Effect of ageing on the physicochemical properties of musculus longissimus lumborum of young bulls of five breeds

Abstract

Recent years have seen increasing interest in the conservation and use of native breeds of livestock raised in traditional farming systems. The experience of many European countries shows that promotion of raw materials and products derived from these breeds through a labelling system has a beneficial effect on the sustainable development of rural areas, contributes to preservation of the cultural heritage of the countryside, and increases the population of the breeds. As yet no beef produced in Poland has been included on the European list of traditional and regional products. For this reason we conducted a study to evaluate selected physicochemical properties of the meat of young bulls of three native breeds, Polish Red, White-Backed and Polish Black-and- White, compared with the meat of young Simmental and Polish Holstein-Friesian bulls, during a 14-day ageing of vacuum-packed meat. The following parameters were measured in m. longissimus lumborum (MLL) taken from half carcasses of 50 young bulls (10 from each breed): pH, electrical conductivity (45 min., 24 h, 2, 7 and 14 days post mortem), colour (according to CIE L*a*b*), shear force and energy. The water-holding capacity of the meat (drip loss, cooking loss and free water by the Grau-Hamm method), TBARS value (on days 2, 7 and 14) and content of haem pigments were determined as well. The physicochemical parameters of the MLL muscle obtained from the native Polish breeds of bulls (Polish Red, White-Backed and Polish Black-and-White) had intermediate values between those of Polish Holstein- Friesian (dairy type) and Simmental (dual-purpose) cattle. No qualitative deviations, such as those associated with DFD syndrome (pH 48 h in the range of 5.51-5.72), were found in any of the samples, which indicates that the raw material is well suited to the production of beef for culinary purposes. The breed of cattle was found to significantly influence the water-holding capacity parameters. The highest (P < 0.001) drip loss was reported on the 14th day post mortem for the MLL of young bulls of the Simmental (6.89%) and Polish Red breeds (6.47%). The highest cooking loss was found on the 7th day post mortem in the MLL of young bulls of the Polish Holstein-Friesian (30.66%) and Simmental breeds (30.92%). Significantly (P < 0.01) the least favourable water-holding capacity (the largest amount of free water) was shown by the muscle of young bulls of the Simmental breed on the 2nd day post mortem (75.31 mg) and the Polish Red breed on the 7th and 14th days post mortem (67.42 mg and 60.36 mg, respectively). On the 2nd and 7th days post mortem, the most tender MLL muscle was found (according to WBSF shear force) in the Polish Holstein-Friesian (76.8 N and 69.3 N) and Polish Black-and-White breeds (89.5 N and 59.1 N). On the last, 14th day of ageing, the instrumental WBSF shear force for the breeds evaluated was definitely more homogeneous and did not differ significantly (shear force in the range of 56.3-65.7 N; P > 0.05). Compared to the muscle of native breeds, that of the Polish Holstein-Friesians showed significantly lower haem pigments (on average 35 ppm less; P < 0.01) and a lower proportion of redness (a*) (P < 0.01) on the 2nd and 7th days post mortem. The MLL muscle of young bulls of the Polish Red breed had the lowest (P < 0.01) percentage content of yellowness (b*) during the whole ageing period. Significantly (P < 0.01) lower oxidative stability (higher TBARS value) was found in the meat from young bulls of the Polish Holstein-Friesian breed (on the 2nd and 7th days post mortem) and the White-Backed breed (on the 14th day) compared to all other breeds analysed. In general, the ageing time had a positive influence on the muscle quality, as the determinants of the visual and sensory attractiveness of the meat, which are also important in the meat industry, remained stable (pH), improved (colour and water-holding capacity G-H) or became more similar among the breeds (tenderness assessed on the basis of shear force, cooking loss)....