Effects of supplementing docosahexaenoic acid-rich microalgae and antioxidants on beef longissimus lumborum steak color stability and sensory characteristics(,)

The objective of this study was to determine the effects of four microalgae and antioxidant feeding regimens on beef longissimus lumborum color stability and palatability. Steers were blocked by weight and randomly assigned to one of four dietary treatments fed during a 45-d feeding period. Treatments (n = 10 per treatment) consisted of a control diet (CON) and control diet plus 100 g∙steer(−1)∙d(−1) microalgae (ALGAE), ALGAE plus antioxidants (103 IU/d vitamin E and Sel-Plex) fed throughout feeding (AOX), and AOX fed for the final 10 d of finishing (LATE). The longissimus lumborum muscle was removed, aged for 14 d, and fabricated into steaks for objective and subjective color and palatability analyses. There were treatment × day of display interactions for a* value and steak surface metmyoglobin percentage (P < 0.01). There were no treatment differences through day 4 of display for a* value (P > 0.16) and day 5 of display for surface metmyoglobin (P > 0.10). By day 10 of display, ALGAE steaks had a smaller a* value than all other treatments (P < 0.01). Steaks from AOX steers had a greater (P < 0.01) a* value than CON steaks, whereas both a* values did not differ from LATE steaks (P > 0.19). By the end of display, ALGAE steaks had more metmyoglobin than the other treatments (P < 0.01). Steaks from AOX steers had less metmyoglobin than CON and LATE steaks (P < 0.04), which did not differ (P > 0.25). Treatment did not affect trained panel ratings (P > 0.15); however, treatment did affect (P < 0.01) off-flavor intensity. Steaks from ALGAE and AOX steers had greater off-flavor ratings than CON steaks (P < 0.03), but did not differ (P = 0.10). Steaks from LATE steers did not differ in off-flavor ratings from the other treatments (P > 0.07). Use of antioxidants improved color stability of steaks from microalgae fed steers; however, panelists still detected off-flavors.