Journal of Animal Science, Vol 76, Issue 7 1869-1874, Copyright © 1998 by American Society of Animal Science

JOURNAL ARTICLE

Effect of freezing on calpastatin activity and tenderness of callipyge lamb

S. K. Duckett, T. A. Klein, R. K. Leckie, J. H. Thorngate, J. R. Busboom and G. D. Snowder
University of Idaho, Moscow 83844-2330, USA.

The longissimus muscles (LM) from 12 lambs (eight = callipyge [CLPG] and four = normal [NML]; 48 kg) were used to 1) assess the effect of freezing with or without prior immersion in liquid nitrogen on calpastatin activity (CA) and on Warner-Bratzler shear force (WBS) in CLPG, 2) determine the freezing time required to reduce CA and WBS of CLPG to that of NML, and 3) compare sensory panel ratings for CLPG that is aged fresh to CLPG that is aged after freezing. At 24 h postmortem, chops (.64 and 2.54 cm) were removed from each CLPG LM and randomly assigned within side to one of six freezing times (0, 2, 4, 8, 20, and 42 d). Left-side chops were vacuum-packaged and frozen at -20 degrees C for the assigned time (FROZEN) and right-side chops were treated similarly, except that they were frozen in liquid nitrogen first (FLASH). After freezing for the assigned time, the .64-cm chop was immediately assayed for CA, and 2.54-cm chop was thawed, aged at 2 degrees C for 14 d, and refrozen for subsequent WBS measurement. Chops (.64 and 2.54 cm) were also removed from the longissimus of NML lamb carcasses. The d-0 CLPG and NML chops (2.54 cm) were vacuum-packaged, aged at 2 degrees C for 14 d, and frozen for subsequent WBS measurement. Calpastatin activity did not differ between freezing treatments (P = .99) or with the freezing treatment x freezing time interaction (P = .80). Freezing reduced (P = .01) CA in CLPG by 44% from d 0 to d 42. Calpastatin activity for CLPG was similar (P > .05) to that of NML lamb after freezing for 8, 20, or 42 d. Freezing at -20 degrees C for 42 d and then aging for 14 d reduced (P = .01) WBS in CLPG by 44% from d-0 values. Shear force values for CLPG-FROZEN were similar (P > .05) to NML after 8, 20, or 42 d of freezing. Sensory panel tenderness scores were higher (P < .05) for CLPG aged after freezing 42 d than for those aged fresh. Juiciness and flavor ratings did not differ (P > .05) between CLPG aged fresh or after freezing. Freezing for at least 8 d before aging seems to be a viable method for increasing the tenderness of CLPG LM without reducing juiciness or flavor ratings.

This article has been cited by other articles:

				S. D. Baker, J. I. Szasz, T. A. Klein, P. S. Kuber, C. W. Hunt, J. B. Glaze Jr., D. Falk, R. Richard, J. C. Miller, R. A. Battaglia, et al. Residual feed intake of purebred Angus steers: Effects on meat quality and palatability J Anim Sci, April 1, 2006; 84(4): 938 - 945. [Abstract] [Full Text] [PDF]

				B. A. Freking and K. A. Leymaster Evaluation of the ovine callipyge locus: IV. Genotypic effects on reproductive traits J Anim Sci, February 1, 2006; 84(2): 311 - 316. [Abstract] [Full Text] [PDF]

				P. S. Kuber, J. R. Busboom, E. Huff-Lonergan, S. K. Duckett, P. S. Mir, Z. Mir, R. J. McCormick, M. V. Dodson, C. T. Gaskins, J. D. Cronrath, et al. Effects of biological type and dietary fat treatment on factors associated with tenderness: I. Measurements on beef longissimus muscle J Anim Sci, March 1, 2004; 82(3): 770 - 778. [Abstract] [Full Text] [PDF]