The effect of clove bud powder at a spice level on antioxidant and quality properties of emulsified pork sausage during cold storage.

BACKGROUND: Clove bud is a widely used spice in meat and meat products, and it contains high level of phenolic compounds. The effectiveness of the clove as a spice has not been fully studied at a general level of addition in the meat products. Therefore, in the present study, the antioxidant, antimicrobial, and nitrite scavenging abilities of clove bud powder (CBP) was assessed at spice level (0.1% and 0.2%) in emulsified pork sausage, during 6 weeks of cold storage. RESULTS: CBP had DPPH radical scavenging ability, but CBP addition at 0.1% and 0.2% did not decrease the TBARS value. An antimicrobial effect of CBP was also not observed during the cold storage. However, residual nitrite at storage weeks 4 and 6 was shown to be lower (P < 0.05). Addition of CBP decreased CIE L* and a* values, but it produced unacceptable sensory properties. Texture profile analysis was not affected by the addition of CBP in emulsified pork sausage (P > 0.05). CONCLUSIONS: The positive effect on nitrite scavenging could be expected by the addition of 0.2% CBP as a spice. However, antioxidant and antimicrobial abilities were not observed, as well as improvement in the quality of characteristics, in emulsified pork sausage. © 2016 Society of Chemical Industry.

Identification of myosin heavy chain isoforms in porcine longissimus dorsi muscle by electrophoresis and mass spectrometry.

Myosin heavy chain (MHC) isoforms have been considered as makers for muscle fiber types in relation to meat quality, whereas MHC isoforms in porcine skeletal muscle have not been fully identified. The improved technique of SDS-PAGE and 2DE were used to separate porcine MHC isoforms. Western blotting with monoclonal antibodies including BA-F8 (anti-MHC slow/I), SC-71 (anti-MHC 2a and 2x), 10F5 (anti-MHC 2b), and BF-35 (anti-MHC slow/I and 2a) and MS were used to confirm MHC migration rate and identify MHC isoforms from separated bands and spots. Up to 45% w/v of glycerol, 8% w/v of acrylamide content, and 25 h of electrophoretic time at 70 V allowed a clear separation of MHC isoforms. Major MHC isoforms such as slow, 2a, 2x, and 2b were clearly separated by SDS-PAGE. A total of 23 MHC spots were separated and identified by 2DE and MS. Therefore, four MHC isoforms such as slow/I, 2a, 2x, and 2b could be identified by the improved SDS-PAGE technique, 2DE and MS. Therefore, these techniques allow more accurate and accessible analysis in muscle fiber typing and in relationship between MHC isoforms, muscle fiber characteristics, and pork quality.

Comparison of beef quality influenced by freeze-thawing among different beef cuts having different muscle fiber characteristics.

The association of muscle fiber characteristics (MFC) with freeze-thawed meat quality was investigated using four different cuts (loin, M. longissimus thoracis; tenderloin, M. psoas major; top round, M. semimembranosus; eye of round, M. semitendinosus) obtained from beef carcasses (n = 10; Hanwoo steer; 28 months of age). Tenderloin had higher (P < .05) composition of muscle fiber type I than the others. Its quality traits except cooking loss were not affected by freeze-thawing (P > .05). However, top round having lower type I and higher type IIX compositions showed lower water-holding capacity and larger discoloration (P < .01) than other beef cuts after freeze-thawing. Increased tenderness after freeze-thawing was observed only for loin (P < .01) which had relatively larger size of type I fibers. In conclusion, individual muscle has different susceptibilities to freezing due to their different MFC. Considering different MFC by meat type when freezing meat will help to prevent excessive deterioration of meat quality.

Differential abundance of proteome associated with intramuscular variation of meat quality in porcine longissimus thoracis et lumborum muscle.

