SC treated sample, which might be attributed to the accelerated accumulation of free Ca2+. The metabolomic profiles of samples from the SC and CC treatments were clearly distinguished based on partial least squares-discriminant analysis (PLS-DA) at each time point. It is noteworthy that more IMP and 4-hydroxyproline were found in the comparison between SC and CC treatments. According to the results of metabolic pathways analysis and the correlation analysis between traits related to tenderness and metabolites with significant differences (SC vs. CC), it can be suggested that the tenderization effect of the SC treatment may be related to the alteration of arginine and proline metabolism, and purine metabolism in the early post-mortem phase. [ABSTRACT FROM AUTHOR]

[Display omitted] • Beef steaks were divided into three groups according to ultimate pH (pHu): N, I, H. • IpHu and HpHu group showed the highest and lowest shear force. • The earlier activation of caspase 9 contributed on the better tenderness of HpHu beef. • Nine differential phosphorylated peptides were detected to link with pH u and WBSF. • Phosphorylation of glycogen synthase may cause the delay of tenderization of IpHu beef. This study investigated the relationship between tenderness and protein phosphorylation levels of normal ultimate pH (pH u , 5.4–5.8, NpH u), intermediate pH u (5.8–6.2, IpH u) and high pH u (≥6.2, HpH u) Longissimus lumborum from beef. During 21 d of ageing, the HpH u group had the lowest Warner-Bratzler shear force (WBSF) values, while the IpH u group showed the highest and even after 21 days of ageing still had high levels. In the late stage of the 24 h post-mortem period the faster degradation rate of troponin T and earlier activation of caspase 9 in the HpH u group were the key reasons for the lower WBSF compared with the NpH u and IpH u groups. The activity of caspase 3 cannot explain the tenderness differences between IpH u and HpH u groups, since their activities did not show any difference. At 24 h post-mortem , 17 common differential phosphorylated peptides were detected among pH u groups, of which nine were associated with pH u and WBSF. The higher phosphorylation level of glycogen synthase may have caused the delay of meat tenderization in the IpH u group. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the shelf-life and microbial community dynamics of super-chilled vacuum-packaged beef striploins imported from Australia to China after approximately five weeks of shipping time and an additional 15 weeks of storage at −1 °C ± 0.5 °C. Data analysis using a mixed model (REML) with time as the fixed effect and portion as a random effect, showed that the only beef quality trait that changed during storage was total volatile basic nitrogen (TVBN; P <.05), which reached the threshold of 15 mg/100 g between 15 and 20 weeks (including 5 weeks of transport). The total viable count (TVC) accounted for 78% of the variance in TVBN, when storage time was included in the model. Sensory scores decreased as storage time extended (P <.05), but were still acceptable at 20 weeks. After 9 weeks, Carnobacterium spp. and Lactobacillus spp. dominated alternately and then Lactobacillus became the most prevalent bacteria. An operational taxominc unit based hierarchical cluster analysis using the unweighted pair-group method with arithmetic means was performed and it was shown that the bacterial communities tended to be consistent as storage time extended. Overall indications are that beef which is safe can be imported into China from Australia and aged for extended periods. Unlabelled Image • Shelf-life of beef cuts imported from Australia to China was evaluated based on TVBN. • TVC accounted for 78% of the variance in TVBN during the storage of beef up to 20 weeks. • The sensory scores decreased as time extended, but were still acceptable at 20 weeks. • Carnobacterium spp. and Lactobacillus spp. dominated alternately after 9 weeks. • Lactobacillus became the most prevalent bacteria in the end of the storage. [ABSTRACT FROM AUTHOR]

