A process in which low methoxyl pectin is applied to the surface of meat carcasses and poultry to reduce shrinkage, maintain color and improve shelf life was evaluated. A 3.0 percent aqueous low methoxyl pectin (acidified with 1.4 percent acetic acid if required) was applied to beef, lamb and turkey carcasses by spraying and caused to form a gel coating by overspraying with a 3.5 percent calcium chloride salt solution. Turkey carcasses treated with acidified pectin or acidified pectin after 3.0 percent acetic acid dip for 30 seconds were not significantly improved in shelf life over carcasses which were acid dipped 30 seconds. Pectin coating of turkey carcasses was determined infeasible due to discoloration. Pectin coated lamb carcasses were significantly lower in shrinkage (0.71 ±0.04 percent) (p Pectin coated beef carcasses were significantly lower in shrinkage (0.44 ±0.38 percent) (p Both acidified pectin (pH 3.5) and unacidified pectin (pH 4.1) significantly (p

Le premier objectif de cette thèse était d’évaluer l’effet de différentes vitesses de dégradation de l’énergie et de la protéine au niveau du rumen sur la prise alimentaire, le bilan azoté, la synthèse de protéines microbiennes dans le rumen (PMic) ainsi que la cinétique des nutriments chez le chevreau en croissance. Huit chevreaux Boer ont été distribué dans un dispositif expérimental en carré latin avec le type de grains (orge vs maïs) en parcelle principale (carré). La dégradabilité de l’énergie (grains traités vs non traités) et la dégradabilité de la protéine [tourteau de soya (TS) vs tourteau de soya chauffé (TSC)] dans le rumen formant les parcelles secondaires selon un arrangement factoriel des traitements 2 × 2. L’orge a été roulé et le maïs a été craqué. Les chevreaux recevant le maïs ont eu une excrétion urinaire de purines plus importante lorsqu’ils recevaient le TS plutôt que le TSC alors que le contraire a été observé avec l’orge (P ≤ 0,01). Le grain non traité couplé au TS a permis une plus grande excrétion de purines que lorsque couplé au TSC alors que la dégradabilité de la protéine dans le rumen n’a eu aucun effet lorsque le grain était traité (P ≤ 0,03). Les résultats de cette expérience ont montré que la synthèse de PMic pourrait être maximisée en combinant des grains lentement fermentescible (maïs ou grains entiers) avec une source de protéines rapidement dégradables (TS) dans le rumen. Avec l’orge, un grain plus rapidement fermenté dans le rumen, une synthèse de PMic supérieure a été observée lorsque couplée à une source de protéines lentement dégradables (TSC). Chaque céréale a des caractéristiques particulières. Ainsi, la seconde expérience de cette thèse a été réalisée afin de comparer les effets du maïs et de l’orge sur les performances de croissance, la qualité de la viande et le profil en acides gras (AG) du gras musculaire. Vingt-quatre chevreaux Boer ont été séparés en blocs selon leur poids et assignés à l’un des traitements qui consistaient en différentes proportions orge:maïs dans le concentré : 1) 100:0, 2) 50:50 et 3) 0:100. Quinze de ces chevreaux (n = 5 chevreaux/traitement) ont été abattus. L’ajout d’orge dans le concentré a provoqué une augmentation linéaire de la consommation de concentré (P < 0,01) et une tendance à l’augmentation du gain moyen quotidien (GMQ; P = 0,08). Les qualités de la carcasse et de la viande n’ont pas été influencées par les traitements et une viande de bonne qualité a été obtenue. Les proportions d’AG n-3 et n-6 ont augmenté de façon linéaire (P < 0,01), alors que le ratio AG n-6/n-3 a diminué de façon linéaire (P < 0,01) avec l’inclusion de maïs dans la ration. Finalement, la race est aussi un paramètre connu pour influencer la production et la qualité de la viande. Le but de la dernière expérience de cette thèse était d’évaluer l’effet de la race et du régime alimentaire sur la croissance, les caractéristiques de la carcasse et la qualité de la viande chez le chevreau. Quarante chevreaux de race bouchère (Boer) ou laitière (Alpine et Saanen) ont été séparés en blocs selon leur poids et nourris avec une ration à base de pâturage en rotation intensive ou une ration à base de concentrés. Les chevreaux de race bouchère ont eu un GMQ supérieur aux chevreaux de race laitière (P < 0,01), alors que le régime alimentaire n’a pas eu d’effet sur la croissance des chevreaux des deux races. Pour la majorité des découpes, les chevreaux de race bouchère ont accumulé plus de gras et moins de muscle lorsqu’ils recevaient la ration à base de concentrés plutôt qu’à base de pâturage alors que ces paramètres étaient peu influencés par le régime alimentaire chez les chevreaux de race laitière (régime × race, P ≤ 0,07). Les chevreaux nourris de la ration à base de concentrés avaient un potentiel glycolytique inférieur menant à un pH ultime supérieur de la viande ainsi qu’un ratio n-6/n-3 presque 4 fois plus grand que celui des chevreaux au pâturage (P < 0,01). Ce ratio a été 1,4 fois plus grand pour les chevreaux de race laitière comparé aux chevreaux de race bouchère (P < 0,01). Le pâturage en rotation intensive a permis un gain de poids moyen quotidien semblable à celui obtenu avec la ration à base de concentrés, une accumulation de gras interne moins importante dans la carcasse et une viande de bonne qualité. De plus, les chevreaux de race laitière représentent une alternative intéressante afin de produire de la viande de chèvre. / It has been suggested that microbial protein synthesis in the rumen would be optimized when dietary carbohydrates and