Influence of myofibrillar protein characteristics on tenderness of Bos indicus-sired steers /
The objective of this research was to measure the myofibrillar protein characteristics in steers produced from different Bos indicus sires to determine the influence on tenderness. Steers (n = 89) from 10 Bos indicus sires and born from Hereford cows (n = 15) or Angus cows (n = 74) were slaughtered...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1997.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=736823861&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The objective of this research was to measure the myofibrillar protein characteristics in steers produced from different Bos indicus sires to determine the influence on tenderness. Steers (n = 89) from 10 Bos indicus sires and born from Hereford cows (n = 15) or Angus cows (n = 74) were slaughtered on one of three days. USDA quality and yield grade characteristics were obtained. Warner-Bratzler shear force (kg) after 0, 7, 14, 21, 28, and 35 d of aging was obtained. Lipid (%), moisture (%), 24 h calpastatin and sarcomere length (Jim) also were determined. Electron micrographs and SDS-PAGE analyses were determined on selected samples that displayed notable tenderness differences. Offspring from Angus dams had higher (P < .05) marbling scores and kidney, pelvic, and heart (KPH) fat. Sire affected (P < .05) hot carcass weight, adjusted fat thickness, ribeye area, KPH fat, USDA yield grade, marbling score, and USDA quality grade; however, overall maturity was not affected (P > .05). Progeny from sire 10 had the lowest calpastatin activity. Sarcomere length was not influenced by sire (P > .05); sarcomere length ranged from 1.70 to 1.84 gm. Aging data revealed that the highest shear force values were observed at d 1, and there was a significant reduction (P < .05) in shear force values at d 7. However, shear force values did not change after 7 d postmortem. Two animals that displayed notable tenderness differences were chosen to further investigate muscle ultrastructure changes due to aging. Animal A, which showed an improvement in shear force values with aging, revealed that transverse and longitudinal splitting became more evident as aging time increased. Animal B, which was tender at 0 d postmortem but did not show a reduction in shear force values as aging time increased, analayses showed that animal A had a more intense band for the 30,000 Da subunit than animal B at d 0, 14, and 28. These data showed that sire influenced the carcass traits and myofibrillar protein characteristics of offspring. Also, the degradation of myofibrillar proteins was related to tenderness differences for the samples analyzed. |
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| Item Description: | Vita. "Major Subject: Animal science". |
| Physical Description: | ix, 72 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 46-53. |