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Title: Influence of sarcomere length on aging and hydrodynamic pressure processing of beef muscle

item Bowker, Brian
item Eastridge, Janet
item Paroczay, Ernest
item Solomon, Morse

Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/9/2008
Publication Date: 7/7/2008
Citation: Bowker, B.C., Eastridge, J.S., Paroczay, E.W., Solomon, M.B. 2008. Influence of sarcomere length on aging and hydrodynamic pressure processing of beef muscle [abstract]. Journal of Animal Science. Vol. 86, E-Suppl. 2, p. 43.

Interpretive Summary:

Technical Abstract: The interacting effects of sarcomere length and proteolysis on meat tenderness are not well understood. Extent of thick and thin filament overlap was hypothesized to influence the protein degradation and tenderness improvements associated with postmortem aging and tenderization techniques, such as hydrodynamic pressure processing (HDP). The objective of this study was to determine the influence of sarcomere length and proteolysis on the tenderness effects of aging and HDP in beef longissimus muscle. One side of each beef carcass (n=4) was subjected to hip suspension (HS) while the opposite side was normally suspended (NS). At 48 h postmortem, longissimus muscles were removed and cut into anterior and posterior halves assigned HDP and control treatments. Steaks for Warner-Bratzler shear force (WBSF) determination and protein analysis were removed and aged at 4°C until 3, 7, and 14 days postmortem. Sarcomere length was greater (p<0.0001) in HS samples than NS samples (2.35 vs. 1.73 µm). WBSF was lower (p<0.0001) in HS samples compared to NS samples, regardless of HDP treatment or aging period. NS samples exhibited a greater (p<0.0001) decrease in WBSF with aging than HS samples. HDP treatment decreased (p<0.0001) WBSF in NS samples but had minimal effects on HS samples. SDS-PAGE analysis of whole muscle protein extracts revealed significant suspension method by aging interactions and strong aging effects. In HS samples there was a greater (p<0.05) decrease in the intensity of the 38 kDa band (relative to the actin band intensity) from 3 to 14 days than in NS samples. The intensity of a 95 kDa band was not influenced by aging in NS samples but was diminished by day 14 in HS samples. The intensity of several smaller bands (<14 kDa) in HS samples increased (p<0.05) more with 14 days of aging than in NS samples. Bands corresponding to 110 and 30-32 kDa increased with aging across all treatments. Overall data suggest that sarcomere length plays a major role in determining a muscle's potential for tenderization and further suggests that the impact of proteolysis on tenderness is mediated by sarcomere length.