• Food Science of Animal Resources
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• v.37 no.6
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• pp.873-883
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• 2017

Variations in the definition of poultry meat quality exist because the quality traits are not solely based on intrinsic and extrinsic factors but also consumers' preference. Appearance quality traits (AQT), eating quality traits (EQT), and reliance quality traits (RQT) are the major factors focused by the consumer before buying good quality of poultry meat. AQT and EQT of poultry meat are controlled by physical and biochemical characteristics of muscle fibers which can be categorized into a total number of fibers (TNF), cross-sectional area of fibers (CSAF), and fiber type composition (FTC). In poultry meat, it has been shown that muscle fiber properties play a key role in meat quality because numerous studies have reported the relationships between quality traits and fiber characteristics. Despite intensive research has been carried out to manipulate the muscle fiber to improve poultry meat quality, demand in a rapid growth of poultry muscle has correlated to the deterioration in the meat quality. The present paper reviews the definition of poultry meat quality, meat quality traits, and variations of meat quality. Also, this review presents recent knowledge underlying the relationship between poultry meat quality traits and muscle fiber characteristics.

• Korean Journal of Agricultural Science
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• v.45 no.1
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• pp.50-57
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• 2018

Meat comes from the skeletal muscles of farm animals, such as pigs, chickens, and cows. Skeletal muscles are composed of many muscle fibers. Muscle fibers are categorized into three types, fiber type I, IIA, and IIB, based on their contractile speed and metabolic properties. Different muscle fiber types have different biochemical, physiological, and biophysical characteristics. Especially, the characteristics of muscle fiber type I and IIB are opposite to each other. Muscle fiber type I has a relatively strong oxidative metabolic trait and a higher content of lipids. In contrast to fiber type I, muscle fiber type IIB has a strong glycolytic metabolic trait and a relatively lower content of lipids and a higher content of glycogen. Muscle fiber type IIA has intermediate properties between fiber type I and IIB. Thus, muscles with different fiber type compositions exhibit different ante- and post-mortem muscle characteristics. In particular, the different metabolic traits of muscles due to the different compositions of the fiber types strongly affect the biochemical and physiological processes during the conversion of muscle to meat and subsequently influence the quality of the meat. Therefore, understating muscle metabolism and muscle fiber characteristics is very important when discussing the traits of meat quality. This review is an overview on basic muscle metabolism, muscle fiber characteristics, and their influence on meat quality and finally provides a comprehensive understanding about the fundamental traits of muscles and meat quality.

• Animal Bioscience
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• v.37 no.4
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• pp.697-708
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• 2024

Objective: The objective of this study was to investigate the influence of dietary supplementation of Eucommia ulmoides leaf extract (ELE) on muscle metabolism and meat quality of pigs with and without pre-slaughter transportation. Methods: In a 43-day feeding experiment, a total of 160 pigs with an initial body weight 60.00±2.00 kg were randomly assigned into four groups in a completely randomized design with 10 replicates. Pigs in groups A and C were fed a basal diet and pigs in groups B and D were fed a basal diet supplemented with 0.5% ELE. Pigs were slaughtered with (group B and D) or without (group A and C) pre-slaughter transport. Muscle chemical composition, postmortem glycolysis, meat quality and muscle metabolome were analyzed. Results: Dietary ELE supplementation had no effect on the proximate composition of porcine muscle, but increased free phenylalanine, proline, citruline, norvaline, and the total free amino acids in muscle. In addition, dietary ELE increased decanoic acid and eicosapentaenoic acid, but decreased heptadecanoic acid, oleic acid, trans-oleic acid, and monounsaturated fatty acids in muscle. Meat quality measurement demonstrated that ELE improved meat water holding capacity and eliminated the negative effects of pre-slaughter transport on meat cooking yield and tenderness. Dietary ELE reduced muscle glycolytic potential, inhibited glycolysis and muscle pH decline in the postmortem conversion of muscle to meat and increased the activity of citrate synthase in muscle. Metabolomics analysis by liquid chromatographic tandem mass spectrometric showed that ELE enhanced muscle energy level, regulated AMP-activated protein kinase (AMPK) signaling, modulated glycogenolysis/glycolysis, and altered the metabolism of carbohydrate, fatty acids, ketone bodies, amino acids, purine, and pyrimidine. Conclusion: Dietary ELE improved meat quality and alleviated the negative effect of pre-slaughter transport on meat quality by enhancing muscle oxidative metabolism capacity and inhibiting glycolysis in postmortem muscle, which is probably involved its regulation of AMPK.

