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Relationship of Fat Quality to Meat Quality Traits of Pork
The objectives of this research were to investigate the relationship of pork fat quality to meat quality, the effect of genetic differences on fat quality, how fat quality and adipocyte cellularity varies amongst anatomical sites, and finally how the seven breeds performed when compared with one another. Our hypothesis was that measures of pork fat and meat quality vary with different breeds of pigs and that a relationship exists between fat and pork quality measures. Barrows and gilts (n=352) of 6 purebred lines and one commercial crossbred line were fed commercial swine diets with dried distillers grains with solubles (DDGS) inclusion at 30% of DM. Pigs began the experiment when the pen average pig weight was 31.8 kg and were harvested at a minimal weight of 111.1 kg. At harvest, carcass characteristics were measured, adipose tissue was collected from the back, belly, and jowl, and meat samples were taken from the longissimus muscle for evaluation of fat and meat quality characteristics. Iodine values varied amongst breed within anatomical site and between anatomical sites within each breed, and, therefore, the anatomical site of adipose tissue sampling may be of importance when evaluating iodine values of pork fat. Jowl fat iodine values are significant (P < 0.0001) predictors of back and belly fat iodine values (R2 = 0.2922 and 0.3604 respectively). Backfat iodine values were not significantly correlated with ultimate pork chop muscle pH (P = 0.0680) but were significantly negatively correlated with visual color (P = 0.0002), visual marbling (P < 0.0001), and visual firmness (P = 0.0346), indicating that an increase in iodine value of pork fat is related to a decrease in pork quality as perceived by consumers. Finally, adipocyte cellularity was significantly affected by breed when compared within anatomical location across breeds (P < 0.05), but significant differences between breeds, within anatomical location, of mean cell size of adipocytes were only found for belly adipose tissues. Overall, these experimental results support our hypothesis that there is a significant relationship between pork fat and pork quality and that pork fat quality and meat quality vary by breed. Additionally, iodine values are a valuable measure of pork quality, and iodine values of jowl fat can be used to predict iodine values of back and belly fat, providing a powerful tool to meat packers for fat quality estimation.
Keywords:
iodine value, pork quality, adipocyte cellularity