- Title
- Muscle nanostructure and physicochemical characteristics of South African A and AB mutton classes
- Creator
- Mdikili, Zizipho
- Subject
- Meat -- Quality -- South Africa
- Date Issued
- 2019
- Date
- 2019
- Type
- Thesis
- Type
- Masters
- Type
- (MSc) (Animal Science)
- Identifier
- http://hdl.handle.net/10353/12005
- Identifier
- vital:39126
- Description
- Significant variations exist in quality of red meat due to the effect of various intrinsic and extrinsic factors. Research has been conducted in early 1990s to prove that carcasses from A and AB classes differ in meat quality due to age variation. This led to a conclusion that the two should be separated in the South African Red meat Classification System (SARCS). However, an interesting debate arose from a carcass classification workshop that A and AB meat classes have the same quality and thus must be integrated into one class in the carcass classification system. In addition, as much as it can be debated that these classes have the same quality, it is also possible that slight differences exist between the two since they are from different age groups. The current study was therefore developed and two trials were conducted to evaluate the impact of age differences on physicochemical attributes and muscle nanostructure of A and AB classes in sheep. In the first trial a total of ninety (n=90) Dorper sheep of the same sex but different age groups slaughtered at a high throughput abattoir in the Eastern Cape province were used to evaluate meat ultimate pH (pH24), colour (L* , a* , b* , H* , C* ), thawing loss (TL%), cooking loss (CL%) and tenderness (Warner Bratzler Shear Force - WBSF) of A and AB classes, whereas, on the second trial forty (n=40) Dorper sheep were used to evaluate muscle nanostructure and its relationship with tenderness. Meat samples were harvested from the Muscularis longissimuss thoracis et lumborum (LTL) for v meat quality and nanostructure measurements. The results showed significant variations (P<0.05) between the two classes for lean a* , H* and CL%. Significant differences (P<0.01) were observed in pH24, TL% and WBSF between A and AB classes. However, there were no significant differences (P>0.05) observed in meat L*, b* and C * . Ultimate pH was negatively correlated with thawing loss and some colorimetric attributes of lamb such as lightness, yellowness and hue angle. Moreover, tenderness was positively correlated with cooking and thawing losses. Significant differences were not (P>0.05) observed in sarcomere length, myofibrilar diameter and shear force between A and AB classes. Both sarcomere length and myofibrilar diameter were not correlated (P>0.05) with meat tenderness. These results suggest that A and AB classes are the same in nanostructure and that muscle nanostructure of these two classes is not related to meat tenderness. It was concluded that meat from sheep carcasses falling under the A and AB classes in the South African classification system vary greatly in physicochemical quality. Moreover, sheep carcasses from A and AB classes have the same sarcomere lengths and hence, they do not differ in meat tenderness (WBSF). However, when these classes were observed under a microscope, slight differences were noted in sarcomere lengths and myofibrilar diameters, which led to a conclusion that the two should remain as separated classes because their combination would result in the expansion of the non-uniformity of red meat tenderness. Therefore, A and AB classes should not be combined in the South African classification system. Further research is, however, recommended to evaluate the influence of other factors that were not examined in the current study.
- Format
- 107 leaves
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
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UFH Department of Livestock & Pasture Science
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| View Details Download | SOURCE1 | Mdikili_201200194_MSc Thesis Animal Science.pdf | 2 MB | Adobe Acrobat PDF | View Details Download |