proteins have synchronized rates and extent of degradation. The first objective of this thesis was to evaluate the effect of varying ruminal degradation rate of carbohydrates and nitrogen sources on intake, nitrogen balance, microbial protein yield in the rumen, and digestive kinetics of nutrients in the rumen of growing kids. Eight Boer goats were used. The treatments were arranged in a split-plot Latin square design with grain sources (barley or corn) forming the main plots (squares). Grain processing methods (rolled barley and cracked corn vs unprocessed grains) and levels of protein degradability [untreated soybean meal (SBM) vs heat-treated soybean meal (HSBM)] formed the subplots in a 2 × 2 factorial arrangement for a total of eight dietary treatments. Kids fed corn had higher excretion of purine derivatives (PD) when coupled with SBM compared with HSBM and the contrary occurred with barley-fed kids (P ≤ 0.01). Unprocessed grain offered with SBM led to a higher PD excretion than with HSBM whereas protein degradability had no effect when processed grain was fed (P ≤ 0.03). Results of this experiment with high concentrate diets showed that microbial N synthesis in the rumen could be maximized in goat kids by combining slowly fermented grains (corn or unprocessed grains) with a highly degradable protein supplement (SBM). With barley, a more rapidly fermented grain, a greater microbial protein synthesis in the rumen was observed when supplementing a low degradable protein (HSBM). Each cereal used in animal feeding has distinct characteristics. Therefore, the second experiment of this thesis was conducted to compare the impact of corn and barley on growth performance, meat quality, and muscle fatty acid (FA) composition of goat kids. Twenty-four Boer males were blocked by body weight (BW) and allotted randomly within block to one of three experimental diets. Treatments consisted in varying ratios of barley to corn in the concentrate: 1) 100:0, 2) 50:50, and 3) 0:100. Fifteen randomly selected kids (n = 5 kids/treatment) were slaughtered to evaluate carcass traits and meat quality. Inclusion of barley in diet linearly increased concentrate intake (P < 0.01) and tended to increase average daily gain (ADG; P = 0.08). There was no significant difference on carcass traits and meat quality among dietary treatments, and overall good meat quality was obtained. Proportions of n-3 and n-6 FA increased linearly (P < 0.01), whereas the n-6/n-3 FA ratio linearly decreased (P < 0.01) in meat fat as corn inclusion increased in the diets. Finally, breed is a parameter also known to influence meat production and quality. The aim of the last study of this thesis was to evaluate the effects of breed and feeding regimen on growth performance, carcass characteristics, and meat quality of male goat. Forty meat (Boer) or dairy (Alpine and Saanen) goat kids were blocked within breed according to BW. Kids within each block were then randomly allotted to intensive rotational grazing or a concentrate-based diet. Meat kids had a greater ADG than dairy kids (P < 0.01), but feeding treatments did not affect growth rate. For most of the primal cuts, meat kids accumulated more fat and less lean when they were fed concentrate in comparison with pasture, whereas these parameters were less influenced by dietary treatments in dairy kids (feed × breed, P ≤ 0.07). Pasture-fed kids had higher glycolytic potential resulting in lower meat ultimate pH. However, Warner-Bratzler shear force was higher for grazing kids compared with concentrate-fed kids (P < 0.01). Concentrate-fed kids showed an almost 4-fold greater n-6/n-3 FA ratio in meat fat compared with pasturefed kids, whereas this ratio was 1.4-fold greater for dairy kids in comparison with meat kids (P < 0.01). Intensive rotational pasture allowed similar average daily gain in comparison with concentrate-based diet, less internal fat accumulation in the carcass, and good meat quality. Furthermore, dairy breeds represented a valuable alternative for producing goat meat.

A pre rigor cut was made through the 12th thoracic vertebrae of one side of a beef carcass, while the other side, processed conventionally, served as the control. The effect of this cut upon yield grade, sensory attributes and tenderness of Longissimus steaks was determined. The treatment caused no differences (P>0.05) in yield grade or in CIE L* a* b* values and oxymyoglobin, reduced myoglobin and metmyoglobin values measured on samples at the treatment site. Sensory panel ratings of visual attributes of color and overall appearance were less desirable (P<0.05) for the treated sides, while for visible texture ratings, there was no significant difference. Purge, cooking loss, percentage moisture, fat and protein, and total collagen were not affected by the treatment (P>0.05). Sarcomere length, and sensory panel ratings of myofibrillar tenderness, connective tissue, and overall tenderness were significantly more desirable for the treated sides. There was no significant difference in fragmentation index or peak force values between treatments, although these values tended to be lower for the treated sides than for the control sides. / Master of Science