Abstract The ageing of beef is essential to provide a tender product which is deemed acceptable by consumers, with beef processors routinely ageing beef for ~ 14 d at 0–2 °C. The rate of tenderisation is directly affected by temperature, and as such the possibility of decreasing the required ageing time by increasing storage temperature could provide an opportunity to decrease associated costs. To test this, 320 beef M. longissimus lumborum portions were subjected to one of 72temperature-time combinations (TTC) incorporating temperatures of 3, 5 or 7 °C and ageing times of 6, 8, 10 or 12 d, with some temperature changes occurring during ageing. Controls (n = 32) were held at ~ 1 °C for 14 d. The application of TTCs did not affect beef quality, however longer storage at higher temperatures resulted in higher microbial loadings. Therefore, it can be concluded that shorter, cooler TTCs could be implemented to decrease ageing time requirements and maintain beef safety. Highlights • Different temperature-time combinations on eating quality and safety were tested. • Higher temperatures and longer ageing time influenced microbial safety. • Temperature-time combinations did not influence colour or quality. • Temperature-time combinations did not influence consumer satisfaction. [ABSTRACT FROM AUTHOR]

Abstract The effect of superchilled storage (SC, −4 °C) on shelf life and quality characteristics of M. longissimus lumborum from Chinese Yellow cattle compared with traditional chilling (TC, 2 °C) and frozen storage (−18 °C) was studied. The shelf life of beef steaks held at −4 °C extended to 12 weeks based on the total volatile basic nitrogen (TVB-N) value, which was 2.4 times longer than steaks stored at 2 °C. As the storage time increased, SC samples showed a lower increase of the total aerobic count (TAC), pH and thiobarbituric acid reactive substances (TBARS) values compared to TC samples. Further, L ⁎ and a⁎ values of SC samples changed more slowly than that of TC samples. Beef steaks held frozen had a longer shelf life than SC steaks, however, the shear force of frozen steaks remained above 55 N throughout the storage time indicative of toughness. Consequently, SC offers an effective approach for maintaining better shelf life and quality of beef steaks. [ABSTRACT FROM AUTHOR]

Abstract Within 24 h post-mortem , loin surfaces of Australian beef carcasses (n = 436) were evaluated using the Nix Pro Color Sensor™ (NIX). The potential for colorimetrics (L*, a*, b*, hue and chroma) to discriminate between dark cutting (DC) and non-dark cutting (nDC) carcasses was compared. For this purpose, a chroma threshold of 30.5 delivered maximum total sensitivity and specificity. The bolar blade, striploin and topside from a selection of DC and nDC carcasses were also removed, aged for 14 d and tested for shear force, drip loss, cooking loss, ultimate pH, colour change over 3 d display (ΔE), and sarcomere length. Association between chroma values and these quality traits were investigated by linear models. The hypothesis of zero slope was rejected (P < 0.05) for pH on striploin and topside, but the models had poor predictive ability (R 2 = 0.23). The NIX was found to be a viable grading tool, with limited capacity to provide additional insights into beef quality. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of homogenisation speed and centrifugation on particle size (PS) evaluation, and examine its relationship with shear force. Beef Longissimus lumborum (LL) muscle portions were randomly assigned to different ageing periods (0, 3 or 5 weeks), and tested for PS and shear force. The PS analysis was conducted at different homogenisation speeds (11,000, 16,000 and 19,000 rpm) with and without a centrifugation step prior to measurement. Samples homogenised at 11,000 rpm and not centrifuged gave PS results significantly different at each ageing time as did samples homogenised at 19,000 rpm and centrifuged. Overall samples homogenised at 11,000 rpm produced the lowest coefficient of variation for PS results. There was a significant correlation between PS and shear force across the different homogeniser speeds and centrifugation statuses. It is concluded that best practice when measuring PS in beef includes a homogeniser speed of 11,000 rpm with no centrifugation prior to measurement. [ABSTRACT FROM AUTHOR]

In this study, carbon monoxide (CO) modified atmosphere packaging (MAP) was used to increase redness (a *) and lightness (L *) values of dark cutting beef (ultimate pH (pHu) ≥ 6.10), compared to normal pHu beef and intermediate pHu beef (pH: 5.40–5.79; pH: 5.80–6.09, respectively) during 20 d chilled storage. Compared with HiOx-MAP, CO-MAP exhibited similar color improvement effects (increased L *, a *, b * values) for all pHu beef groupings. The metmyoglobin (MetMb) content was lower under CO-MAP than that of HiOx-MAP in normal pHu beef, but opposite effects were observed in dark, high pH beef. This result could not be explained by MetMb reducing ability (MRA) and lipid oxidation, as both parameters were higher in CO-MAP beef than either normal or high pHu beef, compared with HiOx-MAP. In conclusion, CO-MAP was effective to maintain the cherry red color for dark cutting beef, but the color improvement mechanisms might be different with HiOx packaging methods. [ABSTRACT FROM AUTHOR]

