Role of freezing-induced myofibrillar protein denaturation in the generation of thaw loss : A review

Formation of thaw loss cannot generally be avoided when meat is frozen and then thawed. Explanations have mainly focused on the damage to muscle fibers resulting from ice crystallization and the freezing-induced denaturation of myofibrillar proteins, the latter of which has, however, not received much research focus. This review discusses the relationship between myofibrillar protein denaturation and water-holding capacity of meat in freezing-thawing with the aim to improve the understanding the relative importance of protein denaturation in the formation of thaw loss. The contribution of decreased pH and high ionic strength in the unfrozen water in freezing is emphasized and we hypothesize that these two factors are causing protein denaturation and conformational changes within muscle fibers, and consequently loss of water-holding capacity. Slow freezing produces more thaw loss than fast freezing, and this is discussed here in relation to the impacts on myofibrillar protein denaturation induced by the freezing rate.Peer reviewe

Myofibrillar protein characteristics of fast or slow frozen pork during subsequent storage at-3 degrees C

This study aimed to investigate the effect of storage at -3 ?C on myofibrillar protein in fast or slow frozen pork. Five pork loins at 48 h post-mortem were subjected to either fast (cold metal plate/-80 ?C) or slow freezing (still air/-20 ?C) followed by storage at -3 ?C for 0, 1, 3, and 7 days before thawing. Freezing rate significantly influenced myofibrillar proteins within 3 days at -3 ?C, evidenced by higher thaw loss, higher surface hydrophobicity and reduced water-holding of myofibrils, and accelerated appearance of a myosin-4 fragment (160 kDa) in slow freezing. However, these observed differences disappeared after 7 days of storage at -3 ?C. The meat pH after thawing did not differ between fast and slow freezing rate. However, the pH values after thawing in both groups decreased with extended storage at -3 ?C. Our results suggest that the beneficial effects of fast freezing are gradually lost by holding at -3 ?C due to more extensive protein denaturation.Peer reviewe

Investigation of Consumer Freezing Practices, Condition and Duration on Palatability of Beef

The objective of these studies was to determine: the impact of extended periods of frozen storage duration and packaging type on palatability traits of cooked beef steaks from two muscles and the impact of freezing type and storage duration on objective and subjective measures of ground beef palatability traits. In study 1, no differences were elicited from any of the possible interactions (P= 0.95) for SSF or CL: package × muscle × freezing duration, package × muscle, package × duration or muscle × duration. However, freezing duration did impact both SSF (P \u3c 0.01) and CL (P \u3c 0.001). Generally, for both SSF and CL steaks that were frozen for 9-months elicited both the highest SSF values as well as the greatest percentage of CL among all treatments. In comparison, EM was impacted by the interaction (P = 0.059) of packaging type muscle freezing duration. Samples from OW GM stored for 9-months elicited the highest percentage of EM while fresh OW LL samples resulted in the lowest. Additionally, expressible moisture was impacted by the interaction (P = 0.047) of muscle freezing duration. Among all treatments, GM steaks that were frozen for 9-months elicited the highest EM values and fresh LL samples the lowest EM values. Contrastingly, there was no significant difference observed in expressible moisture for the interaction (P 0.18) of package type freezing duration or for the interaction (P = 0.70) of package type muscle. Generally, fresh OW GM steaks resulted in the greatest concentration of lipid derived volatile compounds such as aldehydes, hydrocarbons and alcohols which contrasted sensory ratings of trained panelists that indicated oxidized and refrigerator-stale ratings increased as storage time increased for OW steaks. In study 2, The interaction of freezer treatment × storage duration impacted gumminess (P = 0.05), a TPA attribute. In greater detail, samples stored in RF for 6-months resulted in the greatest gumminess values (P \u3c 0.001), while those stored in the CF for 12-months elicited the lowest (P \u3c 0.001). Similarly, flavor development was also impacted by the interaction (P = 0.05) of freezer treatment × storage duration. Three lipid derived compounds were of greatest concentration among RF patties stored for 1-month. In contrast, the interaction of freezer treatment × storage duration elicited no impact on consumer ratings, SF or TBARS. Nonetheless, frozen storage duration impacted TPA, flavor development, consumer ratings, SF and TBARS as a main effect (P \u3c 0.05), especially in regard to tenderness and juiciness. Moreover, beef flavor development, tenderness and juiciness are impacted by freezing duration, muscle, freezer type and packaging, however these factors are not necessarily independent of one another. Furthermore, the retail display period is a critical period for fresh beef steaks, especially when packaged in aerobic conditions. For optimal eating experience, beef products should be stored for extended periods in a vacuum packaging, in a designated freezer that is not opened frequently to allow for optimal air flow regulation and minimize freezer burn to improve tenderness and juiciness

