Enzymes in Tenderization of Meat – The System of Calpains and Other Systems

Effect of sex (ram or wether) and short duration, high volt electrical stimulation on tenderisation of Longissimus thoracis et lumborum and Semimembranosus muscles derived from Boer Goat and large frame Indigenous Veld Goat

This study determined whether castration and electrical stimulation (ES) influenced chevon tenderness and related physiological characteristics in Boer Goat (BG; n = 36; 21 bucks and 15 wethers) and large frame Indigenous Veld Goat (IVG; n = 41; 21 bucks and 20 wethers). Half of buck and wether carcasses were ES (20s, 400 Volts peak, 5 ms pulses at 15 pulses/s) 10 min post-mortem. Dressed carcasses were chilled (4 °C within 1-h post-mortem). pH and temperature decline, % drip loss, sarcomere length (SL), myofibril fragmentation length (MFL; 1- and 4-days post-mortem), Calpain-1, -2 and calpastatin activities (1- and 24-h), Warner-Bratzler shear force (WBSF; 1-day post-mortem) and sensory attributes (tenderness and juiciness; 4-days post-mortem) were measured on Longissimus thoracis et lumborum (LTL) and Semimembranosus (SM) muscles. ES carcasses had significantly lower pH irrespective of sex or breed. Buck LTL and SM were less tender (P ≤ 0.05) supported by longer MFL and higher calpastatin activity (P < 0.05), than wether muscles. ES LTL were more tender (WBSF and sensory) (P ≤ 0.001) while ES SM were less affected (P = 0.055). ES caused lower Calpain-1 activity in the LTL. SL do not support cold shortening and calpastatin played a major role in the tenderisation of chevon early post-mortem. A longer ageing period is recommended for goat meat in general to achieve acceptable levels of tenderness.

Role of Enzymatic Reactions in Meat Processing and Use of Emerging Technologies for Process Intensification

Meat processing involves different transformations in the animal muscle after slaughtering, which results in changes in tenderness, aroma and colour, determining the quality of the final meat product. Enzymatic glycolysis, proteolysis and lipolysis play a key role in the conversion of muscle into meat. The accurate control of enzymatic reactions in meat muscle is complicated due to the numerous influential factors, as well as its low reaction rate. Moreover, exogenous enzymes are also used in the meat industry to produce restructured products (transglutaminase), to obtain bioactive peptides (peptides with antioxidant, antihypertensive and gastrointestinal activity) and to promote meat tenderization (papain, bromelain, ficin, zingibain, cucumisin and actinidin). Emerging technologies, such as ultrasound (US), pulsed electric fields (PEF), moderate electric fields (MEF), high-pressure processing (HPP) or supercritical CO₂ (SC-CO₂), have been used to intensify enzymatic reactions in different food applications. This review aims to provide an overview of the enzymatic reactions taking place during the processing of meat products, how they could be intensified by using emerging technologies and envisage potential applications.

Color attributes and myoglobin chemistry exhibit relationships with tenderness and calpain-1 abundance in postmortem Longissimus lumborum muscles from Holstein heifers

The objective of this study was to determine the extent that myoglobin and beef color are associated with calpain-1 relative abundance relative and tenderness. Longissimus lumborum (LL) samples from the left side of Holstein beef carcasses (n = 31) were collected immediately post-evisceration for 0 h analyses. At 48 h postmortem six steaks were removed from the right side of each carcass for analyses at 48 and 336 h postmortem. Myoglobin concentrations resulted in negative correlations (P < 0.05) to Warner-Bratzler shear force (WBSF) values at 336 h postmortem. L*, a*, and b* values at 48 h resulted in positive correlations (P < 0.05) with WBSF values at 48 and 336 h. Values for b* at 336 h had positive correlations with calpain-1 concentration at 0 and 336 h. Data from this study indicate a potential relationship between myoglobin concentration and meat color with tenderness aspects and calpain-1 relative abundance.

