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.

To improve culture efficiency of Hanwoo myosatellite cells, these cells were cultured at different temperatures. Hanwoo myosatellite cells were compared with C2C12 cells to observe proliferation and differentiation at culture temperatures of 37°C and 39°C and determine the possibility of using them as cultured meat. Immunofluorescence staining using Pax7 and Hoechst, both cells cultured at 37°C proliferated better than cultured at 39°C (p < 0.05). When differentiated cells were stained with myosin and Hoechst, there was no significant difference in myotube thickness and Fusion index (p > 0.05). In Western blotting analysis, Hanwoo myosatellite cells were no significant difference in the expression of myosin between cells differentiated at the two temperatures (p > 0.05). C2C12 cells were no significant difference in the expression of myosin between cells differentiated at the two temperatures (p > 0.05). In reverse transcription and quantitative polymerase chain reaction (RT-qPCR) analysis, Hanwoo myosatellite cells cultured at 39°C had significantly (p < 0.05) higher expression levels of MyHC, MYF6, and MB than those cultured at 37°C. C2C12 cells cultured at 39°C showed significantly (p < 0.05) higher expression levels of MYOG and MB than those cultured at 37°C. To increase culture efficiency of Hanwoo myosatellite cells, proliferating at 37°C and differentiating at 39°C are appropriate. Since results of temperature differences of Hanwoo myosatellite cells were similar to those of C2C12 cells, they could be used as a reference for producing cultured meat using Hanwoo satellite cells.

We review experimental approaches that can be used instead of in vivo studies involving vertebrate animal models and human clinical trials. The existing alternative experimental approaches were classified as in vitro digestion models, invertebrate models, organs-on-a-chip, in silico models, and toxicity tests. In vitro models mimicking the digestive system may help assess pharmacokinetics without the use of animal models. In addition, invertebrate models can be easily applied in genetics research and toxicity assays owing to their advantages, such as effortless handling, low cost, small size, and simple anatomy. Organs-on-a-chip and in silico models can simulate the physiological activity in biological organs and can be useful for monitoring human diseases. Moreover, these alternative models can be adopted as screening platforms to assess candidate drugs during the preclinical phase through rapid and simple monitoring of physiological response to drugs. Therefore, these alternative experimental approaches can contribute to ethical reduction of animal use in biological studies.

Abstract To improve culture efficiency of Hanwoo muscle satellite cells, these cells were cultured at different temperatures. Hanwoo muscle satellite cells were compared with C2C12 cells to observe proliferation and differentiation at culture temperatures of 37 ℃ and 39 ℃ and determine the possibility of using them as cultured meat. Immunofluorescence staining using Pax7 and Hoechst, both cells cultured at 37 ℃ proliferated better than cultured at 39 ℃ (p < 0.05). When differentiated cells were stained with myosin and Hoechst, there was no significant difference in root canal thickness and Fusion index. In Western blotting analysis, Hanwoo muscle satellite cells were no significant difference in the expression of myosin or cytochrome C between cells differentiated at the two temperatures. C2C12 cells were no significant difference in the expression of myosin between cells differentiated at the two temperatrues. In RT-qPCR analysis, Hanwoo muscle satellite cells cultured at 39 ℃ had significantly (p < 0.05) higher expression levels of MyHC, MRF4, and myoglobin than those cultured at 37 ℃. C2C12 cells cultured at 39 ℃ showed significantly (p < 0.05) higher expression levels of myogenin and myoglobin than those cultured at 37 ℃. To increase culture efficiency of Hanwoo muscle satellite cells, proliferating at 37 ℃ and differentiating at 39 ℃ are appropriate. Since results of temperature differences of Hanwoo muscle satellite cells were similar to those of C2C12 cells, they could be used as a reference for producing cultured meat using Hanwoo satellite cells.

