DOMESTIC STRATEGIC ALLIANCE: VITAMIN E PROJECT

Transcription

1 DOMESTIC STRATEGIC ALLIANCE: VITAMIN E PROJECT E. A. Westcott, R. L. Stubbs 2, H.G. Dolezal and J. B. Morgan Story in Brief Approximately 235,000 steers form three commercial feedyards were utilized to evaluate the effects of supplementing 500 IU/animal/day of a -tocopheryl for the last 100 days of the finishing period on retail beef caselife. Following animal harvesting the a -tocopherol concentration of carcasses was determined through a rapid assay process. Subprimal cuts were conventionally transported and aged prior to arrival at four participating retail grocery chains. Supplementation of retail beef cuts resulted in a slightly more desirable lean color. The percentage of vitamin E supplemented (VITE) clod and round cuts removed from the case due to discoloration was lower than that of control (CON) cuts. The obtainable caselife for these retail cuts was also greatly improved by VITE treatment. Additionally, a majority of the retail cuts from the middle meats showed a small improvement in discount percentages and caselife of VITE product over CON. However, top sirloin steaks did not show a benefit from a -tocopheryl supplementation. The VITE ground beef enhanced display life, by decreasing the discount number of VITE beef over CON beef. (Key Words: a -tocopheryl acetate, a -tocopherol, Beef, Retail cuts.) Introduction Supplying customers with a consistent, "high quality" product is a basic element in the satisfaction of consumers. More than ever, todays "fast-track" consumers rely heavily on their own perception of quality. Any deviation from their model of quality results in a flaw of product performance and, most importantly, a poor consumer experience. Consumers have learned, that the desirable color of fresh beef is bright cherry-red and any deviation is unacceptable (Sherbeck et al., 1995). Discoloration of fresh beef is a combined result of lipid oxidation and oxidation of muscle color pigments. Extensive research has documented that supplementing the diet of finishing steers with elevated levels of vitamin E is one method which can help stabilize the fresh cherry-red color of retail beef and, in turn, prolong caselife. Vitamin E functions as an antioxidant which delays the oxidation of oxymyoglobin, thus prolonging the time prior to which the meat becomes discolored and unattractive to consumers. The objectives of this study were to determine the efficacy of supplementing cattle with vitamin E in order to extend the color display life of beef retail cuts, and to determine the economical benefits of caselife extension in "real-world", retail applications. Materials and Methods Animal Feeding. Approximately 235,000 steer calves of various breeds and breedcrosses were fed finishing diets at three commercial feedyards located in different geographical regions of United States. Pens were randomly assigned to CON or VITE treatments with CON diets consisting of the standard amounts a -tocopheryl acetate within routine finishing diets while the

2 VITE treatment diets were formulated to provide each animal with at least 500 IUE/day (as a - tocopheryl acetate). Feed samples were collected from five pens every other week during the feeding period and analyzed for a -tocopheryl acetate. Animal Harvesting and Subprimal Tissue Sampling. Animals were conventionally harvested and fabricated at three participating packing plants. Prior to chilling, a one-ounce neck muscle sample was obtained from 5% of the carcasses during each treatment phase. The a -tocopherol concentrations were determined within two days of collection, through a rapid assay procedure described by Liu et al. (1996). Identification of the VITE product was conducted by students and plant personnel prior. The subprimal boxes were marked for identification with large florescent stickers prior to transport to cooperating distribution warehouses. Following an aging period of approximately 10 days, the boxes were then transported to the alliance retail stores. Retail Data Collection and Retail Cut Tissue Sampling. Each of the alliance grocery chains participated in the selection of retail cuts for the study prior to data collection. The project was designed for two, 2 wk CON sessions alternating with two 4 wk VITE sessions. The daily schedule for data collection involved an initial visit to each of the participating stores between 5:30 and 7:30 a.m. At that time an initial package count for each of the retail cuts being monitored was recorded prior to the removal of any discolored product that remained from the previous day. An initial case temperature was also recorded at that time. Supermarket meat personnel evaluated the retail meat case and identified cuts that did not have an acceptable cherry-red color. Research personnel then determined the number of packages that had been sold, discounted in price and (or) discarded. In addition to package number, loses in monetary value and weight of retail product due to inferior retail caselife were recorded. Production data for each cut was recorded daily for the purpose of calculating discount and discard percentages. A second visit (approximately 12:00 p.m.) was made to each retail store to obtain further discount and discard information. A final visit between 5:00 and 6:00 p.m. consisted of a second recording of the case temperature and documenting the arrival of new product from the warehouse. Sampling of muscle tissue for subsequent determination of a -tocopherol concentration was conducted once per week during both the CON and VITE phases of the trial. Three packages of each retail cut were randomly selected and purchased at each participating store. A specific muscle within each cut was designated for a -tocopherol concentration analysis by the same rapid assay procedures mentioned previously. General Linear Model procedure of SAS was used to test the effect of vitamin E. Differences in means were compared using LS means and Pared T. Results and Discussion Vitamin E levels in the diet averaged 6.1 mg E/lb DM for CON and 24.0 mg E/lb DM for VITE for the last 100 d of the feeding period (P <.01). The 6.1 mg E/lb present in the control diet is attributed to naturally occurring a -tocopheryl in the ration and a small supplementation present in conventional feedyard rations used for animal health purposes. Initial screening of carcasses using neck muscle samples revealed that a -tocopherol concentrations were approximately

