EFFECTS OF ULTRARAPID CHILLING AND AGING ON LENGTH OF SARCOMERES, AND TENDERNESS OF PORK

In this study, the m. longissimus dorsi and the m. semimembranosus of pigs with normal and accelerated glycolysis (pale, soft and exudative, PSE) were used to evaluate the effect of ultrarapid chilling methods (with short-term freezing of the muscle surface) and ageing up to 72 h post-mortem on length of sarcomeres, Warner Bratzler shear force and firmness. The short-term freezing after ultrarapid chilling of musculature with normal glycolysis led to cold shortening with contraction of the sarcomeres by 33.5% (m. longissimus dorsi) and 38.3% (m. semimembranosus). At the same time, a massive increase in shear force and firmness was observed. After ageing up to 48 h post-mortem the sarcomeres increased in length, whereby, in comparison with the measurements before the beginning of the chilling, 88 and 84% of the original length was attained, respectively. In addition, ageing led to a significant improvement of tenderness. After ageing for more than 72 h the shear force and the firmness of meat specimens chilled under normal and ultrarapid conditions became more similar. The lengths of the sarcomeres and the shear force of musculature with accelerated glycolysis were not affected by the chilling procedure.