In this study, we assessed the antioxidative ability of 23 natural sources in a meat model system at the same addition level (1.0%). We evaluated the free radical (2,2-diphenyl-1-picrylhydrazyl, DPPH) scavenging ability of natural plant sources and their peroxides, as well as their aldehyde-inhibiting ability in pork patties, over 10 days of cold storage. It was found that blueberries, cherries, onions, black tea, and clove buds (20.6–25.0 mg AA/g) have a higher DPPH scavenging ability than that of other natural sources (10.80–16.7 mg AA/g) ( P < 0.05 ). Moreover, it was found that peroxides in pork patties are largely inhibited by red wine, lettuce, and red ginseng ( P < 0.05 ), whereas aldehydes are significantly inhibited by blueberries, chokeberries (aronia), blackcurrant, clove buds, elderberries, ginger, and cinnamon ( P < 0.05 ). These inconsistencies detected in the antioxidative ability of these 23 natural sources indicate that it is important to perform comprehensive and practical assessments of the potential antioxidative ability of natural sources. In addition, it is assumed that the interactions between natural plant sources and meat components affect the inhibition of lipid oxidation in meat and meat products.

The aim of this study was to optimize staining procedures for muscle fiber typing efficiently and rapidly in bovine and porcine skeletal muscles, such as longissimus thoracis, psoas major, semimembranosus, and semitendinosus muscles. The commercially available monoclonal anti-myosin heavy chain (MHC) antibodies and fluorescent dye-conjugated secondary antibodies were applied to immunofluorescence histology. Two different procedures, such as cocktail and serial staining, were adopted to immunofluo-rescence analysis. In bovine muscles, three pure types (I, IIA, and IIX) and one hybrid type, IIA+IIX, were identified by the cocktail procedure with a combination of BA-F8, SC-71, BF-35, and 6H1 anti-MHC antibodies. Porcine muscle fibers were typed into four pure types (I, IIA, IIX, and IIB) and two hybrid types (IIA+IIX and IIX+IIB) by a serial procedure with a combination of BA-F8, SC-71, BF-35, and BF-F3. Unlike for bovine muscle, the cocktail procedure was not recommended in porcine muscle fiber typing because of the abnormal reactivity of SC-71 antibody under cocktail procedure. Within the four antibodies, combinations of two or more anti-MHC antibodies allowed us to distinguish pure fiber types or all fiber types including hybrid types. Application of other secondary antibodies conjugated with different fluorescent dyes allowed us to get improved image resolution that clearly distinguished hybrid fibers. Muscle fiber characteristics differed depending on species and muscle types.

This study evaluated the effect of porcine plasma hydrolysates (PPH) on the physicochemical, antioxidant, and antimicrobial properties of emulsion-type pork sausages. Five levels of PPH were added to sausages (CON, 0 g/kg; T1, 5 g/kg; T2, 10 g/kg; T3, 15 g/kg; and T4, 20 g/kg) and their chemical composition, purge loss, lipid oxidation, microbial count, pH, color, texture, and sensory properties were compared on day 1 and after 4 weeks of cold storage. At 4 weeks of storage, hardness, cohesiveness, and gumminess were highest in T3 (P < 0.05). The peroxide value increased in all treatments during the 4-weeks of storage (P < 0.05); however, it was not significantly different between CON, T2, and T3 (P > 0.05). The total aerobic plate count was the lowest in T4 at week 4 (P < 0.05). Therefore, PPH addition could improve the texture of the emulsion-type pork sausages, and an antimicrobial effect was expected following exposure to at least 20 g/kg PPH.