This study was conducted to determine the extent in which Campylobacter jejuni colonized live birds would survive evisceration and contaminate the processed carcasses. Birds were infected with a marker strain of Campylobacter jejuni and allowed to grow to market age. Cloacal and fecal samples were analyzed to determine the level of Campylobacter jejuni present in the live bird. Prior to slaughter, birds were selectively subjected to two different temperatures (21 and 32°C) and three different times of feed withdrawal for chickens (3, 6,and 9 hours and turkeys 0, 4, and 8 hours). Birds were then slaughtered and the carcasses were sampled to determine the level of Campylobacter jejuni that survived. Results indicated a difference between chickens and turkeys, especially regarding the infective dose and bacterial survival rates. No significant differences in carcass contamination due to feed withdrawal times at either temperature were noted. The correlation of fecal samples with cloacal samples was significant for year 2 with r = .53 (p .04). For turkeys, the correlations were not significant. A longitudinal study of turkeys showed that the percentage of birds infected with Campylobacter jejuni peaked when the birds were 5-7 weeks old. The amount of Campylobacter contamination in each turkey peaked when the birds were 5 weeks old and then dropped off quickly. / Master of Science

L'objectif du projet était d'évaluer l'effet du poids d'abattage (PA), de la vitesse de croissance (VC) et des sexes sur la qualité du longissimus dorsi du porc et d'en établir la relation avec certains aspects du métabolisme musculaire. Les caractéristiques histologiques du psoas major ont également été comparées avec celles du longissimus dorsi pour ces traitements. Pour réaliser l'étude, 118 porcs commerciaux du Québec ont été regroupés selon deux VC, rapide (Indice de potentiel génétique moyens des pères de -7 jours) et lente (Indice de potentiel génétique moyens des pères de + 2 jours), trois PA (107 kg, 115 kg, 125 kg) et deux sexes (castrats et femelles). Les mesures de qualité physico-chimiques, d'activités enzymatiques énergétiques (citrate synthase et lactate déshydrogénase) et protéolytique (calpaïnes), ainsi que le profil histochimique et immunohistochimique du muscle ont été effectuées. Le PA et la VC n'ont pas influencé les principales mesures de qualité telles que la couleur, le pH du muscle, 48 heures après l'abattage, les forces de cisaillement, l'indice de fragmentation myofibrillaire, la solubilité des protéines et la teneur en myoglobine Les femelles ont montré des pertes en eau plus élevées et un p H u plus faible que les castrats. Par contre, une VC plus rapide a entraîné une augmentation du pourcentage de fibres de type I ainsi qu'une diminution de la taille de ces mêmes fibres. L'augmentation du poids d'abattage a favorisé l'activité de la citrate synthase et de la lactate déshydrogénase. Les femelles ont présenté un potentiel glycolytique plus élevé, une valeur de pHu inférieure et une plus grande perte en eau que les castrats. Malgré certains effets observés sur l'activité métabolique et les caractéristiques histochimiques du muscle, les effets des traitements sur la qualité de la viande sont très limités. Des différences ont été observées entre les effets des traitements sur les caractéristiques histologiques du psoas major et celle du longissimus dorsi. Les résultats suggèrent l'implication de la croissance longitudinale des fibres comme facteur pouvant expliquer ces différences.

Le but de cette étude était d'évaluer les effets de la vitesse de croissance, du poids d'abattage et du sexe sur la composition de la carcasse et la qualité de la viande de porcs commerciaux. Les porcs sont transportés, abattus et réfrigérés conventionnellement. À 24 heures post mortem, les mesures de qualité de la viande et la dissection de la carcasse sont effectuées. Le poids de carcasse, le rendement et le gras dorsal ont augmenté avec l'accroissement du poids d'abattage. Les proportions en muscle, gras et os n'ont pas varié avec le poids. Des teneurs en muscle plus élevées sont obtenues par les femelles et les porcs à croissance lente. Les paramètres de qualité ne sont pas affectés par les traitements. Le poids d'abattage n'affecte pas les caractéristiques de la carcasse ni la qualité de la viande, mais la vitesse de croissance peut affecter la composition de la carcasse.

Thesis (MScAgric)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Porcine somatotropin (pST) is a naturally occurring protein (hormone), secreted by the pituitary gland of young pigs and is one of the major growth regulating factors. High levels of pST is found in circulating blood of young animals, resulting in the partitioning of nutrients into lean tissue and bone growth. Supplying an exogenous source of pST should increase the deposition of lean muscle and bone and decrease the deposition of fat in the older (above 60 kg) pig. To ascertain whether pST would have a positive influence on production- and meat characteristics in the South African scenario for pigs slaughtered at a high bodymass, a trail was conducted. For group housed animals pST had no significant effect on the following parameters: feed intake, calculated cumulatively on a weekly basis, ADG, live weight, carcass weight, carcass length, ham length or chest depth, intramuscular fat area, muscle depth and colour measured with a Hennessey probe and waterbinding capacity. However, when the FCR of pigs in this investigation were calculated, there was a significant (p<0.05) influence by sex and pST detected. Boars converted their feed to live weight better than barrows and gilts from week ten onwards. Boars had an increased FCR when treated with pST. A significant increase was found in muscle area and a significant decrease in extra muscular (back fat) area of boars