Intramuscular variation of meat quality in the porcine longissimus thoracis et lumborum (LTL) muscle was evaluated by assessing the differential abundance of proteome components. Twenty LTL muscles were individually divided into three regions (anterior, medial, and posterior) according to meat color. CIE L⁎ and b⁎ were higher (P < 0.05), but Warner-Bratzler shear force (WBSF) was lower (P < 0.05) in the anterior region, where myosin-1 and -2, TPM2, MLC1f, MLC2, Hsp27, and TPI1 were highly (P < 0.05) abundant. However, CIE a⁎, drip loss, and WBSF were higher (P < 0.05) in the medial region. Glycolysis enzymes including enolase 3, ALDOA, LDHA, PGM1, and TPI1 were highly abundant in the medial and posterior region, whereas GAPDH and myoglobin were overexpressed in the medial region (P < 0.05). Therefore, intramuscular variations in color, water-holding capacity, and tenderness were associated with differential abundance of the proteome, especially contractile, glycolysis enzymes, and Hsp27.

Intramuscular variations of proteome and muscle fiber type distribution in semimembranosus and semitendinosus muscles associated with pork quality.

Proteome analysis was performed to understand intramuscular variations in muscle fiber distribution in semimembranosus (SM) and semitendinosus (ST) muscles associated with pork quality. Fifteen SM and ST muscles were separated into dark and light portions. The relative area of oxidative fiber was higher (P < .0001) in dark portion than that in light portion, while glycolytic fiber types were distributed primarily (P < .01) in light portions regardless of muscle types. Myosin-1, myosin-4, troponin complex (fast), myosin light chains, and metabolic enzymes responsible for fast-twitch glycolytic types were overexpressed in light portions (P < .05). However, myosin-2, myosin-7, myoglobin, and mitochondrial oxidative metabolic enzymes were closely related to slow-twitch oxidative fibers. These resulted in high pH, redness, and tenderness but low lightness and drip loss of pork quality. In conclusion, differentially expressed muscle proteins are associated with fiber type (oxidative vs. glycolytic) distribution, resulting in intramuscular variations of pork quality.

The Quality Improvement of Emulsion-type Pork Sausages Formulated by Substituting Pork Back fat with Rice Bran Oil.

The effects of pork back fat (PBF) substitution with various concentrations of rice bran oil (RBO) (50%, 45%, 40% and 35%) on the physicochemical characteristics and sensory attributes of emulsion-type pork sausages were studied. The modified pork sausages were compared with control sausages produced using PBF only. The sausages with RBO had significantly lower (p<0.05) moisture content than the control sausages. Sausages made from PBF substituted with 40% RBO showed the lowest cooking loss. Substitution of PBF with RBO had no significant effect on the emulsion stability of pork sausages. All sausages with RBO showed significantly lower (p<0.05) hardness values than control sausages. Sausages with RBO also had significantly higher values (p<0.05) of unsaturated fatty acid and polyunsaturated to saturated fatty acid contents than the controls. RBO substitution had no effect on the flavor intensity of sausages, but it improved the tenderness and produced a softer texture.

The Effects of Natural Antioxidants on Protein Oxidation, Lipid Oxidation, Color, and Sensory Attributes of Beef Patties during Cold Storage at 4℃.

This study aimed to investigate the use of golden thread extract (GTE), clove extract (CE), and commercially available nitrite for retarding lipid and protein oxidation and for maintaining color stability and sensory attributes in beef patties stored at 4℃. GTE, CE, and nitrite treatment samples were found to be efficient in retarding lipid oxidation as all three treatments resulted in low thiobarbituric acid reactive substance (TBARS) content (p<0.05). By using GTE, CE, and nitrite into beef patties, protein oxidation was not developed. Incorporation of GTE and CE into beef patties maintained color stability by protecting against the decrease of L*, a*, b*, chroma, and hue angle values and exhibited significant influence on sensory characteristics, including color and odor of beef patties (p<0.05). Compared to commercially available nitrite, GTE and CE were more effective as antioxidants for inhibiting lipid oxidation, and preserving color stability of fresh beef patties. The study indicated that GTE and CE could be utilized efficiently to extend the shelf life of beef patties.

Comparison of myosin heavy chain content determined by label-free quantification between porcine longissimus thoracis, psoas major and semimembranosus muscles.