Investigation of Consumer Freezing Practices, Condition and Duration on Palatability of Beef

The objective of these studies was to determine: the impact of extended periods of frozen storage duration and packaging type on palatability traits of cooked beef steaks from two muscles and the impact of freezing type and storage duration on objective and subjective measures of ground beef palatability traits. In study 1, no differences were elicited from any of the possible interactions (P= 0.95) for SSF or CL: package × muscle × freezing duration, package × muscle, package × duration or muscle × duration. However, freezing duration did impact both SSF (P \u3c 0.01) and CL (P \u3c 0.001). Generally, for both SSF and CL steaks that were frozen for 9-months elicited both the highest SSF values as well as the greatest percentage of CL among all treatments. In comparison, EM was impacted by the interaction (P = 0.059) of packaging type muscle freezing duration. Samples from OW GM stored for 9-months elicited the highest percentage of EM while fresh OW LL samples resulted in the lowest. Additionally, expressible moisture was impacted by the interaction (P = 0.047) of muscle freezing duration. Among all treatments, GM steaks that were frozen for 9-months elicited the highest EM values and fresh LL samples the lowest EM values. Contrastingly, there was no significant difference observed in expressible moisture for the interaction (P 0.18) of package type freezing duration or for the interaction (P = 0.70) of package type muscle. Generally, fresh OW GM steaks resulted in the greatest concentration of lipid derived volatile compounds such as aldehydes, hydrocarbons and alcohols which contrasted sensory ratings of trained panelists that indicated oxidized and refrigerator-stale ratings increased as storage time increased for OW steaks. In study 2, The interaction of freezer treatment × storage duration impacted gumminess (P = 0.05), a TPA attribute. In greater detail, samples stored in RF for 6-months resulted in the greatest gumminess values (P \u3c 0.001), while those stored in the CF for 12-months elicited the lowest (P \u3c 0.001). Similarly, flavor development was also impacted by the interaction (P = 0.05) of freezer treatment × storage duration. Three lipid derived compounds were of greatest concentration among RF patties stored for 1-month. In contrast, the interaction of freezer treatment × storage duration elicited no impact on consumer ratings, SF or TBARS. Nonetheless, frozen storage duration impacted TPA, flavor development, consumer ratings, SF and TBARS as a main effect (P \u3c 0.05), especially in regard to tenderness and juiciness. Moreover, beef flavor development, tenderness and juiciness are impacted by freezing duration, muscle, freezer type and packaging, however these factors are not necessarily independent of one another. Furthermore, the retail display period is a critical period for fresh beef steaks, especially when packaged in aerobic conditions. For optimal eating experience, beef products should be stored for extended periods in a vacuum packaging, in a designated freezer that is not opened frequently to allow for optimal air flow regulation and minimize freezer burn to improve tenderness and juiciness

The effect of repeated freeze-thaw cycles on the meat quality of rabbit

[EN] We investigated the effect of repeated freeze-thaw cycles on the quality of rabbit meat. Twenty-five Hyla rabbits were slaughtered using standard commercial procedures. A freeze-thaw procedure—i.e., seven days frozen at –18°C followed by thawing at 4°C for 12h— was repeated 5 times, and 9 Longissimus thoracis et lumborum muscles were randomly selected at pre-set cycles (0, 1, 2, 3, and 5). The Longissimus lumborum muscles were used to determine meat quality parameters, while the Longissimus thoracis muscles were used for chemical analysis. During the repeated freeze-thaw process, muscle pH, redness, hardness, and water holding capacity gradually decreased, whereas meat lightness and yellowness gradually increased. The amount of total volatile basic nitrogen significantly increased (P<0.05) and exceeded the threshold value for frozen meat after 5 repeated freeze-thaw cycles. The metmyoglobin proportion, thiobarbituric acid-reactive substances (TBARS) and protein carbonyl content in rabbit meat samples increased with a higher number of freeze-thaw cycles (P<0.05), and the proportions of these compounds were positively correlated. During the repeated freeze-thaw process, extractable haeme iron levels significantly decreased (P<0.05), and non-haeme iron levels markedly increased (P<0.05). An sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis indicated that the degradation of both water- and salt-soluble proteins was more prevalent in samples subjected to higher numbers of freeze-thaw cycles. Additionally, a principal component analysis identified good correlations between physicochemical properties (TBARS, protein carbonyl levels and metmyoglobin content) and quality parameters (thawing loss, redness, lightness and hardness). Taken together, we conclude that the repeated freeze-thaw process can strongly affect rabbit meat quality as well as its physicochemical properties.The authors gratefully acknowledge financial support from the General Program of National Natural Science Foundation of China (31671787), the National Rabbit Industry Technology System Programme (Grant No. CARS-43-E-1), and the Chongqing Herbivorous Livestock Industry Technology System (Y201706).Wang, Z.; He, Z.; Gan, X.; Li, H. (2018). The effect of repeated freeze-thaw cycles on the meat quality of rabbit. World Rabbit Science. 26(2):165-177. https://doi.org/10.4995/wrs.2018.8616SWORD165177262Ali S., Rajput N., Li C.B., Zhang W., Zhou G.H. 2016. Effect of freeze-thaw cycles on lipid oxidation and myowater in broiler chickens. Revista Brasileira de Ciência Avícola, 18: 35-40.https://doi.org/10.1590/1516-635x1801035-040Ali S., Zhang W., Rajput N., Khan M.A., Li C.B., Zhou G.H. 2015. 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Comparison of Domestic Fresh and Frozen and Imported Frozen Goat Meat