and barrows. A significant pST (p< 0.05) effect (3 mm reduction) was seen for backfat depth measured by the Hennessey probe and the intrascope. Porcine somatotropin significantly (p<0.05) increased the muscle area of the loin-cut for all animals. The area covered by subcutaneous fat of boars and barrows were significantly (P<0.05) reduced by pST treatment, with no effect detected for gilts (p>0.05). Porcine somatotropin treatment increased the muscle percentage and decreased the extramuscular fat percentage in such a way that the differences between sexes was reduced. Thus, more uniform fat-muscle distribution between carcasses was obtained by pST treatment. Control animals had a significantly higher pH24 than pST treated animals (P=0.049). Lower values were found for animals receiving pST for L* (p=0.016), a* (p=0.002) and b* (P=0.016). The effect on b* (yellow-blue range) in the M longissimus thoracis of pST treated animals showed slightly (but significantly) less yellow and more green compared to control animals (p=0.016). This combined with the lower L* values (brightness) indicates that pST treated animals had a significantly darker colour meat compared to the control animals. Individually housed animals showed no significant differences for the following characteristics: live weight, carcass weight, head, trotters, shoulder, middle back, middle belly, loin belly, thigh, fillet, carcass fat and kidney. Whereas pST caused a significantly lower percentage of the middle back of boars and barrows, but not in gilts, pST could only precipitate a lower percentage (11.18%) loin back of treated animals (p=0.026) v.s. control animals (12.05%). A trend (p>0.1) was detected for percentage bone in the middle back, with the pST treated (14.17% vs. 13.18%) animals having more bone than that of control animals. pST animals had a higher percentage (p=0.024) skin (5.04%) than the control animals (4.28%). This study shows that there is no negative effect of pST on meat quality characteristics and carcass composition, in fact there is less variation between carcasses obtained from different sexes treated with pST. The producer can bring heavier animals to the market with a reduced backfat percentage and a greater percentage meat with the help of pST. / AFRIKAANSE OPSOMMING: Vark somatotropien (pST) is ‘n natuurlike hormoon wat deur die pituitêre klier in die brein afgeskei word by klein varkies en is een van die belangrikste hormone betrokke by groei regulering. Hoë vlakke van pST kom voor in die bloed van jong varkies, dit veroorsaak dan die verspreiding van nutriente in die liggaam van die varkie sodat dit meer vleis en beengroei toon en minder vet deponeer. Namate die varkie volwasse word neem die bloedvlakke van pST af en begin die liggam meer vet deponeer ten koste van proteien groei, terselfde tyd begin die seksuele kenmerke ontwikkel. Die toediening van ‘n eksterne bron van pST behoort die groei van been en vleis te bevoordeel in ouer diere (bo 60 kg). Vir die doeleindes van die ondersoek wou ons bepaal of pST ‘n positewe effek het op groei en vleiskwaliteitseienskappe van varke wat in Suid Afrikaanse kondisies gebruik word en teen ’n hoër liggamsmassa as gewoonlik geslag word. Vir varke wat in groepe behuis was was daar geen effek op die volgende eienskappe nie: voer inname weekliks bepaa, gemiddelde daaglikse toename, liggaamsmassa, karkasgewig, karkas lengte, ham lengte, bors diepte, intrmuskulêre vet en spierdikte bepaal met ‘n Hennessey sonde asook waterbindigs vermoë. Bere het egter ’n beter voeromsettings faktor gehat as burge en soggies, maar as pST toegedien is het hulle voeromsettingsfaktor toegeneem. ’n Betekenisvolle (p<0.05) toename in spier area van alle diere, met ’n gesamentlike afname in onderhuidse vet area van bere en burge (nie soggies nie) is gevind. ’n Betekenisvolle afname (3 mm) in rugvetdikte is gevind by diere wat met pST behandel is. Hierdie effekte is so in die lewe gebring dat die verskil tussen die geslagte minder prominent is en karkasse meer uniform is. Betekenisvolle hoër pH24 waardes is gevind by kontrole diere as by pST behandelde diere (p=0.049). L* (p=0.016), a* (p=0.002) en b* (p=0.016) waardes was betekenisvol laer vir pST behandelde diere as vir kontrole diere. Die effek op b* waardes (geel-blou reeks) in die M. longissimus thoracis van behandelde diere was in so ‘n mate dat die vleis ietwat minder geel en meer groen was in vergelyking met die kontrole diere (p=0.016), saam met laer L* waardes (helderheid) is ‘n indikasie van ietwat donkerder vleis van behandelde diere. Individueel behuisde diere het geen betekenisvolle effek getoon vir die volgende parameters nie: liggamsgewig, karkasgewig, kop, voete, skouer, middel rug, middel maag, lende maag, dy, haas en niere. ‘n Betekenisvolle laer persentasie middel rug is gevind in bere en burge, maar nie vir soggies nie, maar in die lende rug is ‘n betekenisvolle effek gevind vir alle diere (11.8% vir pST en 12.05% vir kontroe , p=0.026). ‘n Neiging (p>0,1) is gesien vir die hoeveelheid been in die middle rug van diere behandel met pST (14.17% vs. 13.18%) Dier met pSt behandel het’n betekenisvol hoer persentasie vel as kontrole diere gehat (5.04% vs. 4.28%, p=0.024. Die resultate van die ondersoek bewys dat daar geen negatiewe effekte van pST op vleis- en karkaseienskappe is nie, daar is self minder variasie tussen karkasse van verskillende geslagte. Die boer kan swaarder diere bemark met minder rugvet en meer vleis met behulp van pST.