3 doubled as a result of dietary vitamin E supplementation when compared with concentrations of vitamin E in neck muscle samples from steers which were fed a CON diet (P <.01). These results coincide with the retail cut tissue samples. (Table 1). Several previous investigations (Arnold et al., 1993; Sherbeck et al., 1995) have documented that animals supplemented with a - tocopherol, have vitamin E concentrations which differ between muscles within the same animal. The percentage of discounted items for clod and round cuts were not statistically different (P >.05); however, vitamin E was effective in stabilizing the cherry-red color of the product by lowering the number of discounted items. The VITE clod cuts had a lower incidence of discount or discardment due to discoloration during retail display than CON, 26.5% vs 19.4%, (CON, n = 7618; VITE, n = 5104). London broils and top round steaks which had to be reduced in price were also lower by 3.7 and 13.8%,respectively for VITE, as compared to CON, products (CON, n = 3339, n = 1627 and VITE, n = 7054, n = 1978, for London broil and top round steaks, respectively) (Figure 1). The caselife, or number of days and hours a product remains an acceptable lean color without being sold or discarded, was prolonged for VITE clod cuts (P <.01; 3.6 vs 3.2 days for VITE vs CON). Additionally, the caselife of round cuts from VITE steers (3.5 days) was extended (P <.05) over CON steers (2.9 days) (Figure 2). Although not statistically significant (P >.05), the percentage of ribeye, strip loin, T-bone and tenderloin steaks discounted as a result of discoloration was lower for VITE compared with CON (1.9, 3.5, 1.4, 1.6% lower for VITE vs CON, respectively) (Figure 3). Interestingly, VITE supplementation was not beneficial for top sirloin steaks (VITE discount was 23.9% vs 23.7% for CON). The caselife for VITE ribeye and strip loin steaks was enhanced for an extra 15 and 8 hours, respectively, while the caselife for top sirloin and tenderloin was not improved (Figure 4). Ground beef data was collected at one retail grocery store. During this survey, approximately one of every five packages (20%) of CON ground beef were removed from the case due to discoloration in comparison with one of every 7.5 packages for VITE product (Figure 5). This was not statistically significant (P >.05); however, the economic benefit can be seen by comparing the loss of three packages of ground beef vs the loss of one package. In a study by Mitsumoto et al. (1991) they found that vitamin E supplementation delayed the onset of lipid oxidation and color change in ground beef. Previous research coincides with the results of this project, concluding that vitamin E can play an important role in the stabilization of beef retail cuts in a "real world" retail scenario. Arnold, R. N. et al J. Anim. Sci. 71: 109. Literature Cited Liu, Q. et. al J. Anim Sci. 74: Mitsumoto, M. et al J. Food Sci. 56: 96 Sherbeck, J. A. et al J. Food Sci. 60: Acknowledgments

4 A special thanks to the National Cattlemans Beef Association for the opportunity to be involved in the Vitamin E Project. Dr. D. M. Schaefers assistance, guidance and faith were invaluable in the completion of this project. Table 1. α tocopherol concentrations of Control and Vitamin E muscle tissue samples. Item(s) Control Vitamin E Neck muscle 1.53 a 3.10 b Clod steaks 1.98 a 3.41 b Ribeye steaks 1.47 a 2.05 a Striploin steaks 1.56 a 2.72 b T-bone steaks 1.37 a 2.64 b Tenderloin steaks 1.88 a 4.24 b Top sirloin steaks 2.10 a 3.17 b Inside round steaks 1.44 a 3.10 b Ground beef 1.40 a 2.72 b a, bmeans within Item with different superscript are different (P<.05).

5 Figure 1. Effect of dietary vitamin E supplementation of cattle on percentage of clod and round cuts discounted when displayed under supermarket conditions. Figure 2. Effect of dietary vitamin E supplementation of cattle on obtainable caselife of clod and round retail cuts under supermarket conditions

6 Figure 3. Effect of dietary vitamin E supplementation of cattle on percentage of middle meats discounted when displayed under supermarket conditions. Figure 4. Effect of dietary vitamin E supplementation of cattle on obtainable caselife of middle meat retail cuts under supermarket conditions

7 Figure 5. Effect of dietary vitamin E supplementation of cattle on percentage of ground beef discounted when displayed under supermarket conditions Research Report