The objective of the present study was to explore the effect of Fe(III)-protoporphyrin IX (hemin), protoporphyrin IX (PPIX) and free iron on beef M. semitendinosus tenderness and its molecular ...mechanism. Hemin, PPIX and FeCl3 treatment of beef muscles under heating tremendously decreased shear force of beef meat by approximately 24%, 26%, and 30% respectively and weakened the association of actin-myosin. The protein carbonyl content increased and sulfhydryl content decreased significantly in FeCl3 and hemin treated groups, indicating the oxidative modification of actomyosin. The higher surface hydrophobicity and intrinsic fluorescence intensity demonstrated that hemin, PPIX and FeCl3 increased the unfolding of actomyosin, and the crosslinking was formed by hydrophobic interaction and disulfide bonds. Hemin treatment increased the α-helices/random coil and initiated more structural changes in actomyosin as compared to that of PPIX and FeCl3. These biochemical changes might contribute to the dissociation of actomyosin. The obtained results established a link between meat tenderness and porphyrins/free iron content, and gave new insights into the mechanism of how hemin and released PPIX and free iron affect the physicochemical properties of actomyosin.
•Porphyrins and free iron decreased shear force of beef meat.•Porphyrins and free iron could induce actomyosin dissociation.•Unfolding of actomyosin and structural changes led to actomyosin dissociation.
Our objective was to test the effects of freezing temperature and frequency on purge loss and tenderness of eye of round steaks. Commercially sourced USDA Choice beef semitendinosus (n=10) were aged ...24 d postmortem. Twelve steaks were cut from each muscle and randomly assigned to 1 of 12 treatments in a 4×3 factorial treatment structure(unfrozen control at 2.2°C or initial freezing at −17.8°C, −26.1°C, or −34.4°C followed by secondary freezing at −17.8°C, −26.1°C, or −34.4°C). Steaks were weighed after cutting and after thawing following each freezing treatment to determine purge losses. Tenderness was assessed via Warner-Bratzler shear force (WBSF); all data were analyzed via mixed models. Lower total purge losses (6.27%) were observed for steaks initially unfrozen (P<0.001), whereas those initially frozen at −34.4°C, −26.1°C, and −17.8°C lost 8.04%, 8.80%, and 8.53%, respectively. No difference (P>0.501) in WBSF was detected among the freezing treatments. These results suggest that freezing temperature and thus freezing rate impact purge loss of eye of round steaks, but mechanical tenderness was not influenced.
Heat treatment of meat at temperatures between 50 and 65 °C, for extended periods of time, is known as low-temperature long-time (LTLT) cooking. This cooking method produces meat that has increased ...tenderness and better appearance than when cooked at higher temperatures. Public concerns regarding this method have focused on the ability to design heat treatments that can reach microbiological safety. The heat treatment induces modification of the meat structure and its constituents, which can explain the desirable eating quality traits obtained. Denaturation, aggregation, and degradation of myofibrillar, sarcoplasmic and connective tissue proteins occur depending on the combination of time and temperature during the heat treatment. The protein changes, especially in relation to collagen denaturation, along with proteolytic activity, have often been regarded to be the main contributors to the increased meat tenderness. The mechanisms involved and the possible contribution of other factors are reviewed and discussed.
This study aimed to evaluate the sous-vide cooking and ficin treatment effects on the tenderness of beef steak and optimize it for the elderly using response surface methodology (RSM). The M. ...semitendinosus (ST) from Chikso cattle was shaped into 5 × 5 × 2.54 cm pieces. Ficin solution was injected into the ST steak at 10% of the meat weight, and sous-vide cooked in a water bath at 65 °C for 6 or 12 h. As ficin concentration increased, L*- and a*-value, shear force, and hardness decreased, while soluble peptides increased (P < 0.05). As cooking time increased, cooking loss and collagen solubility of the steak increased (P < 0.05). An interaction effect between ficin and sous-vide cooking was found in L*- and a*-value, shear force, hardness, and soluble peptides (P < 0.05). A model to optimize the hardness for elderly people was established (R2 = 0.7991). Optimization conditions by RSM were 0.86 U/L with 8.87 h (23 N/cm3) for tooth intake (grade 1), 16.31 U/L with 13.24 h (3 N/cm3) for gums intake (grade 2), according to KS H 4897 and Universal Design Foods concept for the elderly. These optimized conditions enable the production of customized products tailored to the oral conditions of elderly people.