Thesis (MScAgric) -- Stellenbosch University, 2009. / ENGLISH ABSTRACT: The two main determinants of post-slaughter processing outcomes are rates of pH and temperature decline. Muscle pH and temperature interact continuously during rigor development to affect both the muscle contracture and proteolytic enzyme activity. The pH, however, can be manipulated independently of temperature by electrical inputs applied to the carcass. Electrical inputs that should be considered range from electrical stunning to the various forms of electrical immobilisation (EI) and stimulation (ES) that occur during and after the dressing procedures. EI is used to suppress convulsions that occur after electrical stunning to ensure operator safety to maintain high throughputs speeds while ES is used to induce rapid tenderisation, although having other biochemical and biophysical effects on meat. The objective of the study was to supply information on the effect of different EI and ES treatments, frequencies and pulse widths on the meat quality of beef. There are very little data on the effect of EI when it is combined with ES on meat quality. This study used two different EI frequencies (high – 800 Hz; HFI and low – 15 Hz; LFI) combined with either high (1040 V; HVS) or medium (300 V; MVS) voltage ES to study the effect of these treatments on meat quality. In the following experiment the EI waveform and ES was standardised using HFI with MVS with the frequency being changed to either 5, 15 or 50 Hz. Then the pulse width of the waveform was changed to 0.1, 0.5, 1 and 10 ms to optimise the ES system. Meat quality measurements were made from the Longisimmus dorsi (LD) and Semimembranosus (SM) after 1, 5 and 9 days of chilled storage at 0 C. The LD (shear force = 94.3±2.2; cooking loss = 26.85±0.29; retail drip = 0.996±0.037; storage drip = 2.78±0.155; WBC (water binding capacity) = 45.4±0.36) had significantly lower shear force and higher water binding capacity than the SM (shear force = 103.7±2.5; cooking loss = 34.63±0.25; retail drip = 2.12±0.103; storage drip = 3.63±0.245; WBC = 59.3±0.57). Day of assessment (Day 1 = 122.7±2.9; Day 5 = 87.7±2.2; Day 9 = 81.0±2.4) had a significant effect on tenderness of the LD as shear force declined with an increase of day of assessment. The LFI HVS (storage drip = 3.30±0.223; shear force = 102.9±4.5) produced significantly greater drip during storage and shear force values when compared to the HFI followed by either HVS (storage drip = 2.45±0.261; shear force = 85.2±4.0) or MVS (storage drip = 2.60±0.178; shear force = 94.2±4.2) in the LD, probably attributable to different rates of pH decline post mortem. LFI HVS (a* = 20.79±0.31; chroma = 22.92) and LFI MVS (a* = 20.24±0.27; chroma = 22.23±0.30) had a redder and more vivid bloomed colour than HFI HVS (a* = 19.71±0.33; chroma = 21.49±0.37) and HFI MVS (a* = 20.00±0.27; chroma = 21.98±0.31), while LFI HVS (a* = 15.27±0.40) and HFI MVS (a* = 14.64±0.29) had a redder colour compared to HFI HVS (13.85±0.35) at day 9 for the LD. The oxygen consumption rate (MTT assay) correlated inversely linear (r = -0.63 and -0.73) with the a* values 24 hrs post mortem allowing for 3 hrs of bloom. Stimulation with 15 Hz (0.47±0.040) and 5 Hz (0.41±0.045) had a higher pH decline (ΔpH) during stimulation than 50 Hz (0.29±0.027). Shear force measurements and cooking loss percentage were obtained from the LD after 24 hrs of chilled storage at 0 C. There were no difference between the stimulation treatments for shear force (15 Hz = 121.3±3.3; 5 Hz = 123.8±7.6; 50 Hz =114.8±7.94), while cooking loss was higher in 15 Hz (28.8±0.47) than 50 Hz (25.9±0.71) which correlated (r = 0.43; p = 0.01) with ΔpH. There were no differences between 10 ms (0.46±0.020), 1 ms (0.43±0.020) and 0.5 ms (0.44±0.019) pulse widths on the ΔpH while 0.1 ms (0.33±0.020) had a lower decline. Stimulation with a 1 ms (94.6±5.6) pulse width had the lowest shear force that varied from 10 (111.3±3.8) and 0.1 ms (111.3±5.8). While cooking loss (0.1 = 25.3±0.48; 0.5 = 26.9±0.67; 1 = 25.9±0.63; 10 = 25.5±0.66) and water-holding capacity (0.1 = 36.1±1.60; 0.5 = 37.3±1.42; 1 = 37.5±1.15; 10 = 36.9±1.45) was not affected in the LD after 24 hrs of chilled storage at 0 C. Colour measurements on the SM indicated that a 0.1(a* = 19.38±0.50; chroma = 22.70±0.51), 0.5 (a* = 20.89±0.49; chroma = 24.34±0.56) and 10 ms (a* = 19.69±0.46; chroma = 22.98±0.58) pulse width had a deeper red and a more vivid colour than 1 ms (a* = 16.66±0.37; chroma = 19.99±0.32) at day nine of retail display. In conclusion, HFI improves meat quality when combined with either HVS or MVS and that MVS either improves (colour stability) or has no adverse effects on meat quality (tenderness and WBC) in relation to HVS when combined HFI. In addition, it shows that there are alternative electrical parameters to voltage that can be used to change the pH decline and by changing frequency and pulse width, subtle changes can be made to an ES system. Since every abattoir is different due to layout, chiller space and cooling regime these electrical parameters can be modulated to optimise an electrical stimulation system without expensive modification to the whole system. / AFRIKAANSE OPSOMMING: Die tempo van pH en temperatuur daling is die twee hoof bepalings van na-slag prosseserings uitkomste. Spier pH en temperatuur het ’n gedurige interaksie tydens rigor ontwikkeling en beïvloed die spier sametrekking en proteolitiese ensiem aktiwiteit. Die spier pH kan onafhanklik van temperatuur gemanipuleer word, deur elektriese golfvorms deur die