True retention of nutrients on cooking of Australian retail lamb cuts of differing carcass classification characteristics.

The true retention of nutrients (proximate principles and cholesterol) on cooking of three retail cuts from lambs classified by weight, sex and fatness score was investigated. Fat retentions of the total cut and of the lean portion of lamb legs and mid-loin chops were not affected by carcass fatness, weight and sex or their interactions, however, the fat retention of the total cut and of the lean portion of forequarter chops was affected by fat score, with forequarter chops from fat score 1 retaining more fat than did chops of carcasses of higher fat score. Overall, fat was lost by all cuts (total cut) on cooking, with only 70-80% of fat being retained, but fat content of lean only increased on cooking (retention >100%), indicating the passage of fat into the lean portion from the external fat cover during the cooking process. Carcass factors and their interactions had little or no effect on the protein, water and ash retentions of the total cut or the lean portions of the three cuts. Cholesterol retention by the lean portion of three cooked lamb cuts was not affected by any carcass factors or their interactions. Cholesterol retentions were ∼99% for total cuts and tended to be ∼102% for the lean portions.