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Mohammad Koohmaraie - One of the best experts on this subject based on the ideXlab platform.
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on line prediction of yield grade Longissimus Muscle area preliminary yield grade adjusted preliminary yield grade and marbling score using the marc beef carcass image analysis system
Journal of Animal Science, 2003Co-Authors: S D Shackelford, T L Wheeler, Mohammad KoohmaraieAbstract:The present experiment was conducted to evaluate the ability of the U.S. Meat Animal Research Center's beef carcass image analysis system to predict calculated yield grade, Longissimus Muscle area, preliminary yield grade, adjusted preliminary yield grade, and marbling score under commercial beef processing conditions. In two commercial beef-processing facilities, image analysis was conducted on 800 carcasses on the beef-grading chain immediately after the conventional USDA beef quality and yield grades were applied. Carcasses were blocked by plant and observed calculated yield grade. The carcasses were then separated, with 400 carcasses assigned to a calibration data set that was used to develop regression equations, and the remaining 400 carcasses assigned to a prediction data set used to validate the regression equations. Prediction equations, which included image analysis variables and hot carcass weight, accounted for 90, 88, 90, 88, and 76% of the variation in calculated yield grade, Longissimus Muscle area, preliminary yield grade, adjusted preliminary yield grade, and marbling score, respectively, in the prediction data set. In comparison, the official USDA yield grade as applied by online graders accounted for 73% of the variation in calculated yield grade. The technology described herein could be used by the beef industry to more accurately determine beef yield grades; however, this system does not provide an accurate enough prediction of marbling score to be used without USDA grader interaction for USDA quality grading.
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properties of myofibril bound calpain activity in Longissimus Muscle of callipyge and normal sheep
Journal of Animal Science, 2001Co-Authors: Eduardo Francisquine Delgado, John A. Marchello, Geert H Geesink, Mohammad KoohmaraieAbstract:: Properties of the calpain bound to myofibrils in Longissimus Muscle from callipyge or noncallipyge sheep were examined after 0, 1, 3, and 10 d of postmortem storage at 4 degrees C. Western analysis has shown that most of this calpain is mu-calpain, although the sensitivity of the antibodies used in the earlier studies could not eliminate the possibility that up to 10% of the calpain was m-calpain. The calpain is bound tightly, and very little is removed by washing with the detergent Triton X-100; hence, it is not bound to phospholipids in the myofibril. Over 25% of total mu-calpain was bound to myofibrils from at-death Muscle, and this increased to approximately 40% after 1 d postmortem. The amount of myofibril-bound mu-calpain increased only slightly between 1 and 10 d of postmortem storage. The percentage of autolyzed mu-calpain increases with time postmortem until after 10 d postmortem, when all myofibril-bound mu-calpain is autolyzed. The specific activity of the myofibril-bound calpain is very low and is only 6 to 13% as high as the specific activity of extractable mu-calpain from the same Muscle. It is unclear whether this low specific activity is the result of unavailability of the active site of the myofibril-bound calpain to exogenous substrate. The myofibril-bound calpain degrades desmin, nebulin, titin, and troponin T in the myofibrils, and also releases undegraded alpha-actinin and undergoes additional autolysis when incubated with Ca2+; all these activities occurred slowly considering the amount of myofibril-bound calpain. Activity of the myofibril-bound calpain was partly (58 to 67%) inhibited by the calpain inhibitors, E-64 and iodoacetate; was more effectively inhibited by a broader-based protease inhibitor, leupeptin (84 to 89%); and was poorly inhibited (43 to 45%) by calpastatin. Release of undegraded alpha-actinin and autolysis are properties specific to the calpains, and it is unclear whether some of the myofibril-bound proteolytic activity originates from proteases other than the calpains or whether the active site of myofibril-bound calpain is shielded from the inhibitors. Activities and properties of the myofibril-bound calpain were identical in Longissimus Muscle from callipyge and normal sheep, although previous studies had indicated that the "normal" Longissimus was much more tender than the callipyge Longissimus. Hence, it seems unlikely that the myofibril-bound calpain has a significant role in postmortem tenderization of ovine Longissimus.
