Effects of stepwise dry/wet-aging and freezing on meat quality of beef loins

Effect of wet-aging on meat quality and exudate metabolome changes in different beef muscles

The aim of this study was to evaluate meat quality and changes in the meat exudate metabolome of different beef muscles (5 d postmortem, longissimus lumborum and psoas major muscles) during wet-aging (additional 3, 7, 14, 21, and 28 d of aging). Shear force of meat declined significantly (P < 0.001) with aging, meanwhile, increased myofibril fragmentation index, lipid and protein oxidation with aging were observed (P < 0.01). Psoas major (PM) showed significantly higher (P < 0.05) purge loss, centrifugal loss, and cooking loss, as well as higher tenderness and more severe lipid and protein oxidation (P < 0.01) than longissimus lumborum (LL) during aging. Principal component analysis of the metabolomic profiles revealed distinct clusters according to the period of aging and the type of muscle simultaneously. Overabundant amino acids, peptides, oxidized fatty acids, and hydroxy fatty acids were found in long-term aged meat exudates, and forty metabolites were significantly correlated with meat quality characteristics. Fifty-nine metabolites were significantly affected by muscle type. These results demonstrated the potential possibility of evaluating meat quality using meat exudate metabolomics.

Effects of relative humidity on dry-aged beef quality

This study was conducted to evaluate the effects of relative humidity (RH) on moisture loss and flavor in dry-aged beef. Sixteen strip loins were assigned to one of the four aging treatments: vacuum (WET), dry-aging at 50% RH, dry-aging at 70% RH, or dry-aging at 85% RH and aged for 42 days at 2 °C. Loins were evaluated for evaporation loss, trim loss, tenderness, sensory, and microbiological characteristics. Results show that lower RH results in accelerated moisture loss during the first 3 days of the aging process without significantly affecting the total amount of moisture loss. Pseudomonadales dominated the aerobically dry-aged loins while Enterobacteriales was the most abundant in the wet-aged samples. Dry-aged samples had increased content of free amino acids in the cooked meat juice compared to the wet-aged counterpart. Dry aging at 50% RH tended to associate with more desirable flavor notes.

Beef carcass microbiota after slaughtering and primary cooling: A metataxonomic assessment to infer contamination drivers

The impact of primary cooling on beef microbiota was investigated on six beef carcasses consecutively processed with the parallel use of metataxonomic and culture-dependent analysis. Samples were collected immediately after slaughtering (AS) and after the 24th-hour post-cooling (PC) from three different surfaces, namely neck, flank and thigh. The main objective was to examine whether the microbiota composition of beef carcasses changes as function of the surface sampled, primary cooling (from AS to PC) and animal's origin (breeder). The outcomes underline that primary cooling did not affect qualitatively the composition of the potentially active microbiota or the carcass superficial counts. Although slight changes in chemical-physical parameters like volatile organic compounds (VOCs) were observed after cooling, the carcasses microbiota and its inferred metabolic pathways varied among animals as a function of their origin. Co-occurrence and co-exclusion analyses underlined competition for the colonisation of the carcass surface between Brochothrix-Psychrobacter and Carnobacterium-Serratia-Pseudomonas. Once integrated in a comprehensive monitoring of the supply chain, the metataxonomic characterisation of the beef carcasses microbiota might represent a valid integrative approach to define the cuts' perishability and their appropriateness to specific packaging and storage methods. These new bits of knowledge could be the base to define good strategies for the prevention of meat spoilage.

Effect of ultimate pH on quality of aged Longissimus dorsi muscle of Zebu Nellore (Bos indicus) during long-term frozen storage

Despite the relatively high occurrence of bovine meat with intermediate to high ultimate pH (pHu), there is a lack of studies focused on the effects of long-term conventional air-blasting freezing storage on quality parameters of commercial beefs of Zebu Nellore (Bos indicus) with varying pHu ranges. The objective of this work was to evaluate the influence of pHu ranges [normal (≤5.79), intermediate (5.80 to 6.19), and high (≥6.20)] and long-term frozen storage on quality parameters of aged Longissimus dorsi beefs of Zebu Nellore (Bos indicus). The aging conditions were set at 2 °C for 14 days, while the freezing conditions were set at - 20 °C, and samples were collected after 3, 6, 9, and 12 months of storage. The results indicated that the pHu influenced meat quality parameters, as well as the chemical forms of myoglobin, which changed throughout the frozen storage, leading to a brighter red color, especially for the normal pHu beef samples, likely due to increased oxymyoglobin content. Frozen storage improved tenderness, with high pHu beef samples being the more tender after 12 months, potentially due to lower protein oxidation, as measured by the carbonyl content. Increased drip loss was observed over freezing time, with a concomitant decrease in protein solubility, especially for myofibrillar and sarcoplasmic proteins, which differed among the pHu ranges. These findings are valuable for determining freezing time as a preservation strategy to maintain beef quality within different pHu ranges.

Challenges and processing strategies to produce high quality frozen meat

Freezing is an effective means to extend the shelf-life of meat products. However, freezing and thawing processes lead to physical (e.g., ice crystals formation and freezer burn) and biochemical changes (e.g., protein denaturation and lipid oxidation) in meat resulting in loss of quality. Over the last two decades, several attempts have been made to produce thawed meat with qualities similar to that of fresh meat to no avail. This is due to the fact that no single technique exists to date that can mitigate all the quality challenges caused by freezing and thawing. This is further confounded by the consumer perception of frozen meat as lower quality compared to equivalent fresh-never-frozen meat cuts. Therefore, it remains challenging for the meat industry to produce high quality frozen meat and increase consumer acceptability of frozen products. This review aimed to provide an overview of the applications of novel freezing and thawing technologies that could improve the quality of thawed meat including deep freezing, high pressure, radiofrequency, electro-magnetic resonance, electrostatic field, immersion solution, microwave, ohmic heating, and ultrasound. This review will also discuss the development in processing strategies such as optimising the ageing of meat pre- or post-freezing, and the integration of freezing and thawing in one process/regime to collapse the difference in quality between thawed meat and fresh-never-frozen equivalents.