The objective of this research was to determine differences in carcass evaluation, yield, and meat quality from representative fresh domestic (FSD), frozen domestic (FZD), and frozen imported Australian (FIA) goat carcass sides (n=30 from each source). The U.S. carcasses were split into sides and the right side frozen and stored for 6 weeks. Left sides were fabricated into standardized primal cuts. After frozen storage, right sides and FIA carcasses were thawed for 3 days at 4°C. Three experiments were conducted on the carcass traits and meat yields, quality differences in leg cut, and differences in loin and racks across freezing and packaging treatments. Domestic carcasses were heavier (P\u3c0.05) with more (P\u3c0.05) external fat, but carcass conformation and lean flank color were not different than imported Australian goat carcasses. Australian carcasses had less waste and higher trimmed primal loin, rack, leg, shank, and shoulder yields as % of carcass weight than domestic sides. Freezing and thawing changed the percentages of cuts, but FIA carcasses had higher (P\u3c0.05) yields of lean trimmed primal cuts and FIA legs had higher (P\u3c0.05) drip, cook losses, and water binding, but lower (P\u3c0.05) color values than the FZD legs or FSD legs. With paired t-tests, FZD legs had higher (P\u3c0.05) drip and cook losses and lower (P\u3c0.05) color values than FSD legs. FZD and FIA chops had higher (P\u3c0.05) drip and cook losses than FSD. Freezing lowered (P\u3c0.05) color values of chops, however, packaging with 0.5% CO increased (P\u3c0.05) a* and chroma values of frozen meat over that of fresh goat meat before packaging. Vacuum packaging of goat chops increased (P\u3c0.05) drip and chops in overwrap packaging had the lowest (P\u3c0.05) color values. Packaging did not (P\u3e0.05) affect Warner-Bratzler shear values. FSD chops had higher (P\u3c0.05) shear force values than FZD, which were higher than FIA. Loin chops had greater (P\u3c0.05) drip and cook losses than rib chops. Rib chops were found to have higher (P\u3c0.05) color values both pre and post package and lower (P\u3c0.05) shear force values when compared to loin chops

Characteristics of pre-rigor processed beef

"During the last 25 years, the total production of beef and beef products in the U.S. has markedly increased. Most of this increase has been in the form of ground beef and ground beef products (Sink, 1980). In 1970, 20 percent of the beef consumption was in the ground form, while in 1979 this percentage rose to 45 percent and is expected to reach 60 percent in the early 1980‘s (Nusbaum, 1979). This rise in ground beef consumption reflects the changing eating habits of the American people. It was projected that in 1980 about half of the meals would be consumed outside the home. The growth of the hotel, restaurant and institution (HRI) segment of beef marketing is another aspect of this phenomenon (Anon., 1978). The availability of this rather inexpensive and highly nutritious food commodity was based, mainly, on two production factors: cheap grain and cheap and abundant energy. Currently, the shortage in world grain production will likely increase grain exports, thus decreasing the availability of grain for livestock. The worsening energy crisis affects beef production in two ways, indirectly when grain is used by the chemical industry and for fuel production, and directly when energy is considered as an input in beef production."--Page 1.Hedrick, H. B

Effects of thawing method on palatability and thawing characteristics of beef loins

