Date of Award
Master of Science
Food Science and Technology
M. James Riemann
C.C. Melton, E.R. Lidvall
Forty-eight barrow and forty-eight gilt carcasses (n=96). ranging from 66 to 102 kg hot carcass weight and 1.52 to 4.32 cm average backfat thickness with moderately thick being the minimum acceptable muscling score, were selected from a local Knoxville, Tennessee packing plant, identically fabricated and evaluated for various quality, value, histological and palatability characteristics.
Mean longissimus areas measured at the second, fifth and tenth ribs were all significantly greater (P<.01) for the trimmer carcasses (1.52 to 2.29 cm) and gilts had significantly larger (P<.01) longissimus areas at the second and tenth ribs than barrows.
Mean marbling and lean firmness scores were nonsignificant with respect to average backfat thickness and hot carcass weight, but marbling scores were higher (P<.01) for barrows and displayed a significant interaction (P<.01) between hot carcass weight x sex. Lean firmness scores had significant interactions (P<.05) for backfat x hot carcass weight and backfat x sex.
Visual lean color scores were highly significant with respect to Hunter L color-difference values (P<.0001) and Hunter b values (P<.01) but nonsignificant with respect to Hunter a^ values.
Percents ham, loin, picnic shoulder and belly as well as per cent of the four lean cuts, percent primal cuts and percent ham-loin were all nonsignificant with respect to hot carcass weight and sex condition with the exception of percent lean cuts where gilts had significantly higher (P<.05) percentages than barrows. Heavier carcasses (P<.01) and trimmer carcasses (P<.001) were significantly greater with respect to Boston butt. Percentage lean in various bacon slices decreased significantly (P<.05) only as average backfat thickness increased.
Mean percentages of water and fat (on both a wet and dry basis) were not significantly different (P<.01) with respect to hot carcass weight or sex condition. Fatter carcasses had significantly lower (P<.01) water percentages and trimmer carcasses had significantly lower (P<.01) fat percentages.
Percents volatile, nonvolatile and total cooking losses were not significantly different (P<.01) with respect to hot carcass weight or sex condition, but nonvolatile cooking losses were significantly lower (P<.001) for trimmer carcasses (1.52 to 2.29 cm).
Mean fiber diameters were significantly different (P<.05) only with respect to the backfat x sex interaction.
Mean scores for flavor, juiciness, tenderness and overall acceptability of pork loin chops were nonsignificant (P<.01) with respect to hot carcass weight and sex condition but were significantly lower (P<001) for loin chops from trimmer carcasses (1.52 to 2.29 cm) across all hot carcass weight groups.
Although small, R-squared values for Warner-Bratzler Shear, muscle fiber diameter, fat percentage (wet basis) and volatile, non volatile and total cooking losses were highly significant (P<.0001) with respect to all palatability traits.
Mean weights for all wholesale cuts increased in a linear fashion with increasing hot carcass weights with no differences attributed to sex condition (P<.01). Loin and belly weights were not significantly different (P<.01) with respect to average backfat thickness, while ham, Boston butt and picnic shoulder weights were significantly lower (P<.01) for fatter (3.56 to 4.32 cm) carcasses.
Mean cooking losses for hams decreased with increased carcass fatness (P<.001) but increased with increasing hot carcass weights (P<.001). Mean cooking losses for bellies significantly decreased (P<.001) with increased carcass fatness but were not significantly different (P<.01) with respect to hot carcass weight. Hams were nonsignificant and bellies were significant (P<.05) with respect to cooking losses and sex condition with gilts having greater belly cooking losses than barrows.
It was concluded that carcass quality and cutability is at least maintained or possibly improved with respect to increased slaughter weights as long as backfat deposition is adequately controlled with trimmer carcasses generally having greater total values. This would indicate that it would be beneficial for packers to pay producers premiums for heavier hogs that yield carcasses of superior merit.
Franzreb, Mark Stephen, "A comparison of quality, value, histological and palatability characteristics of pork carcasses of varying weights. " Master's Thesis, University of Tennessee, 1982.