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prerigor and postrigor changes in tenderness of ovine Longissimus Muscle
Journal of Animal Science, 1994Co-Authors: Tommy L. Wheeler, Mohammad KoohmaraieAbstract:A novel approach was used to measure the tenderness of prerigor ovine Longissimus thoracis et lumborum by avoiding the confounding effects of heat-induced shortening resulting from cooking prerigor meat. The objective was to determine the tenderness of the Muscle at the time of slaughter and to monitor changes in tenderness during rigor development and postmortem aging. Nine Romanov and 12 Finnsheep rams were slaughtered at 49.3 kg live weight. Samples of Longissimus thoracis et lumborum were removed at 0, 3, 6, 9, 12, 24, 72, or 336 h after exsanguination. Five of the eight sample times were represented in each carcass and all carcasses were sampled at 0, 12, and 24 h. Prerigor Muscle samples (0, 3, 6, 9, and 12 h) were clamped between two metal plates before excision to prevent shortening. The samples were frozen at -30 degrees C then stored at -5 degrees C for 10 d to allow glycolysis to proceed to completion, and thus ultimate pH and complete rigor mortis were attained. The Longissimus thoracis et lumborum was then cut into chops and cooked and shear force was determined. Sarcomere length decreased through 24 h postmortem, then increased slightly through 336 h postmortem. Warner-Bratzler shear force values were 5.1 kg at 0 and 3 h, increased to 8.3 kg from 3 to 9 h, and then declined to 3.1 kg from 24 to 336 h postmortem. These data imply that Longissimus thoracis et lumborum at slaughter is intermediate in tenderness, rigor shortening toughens the meat, and proteolysis tenderizes the meat, resulting in more tender meat after 14 d of aging than at slaughter.
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Effect of biological type of cattle on the incidence of the dark, firm, and dry condition in the Longissimus Muscle.
Journal of Animal Science, 1994Co-Authors: Steven D. Shackelford, Mohammad Koohmaraie, Tommy L. Wheeler, Larry V. Cundiff, Michael E. DikemanAbstract:The objectives of this experiment were to characterize Longissimus Muscle color, texture, and firmness for beef carcasses of diverse biological types and to determine the genetic parameters of lean color, texture, and firmness. The carcasses (n = 3,641) used in this experiment were from steers produced by mating Angus, Brahman, Braunvieh, Charolais, Chianina, Galloway, Gelbvieh, Hereford, Jersey, Limousin, Longhorn, Maine Anjou, Nellore, Piedmontese, Pinzgauer, Red Poll, Sahiwal, Salers, Shorthorn, Simmental, South Devon, and Tarentaise sires to Hereford and Angus dams. Steers were fed a corn-corn silage diet from weaning until slaughter at 356 to 575 d of age. Steers were slaughtered at commercial packing plants and Longissimus Muscle color, texture, and firmness were scored by trained carcass evaluators. Sire line least squares means for lean color, texture, and firmness ranged approximately one unit on a 7-point scale. Chianina crosses had darker-colored lean than all breed groups except Tarentaise and Simmental crosses (P < .05). Moreover, a higher percentage (P < .05) of Chianina crosses than of all other breed groups had unacceptably dark-colored ("dark red" or darker) lean. Bos indicus sire lines were not different from Bos taurus sire lines in frequency of carcasses with unacceptably dark-colored lean. However, Bos indicus crosses were more likely to be scored "very light cherry-red." Lean color and texture were lowly heritable, whereas lean firmness was moderately heritable. Thus, this experiment demonstrated that there is genetic variation in the incidence of the DFD condition; however, genetic variation was small relative to environmental variation.