karkas te stuur. Die elektriese golfvorms wat in ag geneem moet word varieer van elektriese impulse tydens bedwelming tot die verskeie golfvorms van elektriese immobilisasie (EI) en stimulasie (ES) wat gebruik kan word gedurende en na die slagproses. EI word gebruik om konvulsies te beheer wat onstaan na elektriese bedwelming om werker veiligheid en hoë deurvloei tempos te verseker, terwyl ES die verouderings proses versnel, alhoewel dit ander biochemiese en biofisiese uitwerkings het op vleis. Die studie het verneem om inligting te verskaf oor die effek van verskillende EI en ES kombinasies, frekwensie en puls wydtes op die kwaliteit van beesvleis. Daar is baie min inligting van EI in kombinasie met ES se effek op vleis kwaliteit. Die studie het gebruik gemaak van twee verskillende (EI) frekwensies (hoog – 800 Hz; HFI and laag – 15 Hz; LFI) wat gekombineer is met of hoë (1040 V; HVS) of medium (300 V; MVS) spanning ES se effek op vleis kwaliteit. In die volgende eksperiment was die EI golfvorm en die ES gestandardiseer en HFI met MVS was gebruik met die frekwensie wat verander is tussen 5, 15 en 50 Hz. Daarna was die pulse wydte van die golfvorm verander tussen 0.1, 0.5, 1en 10 ms om die ES sisteem te optimiseer. Vleis kwaliteit van die Longisimmus dorsi (LD) en Semimembranosus (SM) spiere was bepaal na 1, 5 en 9 dae van verkoelde storing teen 0°C. Die LD (skeurkrag = 94.3±2.2; kookverlies = 26.85±0.29; kleinhandel drup verlies = 0.996±0.037; storing drip verlies = 2.78±0.155; WBV (water bindings vermoë) = 45.4±0.36) het ‘n betekenisvolle laer skeurkrag waardes en hoër water bindings vermoë gehad in vergelyking met die SM (skeurkrag = 103.7±2.5; kookverlies = 34.63±0.25; kleinhandel drupverlies = 2.12±0.103; bergings drupverlies = 3.63±0.245; WBV = 59.3±0.57). Die dag van assesering (Dag 1 = 122.7±2.9; Dag 5 = 87.7±2.2; Dag 9 = 81.0±2.4) het ’n betekenisvolle effek gehad op die skeur krag waardes en het afgeneem met ’n toename in die dag van assesering. LFI HVS (storing drupverlies = 3.30±0.223; skeurkrag = 102.9±4.5) het betekenisvolle hoër vog verliese gehad tydens verkoelde storing en skeur krag wanneer dit vergelyk word met HFI gevolg deur of HVS (storing drupverlies = 2.45±0.261; skeurkrag = 85.2±4.0) of MVS (storing drupverlies = 2.60±0.178; skeurkrag = 94.2±4.2). LFI HVS (a* = 20.79±0.31; chroma = 22.92) en LFI MVS (a* = 20.24±0.27; chroma = 22.23±0.30) het ‘n helder en dieper rooi kleur gehad in vergelyking met HFI HVS (a* = 19.71±0.33; chroma = 21.49±0.37) en HFI MVS (a* = 20.00±0.27; chroma = 21.98±0.31), terwyl LFI HVS (a* = 15.27±0.40) en HFI MVS (a* = 14.64±0.29) ’n rooier en helderer kleur as HFI HVS (13.85±0.35) gehad het in die LD. Die suurstof verbruik tempo (MTT analise) korreleer omgekeerd (r = -0.63 en -0.73) met die a* waardes 24 hr post mortem na 3 hr van blootstelling van lug. Stimulasie met 15 (0.47±0.040) en 5 Hz (0.41±0.045) het ’n hoër pH daling (ΔpH) tydens stimulasie as 50 Hz (0.29±0.027). Skeurkrag waardes en kookverliese is verkry vanaf die LD na 1 dag van verkoelde storing teen 0 C. Daar was geen verskil tussen stimulasie frekwensie se effek of skeurkrag (15 Hz = 121.3±3.3; 5 Hz = 123.8±7.6; 50 Hz =114.8±7.94) nie, terwyl die kookverliese hoër was in die 15 Hz (28.8±0.47) as 50 Hz (25.9±0.71) behandeling wat gekorreleer (r = 0.43; p = 0.01) het met ΔpH. Daar was geen verskill tussen 10 (0.46±0.020), 1 (0.43±0.020) en 0.5 ms (0.44±0.019) puls wydtes se effek op ΔpH nie, terwyl 0.1 (0.33±0.020) ms ‘n kleiner afname tot gevolg gehad het. Stimulasie met ‘n 1 ms (94.6±5.6) puls wydte het die laagste skeurkrag gehad wat verskil het van die 10 (111.3±3.8) and 0.1 ms (111.3±5.8) puls wydtes, terwyl kookverliese (0.1 = 25.3±0.48; 0.5 = 26.9±0.67; 1 = 25.9±0.63; 10 = 25.5±0.66) en waterbindingsvermoë (0.1 = 36.1±1.60; 0.5 = 37.3±1.42; 1 = 37.5±1.15; 10 = 36.9±1.45) nie beïvloed was nie. Kleur metings van die SM het getoon dat ‘n 0.1 (a* = 19.38±0.50; chroma = 22.70±0.51), 0.5 (a* = 20.89±0.49; chroma = 24.34±0.56) en 10 ms (a* = 19.69±0.46; chroma = 22.98±0.58 puls wydtes die helder en dieper rooi kleur gehad het as 1 ms (a* = 16.66±0.37; chroma = 19.99±0.32) teen dag 9 van kleinhandel vertoning. Ter opsomming, lei HFI tot beter vleis kwaliteit wanneer dit gekombineer word met of HVS of MVS. Verder lei MVS tot of ’n verbetering (kleur stabiliteit) of geen nadelige effek op vleis kwaliteit (sagtheid en WBV) in vergelyking met HVS wanneer dit gekombineer word met HFI. Die studie bewys ook dat daar ander elektriese parameters bestaan as spanning, wat verander kan word om die pH daling te beïvloed. Deur die frekwensie en pulswydte te verander, kan klein veranderinge aangebring word aan ’n ES sisteem. Elke abattoir is verskillend as gevolg van uitleg, koelkamer spasie en verkoelings tempo en hierdie elektriese parameters kan verander word om ’n ES sisteem te optimiseer sonder enige duur veranderinge aan die hele sisteem.