Master of ScienceDepartment of Animal Sciences and IndustryTravis G O'QuinnThe objective of this study was to investigate the effects of various thawing methods on beef palatability. USDA Choice paired beef strip loins (n = 15) were obtained from a Midwest commercial processing facility for palatability evaluation. Moreover, 6 USDA Low Choice strip loins for thawing characteristic data collection were collected. At day 11 of aging, the paired strip loins were portioned into 6 blocks, and fabricated into 2.5 cm steaks. Each block was then assigned one of six thawing methods, with each loin containing each thawing method. Thaw methods included the four USDA approved thawing methods: thawing in the refrigerator(2-3° C; 882 m), cold water (2-3° C; 637.5 m), microwave (50% power, 7 m), and cooking from frozen, as well as two methods commonly used by consumers: thawing in hot water (40° C; 10.3 m), and on the counter (19±1° C; 264 m). Within each block, steaks were assigned to one of four tests: consumer panel, trained panel, Warner-Bratzler shear force, and lab assay. Steaks were aged a total of 21d prior to freezing. Loins designated for thawing characteristic data collection were fabricated into 2.5 cm steaks at 11 d of aging, assigned a random thawing treatment. Temperature probes were inserted, vacuum packaged, and frozen. End-point thawing temperature was targeted at 0°C for all steaks. For thawing characteristic steaks, temperature probes were connected to data loggers immediately upon removal from the freezer, Thaw rate, time, and temperature at times prior to thawing were all recorded from –6.67° C to 0° C. Data were analyzed as a completely randomized block design. Results from consumer panels indicate no differences (P > 0.05) among all thawing methods for consumer’s ratings for tenderness, juiciness, flavor, and overall liking. Similarly, there were no differences (P > 0.05) among thawing methods for percentage of steaks rated acceptable for tenderness, juiciness, flavor, and overall liking. Moreover, there were no differences (P > 0.05) in consumer perception of quality. In terms of myofibrillar tenderness in trained sensory panels, thawing in the refrigerator and cold water were more tender (P 0.05) for initial juiciness, sustained juiciness, connective tissue, Warner- Bratzler Shear Force, and slice shear force. In terms of objective quality measurements, thawing steaks in the microwave had lower (P < 0.05) a* and b* values than all other thawing methods, while cooking from frozen steaks had lower a* and b* values than thawing on the counter. Additionally, steaks thawing in the microwave had the highest (P < 0.05) cook loss, followed by cooking from frozen, with all other methods being similar. Similarly, steaks thawed in the microwave and in hot water had a higher (P < 0.05) thawing loss than thawing on the counter, in cold water, and in the refrigerator. Also, steaks thawed in the microwave had the highest (P < 0.05) total moisture loss, followed by hot water and cooking from frozen, then thawing in cold water, on the countertop, and in the refrigerator. Lastly, steaks cooked from frozen had a higher (P < 0.05) expressible moisture than thawing steaks on the counter, in colder water, or in the refrigerator. These results indicate thawing method had minimal differences on overall palatability, and objective quality measures. Although, increases in thawing loss should be considered when thawing large quantities of meat for potential overall economic loss. Therefore, consumers and food service establishments should use their preferred thaw method, taking food safety and time into consideration

Meat tenderness: advances in biology, biochemistry, molecular mechanisms and new technologies

Meat tenderness is an important quality trait critical to consumer acceptance, and determines satisfaction, repeat purchase and willingness-to-pay premium prices. Recent advances in tenderness research from a variety of perspectives are presented. Our understanding of molecular factors influencing tenderization are discussed in relation to glycolysis, calcium release, protease activation, apoptosis and heat shock proteins, the use of proteomic analysis for monitoring changes, proteomic biomarkers and oxidative/nitrosative stress. Each of these structural, metabolic and molecular determinants of meat tenderness are then discussed in greater detail in relation to animal variation, postmortem influences, and changes during cooking, with a focus on recent advances. Innovations in postmortem technologies and enzymes for meat tenderization are discussed including their potential commercial application. Continued success of the meat industry relies on ongoing advances in our understanding, and in industry innovation. The recent advances in fundamental and applied research on meat tenderness in relation to the various sectors of the supply chain will enable such innovation

The effect of electrical stimulation on the meat quality of impala Aepyceros melampus