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meat tenderness and the calpain proteolytic system in Longissimus Muscle of young bulls and steers
Journal of Animal Science, 1993Co-Authors: J B Morgan, Mohammad Koohmaraie, Tommy L. Wheeler, J W Savell, J D CrouseAbstract:The objectives of this study were to examine the effects of castration on the calpain proteinase system (mu-calpain, m-calpain, and calpastatin) activities and meat tenderness. Six each, MARC III bulls and steers were slaughtered at approximately 12 mo of age. Longissimus Muscle samples were obtained for determining myofibril fragmentation index, Warner-Bratzler shear force, and sensory panel evaluation at 1, 7, and 14 d postmortem, and mu- and m-calpain and calpastatin activities at 24 h postmortem. Bulls produced leaner carcasses with lower (P .05) to detect differences in tenderness or other sensory traits between bulls and steers. Activities of mu- and m-calpain were not affected (P > .05) by castration; however, calpastatin was higher (P < .05) in Muscles from the bull carcasses. Lower (P < .05) myofibril fragmentation index values indicate that less proteolysis occurred in Muscle from bulls than in Muscle from steers during the first 7 d postmortem. Greater calpastatin 24-h activity may be associated with the increased shear force of meat from bulls.
Juan J Loor - One of the best experts on this subject based on the ideXlab platform.
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maternal plane of nutrition during late gestation and weaning age alter steer calf Longissimus Muscle adipogenic microrna and target gene expression
Lipids, 2016Co-Authors: Sonia J Moisa, Daniel W Shike, L M Shoup, Juan J LoorAbstract:The main objective was to evaluate if different planes of maternal nutrition during late gestation and weaning age alter microRNA (miRNA) and target gene expression in offspring Longissimus Muscle (LM). Early (EW) and normal weaned (NW) Angus × Simmental calves (n = 30) born to cows that were grazing endophyte-infected tall fescue and red clover pastures with no supplement [low plane of nutrition (LPN)], or supplemented with 2.3 and 9.1 kg of dried distiller's grains with solubles and soy hulls [medium and high plane of nutrition (MPN, HPN), respectively] during the last 105 ± 11 days of gestation were used. Biopsies of LM were harvested at 78 (early weaning), 187 (normal weaning) and 354 days of age. Results indicate a role of pro-adipogenic miRNA in the control of adipogenesis in LM of NW-MPN steers between 78 and 187 days of age through upregulation of (1) miR-103 which inhibits CAV1, a protein that destabilizes INSR and leads to insulin resistance; (2) miR-143 which inhibits DLK1, a protein that inhibits adipocyte differentiation; and (3) miR-21 which impairs TGFBR2-induced inhibition of adipocyte differentiation. Among the studied anti-adipogenic miRNA, cow plane of nutrition resulted in downregulation of miR-34a expression in MPN steers compared with HPN and LPN at 78 days of age. Data for miR-34a provided a potential sign of epigenetic regulation of LM in beef offspring due to the cow plane of nutrition during late gestation.
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maternal plane of nutrition during late gestation and weaning age alter angus simmental offspring Longissimus Muscle transcriptome and intramuscular fat
PLOS ONE, 2015Co-Authors: Sonia J Moisa, Daniel W Shike, L M Shoup, Sandra L Rodriguezzas, Juan J LoorAbstract:In model organisms both the nutrition of the mother and the young offspring could induce long-lasting transcriptional changes in tissues. In livestock, such changes could have important roles in determining nutrient use and meat quality. The main objective was to evaluate if plane of maternal nutrition during late-gestation and weaning age alter the offspring’s Longissimus Muscle (LM) transcriptome, animal performance, and metabolic hormones. Whole-transcriptome microarray analysis was performed on LM samples of early (EW) and normal weaned (NW) Angus × Simmental calves born to grazing cows receiving no supplement [low plane of nutrition (LPN)] or 2.3 kg high-grain mix/day [medium plane of nutrition (MPN)] during the last 105 days of gestation. Biopsies of LM were harvested at 78 (EW), 187 (NW) and 354 (before slaughter) days of age. Despite greater feed intake in MPN offspring, blood insulin was greater in LPN offspring. Carcass intramuscular fat content was greater in EW offspring. Bioinformatics analysis of the transcriptome highlighted a modest overall response to maternal plane of nutrition, resulting in only 35 differentially expressed genes (DEG). However, weaning age and a high-grain diet (EW) strongly impacted the transcriptome (DEG = 167), especially causing a lipogenic program activation. In addition, between 78 and 187 days of age, EW steers had an activation of the innate immune system due presumably to macrophage infiltration of intramuscular fat. Between 187 and 354 days of age (the “finishing” phase), NW steers had an activation of the lipogenic transcriptome machinery, while EW steers had a clear inhibition through the epigenetic control of histone acetylases. Results underscored the need to conduct further studies to understand better the functional outcome of transcriptome changes induced in the offspring by pre- and post-natal nutrition. Additional knowledge on molecular and functional outcomes would help produce more efficient beef cattle.
