This research was conducted to investigate the connective tissue contribution to toughness of cow beef and to find means to decrease it. Intra muscular connective tissue (IMCT) content of meat from cows (~6 years) and heifers (~16 months) varied significantly among muscles (P<0.0001) and maturity groups (P<0.05). Amount of total collagen in IMCT was a constant (37.3-46.3 %) among muscles and between maturity groups. Shear force of <i>biceps femoris</i>, <i>semimembranosus</i> and <i>longissimus</i> muscles had increased significantly with animal maturity (P<0.0001). Shear stress of <i>gluteus medius</i> was similar between maturity groups. Collagen solubility decreased with animal maturity, except for <i>biceps femoris</i>. <p>
The impact of the temperature of aqueous heating (55 to 95 ºC) and time on thermolabile proteins, amorphous proteins, Ehrlich chromogen, pyridinoline, thickness change, shrinkage, weight gain, shear force, amide bands and morphology of epimysium was studied. Collagen contributed to 90% (w/w) of epimysial proteins. At 55 ºC, epimysial properties were changed only after exposure to long heating times. Shear stress values of raw cow (39.6 N/mm2) and heifer (30.8 N/mm2) epimysium decreased significantly to 11.6 and 2.1 N/mm2, respectively, at 70 ºC. Amount of epimysial amorphous collagen (14-16% w/w) detected after heating at 70 ºC and above was not related to shear stress decrease. Before and after heating, cow epimysium contained more pyridinoline cross-links than heifer epimysium.<p>
The effects of strong and weak acids and alkalis on epimysial properties were studied following heating at 55 and 70 ºC for 15 min. As the concentration of HCl (0.1-0.5 M) and pre-equilibration time were increased at 70 ºC, shear stress decreased to <2 N/mm2. Increasing concentration of CH3COOH (0.1-0.5 M) and pre-equilibration times had decreased shear stress to ~5 N/mm2. At 55 ºC, HCl was not superior to CH3COOH in its ability to decrease epimysial shear stress. Increasing concentration of NaOH (0.01-0.05 M) and high temperature decreased shear stress to ~3 N/mm2. Lack of a shear stress decrease at 55 ºC and increased thermal denaturation temperature (66 ºC compared to 63 ºC in water), indicated that NH4OH had an epimysial stabilization effect, which was not eliminated at 55 ºC.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-03252009-154013 |
| Date | 26 March 2009 |
| Creators | Perera, Anula |
| Contributors | Shand, Phyllis J., Pietrasik, Zeb, Olkowski, Andrew A., Nickerson, Michael, Miller, R., Vujanovic, Vladimir |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-03252009-154013/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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