Comparison of the color stability and lipid oxidative stability of fresh and vacuum packaged lamb muscle containing elevated omega-3 and omega-6 fatty acid levels from dietary manipulation

A series of three experiments were conducted with second cross ([Merino x B order Leicester] x Poll Dorset) wether lambs to evaluate the effects of die tary treatments on manipulation of muscle long-chain (LC) omega-3 fatty aci ds (FA) on the color stability and oxidative stability of fresh and vacuum packaged lamb. At the end of 7-, 6- and 6-week experimental periods for exp eriments (Exp.) 1-3 respectively, lambs were slaughtered at a commercial ab attoir. At 24 h post-mortem, muscle longissimus lumborum (LL) and longissim us thoracis (LT) were removed and evaluated for color and lipid oxidative s tability under specified commercial storage and display condition. Of the d ietary supplements used, fish meal and fish oil moderately (P < 0.01) and m arkedly (P < 0.001) increased muscle omega-3 FA content, while both protect ed canola seed (P < 0.001) and protected sunflower meal protein significant ly (P < 0.02) increased muscle omega-6 FA content or ratio of omega-6/omega -3 of the longissimus muscle. In all experiments, the substantial increase (P(0.001) in muscle LC omega-3 and omega-6 FA had no consistent significant effect on color values (redness (a*), yellowness (b*) and lightness (L*)) for fresh and vacuum packaged lamb over a 6-day display period. Lipid oxida tion, determined by the levels of thiobarbituric acid reactive substances ( TBARS) indicated the enrichment of muscle polyunsaturated fatty acid (PUFA) levels in lambs did not produce significant differences resulting either f rom main treatment effects or for treatment x day x type interactions (wher e type was fresh and vacuum packaged). Present results demonstrated the col or and lipid oxidative stability of lamb longissimus muscle during refriger ated display was not affected by enhanced levels of omega-3 and omega-6 FA due to dietary treatments. (C) 2001 Elsevier Science Ltd. All rights reserv ed.