The biochemical characteristics of muscle make the meat

Meat is a source of high quality nutrients and energy for human populations. Meat, particularly, beef, is one of the leading sources of protein, B vitamins, iron and zinc in the United States. Beef palatability is based on three general criteria; tenderness, juiciness and flavor. All of these characteristics depend upon the biochemical state of the muscle from which the meat is made. While the importance of these three organoleptic properties to overall palatability varies from person to person, inconsistency in tenderness has been reported as the most important in determining consumer satisfaction with a beef eating experience.; Currently, beef carcasses are segregated into palatability classes based on both physiological age and the amount of intramuscular adipose. Such segregation is only moderately successful in predicting the palatability of the beef, with tenderness being especially inconsistent to consumers. To improve this, a method that can predict tenderness of beef after chilling but prior to fabrication (between 36-48 h) and without being destructive or costly, must be developed. One such method would be to use an immunochemcial test strip.; The long term objective in the Wick lab is to develop an immunochemical test stript to segregate carcasses into tenderness categories. To that end, previous research in the Wick lab has shown that the proteomic profile of myofibrils at 36 h postmortem is predictive of tenderness at 7 d postmortem. These data were further mined to determine if the 36 h myofibrillar profile is predictive of and associated with overall palatability based on a consumer taste panel. Using reverse step wise multiple regression, 4 bands were identified that are predictive of overall palatability (r2 = 0.60; p < 0.05). One of those bands, which was positively associated with a pleasurable eating experience is comprised of a myosin heavy chain proteolytic fragment.; To expand upon the myofibrillar work, a larger study was designed to look at all muscle proteins from 36 h samples and determine the relationship between the proteomic profile, sarcomere length and tenderness. A principle component analysis was performed on the 36 h longissimus dorsi sample by separating the proteins into high salt soluble fractions and high salt insoluble fractions. Sarcomere lengths were ascertained at both pre- (0 h) and post rigor (36 h) time points. Warner Bratzler shear force determinations were made on steaks aged for both 7 and 14 d. Pre-rigor, post-rigor and the change in sarcomere length were not correlated with 7 d, 14 d or change in WBS. Proteomic analysis and reverse step wise multiple regression identified bands which were predictive of or associated with 7 d WBS, 14 d WBS, the change in WBS and the post rigor sarcomere length (p < 0.05). Numerous proteins were identified implicating a variety of cellular processes such as the myofibrillar degradation, glycolysis and calcium regulation.; To further refine the process, a similar, but larger experiment was conducted using 44 lambs. Samples for proteomic analysis were taken at 36 h postmortem and WBS of lamb chops taken at 7 d. A whole muscle proteomic analysis was conducted. The proteomic profile was analyzed and 7 bands were found to be predictive of and associated with 7 d WBS (r2 = 0.56; p < 0.01). Taken together, these studies show that an immunochemical test strip as a predictor of tenderness is feasible. Such a test strip, if cheap, safe and timely, could greatly enhance carcass segregation and ensure that consumers who desire increased tenderness are able to purchase tender meat.; While quality grade is not a perfect predictor of tenderness, it is a reasonable predictor of overall palatability, flavor and juiciness. In addition to the physiological age of the animal, marbling in the longissimus dorsi is the criteria for determining quality grade. Marbling is the amount of visible intramuscular adipose depots. (Abstract shortened by UMI.)...