Beef Mission 2001: Chengdu, Guangzhou, Panyu, and Hong Kong, China

The U.S. beef industry has many reasons for optimism about the potential for increasing beef and beef variety meat exports to China. China\u27s recent accession to the World Trade Organization lowers tariff rates on imported beef muscle meats and variety meats, low per capita consumption among Chinese consumers means there is good potential for increased consumption, and increasing incomes will allow consumers to purchase more beef. In addition, the Chinese market is highly complementary to the U.S. domestic market and offers potential for additional exports of beef cuts and variety meats that are underutilized in the United States. Observations from a recent trip to China offer insight into the current and potential market for U.S. beef

Pork Quality: pH Decline and Pork Quality

The properties of fresh and processed pork are dependent on factors related to composition of the product such as moisture, lipid and protein content. It is important to recognize, however, that it is not just the amount of these components, but rather the characteristics of protein, lipid and water that are responsible for differences in pork color, texture, water holding capacity and tenderness. In many cases, it is the proteins in pork that are primarily important in the variations that are observed in these traits. The state and nature of proteins are primarily responsible for pork color, pork texture, pork tenderness and water holding capacity

Application of science, technology, and art in producing meat: A recipe for success

We were pleased to be invited to be guest editors of the first issue ofAnimal Frontiers that is focused on meat production and processing across the globe. There are many important issues in food production and in meat production that relate to efficiency, quality, nutrition, preservation, and food safety. We specifically chose to focus on the connection of meat production in diverse cultures and the advances that will help us continue to improve meat quality and consumer acceptance. We think that the exciting combination of science, technology, and art with an eye toward our cultural heritage is what can help us improve the nutritional contribution to the human diet as well as the quality and value of the meat we produce. When we were invited to work with this issue, we immediately wanted to assemble papers that illustrate the over-arching understanding that technology, science, art, heritage, and tradition are mutually beneficial. In fact, these are all part of the “recipe” that makes our food so much more than just nutrients on our plate

Influence of Harvest Processes on Pork Loin and Ham Quality

The influence of the timing and duration of slaughter processes on pork quality was evaluated.The results demonstrate that reducing the time to evisceration is less important than reducing the time to the initiation of carcass chilling. A shortened interval between stunning and cooling can be accomplished by decreasing time allowed for blood removal (dwell time) and scalding.A dwell time of 3 min should allow harvest facilities to maximize profits from blood yields and allow carcasses to enter the scalder at an earlier time postmortem.Lengthening the duration of scalding may result in a more rapid postmortem pH decline. It is recommended that each individual processing facility monitor scald times to determine the appropriate length of time needed to maximize hair removal and minimize time spent on the slaughter floor

Round Muscle Profiling: Management of Tenderness and Sensory Improvement of Specific Muscles with Aging

At 7 and 14 d postmortem very little troponin-T degradation (30kDa) was seen in the GR, SAR, and VI. However, star probe measurements of GR (d3 and d7), SAR (d7), and VI (d1 and d7) were lower than the LD. The AD showed very little change in the amount of degraded troponin-T. This is mirrored in the star probe results of the AD where very little change is seen over time. The SM and VL were the only muscles to have star probe values higher than the LD. From this we can see that biochemical and tenderness differences exist between different muscles of the round, and some round muscles display biochemical and tenderness characteristics similar to those of the LD. As a result of this there is the potential to add value to some of the muscles (GR, SAR, and VI) of the round by marketing them as individual cuts

High Oxygen Packaging System Negatively Affects Color Stability and Sensory Attributes of Beef Cuts

Beef steaks stored in high-oxygen modified atmosphere packaging (HiOx-MAP) had more discoloration, lipid oxidation, and lower tenderness, juiciness, and flavor during 9 days display compared to the steaks packaged in vacuum (VAC). Therefore, MAP systems with lower oxygen mixture or incorporation of antioxidants through injection enhancement to meat in HiOx-MAP are recommended to minimize oxidation-induced quality deteriorations of beef round muscles

Lower oxygen or addition of antioxidants; High-oxygen MAP system diminishes meat quality attributes through oxidation

Demand for central packaging of case-ready meats is greatly increasing and is driving the use of modified atmosphere packaging (MAP) systems with high oxygen incorporation instead of the traditional polyvinyl chloride (PVC) overwrap packaging system. Despite the fact that the initial appearance of fresh meat in high-oxygen modified atmosphere packaging (HiOx-MAP) appeals to consumers, the oxidative environment it creates has some detrimental effects on meat quality during storage and display time. One solution could be minimising oxidation of meat by incorporating antioxidant to fresh meat in HiOx-MAP

Oxidative environments decrease tenderization of beef steaks through inactivation of μ-calpain

