Physicochemical properties and lipid oxidation parameters of selected muscles of Puławska breed fatteners during 14-day ageing in vacuum packaging

Abstract

The aim of this study was to determine the influence of the ageing period on the physicochemical properties and lipid quality indicators of pig meat from the native Puławska breed. The experiment was carried out on samples of skeletal muscles (adjacent part of M. longissimus thoracis and M. longissimus lumborum – LTL, and M. semimembranosus – SM) collected 24 h after slaughter from 30 carcasses of Puławska castrated male pigs. Following collection, samples were packaged in vacuum and stored for up to 14 day at a temperature of 4°C (± 1°C). The meat pH, colour (CIE L*a*b*), water-holding capacity (drip loss – DL and cooking loss – CL), shear force (WBSF), energy force, and lipid quality indicators (free fatty acids – FFA, peroxide value – PV, and thiobarbituric acid reactive substances expressed as malondialdehyde MDA – TBARS) were measured. A typical course of postmortem glycogenolysis for normal meat was demonstrated. The pH of muscles 45 min after slaughter was 6.55 for LTL and 6.61 for SM, and after 24 h it was 5.62 and 5.66, respectively. As ageing progressed, the DL of the meat increased significantly (on average 2.4 times), while CL were not significantly changed, being 24.83% on average. WBSF decreased by approximately 40% for LTL, and by 18% for SM. The WBSF value adopted for tender meat (< 45 N/cm2) was obtained on day 14 of the experiment. The progressive oxidative changes in intramuscular fat were not advanced, averaging from 2.06% for FFA, 0.62 meq O2/kg for PV and 0.24 MDA/kg for TBARS on day 4 post mortem to 3.71%, 1.82 meq O2/kg and 0.48 mg MDA/kg, respectively, on day 14 post mortem. Ageing of pork under vacuum positively influenced the quality characteristics of the meat, with relatively minor oxidative changes. An extended ageing period of up to 14 days can measurably improve the quality characteristics of fresh meat obtained from Puławska breed pigs, especially for culinary purposes.