Enhancing pork loin quality attributes through genotype, chilling method and ageing time.

The experiment was conducted to examine opportunities for enhancing pork quality through the use of post-mortem ageing when combined with different chilling regimes. Large White (LW, n=24) and Duroc×Large White (Duroc, n=24) barrows were slaughtered and alternate carcass sides were either conventionally or blast-chilled. The longissimus thoracis et lumborum muscle was dissected from the carcass sides (24h post-mortem) and trimmed of cover fat. Three sections (15cm length) were vacuum packaged and assigned to 2, 7 or 14days of ageing (2°C) randomized within muscle location. Blast-chilled meat had lower purge (P=0.009) and drip (P=0.0009) losses and higher hue (P=0.02) than conventionally chilled meat. However chilling by conventional or blast-chilling methods had no effect on sensory characteristics (P>0.1). When breeds were compared, meat from Duroc barrows had lower moisture (P<0.0001) and higher intramuscular fat content (P<0.0001), L∗ (P=0.0003) and hue (P=0.007) values than LW. Overall tenderness (P=0.005), juiciness (P=0.0007) and palatability (P<0.0001), as well as flavour intensity (P<0.0001) and desirability (P<0.0001) values were higher and undesirable flavours were lower (P<0.0001) for meat from Duroc pigs, when compared with LW. Ageing increased purge loss (P<0.0001), L∗ (P<0.0001), hue (P<0.0001), chroma (P<0.0001) and content of protein (P=0.002), with corresponding decreases (P<0.0001) in drip loss and moisture content. Instrumental (P<0.0001) and sensory (initial, P<0.0001 and overall, P<0.0001) tenderness increased from day 2 to 14. Therefore independent of chilling method, ageing improved quality of pork loins. Moreover ageing had greater effect on tenderness, while breed had greater effect on flavour which may be related to differences in intramuscular fat content.