Review of technology and materials for the development of cultured meat

Cultured meat production technology suggested that can solve the problems of traditional meat production such as inadequate breeding environment, wastewater, methane gas generation, and animal ethics issues. Complementing cultured meat production methods, sales and safety concerns will make the use of cultured meat technology easier. This review contextualizes the commercialization status of cultured meat and the latest technologies and challenges associated with its production. Investigation was conducted on materials and basic cell culture technique for cultured meat culture is presented. The development of optimal cultured meat technology through these studies will be an innovative leap in food technology. The process of obtaining cells from animal muscle, culturing cells, and growing cells into meat are the basic processes of cultured meat production. The substances needed to production of cultured meat were antibiotics, digestive enzymes, basal media, serum or growth factors. Although muscle cells have been produced closer to meat due to the application of scaffolds materials and 3 D printing technology, still a limit to reducing production costs enough to be used as foods. In addition, developing edible materials is also a challenge because the materials used to produce cultured meat are still not suitable for food sources.

Effects of quercetin on tenderness, apoptotic and autophagy signalling in chickens during post-mortem ageing

The effect of quercetin on chicken breast muscle tenderness and the associated mechanism were investigated. The results indicated that quercetin significantly decreased the shear force and increased the myofibril fragmentation index (MFI). Haematoxylin-eosin-stained images showed that the internal structure of myofibril bundles in the quercetin-treated group was obviously degraded. Transmission electron microscopy showed that the myofibril structure, especially the M-line and A-band, was seriously degraded after quercetin treatment. Furthermore, quercetin treatment increased caspase-3 activity and the Bax/Bcl-2 ratio. The intensity of BiP, XBP1 and p-IRE1/IRE1 ratio increased significantly, and caspase-12 was activated. In addition, quercetin induced the transition from LC3I to LC3II and increased the expression of ATG7 and Beclin-1. The PI3K/Akt/mTOR signalling pathway was involved in the induction of autophagy and apoptosis by quercetin. These results indicated quercetin can promote meat tenderization, and activate apoptosis and autophagy pathways during post-mortem ageing.

Meat tenderness: advances in biology, biochemistry, molecular mechanisms and new technologies

Meat tenderness is an important quality trait critical to consumer acceptance, and determines satisfaction, repeat purchase and willingness-to-pay premium prices. Recent advances in tenderness research from a variety of perspectives are presented. Our understanding of molecular factors influencing tenderization are discussed in relation to glycolysis, calcium release, protease activation, apoptosis and heat shock proteins, the use of proteomic analysis for monitoring changes, proteomic biomarkers and oxidative/nitrosative stress. Each of these structural, metabolic and molecular determinants of meat tenderness are then discussed in greater detail in relation to animal variation, postmortem influences, and changes during cooking, with a focus on recent advances. Innovations in postmortem technologies and enzymes for meat tenderization are discussed including their potential commercial application. Continued success of the meat industry relies on ongoing advances in our understanding, and in industry innovation. The recent advances in fundamental and applied research on meat tenderness in relation to the various sectors of the supply chain will enable such innovation.

The impact of differential expression of the pectoral muscle proteome in two groups of Japanese quail with different growth rates on‏ meat quality

1. In this study, the proteomics method was applied to genetically evaluate the performance and carcase characteristics of Japanese quail and their molecular mechanisms, and to further determine and analyse the meat quality and muscle proteins. 2. Ten Japanese quail were selected from among 400 quail from the seventh generation of a population. Various traits were recorded and multivariate analysis was applied using Wombat software. 3. Differential expression of pectoral muscle proteins was performed, whereby nine spots were selected (P < 0.05) for determination. All proteins from the quail group with the highest breeding value showed significantly greater relative intensity, except for serum albumin. 4. The results showed that an increase in growth rate can cause disturbances in most organs and their metabolism, although the increase in the expression of some proteins indicated that the bird's body tends to adapt to special conditions. 5. The allocation of genetic resources is likely to maintain the balance between most organs, which does not overlap. However, most evidence shows that meat quality has been reduced, but to a limited extent, by selection for growth.