Introduction Freezing is a commonly used method for meat preservation (Srinivasan et al., 1997). However, freezing induces physical and biochemical changes in meat and consequently is accompanied by deterioration in the meat quality, such as discoloration, protein and lipid oxidation, and detrimental changes of texture (Sebranek, 1982; Leygonie et al., 2012; Kim et al., 2013a). Recently, some studies demonstrated that microstructure damages, including Z-line fracture, I band weakening, and enlargement of gaps between muscle fibers could be caused due to the formation of ice crystals by freezing or repeated freeze-thawing (Zhang et al., 2017; Setyabrata & Kim, 2019). However, damages associated with muscle fiber types have not been studied. Therefore, the purpose of this study is to investigate the impact of freeze-thawing on damages related to different types of muscle fibers as well as on the quality of beef. Methods Twenty longissimus lumborum muscles were obtained from the left side of Hanwoo (Korean native cattle) carcasses at 24 h postmortem from a commercial slaughterhouse. Two chops (approximately 10-cm thickness) were cut from the center of each muscle and randomly allocated to two groups: fresh, stored at 1°C for 5 days; freeze-thawed (FT), frozen at -20°C for 3 days followed by thawing at 1°C for 2 days. Meat quality traits, such as Commission Internationale de l’Eclairage (CIE, 1978) L*a*b*, pH, cooking loss (%), purge or thawing loss (%), Warner-Bratzler shear force (N; WBSF), moisture content (%), and crude fat content (%), were analyzed according to a previous study (Kim et al., 2013b). For typing of muscle fibers, two monoclonal antibodies, such as SC-71 and 6H1 (DSHB, Iowa City, IA, USA), and secondary antibodies conjugated with fluorescence dyes (Alexa Fluor® 405 and 488, Abcam, Cambridge, UK) were used (Fig. 1). Statistical analysis was performed using the SAS 9.4 program (2016). Effects of freeze-thawing on the quality of beef and muscle fiber structure were tested using a paired t-test model and in general linear model, respectively. P < 0.05 was accepted as statistically significant. Results Many cavities were found in both the vertical and horizontal sections of FT muscle (Fig. 1), demonstrating that the fibers of FT muscle were essentially damaged. However, muscle fibers of fresh muscle were not damaged by freezing. It was observed that 53.42±4.10% of the muscle fibers were damaged by FT (Fig. 2A). Moreover, 75.68% of IIX fibers were damaged, the highest among the muscle fiber types (P < 0.05). In contrast, fiber type I had the lowest numbers of damaged fibers (25.45%; P < 0.05). Furthermore, the percentage of areas of the cavities formed showed a similar trend to that of the damaged fibers (Fig. 2B). The cavity area of fiber type IIX was 8.90% and was significantly higher (P < 0.05) than those of types I (2.23%) and IIA (4.56%). Meat quality of the freeze-thawed beef loin was significantly different (P < 0.05) in traits of water-holding capacity and tenderness than that of control (Table 1). Purge (thawing) loss (P < 0.01), and cooking loss (P < 0.05), and WBSF (P < 0.01) were higher in FT muscle than those in fresh muscles. However, the other traits of meat quality, such as pH, meat color, moisture and fat contents were not significantly different between FT and fresh muscles (P > 0.05). Table 1. Comparison of meat quality between fresh and freeze-thawed beef loin

The objective of this study was to evaluate the effect of feeding soybean oil (SO) with varying levels of peroxidation on carcass traits and shelf life of loins. Fifty-six barrows were randomly assigned to 1 of 4 diets containing 10% fresh SO (22.5 °C) or thermally processed SO (45 °C for 288 h, 90 °C for 72 h, or 180 °C for 6 h), each infused with air at a rate of 15 liter/min. Individually housed pigs were provided ad libitum access to feed for 81 d. At 82 d, pigs were slaughtered and hot carcass weight and liver weights were recorded. Carcass characteristics and fresh loin quality were evaluated 1 d postmortem. Loin chops from each carcass were overwrap-packaged and subjected to a 10-d simulated retail display. Daily measurements of L*, a*, b*, reflectance, and visual discoloration were conducted, evaluation of cooking loss and Warner-Bratzler shear force (WBSF) was conducted on chops stored 0, 5, and 10 d, and thiobarbituric acid reactive substances (TBARS) were evaluated on chops stored 0 and 10 d. Shelf life-related data were analyzed as a completely randomized design with repeated measures in time, with storage location (shelf) as a random effect. Carcasses of 90 °C pigs weighed 6.0, 8.6, and 6.9 kg less (P < 0.03) than 22.5 °C, 45 °C, and 180 °C carcasses, respectively. Livers of 90 °C and 180 °C pigs were 14.3% and 11.7%, respectively, heavier (P ≤ 0.02) than those from pigs fed 22.5 °C SO, with livers of 45 °C being intermediate. Livers of 90 °C pigs represented 0.12 percentage units less (P = 0.02) of ending live weight than livers of 180 °C pigs, and 180 °C livers were 0.12 percentage units less (P < 0.01) of ending live weight than those from pigs fed 22.5 °C SO, with 45 °C being intermediate. There was no difference (P ≥ 0.19) in back fat depth, loin muscle area, or estimated carcass lean percentage among SO treatments, nor was there an effect (P ≥ 0.13) of SO on any early post-mortem loin quality traits or loin composition. There was no effect (P > 0.14) of SO on cooking loss, WBSF, L*, a*, b*, hue angle, reflectance, discoloration, or TBARS; however, there was a tendency (P = 0.09) for chops of 45 °C pigs to have greater (P < 0.04) chroma than either 22.5 °C or 180 °C, with 90 °C being intermediate. Overall, feeding SO cooked at 90 °C for 72 h resulted in reduced carcass weight and dressing percentage; however, there was no evidence that feeding peroxidized SO was detrimental to shelf life of loin chops.