We aimed to establish colorimetric thresholds based upon the capacity for instrumental measures to predict consumer satisfaction with beef colour. A web-based survey was used to distribute standardised photographs of beef M . longissimus lumborum with known colorimetrics (L*, a*, b*, hue, chroma, ratio of reflectance at 630 nm and 580 nm, and estimated deoxymyoglobin, oxymyoglobin and metmyoglobin concentrations) for scrutiny. Consumer demographics and perceived importance of colour to beef value were also evaluated. It was found that a* provided the most simple and robust prediction of beef colour acceptability. Beef colour was considered acceptable (with 95% acceptance) when a* values were equal to or above 14.5. Demographic effects on this threshold were negligible, but consumer nationality and gender did contribute to variation in the relative importance of colour to beef value. These results provide future beef colour studies with context to interpret objective colour measures in terms of consumer acceptance and market appeal. [ABSTRACT FROM AUTHOR]

The quality, colour, and shelf-life of wet aged grass and grain-fed beef were compared. Striploins (n = 24) were each divided into 6 portions and were assigned to different ageing periods (0, 3, 5, 8, 11, or 14 weeks). Analysis demonstrated that declines in shear force and particle size occurred within the first 3 weeks of ageing. Extended ageing resulted in increases in beef purge and pH; and decreases in total moisture, drip, and cooking loss. The initial grass-fed beef drip (3.1%) and particle sizes (201.0 μm) were higher than for grain-fed beef (1.8% and 145.2 μm, respectively). Total viable counts were > 7 cfu/g after 5 weeks of ageing. Total volatile basic nitrogen was < 15 mg/100 g, even after 14 weeks of ageing. Product line by ageing period interactions affected vitamin E and colour parameters. In conclusion, wet aged beef maintains 'acceptable' microbial loads for 5–8 weeks, irrespective of product line and without any deterioration in its quality. [ABSTRACT FROM AUTHOR]

The effects of repeated (1 ×, 2 ×, 3 ×) pulsed electric field (PEF) treatment (10 kV, 90 Hz, 20 μs) on the quality of beef loins and topsides were evaluated, including the tenderness, purge loss, cooking loss, myofibrillar protein profile and post-mortem proteolysis. Both muscle types were obtained from each of 12 steers and were processed within 6 h. After PEF treatment samples of both muscle types were subjected to 3, 7, 14 and 21 days ageing. The 1 × and 2 × PEF treatments had no effect on the tenderisation of hot-boned beef Musculus longissimus lumborum muscle for all ageing treatment times, while the 3 × treatment reduced the tenderness. The opposite effect was observed in hot-boned beef Musculus semimembranosus muscles where the 3 × treatment produced meat with lowest shear force at 3 days post-treatment time, but this beneficial effect disappeared with longer ageing times. An increase in proteolysis of troponin T was seen to the largest extent with 1 × PEF treatment and decreased with every extra application of treatment. [ABSTRACT FROM AUTHOR]

The objective of this study was to identify the tenderness and energy metabolism attributes in normal ultimate pH (pH u , 5.4–5.8, NpH u), intermediate pH u (5.8–6.2, IpH u) and high pH u (> 6.2, HpH u) Longissimus lumborum from beef. During 21 days of aging, the IpH u group exhibited a higher Warner-Bratzler shear force, lower activity of μ-calpain, and a higher content of heat shock protein 27 and greater protein oxidation. Metabolomics analysis revealed that 24 differential metabolites were detected during the first 24 h postmortem between pH groups, and these were mainly the products of glycolysis, the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. The relatively higher adenosine triphosphate content in the IpH u group could delay tenderization by being used as key substrate for protein phosphorylation. In addition, the relationship between guanosine triphosphate, diphosphate and monophosphate, and beef tenderness was worthy to be verified in the future study. [ABSTRACT FROM AUTHOR]