Influence of Ageing Time and Method on Beef Quality and Safety

The effectiveness of dry ageing with regard to retaining meat quality is still subject to debate. At 4 d post mortem, samples of boneless strip loins were excised from young Charolais carcasses and then stored for a further 26 d in a cooler, either vacuum-packaged (VP) or dried-aged (DA). Loin samples were also dissected 7 d post mortem as a control treatment (CT). Chemical, instrumental and microbiological data (n = 18) were determined in longissimus dorsi and underwent ANOVA to estimate the differences in the ageing fixed factor split into two orthogonal contrasts: control vs. aged and VP vs. DA. Ageing loss (both surface dehydration and water purge) was greater in DA compared to VP samples, resulting in the lowest moisture content and highest crude protein and fat percentage in DA loins. The ageing method did not affect meat surface colour, except for redness, which had the lowest value in DA samples. Meat tenderness improved a similar amount following both VP and DA ageing treatments. Compared to the control, prolonged ageing raised both the peroxide value and the total microbial count, especially in DA samples, though both remained within the recommended limits. In summation, both ageing methods improved beef meat tenderisation, preserving its shelf life.

Influence of meat sample geometry on dehydration dynamics during dry-aging of beef

Meat geometry may impact on the dehydration kinetics during dry-aging influencing the drying rate and, potentially, aspects of meat quality. In this study, three meat geometries (slices, steaks and sections) were prepared from three bovine Longissimuss thoracis et lumborum at 3 days post-mortem and were dry-aged at 2 °C, 75% relative humidity with an airflow of 0.5-2.0 m/s for 22 days (slices), 48 days (sections) and 49 days (steaks). Weights were recorded during dry-aging and drying curves were obtained for the three geometries, with the larger sections showing limited dehydration due to internal resistance to moisture migration from the core to the surface. Seven thin-layer equations were fitted to the dehydration data in order to model the drying kinetics during dry-aging. Thin-layer models described reliably the drying kinetics of the three geometries. In general, reduced k values (h^-1) reflected the lower drying rates as thickness increased. The Midilli model provided the best fit for all geometries. Proximate analyses of the three geometries and bloomed colour of sections were measured at the start and the end of the dry-aging period. Moisture loss during dry-aging led to the concentration of protein, fat and ash contents; while no significant differences were found for L*, a* and b* values of sections before and after the dry-aging process. In addition, moisture content, water activity (a_w) and LF-NMR measurements were taken at different locations within beef sections to further explore water dynamics during dry-aging.

Rapid Evaporative Ionisation Mass Spectrometry fingerprinting can discriminate lamb meat due to different ageing methods and levels of dehydration

Dry-ageing is a technique for developing characteristic dry-aged flavour through the interplay of dehydration, lipid oxidation and microbial activities. In this study, we tested the hypothesis that the extent of drying influences the metabolite profile and the final flavour of lamb using an "Age-and-Dry" regime; and that Rapid Evaporative Ionisation Mass Spectrometry (REIMS) fingerprinting can be used to discriminate the metabolic fingerprints of lambs due to ageing methods and dehydration levels. Lamb loins (n = 60) were dehydrated with low (12%), medium (17%) and high (22%) weight losses and compared with the wet-aged equivalents using REIMS and evaluated by 12-member sensory panel. Orthogonal projection to latent structures-discriminant analysis (OPLS-DA) models based on 1400 tentatively identified m/z features were obtained for ageing methods (Q² > 0.95) and dehydration levels (Q² > 0.82) with high discrimination accuracy. Increased concentrations of dipeptides and metabolites associated with energy metabolism were observed in aged-and-dried lamb meat which supports the umami and savoury taste perceived by the sensory panel. A reduced concentration of polyunsaturated fatty acids with more aldehydes was observed in aged-and-dried lamb meat contributing to the nutty, roasted, and fatty flavour notes detected by the sensory panellists in these samples compared to the wet-aged. SIGNIFICANCE: Outcomes of this study demonstrated that REIMS can be used to accurately discriminate between different ageing methods and dehydration levels of meat, and the compounds that are associated with lamb flavour. The implications of this finding include: (1) the metabolite concentrating effect of dehydration and the associated effect on aged lamb flavour determined in this study could be used to tailor the processing of dry-aged lamb to deliver specific flavour outcomes in an industrial setting; (2) the ability of REIMS to rapidly detect differences in the aged lamb flavour due to dehydration effect would improve the quality of dry-aged meat and the efficiency with which it can be industrially produced. Thus, REIMS can be used as a rapid authentication and quality prediction tool for different ageing regimes and flavour for the meat industry.

Effects of the Aging Period and Method on the Physicochemical, Microbiological and Rheological Characteristics of Two Cuts of Charolais Beef

Wet-aging (WA) and dry-aging (DA) methods are usually used in the beef industry to satisfy the consumers' tastes; however, these methods are not suitable for all anatomical cuts. In this study, WA and DA were applied to improve the quality of two cuts of Charolais beef (Longissimus dorsi and Semitendinosus). For 60 days (i.e., 2 days, 15 days, 30 days and 60 days of sampling), a physicochemical, rheological, and microbiological analysis were performed at WA (vacuum packed; temperature of 4 ± 1 °C) and at DA (air velocity of 0.5 m/s; temperature of 1 ± 1 °C; relative humidity of 78 ± 10%) conditions. The results showed that the aging method influenced the aging loss (higher in the DA), cooking loss (higher in the WA), malondialdehyde concentration (higher in the DA) and fatty acid profile (few changes). No differences in the drip loss and color were observed, which decreased after 30 days of aging. The WBSF and TPA test values changed with increasing an aging time showing that the aging improved the tenderness of meat regardless of the aging method. Moreover, the aging method does not influence the microbiological profile. In conclusion, both WA and DA enhanced the quality of the different beef cuts, suggesting that an optimal method-time and aging combination could be pursued to reach the consumers' preferences.