The present study was conducted to quantify MHCs in porcine longissimus thoracis (LT), psoas major (PM) and semimembranosus (SM) muscles through the label-free quantification (LFQ). To estimate the accuracy of LFQ, quantitative RT-PCR (qRT-PCR), immunohistochemistry (IHC), and Western-blotting (WB) were performed. MHCs 2x, 2a, 2b and slow were identified by LC-MS/MS analysis and 279 ion spectra were selected for LFQ analysis. The content of MHC 2b was higher in LT and in SM than in PM (p<0.05), while the content of MHC slow was highest in PM among the muscles (p<0.01) regardless of LFQ types. Positive correlation coefficients of MHC 2b and MHC slow between LFQ and IHC (relative area composition) and qRT-PCR results partially supported the LFQ results. Though low-abundant peptides should be considered to estimate MHC contents via the spectral count method, LFQ enables the determination of MHC contents at protein level regardless of LFQ types.

Identification and quantification of myosin heavy chain isoforms in bovine and porcine longissimus muscles by LC-MS/MS analysis.

To identify and quantify the myosin heavy chain (MHC) isoforms in porcine and bovine longissimus thoracis (LT) muscles, LC-MS/MS and label-free quantification were conducted. 2a, 2x, 2b and slow isoforms were identified in porcine LT muscle, whereas bovine LT muscle contained 2a, 2x and slow isoforms. The highest peak intensity (44.32%) of MHC 2b was observed in porcine LT muscle, whereas the peak intensity of MHC 2a was the highest (71.15%) in bovine LT muscle (p<0.05). MHC-based fiber compositions for porcine and bovine LT were also the highest in types IIB (61.13%) and IIA (61.90%), respectively (p<0.05). Spectral count and peak intensity had positive correlations with MHC-based fiber composition (p<0.01), however the spectral count and peak intensity of total peptides were not acceptable for MHC quantification because of the limited reliability of the protein and common peptide, respectively. Therefore, the peak intensity of unique peptides would be the most acceptable trait for MHC quantification.

Protein markers for discrimination of meat species in raw beef, pork and poultry and their mixtures.

The purpose of this study was to find discrimination markers for four major meat species such as beef, pork, chicken and duck. Myofibrillar and sarcoplasmic proteins isolated from each meat type were analyzed by one-dimensional gel electrophoresis and some proteins were identified through LC-MS/MS analysis. We confirmed that troponin I (TnI), enolase 3, l-lactate dehydrogenase (LDH) and triose-phosphate isomerase (TPI) could be useful markers for discrimination of mammals from poultry due to their different electrophoretic mobility. Tropomyosin 1 and carbonic anhydrase 3 were observed as muscle fiber type-related proteins and these could also be markers to distinguish mammals from poultry. Species-specific peptides identified by LC-MS/MS spectra allow the identification of each species regardless of the same protein. Therefore, it is easy to discriminate between mammals and poultry by comparing the electrophoretic mobility of TnI, enolase 3, LDH, TPI and CA3, and each species could be identified through LC-MS/MS analysis.

Comparison of Characteristics of Myosin Heavy Chain-based Fiber and Meat Quality among Four Bovine Skeletal Muscles.

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.

Properties of Frankfurter-type Sausages with Pork Back-fat Replaced with Bovine Heart Surimi-like Materials.

This study investigates the effect of bovine heart surimi-like material (BHSM) used as a back fat replacer, on the physicochemical and sensory characteristics of frankfurter-type sausages. Frankfurter-type sausage with added BHSM had a higher moisture content and lower fat content than the control. In addition, the samples with added BHSM had higher pH, cooking loss and 2-thiobarbituric acid-reactive substance (TBARS) value and lower water exudation than the control. The sausage formulation with 40% BHSM was more effective in delaying lipid oxidation without affecting cooking loss compared to the 60% BHSM treatment sample. Results showed that hardness values increased upon replacement with BHSM, and sausages manufactured with 40% BHSM had higher lightness and lower redness values. Panelists found there were no differences in color, odor, and tenderness scores and the overall acceptability score found that treatment samples containing 20% and 40% BHSM were preferable to the control after storage for 14 d. These results indicate that fat replacement with BHSM was beneficial to the quality of frankfurter-type sausages, and acceptable reduced-fat products can be produced when back fat is replaced with up to 40% BHSM.

Analysis of Methionine Oxidation in Myosin Isoforms in Porcine Skeletal Muscle by LC-MS/MS Analysis.