The current research evaluated the combined effect of oxygen concentration (20%, 50% and 80% O 2) and storage temperature (4°C or −1.5°C) on the fresh and internal cooked color of dark-cutting (DC) beef. Steaks were packaged in modified atmosphere packaging (MAP) over a 12-day storage period. Although the metmyoglobin reducing activity (MRA) of DC steaks decreased with increasing O 2 levels, lower oxygen consumption (OC) and deeper oxygen penetration depth (OPD) improved the surface color of 50%O 2 -MAP and 80%O 2 -MAP DC steaks. 80%O 2 -MAP resulted in the highest (P < 0.05) percentage myoglobin denaturation and alleviated the phenomenon of persistent pink (PP) observed in DC beef. Compared with normal chilling, superchilling significantly increased the redness values of DC steaks through inhibition of lipid oxidation and enhancement of MRA, while it had no effects on PP due to the limited OPD. The results suggest that 80%O 2 -MAP combined with superchilling can be used to improve fresh color and minimize PP of DC beef. • 50%O 2 -MAP and 80%O 2 -MAP effectively improved the surface color of DC steaks. • 80%O 2 -MAP relieved the development of persistent pinking (PP) in cooked DC steaks. • Superchilled beef had higher MRA and redness, but lower TBARS than chilled beef. • Superchilling did not improve the PP of DC steaks due to the limited OPD. [ABSTRACT FROM AUTHOR]

The relationship between instrumental colorimetric values (L*, a*, b*, the ratio of reflectance at 630 nm and 580 nm) and consumer perception of acceptable beef colour was evaluated using a web-based survey and standardised photographs of beef m. longissimus lumborum with known colorimetrics. Only L* and b* were found to relate to average consumer opinions of beef colour acceptability. Respondent nationality was also identified as a source of variation in beef colour acceptability score. Although this is a preliminary study with the findings necessitating additional investigation, these results suggest L* and b* as candidates for developing instrumental thresholds for consumer beef colour expectations. [ABSTRACT FROM AUTHOR]

Abstract: The impact of SmartStretch™ technology and ageing (0 or 14days ageing) on the meat quality traits of m. longissimus lumborum hot-boned from adult cull cattle was assessed. Tenderness, as reflected in reduced shear force measurement, was significantly (P <0.05) improved in 0day aged stretched samples over the non stretched samples. After 14days ageing there was no longer any difference in the tenderness between stretched and non stretched samples and the aged meat was significantly tenderer than either the SmartStretch™ treated or non stretched meat aged for 0days. Sarcomere length was unchanged by stretching. Presentation traits such as purge loss and fresh colour were unaffected by the stretch treatment, whilst cooking loss was significantly (P <0.05) increased by stretching and ageing for 14days. [Copyright &y& Elsevier]

Abstract: The impacts on traits of the m. gluteus medius hot-boned from young cattle were assessed after stretching (SmartStretch™) and ageing (0 or 8days ageing). Tenderness, as reflected in reduced shear force measurement, was significantly (P <0.05) improved in 0day aged stretched samples over the un-stretched control. After 8days ageing there was no longer a difference in the tenderness between stretch treatments. Meat aged for 8days was significantly more tender than 0day aged meat irrespective of treatment. Sarcomere length was significantly (P <0.05) increased by stretching. There was a significant (P <0.05) negative relationship between sarcomere length and shear force. Presentation traits, such as purge loss and fresh colour, were unaffected by the stretch treatment, while cooking loss was significantly (P <0.05) reduced by stretching in the 0day aged samples. [Copyright &y& Elsevier]

