Cuts based MSA lamb development – lamb turn off and packaging effects

Summary

​Phase 1 New versus old season lambs

Consumer eating quality scores of new season (NS; n=150) and old season lambs (OS; n=151) across 8 cuts of the carcase were evaluated. Cuts for grilling were the loin, topside, knuckle, outside and rump, while cuts for roasting included the shoulder, leg and rack. Each cut was scored by untrained consumers for tenderness, juiciness, liking of flavour and overall liking.

Consumers could not differentiate between NS and OS lamb for most cuts across all eating quality traits, though preferred NS lamb for the rump and knuckle cuts by a small margin of 3 consumer points. This is potentially due to decreases in collagen solubility that result in increased muscle toughness, which has been shown to occur rapidly with increased age in those two particular cuts. Our results show little difference in quality between NS and OS lamb, despite the current perception that NS lamb is of higher quality due to its younger age.

Phase 2 Packaging

The impact of high oxygen modified atmosphere packaging (MAP) with 80% oxygen (MAP80), lower oxygen MAP with 40% oxygen (MAP40) and vacuum skin packaging (VSP) under different retail display times (3 or 8 days) on the sensory scores of lamb meat was evaluated.

Consumer sensory scores for overall liking, tenderness, juiciness and liking of flavour were assessed on the M.longissimus lumborum (loin) and M.semimembranosus (topside) of 144 lambs.

Loin samples generally had more acceptable sensory scores than topside samples across all packaging treatments. Increasing the display time from 3 to 8 days reduced sensory scores for both cuts within each MAP treatment, yet remained relatively unchanged for VSP samples.

In general, within a cut and display time, VSP samples had the highest sensory scores, followed by samples under MAP40, followed by samples under MAP80 which had the lowest sensory scores. Similar to previous studies, our results confirm the detrimental impact of high oxygen MAP on lamb meat eating quality. Our results also provide the sheepmeat industry with a new MAP mixture containing lower oxygen concentration which has a reduced detrimental impact on eating quality compared to the widely used high (80%) oxygen MAP.