The purpose of this study was to analyze oxidized methionines in the myosin isoforms of porcine longissimus thoracis, psoas major, and semimembranosus muscles by liquid chromatography (LC) and mass spectrometry (MS). A total of 836 queries matched to four myosin isoforms (myosin-1, -2, -4, and -7) were analyzed and each myosin isoform was identified by its unique peptides (7.3-13.3). Forty-four peptides were observed from all three muscles. Seventeen peptides were unique to the myosin isoform and the others were common peptides expressed in two or more myosin isoforms. Five were identified as oxidized peptides with one or two methionine sulfoxides with 16 amu of mass modification. Methionines on residues 215 (215), 438 (438), 853 (851), 856 (854), 1071 (1069), and 1106 (1104) of myosin-1 (myosin-4) were oxidized by the addition of oxygen. Myosin-2 had two oxidized methionines on residues 215 and 438. No queries matched to myosin-7 were observed as oxidized peptides. LC-MS/MS allows analysis of the oxidation of specific amino acids on specific residue sites, as well as in specific proteins in the food system.

The Assessment of Red Beet as a Natural Colorant, and Evaluation of Quality Properties of Emulsified Pork Sausage Containing Red Beet Powder during Cold Storage.

The purpose of this study was to assess red beet as a natural colorant in emulsified pork sausage and to investigate the effect of red beet on quality characteristics of emulsified pork sausage during 20 d of cold storage. Red beet was prepared as a powder and a substitute with sodium nitrite at 0.5% and 1.0% levels in emulsified pork sausage. Red beet significantly increased the moisture content and pH (p<0.0001) and affected color traits. Lightness of emulsified pork sausage decreased by the addition of red beet powder (p<0.01), whereas lightness with red beet treatments slightly increased during 20 d of cold storage at 4℃ (p<0.05). Redness dramatically increased with red beet powder (p<0.0001). Color by sensory evaluation also showed a significant effect from red beet addition (p<0.05), whereas the other sensory properties such as flavor, tenderness, juiciness, and overall acceptability were not affected by the addition of red beet powder (p>0.05). Texture and 2-thiobabituric acid reactive substance were also not affected by red beet addition (p>0.05). Therefore, red beet could be a good natural colorant in emulsified pork sausage but it needs additional processing, such as betalain concentration and extraction as a juice, to be used as an antioxidant in meat products.

The characteristics of myosin heavy chain-based fiber types in porcine longissimus dorsi muscle.

The aim of this study is to type fibers from porcine longissimus dorsi (LD) muscles according to their distribution of myosin heavy chain (MHC) isoforms as well as to investigate fiber characteristics. Four pure types, including types I, IIA, IIX, and IIB were labeled and two hybrid fiber types were subdivided into type IIAX and IIXB by immunohistochemistry using four monoclonal antibodies. Porcine LD muscles were found to have 92.79 (number) and 92.10% (area) of pure type composition, while the composition of hybrid fibers was 8.22 (number) and 9.71% (area). The activities of myosin ATPase increased in the following order: type I, IIAX, IIA = IIX = IIB and IIXB. The succinate dehydrogenase and glycerol-3-phosphate dehydrogenase activities were higher in fiber types I and IIB, respectively. The characteristics of hybrid fibers were observed that their characteristics did not lie between the properties for their respective pure phenotypes.

Physicochemical Characteristics of Beef Jerky Cured with Salted-fermented Anchovy and Shrimp.

The aim of this study is to evaluate the availability of salted and fermented fish (SFF) including salted and fermented anchovy (SFA) and shrimp (SFS) as a marinade of beef jerky. In curing solutions, half (SFA 1 and SFS 1) or whole (SFA 2 and SFS 2) salt-water was replaced with SFF juices. Higher water activity (aw) was found in the beef jerky cured with SFFs than the control (C) (p< 0.05). The SFFs had the effect of causing a decrease in hardness and an increase in cohesiveness (p<0.05). Among the treatment samples, springiness was the highest in SFA2 and SFS2 (p<0.05) and the lowest values of Warner-Bratzler shear force were found in SFA1 and SFA2 (p<0.05). The SFFs also had the effect of increasing the flavor of the sensory properties; however, color measurements from both the instrumental surface color (L*, a*, b*, chroma, and hue angle) and color of sensory evaluation were decreased by addition of SFFs (p<0.05). Therefore, we conclude the SFFs can improve the texture and sensory properties of the beef jerky. In particular, the SFS is a good ingredient for the curing solution. However, studies are still needed on improving the aw, pH, and surface color of the beef jerky to apply the SFFs for making beef jerky.

