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The sarcoplasmic proteome of beef Longissimus lumborum demonstrating animal-to-animal variation in color stability was examined to correlate proteome profile with color. Longissimus lumborum (36 h post-mortem) muscles were obtained from 73 beef carcasses, aged for 13 days, and fabricated to 2.5-cm steaks. One steak was allotted to retail display, and another was immediately vacuum packaged and frozen at -80°C. Aerobically packaged steaks were stored under display, and color was evaluated on days 0 and 11. The steaks were ranked based on redness and color stability on day 11, and ten color-stable and ten color-labile carcasses were identified. Sarcoplasmic proteome of frozen steaks from the selected carcasses was analyzed. Nine proteins were differentially abundant in color-stable and color-labile steaks. Three glycolytic enzymes (phosphoglucomutase-1, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate kinase M2) were over-abundant in color-stable steaks and positively correlated (P<0.05) to redness and color stability. These results indicated that animal variations in proteome contribute to differences in beef color., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Our objective was to determine the effect of dietary ractopamine and immunocastration on the quality attributes of pork frankfurters. Gilts (GT), surgically castrated male pigs (SR) and immunologically castrated male pigs (IM) were fed diets containing 7.5 ppm ractopamine (RAC) or no ractopamine (CON) for 21 days prior to harvest. Deboned hams were manufactured into frankfurters, and physico-chemical parameters, instrumental color and texture, and sensory attributes were evaluated. Ractopamine increased (P<0.05) L* (lightness) in SR, whereas it decreased (P<0.05) lightness in IM and GT. While ractopamine increased (P<0.05) a* (redness) in GT, a reverse (P<0.05) trend was observed in SR. With respect to instrumental texture, ractopamine increased (P<0.05) hardness, resistance, and springiness in IM, cohesiveness and springiness in GT, and shear force in SR. These results indicated that ractopamine exerted sex-specific effects on frankfurter quality. Swine industry may adopt sex-specific dietary strategies to optimize the quality of further processed meat products., (© 2013.)