The purpose of this research was to study the effect of electrical stimulation of carcasses on the meat quality of impala (Aepyceros melampus). The impala is one of the most important species in game meat production. A total of 40 impala (Aepyceros melampus) were harvested on Mara Research Station (23° 05' S and 29° 25' E; 961 m.a.s.l.) in the Limpopo province, South Africa. Animals were obtained during daytime by shooting from vehicles and by the walk and stalk method. Animals were shot high in the neck with .308 calibre scoped rifles and were immediately exsanguinated by cutting the jugular veins and carotid arteries with a sharp knife. The harvested animals were then taken to the processing facility at Mara Research Station, electrically stimulated, eviscerated and the carcasses cleaned according to standard South African and Zimbabwean practices. The animals were then hung by their Achilles tendon in a cold room at ca 4 ºC and left in the cold room for 24 hours with the skins on after which the skins were removed. The 40 animals were randomly grouped in the following groups and marked accordingly: Group 1: Electrical stimulation (ES) group consisting of 20 impala of which 10 were male and 10 were female (Experimental group). Group 2: Non-electrical stimulation (NES) group consisting of 20 impala of which 10 were male and 10 were female (Control group). Impala were electrically stimulated within 40 minutes after being shot. ES was applied using a Jarvis BV-80 unit (Jarvis Products Corporation, Middletown, CT) that delivered an electrical charge (230V; 50 Hz for 60 seconds) via a clamp attached to the nose and a steel hook (probe) inserted into the anus. The live mass (kg) of each animal was recorded and after dressing the carcass, the dressed out percentage (%) was calculated per individual animal. The average live mass of impala males was 55.5 kg which was significantly (p<0.001) higher compared to the females with an average live mass of 46.4 kg. The dressing percentage however did not differ significantly between the sexes where males had a 60 % dressing percentage and females a 59.4 % dressing percentage. ES, sex and muscle group had a significant (p<0.001) effect on muscle pH as measured at 45 min. 3, 6, and 12 hours post mortem. ES had a significant (p<0.001) effect on the pH of m. semimembranosus (SM), m. semitendinosus (ST), m. biceps femoris (BF) and m. longissimus dorsi (L1-L6) (LM) at 45 min., 3,6 and 12 hours post mortem. The pH of m. triceps brachii (TB) samples from impala in the ES group did not differ significantly (p=0.096) from samples from the NES group, samples from TB had a significantly (p<0.01) lower initial rate of pH decline compared to BF, LM, SM and ST. The interaction between ES x sex was significant (p<0.01). Muscle pH of samples from male impala in the NES group had lower initial pH values (at 45 min., 3,6 and 12 hours post mortem; p<0.001) than samples from the female impala in the NES group while there was no differences between samples from male and female impala in the ES group. Electrical stimulation influenced the pHu-value (p<0.05) of m. semitendinosus, with muscles from the ES group having a lower pHu (pH 5.52 ± 0.02) than muscles from the NES group (pH 5.59 ± 0.02). No significant differences were observed between ES and NES for the pHu-values of m. semimembranosus, m. biceps femoris, m. longissimus dorsi et lumborum and m. triceps brachii. Sex had a significant (p<0.05) effect on the pHu-value of the m. triceps brachii, with muscles from the male group having a higher pHu (pH 5.64 ± 0.02) than muscles from the female group (pH 5.58 ± 0.02). Electrical stimulation had a significant (p<0.05) effect on the L*24-value of the m. biceps femoris muscle, with muscles from the ES group (35.8 ± 0.08) being lighter than muscles from the NES group (33.1 ± 0.08). No significant differences were observed between ES and NES for the a*24- and b*24-values for all muscle groups. The L*-, a*- and b*-values of m. longissimus dorsi et lumborum muscle from ES and NES carcasses declined significantly (p<0.001) from 24 hours post-mortem to post freeze-thaw. ES also had no significant effect on the L*F- and a*F-values of the m. longissimus dorsi et lumborum muscle. ES however, had a significant (p<0.05) effect on the b*F-values. The b*F-value for ES meat (7.1 ± 0.1) was higher than NES meat (6.5 ± 0.2).The muscle x ES interaction was not significant. A significant difference (p<0.01) was found before and after freezing between the L*-values, a*-values and b*-values for both the ES and NES groups whereas the NES b*-value (p = 0.0638), showed a tendency to differ. No significant differences were observed between ES and NES for the thaw loss, drip loss, cooking loss, pH u, sarcomere length and shear force for the m. longissimus dorsi et lumborum muscle. Sex of the animal influenced (p<0.05) the thaw loss and cooking loss of the m. longissimus dorsi et lumborum muscle. No significant differences were observed between male and female for the drip loss, pHu, sarcomere length and shear force of the m. longissimus dorsi et lumborum muscle. In conclusion, it was found that ES did not have a significant effect on the meat quality of impala Aepyceros melampus ES however decreased muscle pH early post-mortem for impala by accelerating post-mortem glycolysis and hastening the onset of rigor mortis. This decrease in muscle pH probably reduced the possibility of cold shortening especially as impala have leaner carcasses. Thus ES may provide a commercial advantage with a decrease in processing and cooling time and an increase in meat production and shelf life. CopyrightDissertation (MSc(Agric))--University of Pretoria, 2009.Animal and Wildlife Sciencesunrestricte