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bioinformatics analysis of transcriptome dynamics during growth in angus cattle Longissimus Muscle
Bioinformatics and Biology Insights, 2013Co-Authors: Sonia J Moisa, Daniel W Shike, Sandra L Rodriguezzas, Daniel E Graugnard, Robin E Everts, Harris A Lewin, Dan B Faulkner, L L Berger, Juan J LoorAbstract:Transcriptome dynamics in the Longissimus Muscle (LM) of young Angus cattle were evaluated at 0, 60, 120, and 220 days from early-weaning. Bioinformatic analysis was performed using the dynamic impact approach (DIA) by means of Kyoto Encyclopedia of Genes and Genomes (KEGG) and Database for Annotation, Visualization and Integrated Discovery (DAVID) databases. Between 0 to 120 days (growing phase) most of the highly-impacted pathways (eg, ascorbate and aldarate metabolism, drug metabolism, cytochrome P450 and Retinol metabolism) were inhibited. The phase between 120 to 220 days (finishing phase) was characterized by the most striking differences with 3,784 differentially expressed genes (DEGs). Analysis of those DEGs revealed that the most impacted KEGG canonical pathway was glycosylphosphatidylinositol (GPI)-anchor biosynthesis, which was inhibited. Furthermore, inhibition of calpastatin and activation of tyrosine aminotransferase ubiquitination at 220 days promotes proteasomal degradation, while the concurrent activation of ribosomal proteins promotes protein synthesis. Therefore, the balance of these processes likely results in a steady-state of protein turnover during the finishing phase. Results underscore the importance of transcriptome dynamics in LM during growth.
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adipogenic and energy metabolism gene networks in Longissimus lumborum during rapid post weaning growth in angus and angus simmental cattle fed high starch or low starch diets
BMC Genomics, 2009Co-Authors: Daniel E Graugnard, L L Berger, P Piantoni, Massimo Bionaz, D B Faulkner, Juan J LoorAbstract:Background Transcriptional networks coordinate adipocyte differentiation and energy metabolism in rodents. The level of fiber and starch in diets with adequate energy content fed to young cattle has the potential to alter intramuscular adipose tissue development in skeletal Muscle. Post-weaning alterations in gene expression networks driving adipogenesis, lipid filling, and intracellular energy metabolism provide a means to evaluate long-term effects of nutrition on Longissimus Muscle development across cattle types.
Xiufang Xia - One of the best experts on this subject based on the ideXlab platform.