Beef longissimus lumborum muscles (24) were each portioned into 6 steaks, and these were held at ~0.5 °C for up to 14 weeks. Total volatile basic nitrogen (TVB-N) data was compared against other measures of quality and freshness: total viable microbial count (TVC), ultimate pH, drip loss, purge, moisture content, cook loss, shear force, particle size, vitamin E, intramuscular fat content (IMF) and colour parameters. There was an association between TVB-N and colour parameters; and between TVB-N and several parameters for microbial load, tenderness and moisture. IMF and vitamin E were not correlated to TVB-N. TVB-N of 5.1 mg/100 g (95% confidence intervals: 4.6–5.5 mg/100 g) was estimated as equivalent to a TVC of log 7 cfu/g. When beef samples were categorised as either spoilt or fresh using this TVC recommendation, TVB-N was correct in 77.9% of its assignments. Additional investigation is necessary to confirm this result against a larger sample population with a broader range of TVB-N values. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the effect of packaging conditions on bacteriological and biochemical changes in beef steaks classified here, as normal ultimate pH (pHu; 5.40–5.79), intermediate pHu (5.80–6.09) or high pHu (≥ 6.10). Steaks were packaged in vacuum packaging (VP) and modified atmosphere packaging with high oxygen (HiO 2 -MAP) or carbon monoxide (CO-MAP). Headspace, bacterial counts, total volatile basic nitrogen, pH, purge loss, surface color, lipid oxidation, and sensory attributes were monitored over a 14-day storage period at 2 °C. HiO 2 -MAP and CO-MAP of high pHu steaks resulted in a bright red color even when observed to be spoilt. Reduced purge loss and lipid oxidation, as well as increased sensory acceptability were observed for steaks with elevated pHu. Higher pHu was also accompanied by an acceleration of microbial proliferation. Of all packaging types investigated, CO-MAP exerted the best preservation, regardless of pHu and based on its antibacterial and antioxidant properties. • CO-MAP had the best preservation due to its antibacterial and antioxidant effect. • The bright red color achieved with CO-MAP and HiO 2 -MAP could mask spoilt DC beef. • DC beef showed low lipid oxidation, purge loss and shear force even under HiO 2 -MAP. • Tenderness, juiciness, and overall liking scores increased as pHu elevated. [ABSTRACT FROM AUTHOR]

[Display omitted] • The quality traits of VSP beef were evaluated after 3% lactic acid spray before packaging (LLA). • LLA samples exhibited the lowest TVBN and TVC values during the storage of 32 days. • LLA showed the best antibacterial potential without any deleterious effects on the VSP chilled beef. • This is attributed to the reduction of Proteobacteria and B. thermosphacta of LLA beef steaks. A long shelf life for fresh meat products is very important both to processors, retailers and consumers. In this work, the effect of repeat acid spraying on the shelf life of vacuum skin-packaged (VSP) chilled beef, as well as the quality and microbial community dynamics was evaluated. Carcasses were sprayed with 300 ppm peroxyacetic acid (PA) or 3% lactic acid (LA) three times during the chilling process, or one more time of LA spray before packaging (LLA). Quality, sensory attributes and microbial load of VSP beef during 32 days of storage at 4 °C were evaluated. The results showed that quality and sensory scores decreased over time for all treatments, but LLA treated samples were still above the rejection threshold at the end of the storage period. Moreover, the total volatile basic nitrogen value and the total viable counts were 15.0 mg/100 g and 7.2 log CFU/g for the control group, while acid treated groups remained below these two values until the end of the storage period. In particular LLA treated beef steaks exhibited the best preservation potential even at the end of storage. This is attributed to the reduction of Proteobacteria in LLA beef steaks shown by the bacterial diversity analysis via high-throughput sequencing, as well as the lower counts of B. thermosphacta and Enterobacteriaceae during storage. This indicates that LLA treatment has the potential to achieve a shelf life extension of VSP steaks without impacting on quality. [ABSTRACT FROM AUTHOR]

This study defined the pH threshold for dark cutting beef of Asian consumers using a web-based survey and examined their preferences for beef appearance. Ninety individual images of beef steaks with different pH values were randomly selected to be scored by 4322 respondents. Gender, age and beef eating habits of respondents were found to impact on color preferences. With respondent's visual score of 4 set as the acceptance threshold, linear regression analysis between visual scores and beef instrumental colorimetrics, showed that the acceptance thresholds of instrumental color values were L* ≥ 31.4, a* ≥ 16.4, b* ≥ 6.5, chroma ≥17.4 and hue ≥22.5. These corresponded to pH threshold values of 6.11, 6.20, 6.28, 6.25 and 6.29, respectively. This pH benchmark (6.11 to 6.29) for dark cutters is higher than pH thresholds applied in most countries, indicating that Asian consumers prefer darker meat than expected, however, the likely tenderness of beef with pH's at this level merits consideration. [ABSTRACT FROM AUTHOR]