Relationship between pork quality and characteristics of muscle fibers classified by the distribution of myosin heavy chain isoforms.

A total of six fiber types, including four pure types (type I, IIA, IIX, and IIB) and two hybrid types (type IIAX and IIXB), were classified according to the expression of myosin heavy chain (MHC) isoforms by immunohistochemistry with MHC specific monoclonal antibodies. The comparison of the muscle fiber characteristics and pork quality between pork quality groups (DFD: dark, firm, and dry; PSE: pale, soft, and exudative; RFN: reddish pink, firm, and nonexudative; and RSE: reddish pink, soft, and exudative) classified by muscle pH, drip loss, and lightness was conducted and the relationship of myofiber characteristics to pork quality was investigated. The DFD group had the highest value of IIAX fiber density (P<0.05). The DFD group also showed the greatest fiber relative area of type I, IIA, and IIAX (P<0.05) whereas there were no significant differences in area composition for types I, IIA, and IIAX among the other groups including PSE, RFN, and RSE (P>0.05). The DFD group had the highest cross-sectional area (CSA) in types I, IIA, and IIX among the groups. The increase in density of type IIAX was related with the higher pH and the lower hue and drip loss. An increase in the fiber number composition of hybrid type IIXB increased the lightness and cooking loss and decreased sarcoplasmic protein solubility (SPS). Regarding fiber relative area, pure type I and IIA and hybrid type IIAX were greater in the DFD group and had lower lightness and drip loss. Hybrid type IIAX influences the desirability of the pork due to its association with low lightness and high pH and water-holding capacity (WHC). In contrast, type IIXB was related to poor quality pork, including pale color, low WHC in cooked meat, and low SPS.

The influence of fiber size distribution of type IIB on carcass traits and meat quality in pigs.

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.

Influence of meat exudates on the quality characteristics of fresh and freeze-thawed pork.

The influence of the accumulated exudates released from pork loin of itself on the quality characteristics of fresh and freeze-thawed pork during cold storage was investigated. Pork loins were divided into four groups (fresh pork with exudates, fresh pork without exudates, freeze-thawed pork with exudates and freeze-thawed pork without exudates) and stored at 1.0°C for 7 days. Exudate amount increased due to freeze-thawing and with storage, and most quality traits such as drip loss, cooking loss, tenderness, lightness, redness, and moisture content were affected by freeze-thawing (p<0.05). Freeze-thaw increased drip loss but decreased moisture content, cooking loss, tenderness, lightness and redness of meat (p<0.05). Microbial growth was solely affected by exudate removal and the removal of initial exudates decreased microbial growth (p<0.05). Exudates were positively correlated with total protein content and total plate count but negatively correlated with pH and cooking loss. Therefore, removing meat exudates and avoiding freeze can slow down the quality deterioration of pork during cold storage.

The relationship between muscle fiber characteristics and meat quality traits of highly marbled Hanwoo (Korean native cattle) steers.

To investigate the relationships between muscle fiber characteristics and meat quality traits of Korean native cattle, Hanwoo, Longissimus dorsi (LD), Psoas major (PM) and Semimembranosus (SM) muscles obtained from 18 Hanwoo steers and the muscle fiber characteristics were measured by histochemical analysis. Fiber number, area percentages and density of type IIA and IIB were lower in SM muscle, but higher in PM muscle than other muscles. LD muscle had higher pH(24h), L* value and fat content whereas SM muscle had lower L* value and fat content. The lowest WBSF with longer sarcomere length was observed in PM muscle, while SM muscle showed the highest WBSF with shorter sarcomere length. Consequently, the percentage of type I and IIB were highly correlated with meat quality traits and inversely correlated with fat content, L* value and WBSF. Fiber number and area percentage of type I had a positive correlation with fat content and L* value and a negative correlation with WBSF. These results suggest that Hanwoo steers had high marbling, more lightness and tenderness when the percentage of type I was high and the percentage of type IIB was low in muscle.