Effect of postmortem pH on the physical, biochemical, and sensory characteristics of bovine longissimus thoracis et lumborum muscle

From a large feeding trial study consisting of 299 bulls and steers, 15 carcasses exhibited stress-related syndromes manifested by atypical color and pH which were then selected for subsequent analysis. Samples of longissimus thoracis et lumborum muscle with postmortem pH in the range of 5.5-6.9 were subjected to a 14-day aging period at 2°C. Sensory panel tenderness, connective tissue, juiciness, and flavor intensity of high pH (6.4-6.9) meat were significantly different (p < .05) from samples of intermediate pH (6.0-6.1) as well as normal pH (5.5). Muscles at pH 6.0-6.1 were the toughest samples. This was confirmed by Warner-Bratzler shear force (WBSF), residual force, and myofibril fragmentation index. Palatability attributes of normal pH (5.5) samples were significantly different (p < .05) from dark-cutting beef in terms of tenderness and flavor and at the high pH extreme. The increase in WBSF at pH 6.0-6.1, lack of extensive degradation of muscle proteins, and the decreased sarcomere length resulted in tougher meat than low or high pH muscles. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis of meat at the high pH extreme (6.7-6.9) revealed that the breakdown of troponin-T to 30 kD was complete while at intermediate pH (6.0-6.1) was incomplete. In addition, the appearance of a 'doublet' on high-molecular-weight resolution gels may also account for the greater tenderness experienced by sensory panelists.

Microbiological safety of aged meat

The impact of dry-ageing of beef and wet-ageing of beef, pork and lamb on microbiological hazards and spoilage bacteria was examined and current practices are described. As 'standard fresh' and wet-aged meat use similar processes these were differentiated based on duration. In addition to a description of the different stages, data were collated on key parameters (time, temperature, pH and aw) using a literature survey and questionnaires. The microbiological hazards that may be present in all aged meats included Shiga toxin-producing Escherichia coli (STEC), Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, enterotoxigenic Yersinia spp., Campylobacter spp. and Clostridium spp. Moulds, such as Aspergillus spp. and Penicillium spp., may produce mycotoxins when conditions are favourable but may be prevented by ensuring a meat surface temperature of -0.5 to 3.0°C, with a relative humidity (RH) of 75-85% and an airflow of 0.2-0.5 m/s for up to 35 days. The main meat spoilage bacteria include Pseudomonas spp., Lactobacillus spp. Enterococcus spp., Weissella spp., Brochothrix spp., Leuconostoc spp., Lactobacillus spp., Shewanella spp. and Clostridium spp. Under current practices, the ageing of meat may have an impact on the load of microbiological hazards and spoilage bacteria as compared to standard fresh meat preparation. Ageing under defined and controlled conditions can achieve the same or lower loads of microbiological hazards and spoilage bacteria than the variable log10 increases predicted during standard fresh meat preparation. An approach was used to establish the conditions of time and temperature that would achieve similar or lower levels of L. monocytogenes and Yersinia enterocolitica (pork only) and lactic acid bacteria (representing spoilage bacteria) as compared to standard fresh meat. Finally, additional control activities were identified that would further assure the microbial safety of dry-aged beef, based on recommended best practice and the outputs of the equivalence assessment.

Metabolic, proteomic and microbial changes postmortem and during beef aging

The purpose of this review is to provide an overview of the current knowledge about proteomic and metabolic changes in beef, the microbiological alteration postmortem and during aging, and observe the influence on beef quality parameters, such as tenderness, taste and flavor. This review will also focus on the different aging types (wet- and dry-aging), the aging or postmortem time of beef and their effect on the proteome and metabolome of beef. The Ca2+ homeostasis and adenosine 5'-triphosphate breakdown are the main reactions in the pre-rigor phase. After rigor mortis, the enzymatic degradation of connective tissues and breakdown of energy metabolism dominate molecular changes in beef. Important metabolic processes leading to the formation of saccharides, nucleotides, organic acids (e.g. lactic acid), creatine and fatty acids are considered in this context as possible flavor precursors or formers of beef flavor and taste. Flavor precursors are substrates for lipid oxidation, Strecker degradation and Maillard reaction during cooking or roasting. The findings presented should serve as a basis for a better understanding of beef aging and its molecular effects and are intended to contribute to meeting the challenges of improving beef quality.

Impact of Various Dry-Aging Methods on Meat Quality and Palatability Attributes of Beef Loins (M. longissimus lumborum) from Cull Cow

The objective of this study was to determine the effect of various dry-aging methods on meat quality and palatability attributes of cull cow beef loins. Paired bone-in loins (m. longissimus lumborum) from 13 cull cow carcasses (Holstein, 42þ mo) were obtained at 5 d postmortem, divided into 4 equal sections, and randomly assigned into 4 aging methods (wet-aging [WA], conventional dry-aging [DA], dry-aging in water-permeable bag [DWA], and ultraviolet light dry-aging [UDA]). The beef sections were aged for 28 d at 2°C, 65% relative humidity, and 0.8 m/s airflow. Following aging, surface crusts and bones were removed, and loin samples were collected for the meat quality, microbiological, and sensory analyses. Results indicated that all dry-aged loins had greater moisture and trimming loss compared with WA (P &lt; 0.05), while DWA had lower loss than DA and UDA (P &lt; 0.05). No differences in shear force, cook loss, or both lipid and protein oxidation across all treatments were observed (P &gt; 0.05). Among all treatments, DWA exhibited the least color stability indicated by rapid discoloration observed in the sample, while UDA had color attributes comparable with WA throughout the whole display. Microbial analysis indicated that UDA had lower microbial concentration on the surface than the other samples (P &lt; 0.05). The consumer panel analysis found that all loins were acceptable, and the trained panel analysis indicated that DA loins decreased sourness and animal fat flavor (P &lt; 0.05) and had a trend of decreasing oxidized flavor (P = 0.07). The results indicate that dry-aging can potentially be utilized as an effective natural process by nullifying some of well-known off-flavor attributes associated with cull cow beef while not compromising other meat quality attrib- utes or microbiological shelf life.

The Quality and Functional Improvement of Retorted Korean Ginseng Chicken Soup (Samgyetang) by Enzymolysis Pre-Treatment with Cordyceps militaris Mushroom Extract

This study aimed to investigate the functional and quality improvement of retorted Korean ginseng chicken soup that was hydrolyzed using a single extract from Cordyceps militaris (CM) mushroom, or in combination with bromelain, flavorzyme, or a mix of both. A total of 36 fat-trimmed breast meat from commercial broilers were hydrolyzed with one of six treatments, (1) flavorzyme as a positive control (PC), (2) no addition as negative control (NC), (3) crude CM extract (CME), CM extract prepared with either (4) bromelain (CMB), (5) flavorzyme (CMF), or (6) bromelain:flavorzyme mixture (CMBF) in a water bath at 55 °C for 2.5 h, and subsequently retorted at 121.1 °C, 147.1 kPa for 1 h. The highest antioxidant activity was observed in the CMB treatment (40.32%), followed by CMBF (34.20%), and CME (32.97%). The suppression of malondialdehyde ranged between 28 and 83%. The water-holding-capacity of the treated samples increased, ranging between 59.69 and 62.98%, and significantly tenderized the meat. The shear force decreased from 23.05 N in negative control to 11.67 N in the CMB samples. The predominant nucleotides across the samples were 5′-IMP and hypoxanthine, and the lowest was adenosine. The intensification of the taste properties was due to the increase of umami substances, both by 5′-nucleotides (5′-IMP, 5′-GMP) and free amino acids (FAAs), whereas the highest improvement was observed in the CMB group. Therefore, the hydrolyzation of Korean ginseng chicken soup using CM extract, prepared using bromelain, improves functional and quality profiles.

