Introduction

Hot carcass weights (HCW) of pigs are expected to further increase in coming years, but the effect of increased HCW on ham and belly processing and quality is unknown. Therefore, the objective of this study was to determine the effects of increasing carcass size on ham and belly processing and quality characteristics.

Objectives

  1. Determine the relationship between hot carcass weight and belly dimensions and composition.
  2. Determine the relationship between hot carcass weight and ham component weights.
  3. Establish the relationship between hot carcass weight and ham processing characteristics and cured ham quality
  4. Assess the feasibility of fresh cut creation from the semimembranosus (SM) of heavy weight pigs.

Materials & Methods

Carcasses (n=85) from pigs slaughtered under experimental conditions were divided into three HCW categories: Average (99 to 109 kg; n=30, Heavy (116 to 126 kg; n=30), and Very Heavy (134 to 144 kg; n=25). Right side whole hams were fabricated into an inside, outside, knuckle, inner shank, and lite butt. Inside, outside, and knuckles from an individual ham were placed together in nylon netting and weighed. The hams were multi-needle injected with a Schroder Injector Marinator model N50 (Wolf-Tec Inc., Kingston, NY) targeting 120% of each green weight. The cure solution targeted 1.52% salt, 0.33% sodium tripolyphosphate, 0.014% sodium nitrite, and 0.05% sodium erythorbate in the cooked ham. Three-piece hams were prepared for each carcass. Hams were cooked for 10 hours to an internal temperature of 65.6 °C and allowed to cool for 24 hours. A 2.54 cm ham steak was cut and instrumental L*, a*, and b* color measures were taken on four visual quadrants of the ham steak and then averaged. Procedures outlined by Kyle et al. (2014) were used in the determination of fresh belly characteristics. A sample for fatty acid profile analyses, which contained all three layers of adipose tissue and was free of lean tissue, was removed from the dorsal edge of the anterior end of each belly. Adipose tissue samples were used to prepare fatty acid methyl esters (FAME) using the procedure outlined by (Lepage and Roy 1986). Bellies were injected with a standard cure solution formulated with water, sugar, salt, sodium nitrite, sodium phosphates, and sodium erythorbate. A pump uptake of 13% was targeted for the final product. Data were analyzed as a one-way ANOVA using the MIXED procedure in SAS with the main effect of weight category and blocked by genotype and sex. Means were considered significantly different at P ≤ 0.05.

Results

Ham results:

Whole and trimmed hams, and ham subprimal weights were heavier (P < 0.01) on an absolute basis in heavier weight categories with the exception of the lite butt that was not different (P = 0.15) between weight categories. In general, ham cuts from Very Heavy carcasses were about 20-25% heavier than those from Average carcasses while Heavy carcass cuts were 10-15% heavier than Average carcasses. Bone and ham trim weight was also increased (P < 0.01) in heavier weight categories. However, on a percentage of chilled side weight basis, weight of whole and trimmed ham, ham subprimals, ham bones and ham trim were slightly reduced (P ≤ 0.05) in Very Heavy carcasses compared with Average carcasses. Given the increased weight of ham cuts, it was expected that fresh three piece ham weight, pump weight, stuffed weight, and cooked weight all increased (P ≤ 0.05) in Very Heavy and Heavy compared with Average. Cooked yield percentage was not different (P = 0.11) between weight categories. There were no differences between weight categories in cured ham instrumental lightness (P = 0.64). Instrumental redness and yellowness decreased (P < 0.01) approximately 0.84 and 0.67 units respectively in cured hams from heavier carcasses.

Belly results:

No interactions between carcass weight category and sex were observed for any belly quality trait (P ≥ 0.18). Belly thickness, length, and width increased (P < 0.01) with increasing carcass weight. Pump uptake was decreased (P = 0.03) for bellies from Very Heavy carcasses compared with bellies from Average and Heavy carcasses. Despite greater pump uptake by bellies from Average carcasses, bellies from Very Heavy carcasses had greater cooked weights and cook yields (P ≤ 0.01) than bellies from Average carcasses. Overall, belly fat from Very Heavy carcasses was more saturated than fat from Average and Heavy carcasses as indicated by decreased PUFA:SFA ratios (P ≤ 0.01). The IV of belly fat from Very Heavy carcasses was reduced (P ≤ 0.01) compared with Average weight carcasses, with IV of Heavy carcasses intermediate but not different from either extreme (P ≥ 0.07).