Sustained Effects of Muscle Calpain System Genotypes on Tenderness Phenotypes of South African Beef Bulls during Ageing up to 20 Days

The most important factor that determines beef tenderness is its proteolytic activity and the balance between calpain1 protease activity and calpastatin inhibition is especially important, while contributions could arise from calpain2 and possibly calpain3. These processes are however affected by the meat aging process itself. To determine whether genotypes in the calpaincalpastatin system can enhance tenderness throughout a 20 day aging period, South African purebred beef bulls (n=166) were genotyped using the Illumina BovineHD SNP BeadChip, through genebased association analysis targeting the cast, capn3, capn2 and capn1 genes. The WarnerBratzler shear force (WBSF) and myofibril fragment length (MFL) of Longissimus thoracis et lumborum (LTL) steaks were evaluated between d 3 d 20 of aging, with protease enzyme activity in the first 20 h postmortem. Although several of the 134 SNP associated with tenderness, only seven SNP in the cast, capn2 and capn1 genes sustained genetic associations, additive to agingassociated increases in tenderness for at least three of the four aging periods. While most genomic associations were relatively stable over time, some genotypes within SNP responded differently to aging, resulting in altered genomic effects over time. The level of aging at which genomic associations are performed is an important factor that determines whether SNP affect tenderness phenotypes.

The path from protein profiling to biomarkers: The potential of proteomics and data integration in beef quality research

This study aimed to provide an overview of the strategy of meat quality biomarkers identification from protein profiling to the establishment of putative protein biomarkers with a focus on beef tenderness and colour traits. Further, the current knowledge gained by data-integration, also known as integromics, of published meat proteomics studies during the last decade is briefly discussed in terms of the current list of protein candidate biomarkers revealed using different proteomics platforms and evaluated by proteomics-based approaches. The main biochemical pathways underlying the determination of tenderness and colour traits as important beef eating qualities revealed by bioinformatics analyses such as Gene Ontology annotations, pathway and process enrichments are further considered. This paper also addresses the potential of integromics and data-mining, in the era of big data and data analytics, to broaden our knowledge on the biochemical mechanisms underlying the conversion of muscle into meat and the consequences on beef sensory quality traits (tenderness and colour). Finally, the emerging interest of using such gathered and shortlisted protein biomarkers for first validation and then early post-mortem prediction of the potential quality of beef carcasses is highlighted.

High-Frequency Focused Ultrasound on Quality Traits of Bovine Triceps brachii Muscle

This aim of this study was to evaluate the effect of high-frequency focused ultrasound (HFFU) on quality traits of bovine Triceps brachii. Four treatments (0, 10, 20, and 30 min) of HFFU (2 MHz and 1.5 W/cm2) were applied to bovine T. brachii muscle. Immediately after treatment, evaluations of color, pH, drip loss, water holding capacity, and shear force in meat were undertaken. The application of HFFU slightly decreased (p < 0.05) the redness of meat. In addition, a significant (p < 0.05) decrease in the shear force of meat was observed after the application of HFFU at 30 min. No effect (p > 0.05) was observed on other color parameters, drip loss, and water holding capacity of meat. Overall, HFFU improved beef tenderness without negative impacts on color, pH, drip loss, and water holding capacity of meat. HFFU offers the option of tenderizing specific muscles or anatomical regions of the beef carcass. These findings provide new insights into the potential application of ultrasound in meat processing.

A Proteomic Study for the Discovery of Beef Tenderness Biomarkers and Prediction of Warner–Bratzler Shear Force Measured on Longissimus thoracis Muscles of Young Limousin-Sired Bulls

Beef tenderness is of central importance in determining consumers’ overall liking. To better understand the underlying mechanisms of tenderness and be able to predict it, this study aimed to apply a proteomics approach on the Longissimus thoracis (LT) muscle of young Limousin-sired bulls to identify candidate protein biomarkers. A total of 34 proteins showed differential abundance between the tender and tough groups. These proteins belong to biological pathways related to muscle structure, energy metabolism, heat shock proteins, response to oxidative stress, and apoptosis. Twenty-three putative protein biomarkers or their isoforms had previously been identified as beef tenderness biomarkers, while eleven were novel. Using regression analysis to predict shear force values, MYOZ3 (Myozenin 3), BIN1 (Bridging Integrator-1), and OGN (Mimecan) were the major proteins retained in the regression model, together explaining 79% of the variability. The results of this study confirmed the existing knowledge but also offered new insights enriching the previous biomarkers of tenderness proposed for Longissimus muscle.

Organoleptic properties of pineapple peel juice marinated beef (Ananas comosus L. Merr)

Beef has a high level of toughness that is not liked by consumers. The solution to increasing beef tenderness is to soften the beef. One method for tendering the beef is by marinating using local ingredients that are easily available, abundant, and inexpensive, namely pineapple. Pineapple peel is waste from pineapple that has not been utilized and is usually discarded. In pineapple peel, there is a bromelain enzyme thought to be able to hydrolyse protein so that it can tender beef. The purpose of this study was to find out the organoleptic properties of beef using the marination with various pineapple peel juice concentrations (Ananas comosus L. Merr) namely 0%, 10%, 20%, and 30%. This study used an experimental method with a Completely Randomized Design consisting of 4 treatments and 4 replications. The parameters in this study were organoleptic properties namely colour, aroma, texture, tenderness, and taste. Results of the study showed that beef marination with various pineapple peel juice concentrations had a significant difference (P<0.05) on taste, texture, and tenderness of beef but had no significant difference in colour and aroma (P>0.05)

425 Effects of pre-mortem stress on protein expression, steak color, and myofibrillar fragmentation index in the longissimus lumborum following harvest

Undesirable variation in beef tenderness and stability of flavor and color may be associated with the abundance of heat shock proteins (HSP). This study aimed to determine whether pre-mortem stress impacts HSP expression in the skeletal muscle following harvest. Forty Holstein steers were administered an i.v. bolus dose of adrenocorticotropic hormone (ACTH; 0.1 IU/Kg BW) to mimic an acute pre-mortem stress. Longissimus lumborum (LD) biopsy samples were taken prior to the ACTH challenge. Serum cortisol was measured every 0.5 h from -2 to 6 h relative to the ACTH challenge. Skeletal muscle and blood samples from 10 steers were collected at each harvest timepoint at (2, 12, 24 and 48 h post-challenge). Samples were collected from the LD immediately after harvest and after 14 d of aging. Protein expression of HSPβ1, P-HSPβ1, HSPβ5, and DJ-1 was analyzed in muscle samples taken prior to the ACTH challenge, at harvest, and after 14 d of post-mortem wet aging. In addition, steak color and myofibrillar fragmentation index (MFI) was analyzed in 14 d aged samples. Harvest time point following the ACTH challenge affected (P &lt; 0.05) protein expression of HSPβ1 and P-HSPβ1. Protein expression of DJ-1 prior to the ACTH challenge was different (P &lt; 0.05) among steers harvested at different timepoints. In addition, time of harvest had no effect on HSPβ5 expression (P &gt; 0.05). Regarding steak color, time of harvest had an effect (P &lt; 0.01) on a*, b*, hue, chroma, and ratio, but no effect (P &gt; 0.05) on L*. Lastly, time of harvest had an effect (P &lt; 0.05) on MFI. These data indicate that HSP expression, steak color, and MFI in the LD after harvest may be related to time of harvest following a stressful event pre-mortem.