ARS | Publication request: INFLUENCE OF HYDRODYNAMIC PRESSURE PROCESSING AND AGING ON MYOFIBRILLAR PROTEINS AND TENDERNESS IN FRESH BEEF STRIP LOINS

Submitted to: American Meat Science Association Conference Reciprocal Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 24, 2006
Publication Date: June 16, 2006
Citation: Bowker, B.C., Fahrenholz, T., Paroczay, E.W., Solomon, M.B. 2006. Influence of hydrodynamic pressure processing and aging on myofibrillar proteins and tenderness in fresh beef strip loins [abstract]. American Meat Science Association Reciprocal Meat Conference Proceedings. Paper No. 52P. June 18-21, 2006, Champaign, Illinois.

Technical Abstract: Hydrodynamic pressure processing (HDP) and aging are postharvest techniques for enhancing meat tenderness. HDP utilizes pressure shockwaves to physically disrupt muscle ultrastructure, while aging tenderization is associated with the proteolytic degradation of myofibrillar proteins. The objective of this study was to determine the effect of combining HDP and aging treatments on the tenderness and myofibrillar protein characteristics of boneless beef strip loins. Strip loins (n=12) were split in half at 24 h postmortem, with one end randomly assigned HDP-treatment and the other serving as a control. Following treatment, each half was divided into three portions, which were aged 0, 5, and 8 days. From each portion, a steak was removed for Warner-Bratzler shear force (WBSF) determination and myofibrillar protein isolation. HDP decreased (p<0.0001) WBSF values approximately 23 percent compared to controls at day 0 (6.33 vs. 8.17 kgf), day 5 (5.06 vs. 6.60 kgf), and day 8 (4.52 vs. 5.82 kgf). Myofibrillar fragmentation increased (p<0.001) with HDP treatment compared to controls, and increased (p<0.0001) from 0 to 5 days of aging. HDP treatment also caused an increase (p<0.001) in myofibrillar protein solubility compared to controls. SDS-PAGE analysis of myofibrillar protein profiles demonstrated a strong aging effect. Aging related changes in band intensities were observed for 90-110 kDa bands, desmin, troponin-T, and the 30 kDa fragment. The intensity of the bands in the 90-110 kDa range also increased with HDP treatment compared to controls. No treatment or aging effects were observed in the intensities of the myosin or actin bands. These data suggest that while HDP is more effective than aging alone for tenderizing beef, HDP tenderization is not likely due to the same proteolytic degradation of myofibrillar proteins observed with aging.