The effects of instrumental color and extractable lipid content on sensory characteristics of pork loin chops cooked to a medium-rare degree of doneness

Boneless loins (n = 286) were selected from a population of pigs of a common genetic line and management strategy to be used in an experiment to determine the effects of instrumental color and extractable lipid content on sensory traits of boneless pork chops cooked to an end point internal temperature of 63°C. Loins were cut into 2.54-cm-thick chops and aged until 14 d postmortem. Chop L* values ranged from 57.60 (light) to 43.11 (dark) and extractable lipid ranged from 0.80 to 5.52%. Using these values, chops were assigned to 5 color and 6 marbling categories using National Pork Producers Council (NPPC) standards, resulting in a 5 × 6 factorial arrangement of treatments. Chops were also assigned a quality grade using a proposed grading system. Low-quality loins (n = 56) had marbling scores < 1.5, regardless of color, or had color scores ≤ 2.5 and marbling scores ≤ 2.0. Medium-quality loins (n = 180) had color scores of 2.0 to 3.5 and marbling scores ≥ 2.5 or loins with color scores of 3.0 through 3.5 and marbling scores ≥ 2.0. High-quality loins (n = 50) had color scores > 4.0 and marbling scores ≥ 2.0. Chops were cooked to a medium-rare degree of doneness (63°C) and evaluated for tenderness, juiciness, and pork flavor by trained pan- elists. Slice shear force (SSF) and cooking loss were also evaluated. Data were analyzed using the MIXED procedure of SAS as a 1-way ANOVA with the fixed effect of quality grade and using the REG procedure of SAS. Individually, extractable lipid content and instrumental color accounted for no more than 2% (R² ≤ 0.02) of the variation in tenderness, juiciness, or pork flavor. High-quality chops had 6.5 and 11.2% less SSF (P ≤ 0.04) than medium- and low-quality chops, respectively, and medium-quality chops had 5.6% less SSF (P < 0.04) than low-quality chops. Trained sensory panelists did not detect differences in tenderness (P = 0.09) or juiciness (P = 0.48) among quality grades, but low- and medium-quality chops were more flavorful (P < 0.01) than high-quality chops. Cooking loss tended (P = 0.06) to decrease from 16.57% to 15.32% as quality grade increased. Neither color nor marbling alone was predictive of sensory quality. But when these were used together, as they were in the proposed grading system, pork sensory flavor ratings were greater for low and medium chops than for high quality chops. Also, the proposed grading system was able to discern differences in SSF but not sensory tenderness among the quality grades.