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changes in myofibrillar protein gel quality of porcine Longissimus Muscle induced by its stuctural modification under different thawing methods
Meat Science, 2019Co-Authors: Bo Wang, Xiufang Xia, Qian Liu, Qian Chen, Hongwei Zhang, Baohua KongAbstract:The effects of thawing methods (refrigeration thawing (RT, 4 °C), water immersion thawing (WT, 18 °C), vacuum thawing (VT, 25 °C), ultrasonic thawing (UT, 20 °C) and microwave thawing (MT)) on the conformation and gel qualities of myofibrillar protein (MP) obtained from porcine Longissimus Muscle were investigated. The results showed that MP conformation and gel qualities of porcine Longissimus Muscles by VT and UT were insignificantly changed compared to fresh meat (FM). A significant decrease in free amino groups of MP from MT illustrated that MT induced protein aggregation and oxidation (P < 0.05). The results of circular dichroism (CD) spectra analysis and fluorescence spectroscopy indirectly proved that thawing can cause protein cross-linking and degradation, secondary structure destruction, non-hydrophilic domain exposed and conformational change of samples. The largest changes in solubility, surface hydrophobicity and particle size were obtained with MT. The effects on the conformation and gel quality of MP were verified during thawing process.
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moisture migration microstructure damage and protein structure changes in porcine Longissimus Muscle as influenced by multiple freeze thaw cycles
Meat Science, 2017Co-Authors: Mingcheng Zhang, Xinping Diao, Baohua Kong, Xiufang XiaAbstract:This study investigated the effects of multiple freeze-thaw (F-T) cycles on water mobility, microstructure damage and protein structure changes in porcine Longissimus Muscle. The transverse relaxation time T2 increased significantly when Muscles were subjected to multiple F-T cycles (P<0.05), which means that immobile water shifted to free water and the free water mobility increased. Multiple F-T cycles caused sarcomere shortening, Z line fractures, and I band weakening and also led to microstructural destruction of Muscle tissue. The decreased free amino group content and increased dityrosine in myofibrillar protein (MP) revealed that multiple F-T cycles caused protein cross-linking and oxidation. In addition, the results of size exclusion chromatography, circular dichroism spectra, UV absorption spectra, and intrinsic fluorescence spectroscopy indirectly proved that multiple F-T cycles could cause protein aggregation and degradation, α-helix structure disruption, hydrophobic domain exposure, and conformational changes of MP. Overall, repeated F-T cycles changed the protein structure and water distribution within meat.
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influence of different thawing methods on physicochemical changes and protein oxidation of porcine Longissimus Muscle
Lwt - Food Science and Technology, 2012Co-Authors: Xiufang Xia, Baohua Kong, Jing Liu, Xinping Diao, Qian LiuAbstract:Abstract The objective of the present study was to elucidate the physicochemical changes and protein oxidation of porcine Longissimus Muscle as influenced by different thawing methods. Five kinds of thawing methods, comprising of refrigerator thawing (RT, 4 °C), ambient temperature thawing (AT, 20 °C), water immersion thawing (WT, 14 °C), lotic water thawing (LT, 9 °C), and microwave thawing (MT), were used. There were significant effects on the porcine meat quality due to different thawing methods. RT had the least quality loss and the physicochemical characteristics of pork were closer to fresh Muscle than the other thawing methods. MT significantly increased thawing loss, cooking loss, cutting force, carbonyl content, and TBARS (thiobarbituric acid-reactive substances) value, but decreased a* value and Ca-, K-ATPase activities (P
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decreased gelling and emulsifying properties of myofibrillar protein from repeatedly frozen thawed porcine Longissimus Muscle are due to protein denaturation and susceptibility to aggregation
Meat Science, 2010Co-Authors: Xiufang Xia, Youling L Xiong, Baohua Kong, Yanming RenAbstract:The effects of freeze–thaw cycles (FT, 0, 1, 3 and 5 times) on protein functional properties of porcine Longissimus Muscle were investigated. FT increased gapping between Muscle fibres and tore Muscle fiber bundles. Myofibrillar protein (MP) isolated from FT Muscle showed an increased hydrophobicity (P < 0.05), reduced thermal transition temperatures (Tmax) and enthalpy of denaturation (ΔH) (P < 0.05), and enhanced susceptibility to thermal aggregation. These structural changes resulted in major losses in protein functionalities, e.g., 41–43% reductions (P < 0.05) in MP emulsifying capacity and emulsion stability after five FT cycles. The ability of MP to form a viscoelastic gel network, as analyzed by small-strain oscillatory rheological testing, also attenuated with FT cycles. The FT process lowered (P < 0.05) water-holding capacity (WHC), whiteness, and texture (hardness, springiness, chewiness and cohesiveness) of MP gels. Overall, repeated FT had a detrimental effect on the general functionality of porcine MP, and protein denaturation and aggregation were implicated in the functionality losses.