The effect of medium voltage electrical stimulation (ES), prior ageing (0–4 °C, 7 days), and their combination on the decrease of shear force in beef during superchilled storage (−4 °C) for 24 weeks was evaluated, in the context of a high shear force obtained under this storage condition. Both ES and prior ageing significantly reduced the initial Warner-Bratzler shear force, and the combination of ES and prior ageing shortened the storage time needed to reach an acceptable shear force of superchilled beef, which is mainly due to increased myofibrillar degradation as indicated by changes in desmin (P < 0.01, r = 0.35). Additionally, ES and prior ageing did not negatively affect lipid oxidation, total volatile basic nitrogen or water loss of superchilled beef. Consequently, ES combined with ageing for 7 days offered an effective approach for decreasing shear force and ensuring good quality superchilled beef. [ABSTRACT FROM AUTHOR]

Over the last two decades, proteomics have been employed to decipher the underlying factors contributing to variation in the quality of muscle foods, including beef tenderness. One such approach is the application of high-throughput protein analytical platforms in the identification of meat quality biomarkers. To broaden our understanding about the biological mechanisms underpinning meat tenderization across a large number of studies, an integromics study was performed to review the current status of protein biomarker discovery targeting beef tenderness. This meta-analysis is the first to gather and propose a comprehensive list of 124 putative protein biomarkers derived from 28 independent proteomics-based experiments, from which 33 robust candidates were identified worthy of evaluation using targeted or untargeted data-independent acquisition proteomic methods. We further provide an overview of the interconnectedness of the main biological pathways impacting tenderness determination after multistep analyses including Gene Ontology annotations, pathway and process enrichment and literature mining, and specifically discuss the major proteins and pathways most often reported in proteomics research. Unlabelled Image • Beef tenderness proteomics studies published during the last decade were gathered and analyzed. • 124 protein biomarkers of beef tenderness were retrieved from 28 independent proteomics experiments. • Protein biomarkers of beef tenderness belong to 6 interconnected biological pathways. • 64 biomarkers were identified with a cut-off ≥2 and 33 robust biomarkers were shortlisted with a cut-off ≥4. • Muscle structure, energy metabolism and cellular responses to stress and oxidative stress are the main pathways underpinning beef tenderness determination. [ABSTRACT FROM AUTHOR]

Beef rolls for hot pot are usually stored and transported in a frozen state, and the beef color deteriorates quickly. This paper reports on an investigation into the effect of packaging method, freezing temperature and storage time on instrumental color, pH, myoglobin state, lipid oxidation (TBARS) and total volatile basic nitrogen (TVB-N) of beef rolls. It was shown that the color of beef rolls at −18 °C was better than that at −12 °C overall, and the OxyMb% and pH values were higher, while the MetMb% and TBARS were lower with storage at −18 °C. With the extension of storage time, the instrumental color, OxyMb% and pH values of beef rolls decreased. Correspondingly, the MetMb% and TBARS showed an upward trend. However, the TVB-N of all treatments did not exceed the Chinese standard during 180d of storage. The results of this paper provide a number of recommendations for the storage of frozen beef rolls to extend color-shelf life. [ABSTRACT FROM AUTHOR]

Beef ageing (in vacuo) for tenderisation and flavour development may be accelerated by favourable temperature-time combinations (TTCs), however the effect of such manipulations on volatile organic compounds (VOCs) that are generated during cooking, is unknown. We compared VOCs from grilled beef longissimus lumborum muscle samples which had been subjected to different TTCs. The TTCs consisted of combinations of temperatures (~ 3, 5, or 7 °C) and ageing time periods (6, 8, 10 or 12 d); as well as control samples, which were held at 0-2 °C for a total of 14 d. Sensory quality attributes of these same samples were measured by untrained consumer panellists. Generally, it was found that TTCs had negligible effects on grilled beef VOCs and were comparable to controls. Furthermore, many VOCs were significantly related to flavour intensity, flavour liking and overall liking. These findings support the use of TTCs as a viable means to accelerate the rate of beef ageing without compromising quality. [ABSTRACT FROM AUTHOR]