Transcriptome profiling analysis of muscle tissue reveals potential candidate genes affecting water holding capacity in Chinese Simmental beef cattle

Water holding capacity (WHC) is an important sensory attribute that greatly influences meat quality. However, the molecular mechanism that regulates the beef WHC remains to be elucidated. In this study, the longissimus dorsi (LD) muscles of 49 Chinese Simmental beef cattle were measured for meat quality traits and subjected to RNA sequencing. WHC had significant correlation with 35 kg water loss (r = − 0.99, p < 0.01) and IMF content (r = 0.31, p < 0.05), but not with SF (r = − 0.20, p = 0.18) and pH (r = 0.11, p = 0.44). Eight individuals with the highest WHC (H-WHC) and the lowest WHC (L-WHC) were selected for transcriptome analysis. A total of 865 genes were identified as differentially expressed genes (DEGs) between two groups, of which 633 genes were up-regulated and 232 genes were down-regulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment revealed that DEGs were significantly enriched in 15 GO terms and 96 pathways. Additionally, based on protein–protein interaction (PPI) network, animal QTL database (QTLdb), and relevant literature, the study not only confirmed seven genes (HSPA12A, HSPA13, PPARγ, MYL2, MYPN, TPI, and ATP2A1) influenced WHC in accordance with previous studies, but also identified ATP2B4, ACTN1, ITGAV, TGFBR1, THBS1, and TEK as the most promising novel candidate genes affecting the WHC. These findings could offer important insight for exploring the molecular mechanism underlying the WHC trait and facilitate the improvement of beef quality.

Evaluation of Probiotic Characteristics of Newly Isolated Lactic Acid Bacteria from Dry-Aged Hanwoo Beef

Dry aging is a traditional method that improves meat quality, and diverse microbial communities are changed during the process. Lactic acid bacteria (LAB) are widely present in fermented foods and has many beneficial effects, such as immune enhancement and maintenance of intestinal homeostasis. In this study, we conducted metagenomic analysis to evaluate the changes in the microbial composition of dry-aged beef. We found that lactic acid bacterial strains were abundant in dry-aged beef including Lactobacillus sakei and Enterococcus faecalis. We investigated their abilities in acid and bile tolerance, adhesion to the host, antibiotic resistance, and antimicrobial activity as potential probiotics, confirming that L. sakei and E. faecalis strains had remarkable capability as probiotics. The isolates from dry-aged beef showed at least 70% survival under acidic conditions in addition to an increase in the survival level under bile conditions. Antibiotic susceptibility and antibacterial activity assays further verified their effectiveness in inhibiting all pathogenic bacteria tested, and most of them had low resistance to antibiotics. Finally, we used the Caenorhabditis elegans model to confirm their life extension and influence on host resistance. In the model system, 12D26 and 20D48 strains had great abilities to extend the nematode lifespan and to improve host resistance, respectively. These results suggest the potential use of newly isolated LAB strains from dry-aged beef as probiotic candidates for production of fermented meat.

Effect of pelvic suspension and post-mortem ageing on the quality of three muscles from Holstein Friesian bulls and steers

BACKGROUND

The use of bulls rather than steers from the dairy herd offers a more profitable and environmentally friendly option; however, the beef eating quality from bulls is an issue of concern. This study assessed the effect of two tenderization techniques - pelvic suspension and ageing - on three different muscles of Holstein Friesian males from two different production systems.

RESULTS

The results indicate that a production system based on steers slaughtered at 24 months (S24) produced beef with better eating quality than from bulls slaughtered at 19 months (B19) when tenderization techniques were not applied. Instrumental texture of longissimus thoracis and gluteus medius muscles was improved with ageing and/or pelvic suspension, with both tenderization techniques exerting greater impact on B19 meat. No differences were found in semitendinosus muscle due to suspension method, whereas ageing for longer than 14 days decreased its instrumental tenderness. Sensory results indicate that, after 14 days of ageing, panellists still preferred meat from S24, and they could differentiate between pelvic and traditional suspension.

CONCLUSION

Tenderization methodologies should be optimized for each production system and muscle; however, both panel and instrumental texture results indicate that eating quality of beef from either production systems is acceptable after 14 days of ageing, or even earlier if the suspension method is applied. © 2020 Society of Chemical Industry.

Utilizing Pork Exudate Metabolomics to Reveal the Impact of Aging on Meat Quality

This study was performed to assess the changes in meat quality and metabolome profiles of meat exudate during postmortem aging. At 24 h postmortem, longissimus lumborum muscles were collected from 10 pork carcasses, cut into three sections, and randomly assigned to three aging period groups (2, 9, and 16 d). Meat quality and chemical analyses, along with the metabolomics of meat exudates using ultra-high-performance liquid chromatography coupled with a quadrupole time-of-flight mass spectrometer (UHPLC-QTOF-MS) platform, were conducted. Results indicated a declined (p < 0.05) display color stability, and increased (p < 0.05) purge loss, meat tenderness, and lipid oxidation as aging extended. The principal component analysis and hierarchical clustering analysis exhibited distinct clusters of the exudate metabolome of each aging treatment. A total of 39 significantly changed features were tentatively identified via matching them to METLIN database according to their MS/MS information. Some of those features are associated with adenosine triphosphate metabolism (creatine and hypoxanthine), antioxidation (oxidized glutathione and carnosine), and proteolysis (dipeptides and tripeptides). The findings provide valuable information that reflects the meat quality’s attributes and could be used as a source of potential biomarkers for predicting aging times and meat quality changes.