• Journal of Animal Science and Technology
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• v.66 no.2
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• pp.251-265
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• 2024

Meat derived from skeletal muscles of animals is a highly nutritious type of food, and different meat types differ in nutritional, sensory, and quality properties. This study was conducted to compare the results of previous studies on the muscle fiber characteristics of major porcine skeletal muscles to the end of providing basic data for understanding differences in physicochemical and nutritional properties between different porcine muscle types (or meat cuts). Specifically, the muscle fiber characteristics between 19 major porcine skeletal muscles were compared. The muscle fibers that constitute porcine skeletal muscle can be classified into several types based on their contractile and metabolic characteristics. In addition, the muscle fiber characteristics, including size, composition, and density, of each muscle type were investigated and a technology based on these muscle fiber characteristics for improving meat quality or preventing quality deterioration was briefly discussed. This comparative review revealed that differences in muscle fiber characteristics are primarily responsible for the differences in quality between pork cuts (muscle types) and also suggested that data on muscle fiber characteristics can be used to develop optimal meat storage and packaging technologies for each meat cut (or muscle type).

• Food Science and Biotechnology
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• v.14 no.5
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• pp.667-671
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• 2005

The aim of this study is to investigate the effects of the muscle mass and fiber number on post-mortem metabolic rates and pork quality. Carcass traits, muscle fiber characteristics, and type of fiber composition were evaluated using a sample of 200 cross-bred pigs. The muscle mass was divided into two groups according to carcass weight and loin-eye area measurements (heavy or light). In addition, the muscle histological characteristics were divided into two groups according to the muscle fiber density and total number of muscle fibers (high or low). All the carcass traits were significantly different in the muscle mass groups. Increasing weight significantly affected the cross-sectional area (CSA) of all fibers. The low group, which had a low muscle fiber number indicating a larger CSA of fibers, and especially the heavy-low group had the highest CSA levels of fibers. The fiber number percentage and the area percentage were significantly different in the groups categorized by fiber number. The heavy-high group indicated a normal rate of pH decline and the R-value. In addition, pigs with a heavy muscle mass and high muscle fiber number indicated normal drip loss, lightness, and protein denaturation. The present results suggest that increasing the total muscle fiber number has a beneficial effect on increasing the muscle mass without deteriorating the meat quality.

• Food Science of Animal Resources
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• v.40 no.1
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• pp.34-43
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• 2020

The objectives of this study was to compare palatability changes of the longissimus thoracis (LT) and vastus lateralis (VL) muscles of Hanwoo steers from different beef quality grades (1⁺ and 1) during 28 d of wet-aging in order to improve the utilization of the VL muscle as a steak. The VL muscle showed a higher collagen content and a lower intramuscular fat content than the LT muscle (p<0.05). As expected, the Warner-Bratzler shear force value was greater in the LT 1 grade (LT-1) muscle than the LT-1⁺ muscle (p<0.05); whereas no difference was observed between the grades in the VL muscle at 24 h postmortem. Compared to 0 d of aging, tenderness scores significantly increased after 14 and 21 d of aging in the LT and VL muscles, respectively (p<0.05). Additionally, there was no difference in tenderness score between the VL-1⁺ aged for 21 d and the LT-1 at 24 h postmortem, although tenderness score was greater in the LT than the VL at each period (p<0.05). Moreover, the VL-1⁺ steak exhibited a higher tenderness score than the VL-1 steak at 21 and 28 d of aging (p<0.05). On the other hand, the effect of aging time on juiciness and flavor in the VL muscle was somewhat limited unlike the LT muscle. Taken together, the VL muscle requires a longer aging time than the LT muscle to improve consumer preference. Considering the tenderness, using a higher quality grade for aging is more useful in the VL muscle.

• Animal Bioscience
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• v.36 no.2_spc
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• pp.374-384
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• 2023

Skeletal muscle metabolism regulates homeostatic balance in animals. The metabolic impact persists even after farm animal skeletal muscle is converted to edible meat through postmortem rigor mortis and aging. Muscle metabolites resulting from animal growth and postmortem storage have a significant impact on meat quality, including flavor and color. Metabolomics studies of postmortem muscle aging have identified metabolisms that contain signatures inherent to muscle properties and the altered metabolites by physiological adaptation, with glycolysis as the pivotal metabolism in postmortem aging. Metabolomics has also played a role in mining relevant postmortem metabolisms and pathways, such as the citrate cycle and mitochondrial metabolism. This leads to a deeper understanding of the mechanisms underlying the generation of key compounds that are associated with meat quality. Genetic background, feeding strategy, and muscle type primarily determine skeletal muscle properties in live animals and affect post-mortem muscle metabolism. With comprehensive metabolite detection, metabolomics is also beneficial for exploring biomarker candidates that could be useful to monitor meat production and predict the quality traits. The present review focuses on advances in farm animal muscle metabolomics, especially postmortem muscle metabolism associated with genetic factors and muscle type.

