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Title: COMPOSITIONAL ANALYSIS OF BEEF RIB SECTIONS BY DUAL-ENERGY X-RAY ABSORPTIOMETRY

Author
item Mitchell, Alva
item Solomon, Morse
item Rumsey, Theron

Submitted to: Journal of Meat Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Dual-energy x-ray absorptiometry (DXA) was used as a non-invasive method to measure fat and lean content of 9, 10,11 - rib sections obtained from 80 beef carcasses. Each rib section was scanned twice by DXA, once in a horizontal or standing rib position and once in a vertical position. Both DXA measurements consistently overestimated the amount of fat relative to dissection. The DXA scan in the horizontal position measured more lean and less fat than did the scan in the vertical position. In spite of inaccuracies of the direct readings provided by DXA, the high correlations between DXA and dissection results indicate that DXA could be used as a non-destructive method for evaluating composition of cuts of beef. However, attention must be given to orientation of the cut during the DXA scan.

Technical Abstract: Dual-energy x-ray absorptiometry (DXA) was used as a non-invasive method to measure composition of 9, 10,11 - rib sections obtained from 80 beef carcasses. The weights of the rib sections ranged from 2986 g to 6394 g. Each rib section was scanned twice by DXA, once in a horizontal or standing rib position (DXA-1) and once in a vertical position (DXA-2). After scanning each rib section was dissected into fat, muscle and bone. The intramuscular fat content was measured chemically. Dissected lean and fat values were corrected for the amount of intramuscular fat. DXA lean values were corrected for amount of bone (less BMC, bone mineral content). Both DXA measurements consistently overestimated the amount of fat relative to dissection. The DXA-1 scan position measured more lean and less fat than did DXA-2. The correlation (r) between the amount of dissected lean and DXA-1 and DXA-2 lean was .91 and .85, respectively and between the amount of dissected fat and DXA-1 and DXA-2 fat was .94 and .92, respectively. The high correlations between DXA and dissection results indicate that DXA could be used as a non-destructive method for evaluating composition of cuts of beef, however, attention must be given to orientation of the cut during the DXA scan.