Impacts of in Utero Heat Stress on Carcass and Meat Quality Traits of Market Weight Gilts

Simple Summary

This study evaluated the effects of exposure of the porcine fetus to in utero heat stress (IUHS) during the first half of gestation on carcass and meat quality attributes when market weight was reached. Pigs exposed to IUHS had lower head and heart weights at slaughter compared to the thermoneutral group. Most measures of carcass quality were not impacted by the treatments, but lower loin muscle area was observed for IUHS carcasses. Additionally, the loins from the heat stressed pigs were found to be tougher, regardless of the duration of aging. Accordingly, minimizing heat stress experienced by gestating pigs would be considered an important factor in improving both yield and quality of pork production systems.

Abstract

This study evaluated the impacts of in utero heat stress (IUHS) on the carcass and meat quality traits of offspring when market weight was reached. Twenty-four F1 Landrace × Large White gilts were blocked by body weight and allocated among thermoneutral (IUTN) or IUHS treatments from d 6 to d 59 of gestation. The offspring were raised under identical thermoneutral conditions, and gilts (n = 10/treatment) at market weight (117.3 ± 1.7 kg) were harvested. At 24 h postmortem, the loins (M. longissimus lumborum) were obtained, and sections were allocated among 1 d and 7 d aging treatments at 2 °C. Carcasses from IUHS pigs had lower head and heart weights (p < 0.05), as well as decreased loin muscle area (p < 0.05) compared to IUTN pigs. Loins from the IUHS group had a higher shear force value than the IUTN group (p < 0.05). Treatments had no other impacts on carcass and meat quality traits (p > 0.05), and Western blots suggested increased toughness of IUHS loins would not be attributed to proteolysis. These results suggest minimizing IUHS during the first half of gestation may be beneficial in improving pork yield and quality, though in general the effects of IUHS would be minimal.

Myofibrillar protein characteristics of fast or slow frozen pork during subsequent storage at -3 °C

This study aimed to investigate the effect of storage at -3 °C on myofibrillar protein in fast or slow frozen pork. Five pork loins at 48 h post-mortem were subjected to either fast (cold metal plate/-80 °C) or slow freezing (still air/-20 °C) followed by storage at -3 °C for 0, 1, 3, and 7 days before thawing. Freezing rate significantly influenced myofibrillar proteins within 3 days at -3 °C, evidenced by higher thaw loss, higher surface hydrophobicity and reduced water-holding of myofibrils, and accelerated appearance of a myosin-4 fragment (160 kDa) in slow freezing. However, these observed differences disappeared after 7 days of storage at -3 °C. The meat pH after thawing did not differ between fast and slow freezing rate. However, the pH values after thawing in both groups decreased with extended storage at -3 °C. Our results suggest that the beneficial effects of fast freezing are gradually lost by holding at -3 °C due to more extensive protein denaturation.

Dry-aging of beef as a tool to improve meat quality. Impact of processing conditions on the technical and organoleptic meat properties

Meat consumers are demanding products of higher and consistent quality, with a distinctive flavor and aroma, able to provide a particular sensorial experience when consuming beef. The impact of all the factors affecting the final eating quality, known as the farm to fork approach, has been extensively studied in the last decades. This includes genetic factors, production system, transport, carcass intervention, aging, packaging and cooking method, among others. Aging is, one of the most important steps in producing high quality tender beef. During this step, flavor is developed and the meat is tenderized. Dry-aging although considered a traditional method, is currently attracting attention from consumers, producers and researchers because of the characteristics of the final products in terms of flavor, aroma and texture. This chapter will describe the series of biochemical changes, which combined with the loss of water, generates a final product that is highly appreciated by niche consumers. This will include the changes that the muscle undergoes to be transformed to meat, the main factors driving the dry-aging process and how the flavor and aroma compounds are generated during this process.

The Physicochemical and Sensory Properties of Whey-Fed Pork Loin after Salting, Dry Aging, and Sous Vide Cooking

This study was conducted to evaluate the physicochemical properties of whey-fed pork loin subjected to salting, dry aging, and sous vide cooking. We compared raw and treated pork loin from pigs fed a basal diet (control) and those fed a diet supplemented with whey powder. Treated pork was salted, dry aged for 0–30 d, and then cooked using sous vide. The crude fat, total lipid, and cholesterol content and shear force of raw whey powder-fed pork loin were significantly lower than those of the control, while the crude protein content was higher. Cooking loss, hardness, and gumminess were found to decrease with the aging period in sous vide-treated pork. Dietary supplementation with whey had positive effects on pork color stability, texture, and sensory evaluation, and it significantly inhibited the growth of bacteria. The results suggest that supplementing the diet of pigs with whey powder can enhance meat quality, especially when combined with salting, dry aging, and sous vide cooking.

Sensorial, color, lipid oxidation, and visual acceptability of dry-aged beef from young bulls with different fat thickness

The reduction in slaughter age with minimum fat and dry aging process improves meat tenderness, however, its shelf-life in display has not been studied. It was evaluated the sensorial, and the color, lipid oxidation, and visual acceptance in display of dry-aged beef (0, 14, and 28 days) from young bulls slaughtered with different subcutaneous fat thickness (2.00, 3.00, and 4.00 mm). Meat with 2.00 and 3.00 mm fat had higher acceptability than 4.00 mm (p < .05). Dry aging improved overall acceptability of consumers. Meat with 2.00 and 3.00 mm fat presented higher lightness and lipid oxidation values than 4.00 mm (p < .05) but similar visual acceptance was observed. Dry-aged beef (14 and 28 days) had lower lightness, but higher redness (p < .05) than not dry aged (0 days). Display reduced color over time, for all dry-aged treatments (p < .05). Dry aging process increased lipid oxidation but these values were below 2.00 mg/kg of malonaldehyde only in the first day of display. Dry aged for 14 days had similar visual acceptability to not dry-aged beef until the third day of display (p < .05). Shelf-life of 0, 14, and 28 days of dry aged was 5.41, 2.55, and 0.23 days. Despite of the increase in lipid oxidation and lightness, the sensorial and display acceptability of meat from young bulls was not prejudiced by the reduction in fat thickness. Beef dry-aged for 14 days was visually well accepted and could be displayed for 2.55 days without compromising acceptability.