This study was conducted to estimate the effect of partially replacing NaCl by blends of CaCl2, MgCl2 and KCl on quality changes in fat-reduced emulsified pork sausages. All blends of salts increased redness (P < 0.001) and decreased yellowness (P < 0.001) over storage time. MgCl2 at 15% replacement of NaCl strongly affected texture and chewiness, however negatively affected lipid oxidation at five weeks of refrigeration. Sausages partially replaced NaCl with 5% CaCl2 did not reveal improved quality despite having the highest ionic strength. Sausages formulated with a blend of all chloride salts (replacing 70% NaCl: 5% CaCl2, 15% MgCl2 and 50% KCl) were not acceptable for sensory properties at initial refrigeration (P < 0.01) and were worse at three weeks of storage (P < 0.05). Except for this formulation, blends with one or two other NaCI substitutes (CaCl2, MgCl2, and KCl) are acceptable for partial replacement of NaCl for processing fat-reduced emulsified sausages without impairing quality property.

Objectives were to evaluate effects of feeding soybean oil (SO) with varying levels of peroxidation on fresh belly characteristics, processing yields, and shelf life of commercially manufactured bacon stored under food-service-style conditions. Fifty-six barrows were randomly assigned to 1 of 4 diets containing 10% fresh SO (22.5 °C) or thermally processed SO (45 °C for 288 h, 90 °C for 72 h, or 180 °C for 6 h), each infused with air at a rate of 15 L/min. Individually housed pigs were provided ad libitum access to feed for 81 d. On day 82, pigs were slaughtered, and on day 83, carcasses were fabricated and bellies collected for recording of weight, dimensions, and flop distance. Belly adipose tissue cores were collected for the analysis of iodine value (IV) by near-infrared spectroscopy (NIR-IV). Bacon was manufactured at a commercial processing facility, and sliced bacon was subsequently transferred to food-service-style packaging and subjected to 0-, 30-, 60-, or 90-d storage at -20 °C. Stored bacon was evaluated for thiobarbituric acid reactive substances (TBARS) and trained sensory evaluation of oxidized odor and flavor. Fresh belly and bacon processing traits were analyzed as a 1-way ANOVA with the fixed effect of SO, whereas shelf life traits were analyzed as a 1-way ANOVA repeated in time. There was no effect (P ≥ 0.30) of SO on belly weight, length, width, or thickness, but bellies of pigs fed 90 °C SO had greater (P ≤ 0.04) flop distance (more firm) than all other SO treatments. Belly fat NIR-IV of pigs fed 90 °C SO were 10.22 units less (P < 0.0001) than pigs fed 180 °C SO, which were 2.99 and 3.29 units less than belly adipose tissue of pigs fed 22.5 and 45 °C SO, respectively. There was no effect of SO on brine uptake or cooking yield of commercially manufactured bacon. There was a trend (P = 0.09) for bacon manufactured from bellies of pigs fed 45 and 90 °C SO to have greater slicing yields than those from pigs fed 22.5 and 180 °C SO. There were no SO × storage time interactions (P ≥ 0.27) for any shelf life trait. There was no difference in TBARS, oxidized odor, or oxidized flavor among the 4 SO treatments, although all 3 shelf life metrics increased (P < 0.0001) with storage time. Overall, feeding SO thermally processed at 90 and 180 °C reduced belly adipose tissue IV, but feeding peroxidized SO did not affect processing yields or shelf life characteristics of commercially manufactured bacon.

