Low Atmospheric Pressure Stunning (LAPS) has recently become available to the broiler industry. Therefore, research was conducted to determine the effect of stunning method (LAPS and Electrical Stunning(ES)) and postmortem deboning time (0.75 hr and 4 hr) on the instrumental and sensory acceptability (3 replications) of breast meat (n=576, 144 birds per treatment) prepared using different cooking methods (fried, baked, sous vide). Breast meat was evaluated for pH, CIE L*a*b*, yields, shear force, and consumer acceptability. Postmortem pH decline was more rapid (P<0.05) in the breast meat of LAPS stunned birds when compared to ES stunned birds, but no differences existed (P>0.05) among treatments with respect to final pH. On average, no differences (P > 0.05) existed in the sensory acceptability of fried and sous vide cooked broiler breast treatments. However, for the baked cooking method, the LAPS treatment that was deboned at 4 hr was more acceptable (P<0.05) than other treatments and the ES and LAPS 4 hr postmortem treatments had more acceptable (P<0.05) texture than the ES and LAPS 0.75 hr treatments. Since consumers were highly variable in their liking of chicken breast treatments, consumers were grouped into 6 clusters for each cooking method based on liking and preference. Cluster analysis data revealed that the greatest number of consumers liked all chicken breast treatments, but a larger proportion of consumers liked the 4 hour LAPS and ES treatments when compared to the 0.75 hr LAPS and ES treatments for all cooking methods. In addition, the consumers that indicated that baked chicken breast was highly acceptable preferred (P<0.05) breast meat from the 4 hr LAPS treatment over chicken breast meat from the 4 hr ES treatment. Based on sensory results, chicken breast meat from all stunning and deboning method combinations was highly acceptable to the majority of consumers, but the LAPS 4 hr treatment was slightly more acceptable than other treatments when baked.

Thesis (MScSportSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: There are extensive literature on the PEH response after acute and chronic aerobic and resistance exercise, as well as a few studies on concurrent and water exercise. However, there is comparatively little evidence that high intensity interval training (HIIT) elicits similar post exercise blood pressure reductions (PEH) compared to other types of exercise. Furthermore, it is difficult to quantify the magnitude of the hypotensive response following these exercises, due to variations in exercise protocols in terms of intensity and duration. Both these training variables are considered important determinants of the magnitude and duration of the PEH response. The current study determined the magnitude of the PEH response after an acute bout and six sessions of HIIT, and the effects after two weeks of detraining in overweight/obese young women. Twenty young women (aged 21 ± 2 years) volunteered for the study. All the subjects were normotensive (SBP: 119.2 ± 5.6 mmHg and DBP: 78.8 ± 4.1 mmHg). Subjects performed six sessions of HIIT within two weeks and detrained for two weeks. SBP, DBP, MAP and HR were monitored during seated recovery after exercise for 60 min to determine the change from resting values. The overall outcome showed that an acute HIIT session resulted in a reduction of 2.9 mmHg in SBP which approached near clinical significance, while six sessions of HIIT caused a clinically significant reduction of 5.3 mmHg; this response was almost totally reversed after detraining. There were no clinically significant reductions in DBP after the acute or six sessions of HIIT (1.7 and 2.7 mmHg, respectively). However, a clinically significant hypotensive response of 3.9 mmHg was sustained after detraining following the maximal exercise capacity test. MAP also reduced by a magnitude of 2.3 and 5.6 mmHg, respectively, after the acute bout and six sessions of HIIT, and detraining values were still 2.9 mmHg lower than resting values and approached near clinical significance. The results indicate that both an acute bout and six sessions of HIIT elicited a meaningful PEH response. However, the six sessions of HIIT caused a clinically significant reduction which was approximately twice the acute session. Likewise, detraining showed clinically significant effects in DBP and MAP, but SBP returned to near baseline values. This suggests that in only two weeks, the accumulated effects of six sessions of HIIT elicited a greater hypotensive response than after an acute session of HIIT. / AFRIKAANSE OPSOMMING: Daar is omvattende literatuur oor die post-oefening hipotensie (POH) na afloop van akute en kroniese aërobiese en weerstandsoefeninge, asook enkele studies oor gelyktydige krag- en uithouvermoë- en wateroefeninge. Daar is egter relatief min bewyse dat hoë intensiteit interval oefening (HIIO) soortgelyke post-oefening afnames in bloeddruk (POH) in vergelyking met ander tipes oefening veroorsaak. Voorts is dit moeilik om die omvang van die hipotensiewe respons na afloop van oefening te kwantifiseer, hoofsaaklik as gevolg van die variasies in oefeningprotokolle in terme van intensiteit en tydsduur. Beide hierdie inoefeningveranderlikes word as belangrike determinante van die omvang en die tydsduur van die POH respons beskou. Die huidige studie het die omvang van die POH respons