Physical Changes during Post-Mortem Ageing of High-Value Impala (Aepyceros Melampus) Steaks

Antelope meat production is rapidly growing, not only due to their adaptation to marginal land usage, but also because of its favorable nutritional properties and free-range production. However, limited information is available on the meat quality and processing potential of game meat for commercial consumption. The objective of this study was to determine the ageing period to achieve maximum tenderness of longissimus thoracis et lumborum (LTL) muscles of impala. The LTL muscles of 11 male and 11 female impala were harvested, and divided into eight portions. Each portion was randomly allocated to 1, 2, 4, 6, 8, 10, 12, or 14 days of wet-ageing (4 °C) in vacuum packaging. The meat pH, color, weep loss, cooking loss, and Warner–Bratzler shear force were measured throughout ageing. Initially the ageing profile differed depending on the sex of the animal from which the muscle was harvested; however, after 8 days of ageing, maximum tenderness was reached (13.5 ± 0.91 N) and no further sex differences were seen. Ageing improved the surface color of all meat until day 8, after which discoloration occurred. Therefore, it is recommended that impala LTL steaks should be wet-aged at 4 °C for eight days to achieve maximum tenderness and minimize sex variability.

Experience of biotechnology method applications in meat processing industry

Nowadays one of the main regulatory documents governing the future of food production in Russia is the “Food Security Doctrine of the Russian Federation” formulated in order to implement the state economic policy in the field of ensuring food security of the Russian Federation, aimed at reliable provision of the country’s population with food products, the development of domestic agricultural and fishery complexes. In the past 40 years, the use of nano- and biotechnologies in the processing of animal and fish raw materials has been widely developed. A large number of scientific studies are aimed at biotechnology method applications in the production of meat products, in particular the use of enzyme proteolytic preparations. The aim of the research presented in this article was to study the dynamics of the hydrolysis of water-, saltand alkali-soluble fractions of low-grade beef and lamb proteins with Megaterin, an enzyme preparation of animal origin. The fulfilled studies allow more precise approach to the use of enzyme preparations for the processing of basic raw materials by the meat industry.

Volatile Flavor Components as a Function of Electrical Stimulation and Chiller Aging for m. longissimus and biceps femoris of Hanwoo Beef

The aim of the study was to evaluate the effect of an early post-mortem low voltage electrical stimulation (ES) to localized part of carcasses [m.longissimus lumborum (LL) and m.biceps femoris (BF)] and determined the tenderness and flavor compounds of Hanwoo steers (n=16). Carcasses were stimulated within 30 min post-mortem for 60s using 60 volts and muscles aged 2 and 14 d. Degradation of Troponin-T were accelerated by ES and degraded little faster in BF muscle than LL. Level of free amino acid content of stimulated and aged muscles was significantly (p<0.05) greater than control for both muscles. Totally 63 volatile compounds were identified by using SPME-GC. The ES treatment significantly (p<0.05) affected the level of 20 volatile compounds of LL as well 15 volatiles in BF muscle along with total amounts of ketones, sulfur containing, pyrazines and furans. Low voltage ES could be applied to reduce the aging time and improve volatile flavor development by increasing important desirable volatile compounds such as 2-methylpyrazine, 2,5-dimethylpyrazines and 2-acetylthiazole etc. due to released free amino acids from protein degradation.