•Beef eating quality (EQ) is highly variable, which negatively affects consumption.•Beef EQ is an intrinsic quality trait which depends on pre and post slaughter factors.•The main attributes of EQ ...are; flavor, juiciness, tenderness and overall liking.•Tenderness is the most sensitive to any change in pre and post slaughter parameters.
Eating quality is one of the most important traits by which consumers evaluate satisfaction and make decisions on future beef purchases. Unfortunately, the beef on the market is of inconsistent quality. Therefore, meat producers supplying beef of good and consistent quality would be more competitive in the beef market. The main attributes of eating quality are flavor, juiciness, tenderness, and overall liking. Beef eating quality is an intrinsic quality trait, which depends on both pre- and post-slaughter factors. In this review, we attempt to describe the impact of the major factors determining beef eating quality throughout the production chain such as: breed, farming systems, animal welfare, electrical stimulation, carcass suspension methods, chilling process associated with pH drop and aging methods. As part of this review, some the effects were extracted and summarized to give an overview of the magnitude of the effects and to understand which effects have the greatest impact.
It is certain that meat tenderness is a highly valued consumer trait and thus definition of the multiple processes that influence meat tenderness will provide clues toward improving meat quality and ...value. The natural process by which meat becomes tender is complex. Tenderness development is dependent on the architecture and the integrity of the skeletal muscle cell and on events that modify those proteins and their interaction. Specifically protein degradation and protein oxidation have been identified as processes that modify proteins as well as the tenderness of meat. The intracellular environment is a major factor that controls these events. Ultimately, the interplay between these events determines the rate and extent of tenderization. Given the intricacy of the structure of the muscle cell, coupled with the complexity of the regulation of protein modification and the ever-changing intracellular environment it is not surprising that this area of research is a very dynamic field. Just as the overall integrity and function of muscle cells does not depend on a single protein, but rather on the coordinated interaction of several proteins, the structural weakening of muscle cells during postmortem aging also must not depend on the degradation of a single myofibrillar or other cytoskeletal protein. The proteins mentioned in this review are located in different regions of the muscle cell, and most have been implicated in some manner as being important in maintaining the structure and function of the muscle cell. Oxidation of myosin heavy chain, a predominant protein in the myofibril, is known to promote aggregation and toughening of meat. Degradation of proteins such as desmin, filamin, dystrophin, and talin (all located at the periphery of the Z-line) may disrupt the lateral register and integrity of the myofibril themselves as well as the attachments of the peripheral layer of myofibril to the sarcolemma. Degradation of the proteins within the myofibril that are associated with the thick and thin filaments may allow lateral movement or breaks to occur within the sarcomeres of postmortem aged samples. Titin, nebulin, and troponin-T, by their ability to directly interact with, or modulate the interaction between, major proteins of the thick and thin filaments and (or) the Z-line, play key roles in muscle cell integrity. Disruption of these proteins, especially titin and nebulin, could initiate further physicochemical and structural changes that result in myofibril fragmentation and loss of muscle cell integrity, and ultimately in tenderization of the muscle. In order to make real progress in this area, the scientific community must have a global appreciation of how both the structural proteins and the key proteases are influenced by the vast changes that occur during the conversion of muscle to meat.
During the thermal processing, proteins of Hengshan goat meat undergo structural modifications such as degradation, oxidation and denaturation, ultimately affect the palatability and acceptability. ...The results of several objective metrics demonstrated that thermal processing exhibited significant impacts on the tenderness of goat meat. The 551, 84, 72, and 121 proteins were identified in the control and thermal processed groups (boiled, steamed, and roasted), respectively. Compared with the control group, the 101, 98, and 109 differentially-expressed proteins were explored in the treatment groups. Furthermore, the functions of metabolic and skeletal muscle proteome were investigated and discussed. Sensory evaluation and proteomics analysis showed that steaming and boiling treatment had no significant effect on the tenderness of goat meat, while roasting significantly reduced the tenderness, indicating that the available thermal processing methods to ensure the tenderness of goat meat were steaming and boiling treatments. Thus, the established proteomics database of goat meat provided the valuable reference for rational selection of thermal processing methods.
