Relationships among early postmortem loin quality and aged loin and pork chop quality characteristics between barrows and gilts

Abstract

Rapid assessment of pork quality by packers necessitates using early postmortem (∼1 d) traits as an indication of aged pork quality (∼14 d). Efforts have been made to develop a grading system based on color and marbling of the ventral side of boneless loins. In order for this system to be successful, there must be a correlation between early postmortem quality traits observed by packers and the same traits observed by consumers after aging. However, the strength and direction of those correlations are unclear. It is also unknown if the correlations between early and aged postmortem quality differ between barrows (B) and gilts (G). Therefore, the objectives were to determine correlations between early postmortem loin quality characteristics and aged loin quality characteristics, and determine if those correlations differed between barrows and gilts. Early postmortem (∼1 d) quality traits included: instrumental and subjective color, marbling and firmness, and loin pH on the ventral surface of the loin. Loins were aged until 14 d postmortem in vacuum packages. Aged quality traits included traits evaluated early as well as shear force and cook loss. Correlations were compared between barrows and gilts using a Fisher's z test. Overall, early subjective firmness scores of barrows were greater (P < 0.001) than those of gilts. No other early quality traits differed between sexes. Early pH was correlated with aged pH (r = 0.80 B; 0.75 G), ventral lightness (r = –0.57 B; –0.54 G), ventral yellowness (r = –0.55 B; –0.55 G), subjective ventral color (r = 0.55, B; 0.41 G), and subjective chop color (r = 0.42 B; 0.44 G). Correlations of early pH and aged quality did not differ between sexes. Early lightness was correlated with aged ventral pH (r = –0.56) and subjective color (r = –0.39) in barrows but not gilts (P ≤ 0.04). Early lightness was correlated with aged lightness (r = 0.60 B; 0.51 G) and yellowness (r = 0.49 B; 0.55 G), but was not correlated with to any aged chop quality traits. Early marbling was correlated with ventral color (r = 0.42) in barrows and ventral marbling (r = 0.67 B; 0.66 G) and chop marbling (r = 0.57 B; 0.59 G) in barrows and gilts. In summary, early pH and lightness were correlated with aged quality characteristics and correlations rarely differed between barrows and gilts. Sex does not need to be accounted for when relating early and aged quality characteristics.

Correlation comparisons among early postmortem loin quality and aged loin and pork chop quality characteristics between finishing pigs from either Duroc or Pietrain sires

“…Lowell et al (2017) reported that early postmortem (1 d) loin pH was strongly correlated with aged pH (r = 0.80 barrows; 0.75 gilts). Early pH was moderately correlated with aged ventral L* (r = −0.57 barrows; −0.54 gilts), aged subjective ventral color (r = 0.55 barrows; 0.41 gilts), and aged subjective chop color (r = 0.42 barrows; 0.44 gilts) (Lowell et al, 2017). Early ventral L* was moderately correlated with aged ventral L* (r = 0.60 barrows; 0.51 gilts) (Lowell et al, 2017).…”

“…Comparisons of independent correlation coefficients between Pietrain-sired pigs and Duroc-sired pigs were achieved following the example of Kenny (1987) and Lowell et al (2017) using a z-test for comparing 2 independent correlations. First, data were grouped into 2 individual data sets by sire line (Pietrain-sired pigs and Duroc-sired pigs).…”

“…Huff- Lonergan et al (2002) reported that loin pH at 24 h postmortem was weakly correlated to aged L* (r = − 0.32), aged ventral firmness (r = 0.20), cook loss (r = −0.20), tenderness (r = 0.27), juiciness (r = 0.17), and flavor (r = 0.25). It has also been established that there are correlations between early postmortem loin quality characteristics and aged loin and chop quality characteristics, and these correlations largely do not differ between barrows and gilts (Lowell et al, 2017). Lowell et al (2017) reported that early postmortem (1 d) loin pH was strongly correlated with aged pH (r = 0.80 barrows; 0.75 gilts).…”

“…It has also been established that there are correlations between early postmortem loin quality characteristics and aged loin and chop quality characteristics, and these correlations largely do not differ between barrows and gilts (Lowell et al, 2017). Lowell et al (2017) reported that early postmortem (1 d) loin pH was strongly correlated with aged pH (r = 0.80 barrows; 0.75 gilts). Early pH was moderately correlated with aged ventral L* (r = −0.57 barrows; −0.54 gilts), aged subjective ventral color (r = 0.55 barrows; 0.41 gilts), and aged subjective chop color (r = 0.42 barrows; 0.44 gilts) (Lowell et al, 2017).…”

“…Loins were exposed to oxygen (fat side against the table and epimysium removed with the lean side up) for at least 20 min. Then quality measurements for instrumental color, visual color, visual marbling, subjective firmness, and aged ultimate pH were conducted on the ventral surface of the exposed lean using the same procedures as the 1 d postmortem quality evaluations using the manner described by Lowell et al (2017). Ambient room temperature during evaluations was approximately 4 °C.…”