• Food Science of Animal Resources
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• v.39 no.2
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• pp.197-208
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• 2019

The aim of this study was to investigate the relation of sensory quality traits of cooked beef to fresh meat quality and histochemical characteristics, especially muscle bundle traits, in the longissimus thoracis muscle of Hanwoo steers. Cooking loss negatively correlated with softness, initial tenderness, chewiness, rate of breakdown (RB), and amount of perceptible residue (AR) after chewing (p<0.05), and drip loss showed negative correlation with RB and AR (p<0.05). All the attributes of tenderness exhibited negative correlation with the Warner-Bratzler shear force value (p<0.05). Marbling score and the intramuscular fat (IMF) content showed positive correlation with all the organoleptic characteristics, including tenderness attributes, juiciness, and flavor (p<0.05). Regarding histochemical characteristics, muscle fiber size did not have a significant correlation with all the sensory quality traits, although the area percentage of type I fiber was related with softness, initial tenderness, and chewiness (p<0.05). On the contrary, the characteristics of muscle bundle were related to all the sensory tenderness attributes (p<0.05), and the sensory tenderness increased with smaller muscle bundle size (p<0.05). These results suggest that the IMF content and bundle characteristics can be used as indicators for explaining the variations in sensory tenderness in well-marbled beef.

• Food Science of Animal Resources
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• v.40 no.6
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• pp.957-968
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• 2020

The influence of muscle architecture on muscle fiber characteristics and meat quality has not been fully elucidated. In the present study, muscle fiber characteristics on the chop surface of pork loin (M. longissimus thoracis et lumborum, LTL), pennation angle degree, and meat quality were evaluated to understand the pork LTL architecture and its relationship with the loin chop quality. Muscle fiber pennation degree ranged from 51.33° to 69.00°, resulting in an ellipse-shaped muscle fiber on the surface of pork loin chop. The cross-sectional area (CSA) on the sections cut vertical to the muscle length (M-Vertical) was considerably larger (p<0.05) than that on the sections cut vertical to the muscle fiber orientation (F-Vertical) regardless of the fiber type. Pennation angle is positively correlated with CSAs of F-Vertical (p<0.05) and with Warner-Bratzler shear force (r=0.53, p<0.01). Besides the shear force, lightness and pH were positively correlated with the fiber composition and CSA of IIX fiber (p<0.05); however, the redness, yellowness, drip loss, and cooking loss were not correlated with the pennation angle and muscle fiber characteristics on the chop surface (p>0.05). These observations might help us in better understanding pork loin architecture and the relationship between the pennation angle, muscle fiber characteristics, and meat quality of pork loin chop.

• Korean Journal of Radiology
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• v.22 no.11
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• pp.1909-1917
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• 2021

Objective: Muscle quantity and quality can be measured with an automated system on CT. However, the effects of contrast phases on the muscle measurements have not been established, which we aimed to investigate in this study. Materials and Methods: Muscle quantity was measured according to the skeletal muscle area (SMA) measured by a convolutional neural network-based automated system at the L3 level in 89 subjects undergoing multiphasic abdominal CT comprising unenhanced phase, arterial phase, portal venous phase (PVP), or delayed phase imaging. Muscle quality was analyzed using the mean muscle density and the muscle quality map, which comprises normal and low-attenuation muscle areas (NAMA and LAMA, respectively) based on the muscle attenuation threshold. The SMA, mean muscle density, NAMA, and LAMA were compared between PVP and other phases using paired t tests. Bland-Altman analysis was used to evaluate the inter-phase variability between PVP and other phases. Based on the cutoffs for low muscle quantity and quality, the counts of individuals who scored lower than the cutoff values were compared between PVP and other phases. Results: All indices showed significant differences between PVP and other phases (p < 0.001 for all). The SMA, mean muscle density, and NAMA increased during the later phases, whereas LAMA decreased during the later phases. Bland-Altman analysis showed that the mean differences between PVP and other phases ranged -2.1 to 0.3 cm² for SMA, -12.0 to 2.6 cm² for NAMA, and -2.2 to 9.9 cm² for LAMA.The number of patients who were categorized as low muscle quantity did not significant differ between PVP and other phases (p ≥ 0.5), whereas the number of patients with low muscle quality significantly differed (p ≤ 0.002). Conclusion: SMA was less affected by the contrast phases. However, the muscle quality measurements changed with the contrast phases to greater extents and would require a standardization of the contrast phase for reliable measurement.