The Effects of Instrumental Color and Extractible Lipid Content on Sensory Characteristics of Pork Chops Cooked to a Medium-Rare Degree-of-Doneness

The objective was to determine the effect of instrumental color and extractable lipid on sensory ratings of pork chops cooked to an internal temperature of 63 °C. Approximately 300 boneless loins (NAMP #414) were selected from a group of pigs with the same genetic background, housing, and management, cut into 2.54 cm chops and aged 14-d postmortem. Instrumental L* color scores of the chops ranged from 43.11 to 57.60 and extractable lipid ranged from 0.80% to 5.52%. Chops were assigned a quality grade using the newly proposed National Pork Board (NPB) quality grade standards. Low (n=56) quality included loins with color scores < 1.5 regardless of color or loins with color ≤ 2.5 and marbling scores ≤ 2.0. Medium (n=180) quality included color scores 2.0 through 3.5 with marbling ≥ 2.5 and color scores from 3.0-3.5 with marbling scores ≥ 2.0. High (n=50) quality included color scores of > 4.0 with marbling scores ≥ 2.0. Chops were assigned to sensory panel sessions in an incomplete block arrangement, cooked to a medium-rare degree-of-doneness (63 °C), and evaluated for tenderness, juiciness, and pork flavor by trained sensory panelists. Slice shear force (SSF) and cooking loss were also determined from each loin cooked to 63 °C. Data were analyzed using the MIXED procedure in SAS as a one-way ANOVA where quality grade was considered a fixed effect and using the REG procedure in SAS. Extractable lipid content and instrumental chop color individually accounted for a maximum of 2% (R² = 0.02) of the variation of tenderness, juiciness or pork flavor. Chops categorized as NPB high quality (SSF = 17.50 kg) were 6.5% more tender (P = 0.04) than chops categorized as medium (SSF = 18.56 kg) and 11.2% more tender (P < 0.01) than chops categorized as low quality (SSF = 19.60 kg) and medium quality chops were 5.6% more tender (P = 0.04) than low quality chops. However, trained sensory panelists did not discern sensory tenderness differences (P = 0.13) among NPB quality grades. Juiciness (P = 0.48) scores did not differ among NPB quality grades. Cook loss tended (P = 0.06) to decrease from 16.57% to 15.32% as quality grade increased. When color or marbling was used as a single trait, it was not predictive of sensory quality. However, using these traits in combination such as with the NPB quality grades may result in differences in sensory quality between pork loins.