Label-free proteomics was applied to understand the color and color stability development of dark cutting beef (DC). The color traits of DC (pH = 6.86) and normal beef (pH = 5.49) were determined during 7 days of display. DC had a lower redness and greater color stability, which was attributed to its higher deoxy-myoglobin content, greater oxygen consumption, as well as higher metmyoglobin reducing activity and lower lipid oxidation. A total of 28 differentially expressed mitochondrial proteins (fold change >1.8) between the two groups were identified, with 21 proteins overexpressed in DC mainly involved in oxidative phosphorylation, generation of reducing equivalent, TCA cycle and chaperones. These enhance the level of mitochondrial respiration, the stability of reducing MetMb and myoglobin and mitochondria function, leading to color characteristics of DC. Moreover, Glutaryl-CoA dehydrogenase was for the first time reported to be significantly associated with color parameters and its direct relationship with meat color is worthy investigation. [ABSTRACT FROM AUTHOR]

A study was undertaken to establish a consumer threshold for the colour of beef rolls used for hot pot cooking in China. This was achieved by using an internet-based online survey, in which Chinese respondents recorded their preferred meat colour from a selection of 12 different images that represented a range of objective colour measures (CIE colorimetrics). The results indicated that, of the 2021 respondents, 97.6% liked to eat hot pot. When colour preference was modelled against objective measures of colour, the a * value was identified as providing the most suitable insight into respondents' preferences for the colour of frozen beef rolls to be used in hot pot cooking. Based on the results an acceptance threshold of a * value ≥16.4 proposed. [ABSTRACT FROM AUTHOR]

To evaluate different methods for the determination of postmortem myofibrillar fragmentation, three protocols were compared: fragmentation index method (FI) after drying the filtrate residue at room temperature for 10 min (FI room) or at 105 °C for 12 h (FI oven); and myofibrillar fragmentation index (MFI) by the absorbance method. Beef Longissimus thoracis steaks (n = 34) were randomized into two treatments (frozen/thawed and unfrozen) and aged for 0, 7, 14 or 21 days. An interaction (P < 0.05) between method and treatment, method and aging and treatment and aging was found. FI room was the best to detect a difference in fragmentation at all aging days. In addition, FI room and FI oven both detected the tenderization process that occurs by freezing while the MFI method did not, yet all three methods were similarly related to tenderness as measured by shear force. It is suggested that FI room is the most effective method (time, cost) to indicate myofibrillar fragmentation, under the conditions imposed herein. • Three protocols were compared to determine the myofibrillar fragmentation. • The choice of the better method implications better results. • The faster and less laborious method (FI room) was most effective than others. • The FI room detected the extent proteolysis at all aging days. • The FI room detected the myofibrillar changes induced by the freezing process. [ABSTRACT FROM AUTHOR]

Temperature-time combinations (TTC) effects on beef fatty acid (FA) composition, moisture content and oxidative traits were investigated. TTC were designed so temperatures were constant over each time period, and there was at most one variation in temperature within a sample's combined (total) time period. Therefore, three temperatures (~ 3, 5 and 7 °C) and five time periods (6, 8, 10 and 12 d) resulted in 72 different TTC, which were compared to control samples held for 14 d at ~ 1 °C. It was found that moisture losses increased as TTC temperature and time periods increased. There were negligible effects of TTC on FA composition. Sample TBARS and vitamin E content did not respond to TTC. A positive relationship between beef vitamin E and long chain polyunsaturated FA contents was observed. We concluded that TTC could be applied to accelerate the rate of ageing for beef and achieve comparable yield, oxidative and FA characteristics compared to conventional ageing approaches. [ABSTRACT FROM AUTHOR]