In-Bag Dry- vs. Wet-Aged Lamb: Quality, Consumer Acceptability, Oxidative Stability and In Vitro Digestibility

The aim of this study was to produce in-bag dry-aged lamb and compare its meat quality, consumer acceptability, oxidative stability and in vitro digestibility to the wet-aged equivalents. Significantly higher pH, weight loss and reduced cook loss were observed in dry-aged lamb compared to the wet-aged (p < 0.0001). Dry-aged lamb had harder and chewier texture profiles and lower colour attributes (L*, a* and b*) than the wet-aged (p < 0.001). The dry-aged and wet-aged lamb were equally preferred (around 40% each) by the consumer panel, underpinning the niche nature of dry-aged meat. Significantly (p < 0.05) higher yeast and thiobarbituric acid reactive substances (TABRS) levels were observed in dry-aged lamb compared to the wet-aged. There was no difference in fatty acid profile, protein carbonyl content and pattern of proteolysis between ageing regimes (p > 0.05). Ageing regimes had no impact on overall digestibility; however, a greater gastric digestibility was observed in dry-aged lamb through the increased release of free amino acids (FAAs) compared to the wet-aged. Outcomes of this study demonstrated for the first time the possibility of producing dry-aged lamb legs of acceptable quality, oxidative stability and superior digestibility compared to the equivalent wet-aged lamb.

The effects of time and relative humidity on dry-aged beef: Traditional versus special bag

The objective of this study was to evaluate the effects of relative humidity (RH) and different dry aging methods on the quality of beef. Sixteen loins, from eight carcasses, were used in this experiment. Each pair of loin was cut into eight sections with equal size, which were evenly assigned to eight treatments, by the combination of two dry aging methods (traditional and highly moisture-permeable special bag), two relative humidity (65 and 85% RH) and two aging times (21 and 42 days). At 85% RH, neither special bag nor the traditional dry aging methods were viable, since samples presented high microbiological counts, mucus and bad odor. At 65% RH, Enterobacteriaceae and lactic acid bacteria were not detected in any treatment. The highest aerobic plate count and psychrotrophic count were observed in the samples of the traditional dry-aged process whereas the special bag showed the greatest mold and yeast count. Regarding dry aging in special bag, there was a reduction in the weight loss (P < 0.05) and no change in the physical-chemical characteristics (P > 0.05) compared to traditional dry aging. The values of pH, moisture and Warner-Bratzler shear force were not affected (P > 0.05) by aging method and relative humidity. Thus, the results indicate that high RH should be avoided for both dry aging methods. Furthermore, the special bag dry aging can be considered an alternative to produce dry-aged beef, as it reduces weight losses even at conditions of lower relative humidity.

The dry aged beef paradox: Why dry aging is sometimes not better than wet aging

An increasing consumer demand for a higher quality and eating experience has led to a revisit to the dry aging process. Therefore, research also focuses on the effects of different dry aging methods and aims to improve the dry aging process. However, an optimal process cannot be defined and, unfortunately, most of the dry aging results only hold true for the individual experiment. If one repeats a dry aging process in a different facility, the result might differ. The same dry aging process in two different ripening chambers does not inevitably contribute to equal tenderness and flavor. Since this is still not been understood well, this review presents results of the most relevant dry aging studies by illustrating different process parameters and cuts. Some conclusions which may be useful to explain the paradox are derived from the literature in order to understand the crucial factors and commonalities in the dry aging process.

Bone and Subcutaneous Fat Influence on Yield, Physicochemical Traits, and Color Stability of Dry-Aged Loin From Grass-Fed Nellore Bulls

The objective of the current study was to evaluate the influence of bone and subcutaneous fat on yield, physicochemical traits, and color stability of dry-aged beef from grass-fed Nellore bulls. Paired bone-in loins (from the 10th thoracic vertebra to 6th lumbar vertebra) from 8 carcasses were collected and cut in half, and the sections from each carcass were assigned to 4 treatments (n = 8): bone-in with subcutaneous fat, bone-in without subcutaneous fat, boneless with subcutaneous fat, and boneless without subcutaneous fat. Loin sections were dry-aged for 21 d, at 2°C and 70% relative humidity. After dry aging, the half-loins were weighed, trimmed, and weighed again to determine the evaporation loss, trimming loss, and yield. Additionally, water activity, pH, thiobarbituric acid-reactive substances, moisture content, cooking loss, pressed juice percentage, Warner-Bratzler shear force, and color stability (during 9 d of display) were analyzed. No interactions (P &gt; 0.05) between bone and subcutaneous fat were found for evaporation and trimming loss, yield, and physicochemical traits. The treatments did not affect Warner-Bratzler shear force, pressed juice percentage, thiobarbituric acid-reactive sub-stances, and pH values (P &gt; 0.05). Regarding color stability, there was a bone-by-time interaction (P &lt; 0.05) for a* and b* parameters. Boneless treatments showed higher a* and b* values (P &lt; 0.05) than bone-in treatments, after 6 and 7 d of display, respectively. Bone-in treatments and treatments with subcutaneous fat had lower evaporation and trimming loss and higher yield compared to boneless treatments and treatments without subcutaneous fat, respectively (P &lt; 0.05). Therefore, although bone-in treatments showed lower color stability, bone and subcutaneous fat were considered important factors to the dry-aging process, as both resulted in a greater yield over dry-aged product that had bone and/or fat removed, without compromising other physicochemical traits of dry-aged beef from grass-fed Nellore bulls.

Effect of animal age, postmortem chilling rate, and aging time on meat quality attributes of water buffalo and humped cattle bulls

The study was aimed to investigate the influence of animal age, post-slaughter chilling rate, and aging time on meat quality of M. longissimus dorsi (LD) of water buffalo (Bubalus bubalis) and humped cattle (Bos taurus indicus) bulls. After slaughtering, one side of carcasses was subjected to rapid chilling (RC) (0 ± 2°C) and other side was hanged in controlled room temperature (25 ± 2°C) for 3 hr, then allowed to the chiller (0 ± 2°C). The meat quality traits were analyzed at 1, 7, and 14 days of storage. It was noted that rapidly chilled carcasses from the younger animals of both species missed the ideal pH/temperature window, which affects the toughness of the meat. Buffalo meat presented higher shear force, color L* values, and lower b* value as compared to the cattle meat. Moreover, meat shear force values decreased while all color coordinates and cooking loss values increased with lengthening the storage time in both age groups of cattle and buffalo. In conclusion, the tenderness of cattle meat was superior to that of buffalo and RC adversely affect the shear force values of young cattle and both age groups of buffalo bulls.

