Relationship between intramuscular fat content and meat quality in lambs with emphasis on sensory characteristics

IMF content in lamb or sheep meat relates to sensory characteristics. Research on defining an optimal fat content and the verification of IMF content in local breeds is necessary before IMF can be considered as a part of quality assessment program. Investigations were made on longissimus dorsi (LD) and semimembranosus (SM) muscles of 113 German Longwool Merino lambs, ranging in their final weights from 30 and 50 kg. The average IMF content of muscles varied between 1.9-3.2%, depending on slaughter weight and sex. The IMF was correlated (r=0.25 n.s. to r=0.45 p<0.05) with meat colour (a-value). There were significant correlations to drip loss (LD, r=0.61) and cooking loss (both muscles, r=-0.48) within the 35 kg group and conductivity within the 40 kg group (r=-0.43 in LD; r=0.59 in SM), depending on slaughter weight. An increase in IMF resulted in slightly better scores for sensory properties in LD. IMF contents greater than >2.3% profound effects on sensory characteristics, especially on flavour and overall acceptance ratings. Meat from LD with a content of 3.5-4.5% IMF was scored best in all sensory traits. No differences in sensory scores were found in meat samples from SM muscle, Because of the given correlations to kidney fat as well as to subcutaneous fat (r = 0.3) these IMF contents are related to an undesirable increase in the other fat depots. Thus, the optimal IMF content need to be discussed depending in the context of specific marketing conditions.