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The optimization of chilling regimes, carcass weight and electrical inputs to mitigate the risk of high rigor temperature carcasses – a case study
Thesis (MScAgric)--Stellenbosch University, 2024.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2024
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| _version_ | 1867613959929987072 |
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| access_status_str | Open Access |
| author | Van Wyk, Robert |
| author2 | Strydom, P. E.
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| author_browse | Strydom, P. E.
Van Wyk, Robert |
| author_facet | Strydom, P. E.
Van Wyk, Robert |
| author_sort | Van Wyk, Robert |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/130486 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:44:25.612Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2024 |
| publishDateRange | 2024 |
| publishDateSort | 2024 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/130486 The optimization of chilling regimes, carcass weight and electrical inputs to mitigate the risk of high rigor temperature carcasses – a case study Van Wyk, Robert Strydom, P. E. Marais, Jeannine Hope-Jones, Michelle Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Science. Rigor mortis Postmortems --Technique Animal carcasses -- Quality Proteins Feedlots -- South Africa Meat -- Electric properties -- Measurement Carcasses -- Effect of heat on Sensory evaluation Meat -- Effect of high temperatures on UCTD Thesis (MScAgric)--Stellenbosch University, 2024. ENGLISH ABSTRACT: The objective of this study was to investigate varying post-mortem (PM) management techniques involving chiller efficiencies and the application of electrical stimulation (ES) for adjustable carcass weight categories in order mitigate or limit the incidence of high rigor temperatures (HRT) as well as the quality defects linked to the condition. Considering the varying set of operational chillers within the case studied abattoir, chiller efficiencies were established on the rates of chilling over an initial 4 h PM period, chillers which resulted in a faster rate of chilling were deemed as ‘efficient chillers’ while slower chilling rates were classified as ‘inefficient chiller’. Two carcass weight categories were established and were based on the mean weight of carcasses being processed at the meat plant at the time of the study, heavy carcasses (>310kg) and light carcasses (<290kg). The application of ES was applied for a short duration (10 s) post dressing and done so to not drastically decrease muscle pH but provide a ‘kick-start’ to the conversion of muscle to meat and reap the benefits of the practice. Quality was measured and quantified through a series of measurements; muscle temperature and pH decline, estimation of temperature at rigor mortis (RM), chemical composition (moisture, ash, fat and protein), physical attributes (colour, drip loss, cooking loss, thaw loss and instrumental tenderness), ageing potential [myofibril fragmentation lengths (MFL)] and sensory attributes (aroma, palate and texture). All main factors (chiller efficiency, weight category and electrical stimulation) influenced quality traits in some form, dominantly being due to the denaturation of sarcoplasmic and myofibrillar proteins. Heavy carcasses resulted in higher temperatures at 1 and 2 h PM (p<0,001; p<0,001, respectively) and therefore higher temperatures were estimated at RM (p=0,015). Similarly, the application of electrical stimulation led to higher temperatures at RM, due to the elevated rates of pH decline at 1 and 2 h PM (p<0,001; p<0,001, respectively). Chiller efficiency, failed to present any significant differences in temperatures at RM at a main factor level (p=0,989). Meat treated with factors leading to elevated temperatures at RM resulted in higher lightness (L*) and chorma values at 3 d PM. After 21 d ageing factors resulting in increased pH decline (electrical stimulation) produced lighter meat (p=0,041) with a higher hue angle (vividness; p=0,044). Moisture losses (drip and cooking loss) were influenced by chiller efficiency, leading to a slight misnomer where increased drip was recorded under efficient chilling. Descriptive sensory analysis and instrumental tenderness revealed no major significant differences between main factors. Myofibrillar fragmentation lengths were decreased by inefficient chilling (p=0,001) and the application of electrical stimulation (p=0,041), demonstrating the loss of protein functionality. Through judicious combinations of factors, the quality deteriorating phenomenon of high rigor temperatures can be avoided. However, emphasis must be placed on chiller efficiency, especially when considering larger carcasses. The benefits of the shortened electrical stimulation did not demonstrate the expected positive effects; however, this may be due to the shortcomings of chiller incapabilities to avoid higher temperatures at RM. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2024-02-22T11:57:35Z 2024-04-26T19:21:49Z 2024-02-22T11:57:35Z 2024-04-26T19:21:49Z 2024-03 Thesis https://scholar.sun.ac.za/handle/10019.1/130486 en_ZA Stellenbosch University xv, 117 pages : illustrations (some color) application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Rigor mortis Postmortems --Technique Animal carcasses -- Quality Proteins Feedlots -- South Africa Meat -- Electric properties -- Measurement Carcasses -- Effect of heat on Sensory evaluation Meat -- Effect of high temperatures on UCTD Van Wyk, Robert The optimization of chilling regimes, carcass weight and electrical inputs to mitigate the risk of high rigor temperature carcasses – a case study |
| title | The optimization of chilling regimes, carcass weight and electrical inputs to mitigate the risk of high rigor temperature carcasses – a case study |
| title_full | The optimization of chilling regimes, carcass weight and electrical inputs to mitigate the risk of high rigor temperature carcasses – a case study |
| title_fullStr | The optimization of chilling regimes, carcass weight and electrical inputs to mitigate the risk of high rigor temperature carcasses – a case study |
| title_full_unstemmed | The optimization of chilling regimes, carcass weight and electrical inputs to mitigate the risk of high rigor temperature carcasses – a case study |
| title_short | The optimization of chilling regimes, carcass weight and electrical inputs to mitigate the risk of high rigor temperature carcasses – a case study |
| title_sort | optimization of chilling regimes carcass weight and electrical inputs to mitigate the risk of high rigor temperature carcasses a case study |
| topic | Rigor mortis Postmortems --Technique Animal carcasses -- Quality Proteins Feedlots -- South Africa Meat -- Electric properties -- Measurement Carcasses -- Effect of heat on Sensory evaluation Meat -- Effect of high temperatures on UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/130486 |
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