Tel.+49 30 838 62550 Fax.+49 30 838 46029
Summary To describe the effects of sex, genotype and day of slaughter on post-mortem glycogenolysis in pork of different crossbred pigs, the pH-value and the lactate and glycogen levels were determined in M. semimembranosus and M. longissimus dorsi 45 minutes and 24 hours post-mortem. Muscle meat of 116 male and 106 female pigs of the populations DL x DL, DL x DE, DL / DE x Pi, DL x Du, DL x Pi and Ha x Pi was examined. The slaughter of the animals and the sampling of tissues were carried out at the same slaughterhouse on different days over a period of 16 months. The pH was measured using a needle-tip electrode. An enzymatic assay and a direct iodometric assay were used to determine the lactate and glycogen levels, respectively. In these investigations, no significant effect of the pigs' sex on the pH, lactate or glycogen levels in M. semimembranosus or M. longissimus was found in either early or late post-mortem measurements, with male animals tending to degrade glycogen at a faster rate. For the total investigated material, the pH was within normal ranges (6.41 and 6.56 for M. semimembranosus and longissimus dorsi, respectively) in most early post- mortem measurements. The lactate estimation showed results between 0.466 and 0.893 g per 100 g M. semimembranosus; the glycogen readings for the entire material ranged between 0.0 and 4.688 mg / g M. semimembranosus. In 94.6% of the samples, the glycogen level was <_ 2.6 mg / g muscle meat. In samples tested early after death, the genotype was found to have no effect on the pH. However, there were significant genotype-dependent differences in the lactate levels between the populations tested. The lactate levels ranged between 0.637 g / 100 g M. semi- membranosus for DL x DL and 0.717 g / 100 g for Ha x Pi. Glycogen levels in M. semimembranosus were found to be between 0.614 mg / g in DL / DE x Pi and 0.899 mg / g in Ha x Pi animals. There were indications of genotype differences, but these were not significant. Significant genotype-dependent differences were detected.