Modifying fabrication specifications of domestic pork carcasses to reflect product specifications in key export markets may increase gross value for U.S. pork. Changes in specifications may also yield value-added cuts that increase demand for U.S. pork in both export and domestic markets. The objective was to evaluate differences in value of carcasses fabricated using either typical U.S. cutting specifications, or alternative specifications. Paired left and right sides (30 sides total; n = 15) were weighed and cut into primal and subprimal pieces according North American Meat Institute (NAMP, DOM) or alternative-style specifications (ALT). Alternative-style carcasses were separated into shoulder (4th/5th rib separation), loin, belly, and ham (sirloin-on) primals. Alternative-style shoulders were fabricated into a cellar-trimmed (CT) butt, triceps brachii (cushion), boneless picnic, and a brisket. Carcass values for all three pricing scenarios were calculated using the USDA Agriculture Marketing Service Carlot Report values from the weeks of April 5, 2013, to April 7, 2017. Value for the pork brisket was estimated based on relative value of the beef brisket compared to the beef shoulder clod (NAMP #114) resulting in a value of $2.485/kg for the pork brisket. Comparisons between fabrication styles and value of each side were made using a paired T-test. Whole bone-in loin yields of ALT carcasses were 6.23 units less (P < 0.0001) than DOM carcasses. Similarly, yields from trimmed and squared bellies of ALT carcasses were 0.83 units less than (P ≤ 0.01) DOM carcasses. In contrast, trimmed shoulders of ALT carcasses were 3.81 units greater (P < 0.0001) and hams were 3.39 units greater (P < 0.0001) than DOM carcasses. Despite reductions in yield of loins and bellies, ALT carcasses were numerically $1.29 (P = 0.17) and $0.66 (P = 0.56) more valuable than DOM carcasses in the 4 yr average and best pricing scenarios, respectively. Alternative-style carcasses were $1.99 (P = 0.03) more valuable than DOM carcass when using the most depressed pricing scenario. Fabricating pork carcasses using alternative-style specifications reduced the yield, and therefore the value, of the loin and belly compared with DOM carcasses. However, added value from the pork brisket and CT butt recuperated this value. Therefore, alternative-style fabrication methods may increase gross carcass value in some pricing scenarios.

The effects of substitution of sodium chloride (NaCl) by other chloride salts, such as calcium chloride (CaCl2), potassium chloride (KCl) and magnesium chloride (MgCl2) on quality characteristics of emulsion-type pork sausages were investigated. The pH, cooking loss, lightness and overall acceptability of sausages were gradually worse by substitution of CaCl2 (P<0.01), whereas MgCl2 raised water-holding capacity and instrumental colors except for redness by its substitution level (P<0.05). KCl did not affect quality characteristics of emulsion-type sausages. The partial replacements of NaCl with KCl up to 50% and with MgCl2 up to 25% are acceptable for processing of emulsion-type pork sausages without quality degradation, however CaCl2 at small amount (below 5%) could be available for NaCl substitution in emulsion-type sausages due to gradual degradation in water-holding capacity and color at over 5% substitution level.

The purpose of this study was to evaluate the effects of bundle type (BT) and substitution with spent laying hen (SH) surimi on quality characteristics of imitation crabsticks made from Alaska Pollack (AP) during 6 wk of cold storage. Diagonally bundled samples had poorer gel characteristics and more lipid oxidation when compared with straight bundled ones (p<0.05). The color of diagonally bundled imitation crabsticks deteriorated with storage time (p<0.01). However, BT did not affect sensory characteristics (p>0.05). SH substitution had an effect on most quality characteristics of imitation crabsticks; darker and poorer gel characteristics were observed and its effect on sensory evaluation was seen at the initial storage. Thus, BT and SH substitution can be considered to have a slight effect on eating quality of imitation crabsticks, despite their negative effects on color, gel characteristics, and lipid oxidation.

Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to investigate the relationship between muscle fiber characteristics, intramuscular fat (IMF) content and fatty acid composition in the porcine longissimus thoracis muscle. The cluster with the highest IMF content had the highest saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and muscle fiber characteristics of type I (P<0.05). The polyunsaturated fatty acid (PUFA) showed positive correlations with the cross-sectional area and relative area of type IIB and the relative number of fiber type IIA in the HCA and PCA results. Therefore, porcine muscle with a high density, relative area and cross-sectional area of type I was found to have a high content of IMF, SFAs and MUFAs, whereas in the case of a large cross-sectional area and relative area of type IIB, the proportion of PUFAs increased. These findings lead to a better understand of different fatty acid compositions in skeletal muscles which have different metabolic and contractile properties.