Baohua Kong - One of the best experts on this subject based on the ideXlab platform.
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changes in myofibrillar protein gel quality of porcine Longissimus Muscle induced by its stuctural modification under different thawing methods
Meat Science, 2019Co-Authors: Bo Wang, Xiufang Xia, Qian Liu, Qian Chen, Hongwei Zhang, Baohua KongAbstract:The effects of thawing methods (refrigeration thawing (RT, 4 °C), water immersion thawing (WT, 18 °C), vacuum thawing (VT, 25 °C), ultrasonic thawing (UT, 20 °C) and microwave thawing (MT)) on the conformation and gel qualities of myofibrillar protein (MP) obtained from porcine Longissimus Muscle were investigated. The results showed that MP conformation and gel qualities of porcine Longissimus Muscles by VT and UT were insignificantly changed compared to fresh meat (FM). A significant decrease in free amino groups of MP from MT illustrated that MT induced protein aggregation and oxidation (P < 0.05). The results of circular dichroism (CD) spectra analysis and fluorescence spectroscopy indirectly proved that thawing can cause protein cross-linking and degradation, secondary structure destruction, non-hydrophilic domain exposed and conformational change of samples. The largest changes in solubility, surface hydrophobicity and particle size were obtained with MT. The effects on the conformation and gel quality of MP were verified during thawing process.
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moisture migration microstructure damage and protein structure changes in porcine Longissimus Muscle as influenced by multiple freeze thaw cycles
Meat Science, 2017Co-Authors: Mingcheng Zhang, Xinping Diao, Baohua Kong, Xiufang XiaAbstract:This study investigated the effects of multiple freeze-thaw (F-T) cycles on water mobility, microstructure damage and protein structure changes in porcine Longissimus Muscle. The transverse relaxation time T2 increased significantly when Muscles were subjected to multiple F-T cycles (P<0.05), which means that immobile water shifted to free water and the free water mobility increased. Multiple F-T cycles caused sarcomere shortening, Z line fractures, and I band weakening and also led to microstructural destruction of Muscle tissue. The decreased free amino group content and increased dityrosine in myofibrillar protein (MP) revealed that multiple F-T cycles caused protein cross-linking and oxidation. In addition, the results of size exclusion chromatography, circular dichroism spectra, UV absorption spectra, and intrinsic fluorescence spectroscopy indirectly proved that multiple F-T cycles could cause protein aggregation and degradation, α-helix structure disruption, hydrophobic domain exposure, and conformational changes of MP. Overall, repeated F-T cycles changed the protein structure and water distribution within meat.
