Effect of gender/castration status on color and lipid oxidation stability of long-term chilled lamb muscles

Abstract Text:

Fresh meat color is one of the most important quality attributes that impact consumers’ meat purchasing decisions. The New Zealand meat industry questions whether differences in gender/castration status influence the color and color stability of long-term chilled lamb meat. The objective of the present study was to determine the effect of different gender/castration status (ewe, wether, ram and cryptorchid) on the color and lipid oxidation stabilities of individual loin and leg muscles from the lambs. Seventy-six lambs (ewe = 18, wether = 18, ram = 20 and cryptorchid = 20; 11 months old) were slaughtered, and then loins and legs were excised from carcasses at 24 h post mortem, vacuum packed and then transported to AgResearch. Following storage at -1.5°C for 8 weeks, sub-samples were taken from each loin (M. longissimus dorsi (LD) and leg muscles (Mm. semimembranosus (SM), semitendinous (ST) and biceps femoris (BF)) and re-packaged into high-oxygen modified atmosphere (80% O₂/20% CO₂) and displayed for 7 days at 4°C under light. Lipid oxidation, pH, myoglobin content and color stability were determined. Data were analyzed using the ANOVA directive of GenStat. Results indicate that different gender/castration status influenced the chemical attributes and color stability of the long-term chilled lamb loin and leg muscles. In general, the loin and leg muscles from ram and cryptorchid lambs had higher pH and less myoglobin contents (P< 0.05), and consequently resulted in less lipid and myoglobin oxidation (less discolored) than the muscles from ewe and wether lambs at the end of display (d 7). The individual muscle types revealed different myoglobin contents and different color stability, where ST was the most color stable (least discoloration) followed by LD, BF and with SM being the least color stable (most discoloration). These results suggest that different gender/castration status of lambs could affect to some extent the color and lipid oxidation stability of lamb meat when displayed longer than 4 days. Furthermore, the results of this study indicated that the physiological difference in lamb muscle types played a more substantial role in meat color and lipid oxidation stabilities than the gender/castration did. Therefore, taking into account the difference in the color stability of muscles, while developing new packaging strategies, would be beneficial to maximize the color shelf-life of long-term chill-stored lamb muscles.

Keywords: lamb, gender/castration, oxidation