This study was designed to test the hypothesis that oxidative conditions in postmortem (PM) tissue decrease calpain activity and proteolysis, subsequently minimizing the extent of tenderization. To achieve different levels of oxidation, the diets of beef cattle were supplemented with vitamin E for the last 126 d on feed, and beef steaks were irradiated early PM. Ten steers were fed a finishing diet with the inclusion of vitamin E at 1,000 IU per steer daily (VITE). Another 10 beef steers were fed the same finishing diet without added vitamin E (CON). At 22 to 24 h PM, strip loins from each carcass were cut into 2.54-cm-thick steaks and individually vacuum packaged. Within 26 h PM, steaks were irradiated at 0 or 6.4 kGy and then aged at 4°C for 0, 1, 3, 7, and 14 d postirradiation. Steaks from each time point were used to determine Warner-Bratzler shear force (WBSF) and calpain activity, and for western blotting of sarcoplasmic proteins and myofibrillar proteins. Calpastatin activity was determined at 0, 3, and 14 d postirradiation. At 1, 3, 7, and 14 d postirradiation, WBSF values of irradiated steaks were higher (P \u3c 0.03) than for nonirradiated steaks. Western blots of troponin-T and desmin showed decreased proteolysis in irradiated samples compared with nonirradiated samples. At 2 d PM, troponin-T degradation products were more evident (P \u3c 0.03) in nonirradiated steaks supplemented with VITE than nonirradiated steaks from the CON diet. Similarly, VITE treatment resulted in steaks with lower (P \u3c 0.05) calpastatin activity at 1 d PM than in steaks from steers fed the CON diet. Irradiation diminished the rate of calpastatin inactivation. Irradiated samples, regardless of diet, had no detectable levels of intact titin or nebulin. Irradiation decreased μ-calpain activity and autolysis, whereas m-calpain activity was not affected by diet or irradiation. Inactivation of μ-calpain by oxidation during early times PM decreased the amount of myofibrillar proteolysis, thereby decreasing the extent of tenderization of beef steaks

Effect of dietary protein on calpastatin in canine skeletal muscle

The cysteine proteinases, μ- and m-calpain, along with their inhibitor, calpastatin, have been hypothesized to play a role in skeletal muscle protein degradation. Because nutrition has previously been shown to influence the expression of calpastatin, the working hypothesis of this study was that the quantity and source of dietary protein could influence regulation of the calpain system in muscle. The objectives to support this hypothesis were to determine the effects of dietary protein (amount and source) on the expression of calpastatin in canine skeletal muscle. This study comprised eight diets with seven dogs per diet. A biopsy was taken from the biceps femoris of all 56 dogs before and after 10 wk on their respective diets. This experimental design allowed examination of change within individual dogs. Diets 1 to 4 contained 12% total protein derived from chicken and/or corn gluten meal in ratios of 100:0, 67:33, 33:67, and 0:100%, respectively. Diets 5 to 8 contained 28% total protein with protein sources and ratios identical to Diets 1 to 4. Differences in calpastatin were examined qualitatively using SDS-PAGE and immunoblotting, and semiquantitatively with densitometric analyses. The majority of the calpastatin blots showed three distinct calpastatin bands, the uppermost appearing at approximately 110 kDa. Diet 5 (28% CP, 100% chicken) resulted in an increase in the expression of the 110-kDa calpastatin band compared with the other two lower molecular weight bands in the same samples. Muscle from dogs fed Diet 5 showed greater increase in (P \u3c 0.05) calpastatin intensity of the topmost band than those fed Diet 8 (0:100; chicken:corn gluten meal). Diet 5 (100:0; chicken:corn gluten meal) showed greater total calpastatin intensity than Diet 8 (0:100; chicken: corn gluten meal). These data suggest that dogs fed a diet containing a higher total percentage of chicken protein may have a greater potential to regulate calpain-mediated degradation of muscle protein than dogs fed diets containing corn gluten meal

Influence of early postmortem protein oxidation on beef quality

The objective of this study was to examine the effect of early postmortem protein oxidation on the color and tenderness of beef steaks. To obtain a range of oxidation levels, the longissimus lumborum muscles (LM) from both strip loins of 20 steers fed either a finishing diet with vitamin E (1,000 IU per steer daily, minimum of 126 d [VITE]; n = 10 steers) or fed the same finishing diet without vitamin E (CON; n = 10 steers) were used. Within 24 h after slaughter, the LM muscle from each carcass was cut into 2.54-cm-thick steaks and individually vacuum packaged. Steaks from each steer were assigned to a nonirradiated group or an irradiated group. Steaks were irradiated within 26 h postmortem, and were aged at 4°C for 0, 1, 3, 7, and 14 d after irradiation. Steaks from each diet/irradiation/aging time treatment were used to determine color, shear force, and degree of protein oxidation (carbonyl content). Steaks from steers fed the VITE diet had higher (P \u3c 0.01) α-tocopherol contents than steaks from steers fed the CON diet. Immediately following irradiation, steaks that had been irradiated had lower (P \u3c 0.05) L* values regardless of diet. Irradiated steaks, regardless of diet, had lower a* (P \u3c 0.05) and b* (P \u3c 0.01) values than nonirradiated steaks at all aging times. Carbonyl concentration was higher (P \u3c 0.05) in proteins from irradiated steaks compared to nonirradiated steaks at 0, 1, 3, and 7 d postirradiation. Immunoblot analysis showed that vitamin E supplementation decreased the number and extent of oxidized sarcoplasmic proteins. Protein carbonyl content was positively correlated with Warner-Bratzler shear force values. These results indicate that increased oxidation of muscle proteins early postmortem could have negative effects on fresh meat color and tenderness