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influence of different thawing methods on physicochemical changes and protein oxidation of porcine Longissimus Muscle
Lwt - Food Science and Technology, 2012Co-Authors: Xiufang Xia, Baohua Kong, Jing Liu, Xinping Diao, Qian LiuAbstract:Abstract The objective of the present study was to elucidate the physicochemical changes and protein oxidation of porcine Longissimus Muscle as influenced by different thawing methods. Five kinds of thawing methods, comprising of refrigerator thawing (RT, 4 °C), ambient temperature thawing (AT, 20 °C), water immersion thawing (WT, 14 °C), lotic water thawing (LT, 9 °C), and microwave thawing (MT), were used. There were significant effects on the porcine meat quality due to different thawing methods. RT had the least quality loss and the physicochemical characteristics of pork were closer to fresh Muscle than the other thawing methods. MT significantly increased thawing loss, cooking loss, cutting force, carbonyl content, and TBARS (thiobarbituric acid-reactive substances) value, but decreased a* value and Ca-, K-ATPase activities (P
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decreased gelling and emulsifying properties of myofibrillar protein from repeatedly frozen thawed porcine Longissimus Muscle are due to protein denaturation and susceptibility to aggregation
Meat Science, 2010Co-Authors: Xiufang Xia, Youling L Xiong, Baohua Kong, Yanming RenAbstract:The effects of freeze–thaw cycles (FT, 0, 1, 3 and 5 times) on protein functional properties of porcine Longissimus Muscle were investigated. FT increased gapping between Muscle fibres and tore Muscle fiber bundles. Myofibrillar protein (MP) isolated from FT Muscle showed an increased hydrophobicity (P < 0.05), reduced thermal transition temperatures (Tmax) and enthalpy of denaturation (ΔH) (P < 0.05), and enhanced susceptibility to thermal aggregation. These structural changes resulted in major losses in protein functionalities, e.g., 41–43% reductions (P < 0.05) in MP emulsifying capacity and emulsion stability after five FT cycles. The ability of MP to form a viscoelastic gel network, as analyzed by small-strain oscillatory rheological testing, also attenuated with FT cycles. The FT process lowered (P < 0.05) water-holding capacity (WHC), whiteness, and texture (hardness, springiness, chewiness and cohesiveness) of MP gels. Overall, repeated FT had a detrimental effect on the general functionality of porcine MP, and protein denaturation and aggregation were implicated in the functionality losses.
Qian Liu - One of the best experts on this subject based on the ideXlab platform.
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changes in myofibrillar protein gel quality of porcine Longissimus Muscle induced by its stuctural modification under different thawing methods
Meat Science, 2019Co-Authors: Bo Wang, Xiufang Xia, Qian Liu, Qian Chen, Hongwei Zhang, Baohua KongAbstract:The effects of thawing methods (refrigeration thawing (RT, 4 °C), water immersion thawing (WT, 18 °C), vacuum thawing (VT, 25 °C), ultrasonic thawing (UT, 20 °C) and microwave thawing (MT)) on the conformation and gel qualities of myofibrillar protein (MP) obtained from porcine Longissimus Muscle were investigated. The results showed that MP conformation and gel qualities of porcine Longissimus Muscles by VT and UT were insignificantly changed compared to fresh meat (FM). A significant decrease in free amino groups of MP from MT illustrated that MT induced protein aggregation and oxidation (P < 0.05). The results of circular dichroism (CD) spectra analysis and fluorescence spectroscopy indirectly proved that thawing can cause protein cross-linking and degradation, secondary structure destruction, non-hydrophilic domain exposed and conformational change of samples. The largest changes in solubility, surface hydrophobicity and particle size were obtained with MT. The effects on the conformation and gel quality of MP were verified during thawing process.
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influence of different thawing methods on physicochemical changes and protein oxidation of porcine Longissimus Muscle
Lwt - Food Science and Technology, 2012Co-Authors: Xiufang Xia, Baohua Kong, Jing Liu, Xinping Diao, Qian LiuAbstract:Abstract The objective of the present study was to elucidate the physicochemical changes and protein oxidation of porcine Longissimus Muscle as influenced by different thawing methods. Five kinds of thawing methods, comprising of refrigerator thawing (RT, 4 °C), ambient temperature thawing (AT, 20 °C), water immersion thawing (WT, 14 °C), lotic water thawing (LT, 9 °C), and microwave thawing (MT), were used. There were significant effects on the porcine meat quality due to different thawing methods. RT had the least quality loss and the physicochemical characteristics of pork were closer to fresh Muscle than the other thawing methods. MT significantly increased thawing loss, cooking loss, cutting force, carbonyl content, and TBARS (thiobarbituric acid-reactive substances) value, but decreased a* value and Ca-, K-ATPase activities (P
