Correlation comparisons of early and aged quality traits of pork aged either as intact loins or case-ready chops

Authors: KLEHM, BRANDON - University Of Illinois; OVERHOLT, MARTIN - University Of Illinois; LOWELL, JESSICA - University Of Illinois; King, David - Andy; Shackelford, Steven; DILGER, ANNA - University Of Illinois; BOLER, DUSTIN - University Of Illinois

Submitted to: Meat and Muscle Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/21/2018
Publication Date: 11/29/2018
Citation: Klehm, B.J., Overholt, M.F., Lowell, J.E., King, D.A., Shackelford, S.D., Dilger, A.C., Boler, D.D. 2018. Correlation comparisons of early and aged quality traits of pork aged either as intact loins or case-ready chops. Meat and Muscle Biology. 2(1):353-361. https://doi.org/10.22175/mmb2018.06.0016.
DOI: https://doi.org/10.22175/mmb2018.06.0016

Interpretive Summary: Pork loins are often sorted into quality classifications, and ultimately, product lines based on observation of the lean exposed by back rib removal at approximately 24 hours postmortem. Loins are then generally aged and distributed either as vacuum-packaged loins or as chops in packages ready for retail sale. Color and other quality attributes are affected by the form in which the loin is kept during aging and distribution. It is not known whether packaging and storage conditions alter the relationships between quality attributes evaluated early postmortem and those evaluated on aged chops. We conducted a study to evaluate these relationships. Storing loins intact in vacuum packages resulted in chops that were darker and redder in color than those aged as chops in retail packages. However, the degree of correlation of quality attributes evaluated early postmortem to those evaluated on aged chops was not affected by packaging and storage condition.

Technical Abstract: Approximately half of retail pork chops in the U.S. arrive at the store in case-ready packages. The other half arrives as intact-loins and are sliced when needed. Cutting chops from loins may increase moisture loss leading to lighter colored and less juicy meat. Therefore, it is possible that correlations between loin quality traits observed early postmortem (PM) and aged quality traits would differ between intact-loin aged (ILA) chops and case-ready aged (CRA) chops. Loins (288 total) were selected to fill a matrix that varied in visual color and marbling. Loins were assigned to 1 of 2 packaging treatments (n = 144): ILA or CRA. Loins assigned as ILA remained vacuum-packaged at 4°C until 12d PM, sliced and chop surface was evaluated. Loins assigned to CRA were sliced into 28-mm thick chops at 2d PM, packaged in individual Styrofoam trays overwrapped in polyvinyl-chloride (PVC) film, and gas flushed in bulk packages. Quality parameters of packaging treatments at early and aged time points were compared as a randomized complete block design. Pearson correlation coefficients between early and aged quality traits for packaging treatments were transformed using Fisher’s r to z transformation for independent correlation comparisons of packaging treatments. Chops from LA were darker and redder at 12d PM than CRA chops (P < 0.0001). Lightness and redness values on ventral surface for ILA loins (r = 0.52 lightness; r = 0.63 redness) and CRA loins (r = 0.45 lightness; r = 0.61 redness) at 1d PM were both correlated with aged lightness and redness values on aged chop face at 12d PM and the correlations did not differ (P => 0.43) for either trait. Overall, aging intact loins in vacuum-packaging improved color after 12d of aging compared with aging chops in case-ready packaging. Despite the differences between aging methods, the correlations between early and aged loin quality didn’t differ.