Meat quality attributes and oxidation stability of loin chops from finishing gilts and cull sows

The objective of this study was to compare the meat quality attributes, color stability, and lipid oxidation of loin chops from finishing gilts and cull sows in a three-way crossbreeding system: landrace × large white × duroc finishing gilts (n = 20) and landrace × large white sows (n = 20). No significant differences in pH, proximate composition, or total collagen content were found between the two pig groups. However, sow loin chops exhibited different quality characteristics for color, cooking loss, protein solubility, and shear force, in which an increased cooking loss and shear force might be associated with a lower heat-soluble collagen content compared to the gilt loin chops (p < 0.05). Moreover, more rapid changes in redness and chroma during 7 days of aerobic display were observed in the sow loin chops (p < 0.05). Therefore, the results presented here highlight the possibility of issues regarding color and tenderness in sow meat compared to retail pork produced from finishing gilts.

Effects of Different Moisture-Permeable Packaging on the Quality of Aging Beef Compared with Wet Aging and Dry Aging

The objective of this study was to investigate the effects of six different aging methods (four types of moisture-permeable packaging, wet aging, and dry aging) and aging time (0, 7, and 14 d) on the quality of aging beef, especially physicochemical properties. The weight loss, aerobic bacterial counts, yeast counts, and mold counts increased with the increase of moisture permeability and aging time. However, shear force, hardness, cohesiveness, and chewiness followed an opposite trend with increasing moisture permeability. The values of L* and b* appeared to decrease in the dry-aged samples compared with those of the others. In addition, water content in dry-aged samples for 7 and 14 d showed a significant decrease. The higher myofibril fragmentation index was observed in dry-aged samples for 7 and 14 d compared with groups using moisture-permeable packaging. Meanwhile, the percentage of bound water and free water appeared to decrease with the increase of moisture permeability. Thus, different moisture-permeable packaging was able to control different levels of water loss and effectively reduce microbial contamination compared with dry aging. The changes of both myofibrillar fragmentation index (MFI) and distribution of water indicated that moisture-permeable packaging affected the structure of myofibrils, which influenced the shear force.

The Effect of Aging/Freezing Sequence and Freezing Rate on Quality Attributes of Beef Loins (M. longissimus lumborum)

The objective of this study was to determine the effect of different aging/freezing sequences combined with different freezing rates on quality attributes of beef loins (M. longissimus lumborum). Loins from 1 side of 8 beef carcasses (USDA Low Choice grade) were obtained at 2 d postmortem, cut into 10 steaks (2.54 cm), and randomly assigned into 5 treatments, where factorial combinations of 2 aging/freezing sequences (aging first then freezing/thawing [AFT] and freezing first then thawing/aging [FTA]) and 2 freezing rates (fast freezing [FF] and slow freezing [SF]) were used and compared to an aged only (AO) treatment as a control. Samples frozen using the FF condition were found to have a critical freezing time (Tc) of 21.5 min while the SF counterpart had a Tc of 175 min. Histological observation showed more visually enlarged gaps between muscle fibers in the SF samples, regardless of aging/freezing sequence. The SF-FTA samples had a significantly higher purge/ thaw loss followed by FF-FTA, while the loss from FF-AFT, SF-AFT, and AO were not different from each other (P > 0.05), suggesting that freezing rate effect might be more profound when applied in FTA. Cook loss was higher in AO compared to both FTA treatments (P < 0.05); however, it was not different when compared to AFT (P > 0.05). A lower shear force value and higher troponin-T protein degradation were found in both AFT and FTA compared to AO (P < 0.05), which would be attributed to the ice-crystal damage due to freezing. These results suggest that aging/freezing sequence could be an overriding factor in determining major meat quality attributes of frozen/thawed meat over freezing rate. However, fast freezing could negate some quality defects associated with the FTA process.

Effects of freezing and thawing on microbiological and physical-chemical properties of dry-aged beef

This study evaluated the effects of freezing, prior to and after dry aging, on the microbiological and physical-chemical quality of beef. Strip loins (n = 24) from 12 carcasses were assigned to four treatments: non-frozen dry aging (Dry); dry aging, steak fabrication, freezing and slow thawing (Dry + ST); freezing, fast thawing (FT; 20 °C/15 h) and dry aging (FT + Dry); freezing, slow thawing (ST; 4 °C/48 h) and dry aging (ST + Dry). Freezing conditions were - 20 °C/28 days and dry aging conditions were 2 °C/70% relative humidity, for 28 days. Freezing prior to dry aging did not affect the microbial counts compared to Dry. However, FT + Dry and ST + Dry increased (16%) total process loss (P < .05) compared to Dry and Dry+ST. Moreover, freezing changed volatile compounds profile. Thus, freezing prior to dry aging was not a feasible process due to increased process loss, while freezing after dry aging was considered a viable alternative to preserve the steaks without compromising beef physical-chemical traits.

Quality and Acceptability of Fresh and Long-Term Frozen In-Bag Dry-Aged Lean Bull Beef

In-bag dry-aged lean beef was produced using a stepwise ageing process. Lean bull beef striploins were dry-aged at 2°C, 75% RH under three different air velocities: 0.5, 1.5, and 2.5 m·s−1for 7 days followed by wet-ageing for 14 days. The quality and acceptability of the dry-aged beef were compared with equivalent beef dry-aged for 21 days at 0.5 m·s−1which served as a control. Two portions of the dry-aged beef (7/21 days) were randomly selected and held frozen at −18°C for 12 months. Shear force, drip, and cook loss decreased significantly (p<0.05) with dry-ageing time. Increased air velocities accelerated dehydration process with no negative impact on the meat quality, microbiological safety, and consumer acceptability compared to the control (p>0.05). Frozen storage for 12 months had little or no effect on the quality and acceptability of the dry-aged lean beef (p>0.05). Dry-aged lean beef of equivalent quality and palatability, with a lower level of surface microorganisms and higher yield compared to the control, could be produced using the stepwise ageing process.

