Forty eight gilts were fed one of four dietary treatments containing 0, 0.25, 0.5 and 1% CLA, until their weight reached 95 kg and were then slaughtered. There were a lack of significant differences in pig performance and growth traits (weight increase, ADG, ADFI, FCR), and slaughter characteristics (SLW, hot carcass weight, cold carcass weight, dressing percentage, BFT, MT and LMC). There were no change in M.longissimus thoracis area, drip loss, WHC, pH45 and pH 24, while L*-and b* values decreased with increased dietary CLA. Colour a*-values and SI also did not differ between the four treatments. For the BF, IVs decreased with increased dietary CLA, while RI, colour a* and SI values remained unchanged, and colour b* values and hardness increased.
Conjugated linoleic acid supplementation resulted in improved technological quality of subcutaneous fat, demonstrated by reduced IVs, unchanged RI and extractable fat content, and increased FFDM. With increase in CLA supplementation, C18:0, cis 9, trans 11, trans 10, cis 12, UFA, SFA, n-6/n-3, PUFA/SFA, dienoic acid, C16:0+C18:0, C16:0/C18:2, C16:1+C18:1c9/C16:0+C18:0 and C18:0/C:18:2 increased, C18:1c9/C18:0, MUFA, PUFA, MUFA/SFA, n-3, PI, trienoic, tetraenoic, penta + hexaenoic acid and DBI decreased, while n-6 remained unchanged. There was a tendency for sampling positions on the dorsal (neck, BF, chuck) and lateral (rib area) sides of the carcass to have higher CLA content. Differential scanning calorimetry of subcutaneous fat showed the presence of βâ-crystals in fat from 0.25 and 0.5% CLA-fed pigs and β-crystals in fat from 1% CLA-fed pigs.
For IMF samples, increased dietary CLA led to no change in IV, C18:0, C18:1t9, C18:1c7, C18:3n-3, PUFA/SFA, tetraenoic acid, C16:0/C18:2 and C18:0/C18:2 contents, while C16:1c9, cis-9, trans-11, trans-10, cis-12, C22:5, C22:6, SFA, AI, PI, n-3, n-6/n-3, PUFA, n-6, dienoic acid, trienoic acid, penta- + hexaenoic acid, C16:0+C18:0 and C16:1+C18:1c9/C16:0+C18:0 contents increased and C18:1c9, C20:1c11, C18:1c9/C18:0, C18:2, C18:3n-6, C20:3n-3, C20:2, C20:4, C20:5, MUFA, UFA, MUFA/SFA and AI contents decreased. Most CLA was deposited on the lateral sides of the carcass, namely the M.triceps brachi. M.supra spinatus showed an atypical FA composition.
Descriptive sensory analysis was performed on oven-broiled pork chops and fat samples by a trained panel. The control was rated most tender, confirming the results from the physical texture analysis. The control also had least resistance for first bite, with the 0.5% CLA treatment having most resistance. The 0.5% CLA treatment had a chemical aroma for the fat. The accelerated oxidation test indicated that BF from the control did not become rancid faster than BF from the three CLA treatments. Refrigerated display of pork chops for 8 days resulted in increased L*and b* values for the CLA treatments, unchanged TBARS values, while SI decreased. After frozen storage for 3 months, TBARS values remained unchanged for pork chops from the different dietary treatments. After 6 months of frozen storage, TBARS values decreased for pork chops from CLA supplemented pigs. After eight and 16 weeks of frozen storage, PVs for frozen patties decreased for the 0.5 and 1% CLA treatments. Differences in TBARS values became evident after eight weeks for the frozen patties, compared to sixth months for frozen pork chops. The TBARS values for the frozen chops were lower than the frozen patties. At the end of the ripening period, PVs for salamis from the 0.5 and 1% CLA treatments decreased, along with TBARS values. Belly fat from the CLA treatments was firmer than the control. No significant differences were observed between the four bacon treatments for either PV or TBARS values over the course of the six week refrigerated storage. According to the consumer panel, the control bacon was preferred to the 0.25% CLA bacon.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-05272013-110902 |
| Date | 27 May 2013 |
| Creators | Bothma, Carina |
| Contributors | Prof HL de Kock, Prof A Hugo |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-05272013-110902/restricted/ |
| 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 Free State 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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