COMPARISON OF DEHIDING VERSUS SCALDING AND SINGING - EFFECT ON TEMPERATURE, PH AND MEAT QUALITY IN PIGS

The aim of this work was to investigate the temperature and pH changes taking place at the slaughter line and during the chilling process, a nd the subsequent effect on meat and eating quality in pig carcasses t hat had either been scalded and singed or dehided. Both processes were followed by fast chilling. 219 halothane-gene-free Duroc Sire and Lan drace-Yorkshire pigs were delivered from three farms and slaughtered-o ver 2 weeks at either a dehiding or a scalding singeing slaughterhouse . Temperature and pH were measured at intervals from exsanguination un til 6 hours post mortem. Ultimate pH, internal reflection, drip loss a nd colour (Minolta) were measured the day after slaughter. Colour (JPC S scale) was evaluated after freezing and thawing, and eating quality was estimated on unaged and aged (4 days at 4 degrees C) m. longissimu s dorsi (LD), using a trained taste panel. At the slaughter line the d ehided carcasses had an almost constant and lower temperature compared to the scalded and singed carcasses. During chilling there is a shift in temperature curves between treatments, where the scalded carcasses had the lowest muscle temperature in LD and m. biceps femoris (BF) fr om 2 hr post mortem and throughout the measuring period. In spite of t he shift in temperature, the dehided carcasses had the highest pH in L D and BF from exsanguination and throughout the measuring period. The rate of pH fall in LD and BF was slowest in the dehided carcasses from exsanguination until 3 and 2 hr respectively, post mortem. Dehided ca rcasses showed a 40% lower drip loss, a darker meat colour and a lower internal reflection in LD and BF compared to scalded and singed carca sses, thus indicating less protein denaturation in dehided carcasses. Scalding and singeing, however, lead to increased tenderness compared to dehiding, and this difference persisted even after ageing for 4 day s at 4 degrees C. The differences in toughness may be caused by increa sed proteolysis by released lysosomal cathepsins. (C) 1998 Elsevier Sc ience Ltd. All rights reserved