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: A total of 32 cattle were divided into four groups of eight each (A1-8, A9-16, A17-24, B1-B8) to be slaughtered on different days over a period of 45 days. All the cattle in Groups A were of Bonsmara type and those in Group B were of Charolais type. Three treatments, Tenderstretch (TS), Tendercut (TC) and Hock suspension (HS) were randomly allocated to each of the 48 sides from group A. Only two treatments (TC and HS) were implemented on the carcass sides in Group B alternating between the right and left sides. Two muscles from each side namely Gluteus medius and Longissimus dorsi were evaluated for purge, cooking loss, shear force and sarcomere length after 2, 4, 6, 10 and 14 days of aging. Paired t-Tests were performed for each pair of treatments and each day separately, on all variables accessed (Snedecor, 1980). The differences in purge and cooking loss between treatments were all found to be inconclusive for each day of aging. Although purge had significant differences between the treatments TC and TS for the GM and LD muscle after 14 days of aging (P = 0.0341 and P = 0.0348 respectively) these were found to be open to doubt as the treatment that delivers the most purge differs between muscles and that the two treatments delivered no differences compared to its HS values. Aging had a significant effect on purge as it doubles after 14 days of aging. Cooking loss values only differed significantly on day 2 for the LD muscle between treatments TC and HS. The differences in shear force were all smaller than 0.3205 kg/ 1.27cm and not consistent over all carcasses. A mean positive improvement in tenderness was calculated from high difference in mean values from some carcasses although some carcasses showed a decrease in tenderness when using TS and TC, which suggests that the treatments are of no relevance towards the industry. Although the differences in shear force become smaller as aging commences, it is not constant, a phenomenon most probably due to the variance between animals. Aging again had the most significant effect (P<.0001) on shear force. Correlations between sarcomere lengths and shear force were low for all the treatments on the GM muscle (HS = -0.453; TC = -0.401 and TS = -0.2) but in the LD muscle the TS method showed a higher correlation (TS = -0.665) than the other treatments (HS = 0.059 and TC = 0.059). / AFRIKAANSE OPSOMMING: `n Totaal van 32 beeste was opgedeel in vier groepe van agt elk (A1-8, A9-16, A17-24, B1-B8) wat geslag is op verskillende dae oor n periode van 45 dae. Beeste van die A groep was almal Bonsmara tipe en die van die B groep charolais tipe. Drie behandelings naamlik Tenderstretch (TS), Tendercut (TC) en Hak suspensie (HS) was ewekansig tot die 48 sye van die karkasse van groep A toegedeel. Groep B se 16 sye is net met TC en HS ewekansig tot die linker en regter sy toegedeel. Twee spiere naamlik Gluteus medius en Longissimus dorsi was geevalueer vir drup verlies, kook verlies, sarkomeer lengte en taaihied na 2, 4, 6, 10 en 14 dae se veroudering. Gepaarde t – toetse is gedoen vir elke paar behandelings vir elke dag van veroudering op al die veranderlikes genoem. Die verskil in drup verlies en kook verlies tussen behandelings was as nie betekeinisvol bestempel. Behalwe vir die feit dat drup verlies betekenisvolle verskille getoon het tussen die behandelings TC en TS vir die GM (P = 0.0341) en die LD (P = 0.0348) spiere na 14 dae se veroudering was dit bevind as nie betekenisvol juis oor dat die twee behandelings teenoor hul HS waardes geen verskille getoon het nie. Veroudering van die vleis het wel die grootste betekenisvolle verskil in drupverlies gemaak waar dit amper verdubbel soos die vleis verouder vir 14 dae. Kookverlies het net op dag twee n betekenisvolle verskil getoon in die LD spier vir die HS – TC kombinasie. Die verskil in taaiheid was almal kleiner as 0.3205 kg/ 1.27cm en nie kostant vir alle karkasse nie. n’ Positiewe gemiddelde verbetering in sagtheid is verkry deur die kalkulasie van hoë positiewe waardes en lae negatiewe waardes vir sommmige karkasse wat n laer sagtheid getoon het wanneer TS en TC gebruik is. Hierdie onkonsekwente verbeterings in sagtheid maak dat hierdie behandelings van min praktiese nut vir die bedryf is. Alhoewel hierdie verskille tussen behandelings kleiner raak tydens veroudering, is dit nie konstant nie, wat as gevolg van die variasies tussen diere kan wees. Veroudering het weereens die mees betekenisvolle effek op die vleis getoon (P< 0.001). Die korrelasie tussen sarkomeer lengte en WBSF taaiheid was laag vir alle behandelings in die GM spier (HS = -0.453; TC = -0.401 en TS = -0.2) behalwe vir die LD spier waar die TS behandeling n hoer korrelasie van TS = -0.665 as die ander twee behandelings (HS = 0.059 en TC = 0.059) opgelewer het.

Thesis (MScVoedselwet)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The objective of this investigation was to evaluate the effects of age (adult, sub-adult and lamb), gender (male and female) and production region on the morphological characteristics of springbok (Antidorcas marsupialis). In addition, the effects of the latter on the physical, chemical and sensory quality of the M. longissimus dorsi (LD) muscle were determined. Where applicable, correlations within the various physical and chemical attributes of the meat were verified in the experiments. The sensory ratings of the meat were correlated with the data on the physical and chemical attributes of the LD muscle, where applicable. The mean live mass of male and female adult springbok differed significantly (p < 0.05) and averaged 31.7 ± 0.70 and 28.3 ± 0.60 kg respectively. Gender had no significant effect on the mean live mass of the sub-adult category. The mean dressing percentage of the males (58.83 ± 0.53%) was noted to be significantly higher than that of the females (55.79 ± 0.50%). The lambs (58.98 ± 1.07%) had the highest dressing percentage of all the age categories. An increase in carcass measurements was noted with an increase in animal age. Gender did not have a significant (p > 0.05) effect on the carcass measurements. Inverse