Evaluating the quality characteristics of fresh pork cuts was University of Nebraska graduate student, Tony Holthaus’, objective. He collected data on 479 fresh, boneless, center-cut pork loins to determine quality characteristics after being stored for 21 days and 42 days at 2°C.
Holthaus collected loins from hybrid pigs slaughtered in eight groups during August and September. The loins were processed under normal commercial conditions. At 24 hours post mortem the loins were weighed, vacuum packaged, boxed and delivered on a refrigerated truck to the University of Missouri for the actual quality measurements. Holthaus chose storage durations to simulate domestic (21 days) and export (42 days) intervals.
After being stored for those intervals, researchers measured a variety of quality traits, including purge loss, color scores (instrumental and subjective), subjective marbling scores, pH, Warner-Bratzler shear-force measurements and percentage cooking loss.
Next, researchers recorded light reflectance scores, L* (lightness/darkness), a* (redness) and b* (yellowness) on the cut lean surface of the blade, center and sirloin sections.
Following the measurements, researchers cooked the chops to 70°C, allowed them to cool and then reweighed the cuts to determine cooking loss. Six, 1.3 cm cores were removed parallel to the muscle fibers and measured for shear force.
Compared to domestic storage, loins stored for simulated export periods had lower L* values recorded on the blade, center and sirloin surfaces. Subjective (National Pork Producers Council) color scores were opposite to the L* values, with domestic color scores higher than export for the blade and sirloin end. Export storage purge loss was higher than for the domestic storage, and shear force was higher for export vs. the domestic loins. Researchers didn’t observe any differences in pH or cooking loss between the two storage periods.