na ʼn akute sessie en ses sessies HIIO, en die gevolge na afloop van twee weke se nie-inoefening (“detraining”) by oorgewig/vetsugtige jong dames, bepaal. Twintig jong dames (ouderdom 21 ± 2 jaar) het vrywillig ingestem om aan die studie deel te neem. Al die deelnemers was normotensief (SBD: 119.2 ± 5.6 mmHg en DBD: 78.8 ± 4.1 mmHg). Die deelnemers het ses sessies HIIO binne twee weke voltooi en het daarna vir twee weke geen inoefeningsessies gehad nie. SBD, DBD, GAD en HS is tydens ʼn sittende herstelfase vir 60 minute gemonitor om die verandering vanaf rustende waardes te bepaal. Die algehele uitkoms toon dat ʼn akute HIIO sessie ʼn afname van 2.9 mmHg in SBD tot gevolg gehad het wat aan kliniese betekenisvolheid grens, terwyl ses sessies van HIIO ʼn klinies betekenisvolle afname van 5.3 mmHg veroorsaak het; hierdie respons wat bykans volledige omgekeerd na die twee weke met geen inoefening. DBD het geen kliniese betekenisvolle afname na afloop van die akute of ses sessies van HIIO getoon nie (1.7 en 2.7 mmHg, respektiewelik). ʼn Klinies betekenisvolle hipotensiewe respons van 3.9 mmHg is egter gevind na die geen inoefeningsperiodes. GAD het ook met ʼn omvang van 2.3 en 5.6 mmHg, respektiewelik, verminder na afloop van die akute sessie en ses sessies van HIIO. Die geen inoefening waardes was steeds 2.9 mmHg laer as die rustende waardes en het aan kliniese betekenisvolheid gegrens. Die resultate toon dat beide ʼn akute sessie en ses sessies van HIIO ʼn betekenisvolle POH respons ontlok het. Ses sessies van HIIO het egter ʼn klinies betekenisvolle afname, wat ongeveer twee keer soveel as die afname van die akute sessie was, veroorsaak. In dieselde lig het ʼn twee weke geen inoefeningsperiode steeds klinies betekenisvolle veranderinge in DBD en GAD getoon, maar SBD het tot naby aan die basislyn waardes teruggekeer. Hierdie resultate suggereer dat in slegs twee weke die geakkumuleerde effekte van ses sessies van HIIO ʼn groter hipotensiewe respons as na ʼn akute sessie van HIIO ontlok het.

L’extrapolation des réacteurs catalytiques nécessite l’acquisition des données cinétiques sur des réacteurs à petite échelle dans les conditions opératoires industrielles. Le critère de dimensionnement utilisé lors de la réduction d’échelle est la conservation de la vitesse volumique horaire, ce qui conduit à des vitesses de circulation très faibles dans les réacteurs pilotes à lit-fixe. A ces vitesses, les flux de transfert de matière externes peuvent devenir limitant par rapport au flux de réaction. Dans ce contexte, une nouvelle géométrie de réacteur a été imaginée pour intensifier les transferts de matière et chaleur et pour augmenter les vitesses de circulation des fluides : le réacteur "filaire". Il s’agit d’un réacteur dont le diamètre est égal ou proche de celui des grains de catalyseur et avec un ratio longueur sur diamètre très élevé. Le principal objectif de cette thèse est de caractériser ce réacteur en termes d’hydrodynamique et de transferts de matière externes pour définir ses limites d’utilisation. En écoulement diphasique, ce réacteur est relativement piston et la rétention liquide est élevée, ce qui permet d'assurer un mouillage total du catalyseur. En ce qui concerne les vitesses des transferts de matière externe, celles-ci sont proches de celles d'un réacteur agité avec panier et sont supérieures à celles caractéristiques d'un réacteur pilote à lit-fixe conventionnel. Cette observation est liée à l’augmentation des vitesses locales du liquide et à la présence d'un écoulement du type Taylor modifié. En conclusion, le réacteur "filaire" constitue une alternative efficace aux réacteurs pilotes à lit-fixe pour l’étude de catalyseurs mis en forme. / Small size fixed-bed reactors are a common choice for testing industrial supported catalyst under industrial operating conditions. The most common criterion for reactor’s scale-down is based on the conservation of the liquid hourly space velocity which leads to a very low fluid flow velocity at the laboratory scale. Under these conditions, the external mass transfer flux can become the limiting step of the process. In this context, a new reactor geometry was proposed to intensify mass and heat transfers and to increase fluid flow velocities: the single pellet string reactor. This reactor is composed of a tube with an internal diameter close to that of the catalyst particles and with a high length over diameter ratio. The main goal of this thesis is to characterise the hydrodynamic and external mass transfer performances of this new reactor in order to define its application domain. In two-phase gas-liquid flow, the reactor flow is plug flow and the liquid hold-up values are high, which insures a complete wetting of the catalyst particles. The mass transfer coefficients were quantified and the measured rates are much higher than those observed in conventional pilot fixed-bed reactors, which can be explained by the increased local liquid velocities and by the modified Taylor flow regime. Catalytic tests with a very fast model reaction revealed that the external mass transfer performances of the single pellet string reactor are close to those measured in a stirred tank reactor equipped with a catalytic basket. In conclusion, the single pellet string reactor represents a new and efficient alternative to fixed-bed pilot reactors to study shaped catalysts.