Muscle fiber characteristics account for meat quality and muscle fibers are mainly classified into three or more types according to their contractile and metabolic properties. However, the majority of previous studies on bovine skeletal muscle are based on myosin ATPase activity. In the present study, the differences in the characteristics of muscle fibers classified by the expression of myosin heavy chain (MHC) among four bovine skeletal muscles such as longissimus thoracis (LT), psoas major (PM), semimembranosus (SM) and semitendinosus (ST) and their relationships to beef quality were investigated. MHCs 2x, 2a and slow were identified by LC-MS/MS and IIX, IIA and I fiber types were classified. PM, which had the smallest size and highest density of fibers regardless of type, showed the highest myoglobin content, CIE L*, a*, b* and sarcomere length (p<0.05), whereas ST with the highest composition of IIX, showed high shear force and low sarcomere length (p<0.05). The correlation coefficients between muscle fiber characteristics and meat quality showed that type IIX is closely related to poor beef quality and that a high density of small-sized fibers is related to redness and tenderness. Therefore, the differences in meat quality between muscles can be explained by the differences in muscle fiber characteristics, and especially, the muscles with good quality are composed of more small-sized fibers regardless of fiber type.

•Degree of hydrolysis (DH) of bovine plasma protein increased with the duration of Alcalase hydrolysis.•The DPPH radical scavenging activity was obtained maximally at critical value of 51.66°C and 422.08min.•The Fe2+ chelating activity of hydrolysates increased along with DH.

The purpose of this study was to analyze myosin heavy chain (MHC) isoforms in bovine longissimus thoracis (LT) muscle by liquid chromatography (LC) and mass spectrometry (MS). LT muscles taken from Hanwoo (Korean native cattle) steer (n=3) used to separate myosin bands by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The peptide queries were obtained from the myosin bands by LC-MS/MS analysis following in-gel digestion with trypsin. A total of 33 and 43 queries were identified as common and unique peptides, respectively, of MHC isoforms (individual ions scores >43 indicate identity or extensive homology, p<0.05). MHC-1 (IIx), -2 (IIa), -4 (IIb), and -7 (slow/I) were identified based on the Mowse score (5118, 3951, 2526, and 2541 for MHC-1, -2, -4, and -7, respectively). However, more analysis is needed to confirm the expression of MHC-4 in bovine LT muscle because any query identified as a unique peptide of MHC-4 was not found. The queries that were identified as unique peptides could be used as peptide markers to confirm MHC-1 (14 queries), -2 (8 queries), and -7 (21 queries) in bovine LT muscle; no query identified as a unique peptide of MHC-4 was found. LC-MS/MS analysis is a useful approach to study MHC isoforms at the protein level.

Color is considered the most important sensory property, having a significant influence on the consumer's decision. Numerous studies have been conducted on the factors influencing the color of muscle foods. In this review, muscle pigment and myoglobin (Mb) chemistry are explored with the current and advanced methods to measure color of muscle foods. The color of muscle foods depends on concentration of heme pigments and their chemical state. Pigment concentrations in muscle foods are dependent on age, breed, sex, species, and muscle of the animal. Mb can exist in one of three forms: deoxyMb, oxyMb, or metMb in intact muscle. MetMb reducing enzyme systems allow the maintenance of reduced Mb or to reduce MetMb, resulting in extending the shelf-life of muscle foods. The color of meat may be measured by several methods including reflectance, visual evaluation, instrumental color measurements, and computer vision analysis.

The effects of detailed characteristics such as the size and proportion of type IIB fibers in longissimus thoracis muscle on carcass traits and pork quality were investigated. A total of 96 pigs were classified into four groups by the proportion of different IIB fiber sizes. Group NS (high proportion of both small- and normal-sized IIB fibers) had a higher total number (136.4) and density (231.31) of type IIB fibers, backfat thickness (37.20 mm) and intramuscular fat content (4.77%) than the other groups (P<0.05), whereas Group NS had the lowest values of cross-sectional area (3413.85 μm2) and diameter (60.15 μm) of type IIB fiber among the groups (P<0.05). Pig muscles with higher percentage of large IIB fibers exhibit tougher, lighter and more exudative meat than pig muscles with a higher proportion of small- or normal-sized IIB fibers. Therefore, an increase in the proportion of large IIB fibers causes poor quality of pork.