A comparison of the nutrient content of uncooked and cooked lean from New Zealand beef and lamb

The composition in terms of proximate analysis, cholesterol, vitamins, minerals, and fatty acids of the lean tissue of 17 beef cuts and 18 lamb cuts was determined on within-cut composite samples (each containing lean tissue from at least 7 animals), following the knife-separation of raw and cooked cuts into lean, fat, and bone. Composite lean samples for 4 beef cuts and 4 lamb cuts were also analysed for amino-acid composition. For analysis, different cuts were the experimental unit as individual animal data were not available. The composition of lean from beef and lamb was shown to be highly desirable with a high nutrient density (mg/kJ) for many nutrients. Although lean from beef and lamb were very similar in many respects, several significant differences were detected. Changes in composition with cooking were largely eliminated when considered on a dry-matter basis, but proportions of the n-3 and n-6 polyunsaturated fatty acids increased with cooking (P < 0.05). The amino acid composition was similar for lean from beef and lamb but showed small deviations from recommended patterns for human nutrition with branched chain amino acids being limiting.