Effects of rapid chilling of carcasses and time of deboning on weight loss and technological quality of pork semimembranosus muscle

The effect of rapid air chilling of carcasses in the first 3 h of chilling at −31 °C (then at 2–4 °C, till 24 h post-mortem) and the possibility of earlier deboning (8 h post-mortem) after rapid air chilling, compared to conventional air chilling (at 2–4 °C, till 24 h post-mortem) on weight loss and technological quality (pH value, tenderness, drip loss, cooking loss and colour - L∗a∗b∗ values) of pork M. semimembranosus was investigated. Under the rapid chilling conditions, weight loss was 0.8% at 8 h post-mortem and increased to 1.4% at 24 h post-mortem when weight loss was 2.0% under conventional chilling. Carcasses that were rapid chilled had significantly lower (P < 0.001) internal temperature in the deep leg at 4 (25.7 °C), 6 (13.0 °C), 8 (6.2 °C) and 24 h (3.8 °C) post-mortem compared to conventional chill treatment (32.7, 24.2, 19.1 and 5.1 °C, respectively). Rapid chilling reduced significantly (P < 0.05) the rate of pH value decline at 8 h (6.02) post-mortem in M. semimembranosus compared to conventional chill treatment (5.88). Compared to conventional chilling, in M. semimembranosus deboned in different time post-mortem, rapid chilling had a positive significant effect on drip loss (P < 0.05, muscles deboned 8 h post-mortem), cooking loss (P < 0.001) and incidence of pale colour (L∗ value). Rapid chilling i.e. rapid chilling and earlier deboning had neither positive nor negative significant effects (P > 0.05) on other investigated technological quality parameters of M. semimembranosus (tenderness, a∗ value and b∗ value) compared to conventional chilling.