The effect of blast chilling on fresh pork quality in cuts from the Longissimus dorsi, Psoas major, Semimembranosus, and Triceps brachii

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Blakely, Aaron
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Steven M. Lonergan
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Animal Science

The Department of Animal Science originally concerned itself with teaching the selection, breeding, feeding and care of livestock. Today it continues this study of the symbiotic relationship between animals and humans, with practical focuses on agribusiness, science, and animal management.

The Department of Animal Husbandry was established in 1898. The name of the department was changed to the Department of Animal Science in 1962. The Department of Poultry Science was merged into the department in 1971.

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The objective of this study was to investigate the effects of blast chilling on sensory and proteolysis in cuts from the Longissimus dorsi (LM), Psoas major (PM), Semimembranosus (SM), and the Triceps brachii (TB). The SM was further divided into a superficial (SMS) and the deep (SMD) portions. Carcasses were selected for fat-free lean (FFL) and HCW approximately 45 minutes postmortem. Carcasses were split and sides were assigned to either blast chill (BC, -32° C for 90 minutes) or conventional chill (CC, spray chilled at 2°C for 24 h) regimens. BC sides had lower (P<0.05) temperature exiting chilling treatment (CC 21.8°C approximately 2 h postmortem, BC 9.7°C BC), 4 h (CC 13.3°C, 3.8°C BC), 22 h (CC 4.2°C, BC 1.4°C), and 30 h (CC 0.4°C, BC -0.2°C) as measured at the tenth rib in the LM. This was associated with a higher (P<0.05) pH in BC sides 4 h (CC 6.09, BC 6.34), 22 h (CC 5.81, BC 5.89) and 30 h (CC 5.68, BC 5.74) postmortem. Chilling regime resulted in higher (P<0.05) 30 h postmortem pH in the SM from BC sides (CC 5.68, BC 5.74). Cuts from BC sides had increased (P<0.05) purge loss in the PM (CC 0.48%, BC 0.74%) and increased (P<0.05) cook loss in chops from the LM (CC 22.37%, BC 24.24%). Trained sensory analysis (n=4) found that the PM from BC sides was more juicy (CC 7.50, BC 8.30), less chewy (CC 2.80, BC 2.10), and more tender (CC 7.90, BC 8.60). Chops from the LM of BC sides had greater Warner-Bratzler shear force (CC 2.00, BC 2.30). Color was affected in the SM with BC sides showing darker color score (CC 3.00, BC 3.20) and reduced Hunter a value (CC 16.35, BC 16.02). Chilling treatment did not have an effect on postmortem proteolysis across muscle groups. This study confirmed that chilling has different impacts across muscle groups which may be caused by location, rate of chilling, and fiber type.

Thu Jan 01 00:00:00 UTC 2015