•Thermal processing affects tenderness-related parameters and proteome of goat meat.•Proteomics profile among raw, boiled, steamed and roasted goat meat were compared.•Boiling had a similar effect on tenderness and protein as steaming.•Most significant changes of proteome in roasting are related to lowest likeness score.•Boiled and steamed Hengshan goat meats have better tenderness and sensory property.
Two experiments have been conducted in this research to determine the effects of hydrostatic pressure on Iraqi rams and calves’ meats. (One experiment for each kind of meat), Four treatments were ...designed for each experiment: control with no hydrostatic pressure, T1 with 100 bar exposed pressure, T2 with 200 bar and T3 with 300 bar. The pressures were generated and handled via a device designed and manufactured for this goal. The studied properties were water holding capacity WHC, thaw loss, fragmentation index FI, myofibril fragmentation index MFI, protein solubility and shear force. All these properties are strongly related to meat tenderness. All studied properties were affected significantly by applying hydrostatic pressure on meat samples to rams and calves’ meat samples. Therefore, exposing the meat to hydrostatic pressure enhances its tenderness-related properties.
Keywords: hydrostatic pressure; tenderness; Protein solubility.
The study aimed to determine the effect of sex, muscle-type, and ageing on the physical properties of blesbok (Damaliscus pygargus phillipsi) Longissimus thoracis et lumborum (LTL) and Biceps femoris ...(BF) muscles. Randomly assigned steak samples from twenty mature blesbok (10 of each sex) antelope were vacuum-packed and stored at 4.4 ± 1 °C for 2, 4, 7, 10, 17 and 28 ageing days. Cumulative purge loss, pH, colour (L*, a*, b), cooking loss, and Warner Braztler shear force were determined. Males had meat with higher (P = 0.032) pH values than females, while all other attributes were similar (P > 0.05). The LTL had greater (P < 0.05) purge losses, L* and a* values than the BF muscle, while other quality attributes were greater (P < 0.05) for the BF muscle. Despite fluctuations, there was an overall decrease in shear force with ageing time. According to all quality parameters measured, the optimum ageing period for blesbok would seem to be 10 days.
This study aimed to investigate the mechanism of ferroptosis mediated by mitochondrial oxidative stress and its potential associations with tenderness of beef during refrigeration. Results showed ...that mitochondrial reactive oxygen species (ROS) reached a maximum at day 3 (116.67 ± 8.50 mg protein), the degree of mitochondrial swelling, mitochondrial membrane permeability increased with the increase of refrigeration time, and mitochondrial free iron content increased significantly (p < 0.05), while mitochondria showed the morphological features of ferroptosis. In addition, the decreased levels of reduced glutathione, total antioxidant capacity and the activity of glutathione peroxidase, and the accumulation of malondialdehyde reflected an imbalance in mitochondrial antioxidant defense system, presenting the physiological characteristics of ferroptosis. Furthermore, mitochondrial TMT quantitative proteomics identified 7 differentially expressed proteins (DEPs) enriched to the ferroptosis pathway, including ACSL1, LOC788801, ACSL4, PRNP, VDAC2, ACSL3 and LPCAT3, which were primarily involved in lipid metabolism pathway and were the major mitochondrial pathway involved in ferroptosis during beef refrigeration. Besides, ROS and lipid peroxidation from mitochondrial oxidative stress-mediated ferroptosis attacked tissue myofibril structure and increased myofibrillar fragmentation index, which promoted the improvement of postmortem meat tenderness. These findings provided new perspectives on the role of mitochondria in cell death and the effect of ferroptosis on muscle tenderization.
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•Mitochondrial oxidative stress-mediated ferroptosis promoted beef tenderization.•Beef mitochondria showed oxidative stress and typical ferroptosis characteristics.•Lipid metabolism was the main mitochondrial pathway involved in ferroptosis.
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