correlations were noted between pH24 and drip loss (r = -0.26, p < 0.01) and cooking loss (r = -0.42, p < 0.0001) of the LD muscle. It was noted that stressed animals had a significantly (p < 0.05) higher ultimate pH24 (6.30 ± 0.07), as observed in the meat originating from the Caledon region and this meat consequently had a significantly (p < 0.05) lower cooking loss (27.18 ± 0.62%) and drip loss (1.79 ± 0.08%). Meat shear force values ranged between 1.67 ± 0.05 and 2.67 ± 0.16 kg. 1.27 cm-1 diameter. Age-related effects on tenderness were found to be minor in comparison to pH24 effects. The females (3.13 ± 0.28%) were noted to have a significantly (p < 0.05) higher fat content than the males (1.35 ± 0.08%). The adult (2.45 ± 0.26%) and sub-adult (2.50 ± 0.28%) animals had a significantly higher fat content in comparison with the lambs (1.32 ± 0.11%). The protein content of the springbok meat originating from the four production regions varied between 18.80 ± 0.35 and 21.16 ± 0.51%. Gender had no significant effect on the protein content, except for the meat originating from Rustfontein Nature Reserve where the females had a significantly higher protein content. The two major amino acids noted for springbok LD muscle were glutamic and aspartic acid. Phosphorous was the predominant mineral, followed by potassium and calcium. Production region had a significant (p < 0.05) effect on both the amino acid and mineral content of the meat. The saturated fatty acid (SFA) content of the LD muscle contributed 38.40 to 42.69% of the total identified fatty acids. The poly-unsaturated fatty acid (PUFA) content (36.34 - 40.98%) of the meat was very close to this range, meaning that optimal polyunsaturated to saturated (P:S) ratios (0.96 - 1.18) were present. The effects of age and gender on the fatty acid composition were minor in comparison with regional effects. Warner-Bratzler Shear force (kg. 1.27 cm-1 diameter) values were inversely correlated with the following sensory attributes: tenderness (r = -0.70, p < 0.01), residual tissue (r = -0.68, p < 0.01) and sustained juiciness (r = -0.43, p < 0.05). Decreased acceptance of the meat was noted with an increase in ultimate pH (pH24) from 5.4 to 5.8. As the ultimate pH of the meat increased, the rankings for tenderness (r = -0.46, p < 0.05) and sustained juiciness (r = -0.54, p < 0.05) decreased significantly. / AFRIKAANSE OPSOMMING: Die doel van hierdie ondersoek was om die invloed van ouderdom, geslag en produksie area op die morfologiese eienskappe van springbok (Antidorcas marsupialis) te evalueer. Die effek van laasgenoemde faktore op die fisiese, chemiese en sensoriese kwaliteit van die M. longissimus dorsi (LD) is ook ondersoek. Korrelasies in die fisiese en chemiese eienskappe van die vleis is bestudeer. Die resultate van die sintuiglike evaluering van die vleis is gekorreleer met die fisiese en chemiese data van die LD spier, indien van toepassing. Die gemiddelde gewig van die manlike (31.7 ± 0.70 kg) en vroulike (28.2 ± 0.60 kg) diere het betekenisvol (p < 0.05) verskil. Geslag het geen betekenisvolle effek op die gemiddelde gewig van die sub-volwasse diere getoon nie. Die gemiddelde uitslag persentasie van die manlike diere (58.83 ± 0.53%) was betekenisvol (p < 0.05) hoër in vergelyking met die vroulike diere (55.79 ± 0.50%). Met ‘n toename in ouderdom is ‘n toename in karkas metings waargeneem. Geslag het geen effek op die karkas metings getoon nie. Negatiewe korrelasies is genoteer tussen die finale pH (pH24) en drupverlies (r = -0.26, p < 0.05) en tussen pH24 en kookverlies (r = -0.42, p < 0.0001) van die LD spier. Gestresde diere van die Caledon area het ‘n betekenisvolle (p < 0.05) hoër pH24 (6.30 ± 0.07) getoon en gevolglik ‘n laer (p < 0.05) kookverlies (27.18 ± 0.62%) en drupverlies (1.79 ± 0.08%). Die skeurkrag waardes van die LD spier het gewissel van 1.67 ± 0.05 tot 2.67 ± 0.16 kg. 1.27 cm-1 diameter. Die effek van ouderdom op taaiheid was klein in vergelyking met die effek van pH24. Die vroulike diere (3.13 ± 0.28%) het ‘n hoër (p < 0.05) vetinhoud as die manlike diere (1.35 ± 0.08%) getoon. Die volwasse (2.45 ± 0.26%) en sub-volwasse (2.50 ± 0.28%) diere se vetinhoud was hoër as die van die lammers (1.32 ± 0.11%). The proteininhoud het gewissel van 18.80 ± 0.35 tot 21.16 ± 0.51%. Geslag het geen effek (p > 0.05) getoon op die proteieninhoud, behalwe vir die vleis van die Rustfontein Natuur Reservaat. Glutamien en aspartien suur was kwantitatief die belangrikste aminosure. Fosfor was die belangrikste mineraal, gevolg deur kalium en kalsium. Produksie area het ‘n betekenisvolle (p < 0.05) effek op die aminosuur en mineraalinhoud getoon. Die versadigde vetsuur (SFA) inhoud het gewissel van 38.40 tot 42.69% van die totale geïdentifiseerde vetsure. Die poli-onversadigde vetsuur (PUFA) inhoud het gewissel van 36.34 tot 40.98% en daarom is optimale poli-onversadigde tot versadigde (P:S) verhoudings (0.96 - 1.18) genoteer. Die effek van ouderdom en geslag op die vetsuursamestelling was minimaal in vergelyking met die effek van produksie-area. Warner-Bratzler skeurkrag (kg. 1.27 cm-1 diameter) waardes was negatief gekorreleer met die volgende sensoriese eienskappe: taaiheid (r = -0.70, p < 0.01), residuweefsel (r = -0.68, p < 0.01) en volgehoue sappigheid (r = -0.43, p < 0.05). Daar is ‘n afname in die aanvaarbaarheid van die vleis waargeneem met ‘n toename in pH24 van 5.4 tot 5.8. Met ‘n toename in pH24, het die taaiheid (r = -0.46, p < 0.05) en volgehoue sappigheid (r = -0.54, p < 0.05) van die vleis afgeneem