Backfat quality of South African pigs: a meat processing perspective

English: Fat quality of backfat from 2107 baconer pig carcasses, sampled at a major South African pig abattoir, were evaluated to obtain an overview of the backfat quality of South African pigs. Extracted fat was used to determine iodine and refraction index values as well as fatty acid profiles of these samples. Significant differences (P < 0.001) in terms of backfat quality were observed between the different classification groups. Improved fat quality was associated with increased backfat thickness and decreased lean meat content, caused by an increase in the total saturated and mono-unsaturated fatty acid contents and a decrease in the total unsaturated and polyunsaturated fatty acid contents as well as double bond and peroxidizability indexes. The Pand 0 classification groups (with backfat thickness measurements less than 17 mm) could not conform to the international standards proposed for backfat of good technological quality. The C, U and S groups (with backfat measurements of 23 to more than 32 mm) possessed backfat with good technological qualities. The R group had borderline fat quality. A high linoleic acid content, leading to a high dienoic fatty acid content, in turn influencing the total polyunsaturated fatty acid content, is the main cause of soft fat with poor technological quality. Correlation analyses and statistical techniques were employed to acquire equations to describe the relationships between iodine value and international fat quality parameters. Sy substituting the international fat quality criteria into the equations it became clear that pigs had to have an iodine value of 60 to comply with most of these criteria, which was unrealistic. The French system predicts fat quality by utilizing backfat thickness and lean meat content. It was proposed, through modification of this system, that South African pig carcasses with a backfat thickness of more than 17.8 mm and a lean meat content of less than 66.8% would have the potential to deliver backfat with good technological properties in terms of iodine value. If these new criteria were applied, the Pand 0 classification groups did not possess good quality fat. The probability of selecting a pig with an iodine value < 70 (indicating good fat quality) from the R group would then be > 55%. In the S group, > 77% of the pigs conformed to these new criteria. Pigs with poor fat quality may escape detection, but the risk of selecting a pig with poor fat quality from these groups is reduced. These values are applicable to either method of carcass evaluation (HGP or Intrascape) employed in South Africa. The method developed in this study therefore provides the South African meat industry with a cost-effective method to improve the probability of selecting pig carcasses with good fat quality. Soars had much better omega-6 to omega-3 ratios, lower slaughter weights and extractable fat contents compared to barrows and gilts combined. A significant seasonal trend in the backfat iodine values was observed. Setter fat quality was detected in mid-summer than in mid-winter. This seasonal effect was so large that improvement of winter backfat quality would cause the overall fat quality to improve. This could possibly be achieved by including feed ingredients rich in saturated fatty acids in the winter rations of pigs because fatty acid composition of the feed is reflected in the backfat of pigs. Large variation in fat quality existed between pigs within the same group originating from different suppliers. Within the P classification group, pigs with both highly acceptable and highly unacceptable iodine values were observed. Feeding, breeding, environmental and/or management differences between the suppliers could account for this. Fat quality influences the consumer, supplier as well as the meat technologist.