A comparison of dry and wet aging on physicochemical and sensory characteristics of pork loin with two aging times

This study investigated the effects of aging methods (wet aging and dry aging) and aging times (7 and 14 days) on the physicochemical and sensory characteristics of meat quality using pork loin. Dry-aged loin (DA) had significantly lower moisture content and higher crude fat protein content than wet-aged loin (WA). The pH of DA was significantly higher than that of WA and it increased with the aging time. DA showed lower cooking loss and higher aging loss than WA (p < 0.001). Lipid oxidation and metmyoglobin content of DA were higher than those of WA (p < 0.001). Shear force in DA was lower than that in WA (p < 0.001) and myofibril protein index (MFI) increased in DA. In addition, DA recorded higher scores of roast color, flavor and overall acceptability compared to WA. These results suggested that the application of dry-aging on pork improved physicochemical, textural and sensory characteristics.

The effect of ATP marination on the depolymerization of actin filament in goose muscles during postmortem conditioning

In order to study the tenderization mechanism of ATP treatments by depolymerizing actin filaments, breast muscles of Eastern Zhejiang White Geese were randomly divided into 3 groups: control, 10 and 20 mM groups. Shear force (SF), sarcomere length (SL) and myofibrillar fraction index (MFI), the content of F-actin and G-actin, the expression of actin associated proteins (cofilins and tropomodulins) were investigated during conditioning. In 20 mM group, cofilins content increased from 48 to 168 h, while tropomodulins decreased; the content of F-actin decreased from 24 to 168 h, while the increased G-actin was observed upto 48 h. In the control, the degraded tropomodulins were observed at 168 h, and the increased cofilins and G-actin were detected at the same time; the increase of MFI and decrease of F-actin content were shown at 96 and 168 h. Compared to control group, 20 mM group accelerated the transformation of F-actin into G-actin; it showed higher SL and MFI, and lower SF at 48, 96 and 168 h, respectively. We concluded that depolymerization of actin filaments, which was regulated by cofilins and tropomodulins, contributed to myofibrillar fraction and low SF during conditioning.

The effects of dry or wet aging on the quality of the longissimus muscle from 4-year-old Hanwoo cows and 28-month-old Hanwoo steers

This study was conducted to discover the differences in physicochemical and sensory qualities of beef from 4-year-old Hanwoo cows and 2-year-old Hanwoo steers after undergoing different meat aging methods. Additionally, the possibility of using 4-year-old cows as value-added aged meat was investigated. Loins from eight cows (average 51 months old) and eight steers (average 28 months old) of quality grade 2 were aged for 28 days using dry and wet aging. Analyses were conducted to evaluate meat quality, including moisture content, pH, cooking loss, shear force, nucleotides, free amino acids (FAA), and sensory evaluation. After 28 days of aging, the moisture and shear force for loins from steers and cows were reduced compared with those of non-aged meat (P < 0.05). Cooking loss was reduced by dry aging. Regardless of aging method and gender, aging decreased inosine-5ʹ-monophosphate content but increased FAA content (P < 0.05). Dry aging increased glutamic acid content in meat, and aging the meat of steer increased the content of aspartic acid and glutamic acid (P < 0.05). Before aging, sensory scores for juiciness, tenderness, flavour, and overall acceptance between cow and steer were significantly different (P < 0.05), but the differences disappeared after aging. Therefore, the quality of lower grade meat from 4-year-old cows is comparable to that of meat from 2-year-old steers after aging, regardless of the aging method used.

The effect of Cytochalasin B and Jasplakinolide on depolymerization of actin filaments in goose muscles during postmortem conditioning

Breast muscles of twenty-four Eastern Zhejiang White Geese were randomly divided into three groups: control, Cytochalasin B (Cyt B) and Jasplakinolide (Jasp) treatments during postmortem conditioning. The myofibrillar fraction index (MFI), actin filaments and the levels of F-actin, G-actin and actin associated proteins (cofilins and tropomodulins) during conditioning were investigated. In control, the degraded tropomodulins, increased G-actin and disrupted actin filaments were observed at 4 and 7days; the increase of MFI and decrease of F-actin content were shown during conditioning. Cyt B treatments accelerated the transformation from F-actin to G-actin, weakened actin filaments and increased MFI compared to the control, while Jasp gained the opposite effect against Cyt B. We concluded that depolymerization of actin filaments regulated by tropomodulins contributed to myofibrillar fraction during conditioning. This work provided a new pathway of tenderization by the depolymerization of actin filaments.

