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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Meat Safety and Quality » Research » Publications at this Location » Publication #367909

Research Project: Strategies to Optimize Meat Quality and Composition of Red Meat Animals

Location: Meat Safety and Quality

Title: Influence of postmortem aging and post-aging freezing on pork loin quality attributes

item SCHULTE, MATTHEW - Iowa State University
item JOHNSON, LOGAN - Iowa State University
item ZUBER, ELIZABETH - Iowa State University
item PATTERSON, BRIAN - Iowa State University
item OUTHOUSE, AMANDA - Iowa State University
item FEDLER, CHRISTINE - Iowa State University
item STEADHAM, EDWARD - Iowa State University
item King, David - Andy
item PRUSA, KENNETH - Iowa State University
item HUFF-LONERGAN, ELISABETH - Iowa State University
item LONERGAN, STEVEN - Iowa State University

Submitted to: Meat and Muscle Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2019
Publication Date: 8/29/2019
Citation: Schulte, M.D., Johnson, L.G., Zuber, E.A., Patterson, B.M., Outhouse, A.C., Fedler, C.A., Steadham, E.M., King, D.A., Prusa, K.J., Huff-Lonergan, E., Lonergan, S.M. 2019. Influence of postmortem aging and post-aging freezing on pork loin quality attributes. Meat and Muscle Biology. 3(1):313-323.

Interpretive Summary: Tenderness is a primary driver of pork consumer satisfaction, and postmortem aging is the most common technology applied to ensure adequate tenderness of pork products. Additionally, freezing is commonly used to extend product life during distribution, though some adverse effects of freezing have been reported on pork quality attributes. This study was conducted to examine the effects of aging and freezing after aging on pork quality attributes. Results indicate that a minimum of 8 days of aging is needed to insure acceptable pork tenderness, and the post-aging freezing did not impact pork quality attributes.

Technical Abstract: The objectives were to determine 1) the interaction between aging duration and post-aging freezing on pork loin quality attributes and 2) the relationship between pork loin star probe (SP) and Warner-Bratzler shear force (WBS). Loins from 20 carcasses were collected 1 d postmortem. Chops (n = 9; 2.54-cm thick) were fabricated from each loin and vacuum packaged. Four chops from each loin were aged at 4°C for 1, 8, 14, and 21 d and immediately evaluated (Fresh). Four adjacent chops were aged (1, 8, 14, and 21 d), frozen for 14 d, and thawed for evaluation (Frozen). An additional chop was used for evaluation of sarcomere length, intact desmin, and troponin-T degradation. Purge, objective color, pH, subjective color and marbling score, cook loss, SP, and WBS were evaluated at each aging period. Desmin and troponin-T degradation, and sarcomere length were measured on fresh samples at each day of aging. Post-aging freezing had no significant impact on SP, WBS, pH, and subjective color or marbling score at any aging period. Fresh chop purge increased at each day of aging (P < 0.01). Post-aging freezing resulted in greater purge at 1, 8, and 14 d aging (P < 0.01). Fresh chop cook loss was greater than post-aging freezing chop cook loss at 14 and 21 d aging (P < 0.05). Across all aging periods and treatments, SP was correlated (r = 0.85; P < 0.01) with WBS. Fresh chop SP and WBS decreased from 1 to 8 d aging but was not different after 8 d aging. The abundance of intact desmin decreased (P < 0.01) between 1, 8, and 14 d aging. Troponin-T degradation increased (P < 0.01) with each aging period. Sarcomere length was not different across aging periods (P > 0.05). Aging, without freezing, for 14 or 21 d did not improve SP or WBS observed at 8 d, corresponding with changes in desmin degradation.