Aging Condition and Retail Display Lighting Impact Retail Display Life and Lipid Oxidation of Beef Biceps Femoris Steaks

The objective of this study was to determine the impact of aging method and retail display lighting type on the discoloration and oxidation of a beef muscle with low color stability. Beef biceps femoris (BF; n = 38) were fabricated 48 h postmortem and aged for 16 d post fabrication in either wet (vacuum packaged) or dry conditions. After aging steaks (n = 9) were cut from each BF and randomly assigned to 1 of 3 retail display lengths: 1, 3, or 5 d and 3 light treatments: light emitting diode (LED), high-UV fluorescent (HFLO), or low-UV fluorescent (FLO). Steaks were removed from retail display, and were subjected to instrumental color analysis (L*, a*, b*), surface myoglobin redox forms, lipid oxidation, and metmyoglobin reducing activity. Dry aging resulted in greater (P < 0.05) redness, as determined by a*, saturation index, and hue angle values of beef BF steaks, compared to wet aging. Significant interactions (P < 0.05) between aging method and retail display day were reported for a/b ratios, hue angle, deoxymyoglobin concentrations, and lipid oxidation values. Dry aging resulted in increased (P < 0.05) lipid oxidation over the duration of retail display, as determined by thiobarbituric acid reactive substances (TBARS), in comparison to wet aging. Light by day interactions (P < 0.05) occurred for b*, metmyoglobin concentrations, oxymyoglobin concentrations, and saturation index values. Data indicate that utilization of fluorescent light sources promoted greater redness retention in a muscle with low color and oxidative stabilities over the duration of retail display in comparison to LED light sources.

Changes in Sensory Compounds during Dry Aging of Pork Cuts

The effects of dry-aging on changes in taste compounds and electronic taste sensing traits of pork were investigated. Ten pork belly and shoulder blade cuts were divided into wet-aging and dry-aging treatments and stored for 21 days at 2°C. The contents of nucleotides and free amino acids, and electronic tongue analysis were investigated at different aging periods (1, 7, 14, and 21 days). The contents of inosine and hypoxanthine of dry-aged pork cuts increased more rapidly, and they were significantly (p<0.05) higher than wet-aged pork cuts. Total free amino acids of dry-aged pork cuts were also significantly (p<0.05) higher than those of wet-aged pork cuts after 21 days of aging. Consequently, umami intensity of dry-aged pork cuts increased more rapidly and the values were significantly (p<0.05) higher than those of wet-aged pork during 21 days of aging. Results suggested that the better palatability of dry-aged pork cuts might be due to higher umami intensity in relation to higher contents of inosine, hypoxanthine, and free amino acids.

Marbled beef quality grades under various ageing conditions

The Russian beef market is growing, which means that the problem of meat quality is getting more and more relevant. The gradually improving culture of meat consumption raises the demand for beef maturation, or ageing. The current research is the first of its kind in Russia. It features the quality of Russian marbled beef in the process of its open-air and vacuum-packed maturation. The authors studied the changes in the quality grades of dry-aged and vacuum-packed marbled beef during 4, 16 and 28-day ageing and defined the optimal maturation conditions and terms. The study included pH, colour, microstructure, organoleptic properties, the qualitative and quantitative composition of the volatile aroma-forming compounds, and the area of intramuscular fat. The samples were on-the-bone beef cuts obtained from 18-month-old Aberdeen-Angus castrated bulls that had received 200 days of grain fattening. The pH value remained stable throughout the ageing period in the dry-aged and vacuum-packed samples. Approaching the end of the test period, the change in pH reached 0.12 for the dry-aged samples and 0.21 for the vacuum-packed ones. The surface of the dry-aged samples obtained a dark red to burgundy-red dry crust after 16 and 28 days of ageing. The colour was significantly different from the colour of the samples after 4 days of ageing. The colour of the vacuum-packed samples remained unchanged throughout the maturation period. However, the microstructure of the packed beef showed a deeper and more widespread decomposition of muscle tissue on days 16 and 28. The changes in the dry-aged samples were less obvious. All in all, the process of extended ageing improved the organoleptic properties of the beef.

Comparison of Meat Quality Characteristics of Wet- and Dry-aging Pork Belly and Shoulder Blade

The physicochemical characteristics and oxidative stability of wet-aged and dry-aged pork cuts were investigated at different aging periods (1, 7, 14 and 21 d). Samples were assigned into four groups in terms of shoulder blade-wet aging (SW), shoulder blade-dry aging (SD), belly-wet aging (BW), and belly-dry aging (BD). SD showed significantly higher pH at 21 d of aging than the other samples. Wet-aged cuts had significantly higher released water (RW) %, lightness (L*) and shear force compared to the dry-aged meats. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed greater degradation of proteins for dry-aged cuts than the wet-aged cuts. At the end of aging, wet-aged cuts showed significantly lower thiobarbituric acid-reactive substances (TBARS) value than the dry-aged samples, indicating higher oxidative stability for wet-aged pork cuts. However, dry-aging led to higher degradation of proteins resulting in increased water-holding capacity (WHC) and decreased shear force value.

Aging of beef rumpsteak on sensory quality, color appereance and texture properties

The aim of the work was to optimize the time of aging of beef - rumpsteak for culinary processing in relation to color, texture and sensory changes.The 8 weeks of dry-aging had an influence on color change by 18% and there was darkening of samples, darker meat linearly, without any variations. During dry-aging decreased softness and increased strength steaks. There was no significant effect of maturation and softness, it has only been affected by less than 5% (p <0.05). The best evaluation was obtained after 7 weeks of aging in descriptors. The main point was in intensity and pleasantness of flavor and intensity and pleasantness and taste. On the other hand, juiciness and texture to bite was evaluated after 4 weeks of aging the best. As the softest sample in descriptor texture in bites it was four-week aging; as the hardest sample was observed in 8 week of dry-aging. Dry-aging affected (p <0.05) the L* value, the trend during dry-aging period had decreasing tendencies. On the other hand, in the course of decreasing lightness fluctuations was observed in lightness value L*. Chromaticity value a* displayed a negative significant (p <0.05) correlation to weeks of dry-aging. Dry aging had a significant negative effect (p <0.05) on the chromatic value b*. The length of the dry-aging had significant statistical impact on the ligthness and both chromatic coordinates. The length of dry-aging had paramount influence on the textural properties of rump steaks evaluated by instrument.