Quality Improvement of Pork Loin by Dry Aging

This study aimed to investigate the effects of dry aging on the quality of pork loin. Longissimus lumborum muscles were dissected from the right half of five pork carcasses and were used as the control samples. The left halves of the carcasses were aged at 2±1℃ and a relative humidity of 80% for 40 d. The total aerobic bacteria count was similar between the control and dry-aged pork loin (p>0.05). Lactic-acid bacteria was absent in both the control and dry-aged pork loins. Dry-aged pork loin contained low moisture and high protein and ash compared to the controls (p<0.05). The pH was higher and cooking loss was lower in dry-aged pork loin compared to that in the control (p<0.05). Flavor related compounds, such as total free amino acid, hypoxanthine, and inosine of pork loin were higher in dry-aged pork loin; whereas, inosine 5'-monophosphate and guanosine 5'-monophosphate were low in dry-aged pork loin than control (p<0.05). There was no difference in carnosine and anserine content between dry-aged pork loin and the control (p>0.05). Dry-aged pork loin had lower hardness and shear force and received higher core in sensory evaluation than the control (p<0.05). According to the results, dry aging improved textural and sensorial quality of pork loin.

Genome-Wide Detection of CNVs and Their Association with Meat Tenderness in Nelore Cattle

Brazil is one of the largest beef producers and exporters in the world with the Nelore breed representing the vast majority of Brazilian cattle (Bos taurus indicus). Despite the great adaptability of the Nelore breed to tropical climate, meat tenderness (MT) remains to be improved. Several factors including genetic composition can influence MT. In this article, we report a genome-wide analysis of copy number variation (CNV) inferred from Illumina® High Density SNP-chip data for a Nelore population of 723 males. We detected >2,600 CNV regions (CNVRs) representing ≈6.5% of the genome. Comparing our results with previous studies revealed an overlap in ≈1400 CNVRs (>50%). A total of 1,155 CNVRs (43.6%) overlapped 2,750 genes. They were enriched for processes involving guanosine triphosphate (GTP), previously reported to influence skeletal muscle physiology and morphology. Nelore CNVRs also overlapped QTLs for MT reported in other breeds (8.9%, 236 CNVRs) and from a previous study with this population (4.1%, 109 CNVRs). Two CNVRs were also proximal to glutathione metabolism genes that were previously associated with MT. Genome-wide association study of CN state with estimated breeding values derived from meat shear force identified 6 regions, including a region on BTA3 that contains genes of the cAMP and cGMP pathway. Ten CNVRs that overlapped regions associated with MT were successfully validated by qPCR. Our results represent the first comprehensive CNV study in Bos taurus indicus cattle and identify regions in which copy number changes are potentially of importance for the MT phenotype.

Relationship between Proteolytic Activities and Cooking Loss Variability in Liver Issued from Force-Fed Mule Ducks

We investigated liver protease activities to better understand the mechanisms responsible for losses during the cooking of Mule ducks' fatty livers. Fatty livers of similar masses (520 g) were randomly selected among a large flock of overfed male Mule ducks and divided into two groups on the basis of their cooking loss rate, L+ (high cooking losses, 36%) and L- (low cooking losses, 21%). In addition to dry matter and total lipid contents, main hepatic protease (matrix metalloproteinase 2, cathepsins, and calpains) activities were measured by zymography. The results show that L+ samples present higher total relative proteolytic activity (6.15 ± 1.07 vs 4.46 ± 0.52 for L+ and L- samples, respectively) and total lipid content (61.0 ± 3.03% vs 53.7 ± 3.22% for L+ and L- samples, respectively) than L- samples. The results imply that proteases could be involved in the fragilization of the hepatocyte structure, resulting thus in higher cooking losses in L+ samples.