Browsing by Author "Britz, T. J."

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    Effect of ascorbic acid and yeast strain on sauvignon blanc wine quality
    (South African Society for Enology and Viticulture, 2001) Swart, E.; Marais, J.; Britz, T. J.
    Sauvignon blanc cultivar-typical aroma is affected by different components of which 2-methoxy-3-isobutylpyrazine and 4-mercapto-4-methylpentan-2-one are probably the most important. Climatic, viticultural and oenological conditions may have a prominent effect on the levels at which these impact aroma components occur in wine. Sauvignon blanc wines were produced from grapes from two climatically different regions. Different ascorbic acid/S02 combinations and different Saccharomyces cerevisiae yeast strains were used during the production of the wines. The wines were sensorially evaluated for specific wine characteristics, namely fruity/ester aroma intensity, grassy/green pepper aroma intensity, sulphur-like aroma intensity and overall wine quality. Significant differences were observed between treatments. A commercially available preparate (ascorbic acid/meta-bisulphite) and yeast strain VL3C produced sulphur-like, low-quality wines under the conditions of this investigation. The highest quality wines were produced from pure ascorbic acid/S02 treatments and fermentation by the yeast strain VIN 13.
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    Effect of hot-deboning on the physical quality characteristics of ostrich meat
    (South African Society for Animal Science, 2006) Botha, S. St. C.; Hoffman, L. C.; Britz, T. J.
    The effects of hot-deboning on the physical meat quality characteristics and shelf-life of ostrich m. gastrocnemius, pars interna (gastroc) and m. iliofibularis (iliof) were investigated during 42 days (d) of refrigeration. The hot-deboned gastroc was initially tougher than the cold-deboned muscles, while hot-deboning had no significant effect on the shear force of the iliof. After 14 d of refrigerated storage, there was no difference in tenderness between the hot- and the cold-deboned muscles. Hot-deboning caused significantly more purge (3.4 ± 2.33%) compared to cold-deboning (2.1 ± 2.06%) throughout the 42-day storage period. All muscle samples were acceptable in terms of Aerobic Plate Counts (APC < 104 cfu/g) and E. coli (E. coli < 101 cfu/g), based on the South African Standards for the microbiological monitoring of meat for refrigerated export. It was concluded that hot-deboning did not influence the shelf-life of ostrich muscles negatively.
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    Effects of post mortem temperature on rigor tension, shortening and pH in ostrich muscle
    (South African Society for Animal Science, 2008) Botha, S. StC.; Hoffman, L. C.; Britz, T. J.
    ABSTRACT: Fully developed rigor mortis in muscle is characterised by maximum loss of extensibility. The course of post mortem changes in ostrich muscle was studied by following isometric tension, shortening and change in pH during the first 24 h post mortem within muscle strips from the muscularis gastrocnemius, pars interna at constant temperatures of 7 °C and 37 °C. Maximum shortening was significantly higher at 37 °C (33.4 ± 3.57%) than at 7 °C (10.7 ± 2.63%). The rate of rigor development was temperature dependent, reaching a maximum tension at 4.08 ± 3.89 h post mortem in muscle strips at 37 °C; while at 7 °C maximum tension was reached at 10.5 ± 6.47 h post mortem. It was concluded that the completion of rigor occurred at the point of minimum pH.
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    Influence of lower substrate pH and retention time on the efficiency of a UASB bioreactor treating winery waste water
    (South African Society for Enology and Viticulture, 1999) Ronquest, L. C.; Britz, T. J.
    A mesophilic laboratory-scale upflow anaerobic sludge bed (UASB) bioreactor design was evaluated for the treatment of winery waste water. In the first experimental study, the hydraulic retention time (HRT) was shortened from 24 h to 13 h which led to an increase in the organic loading rate (OLR) from 6,34 to 10,12 kgCOD.m-3.d-l. The recovery rate of the bioreactor, in terms of pH stabilisation was much slower for HRT's less then 14 h, suggesting that the optimum operational HRT had been reached. At this HRT the average COD removals were between 93 and 97% and the removal rate was 10,94 kgCOD.m-3.d-1. The second experimental study was the reduction in substrate pH from 7 ,5 to 5,0. This study was performed to investigate the lowest substrate pH that the active microbial population in the bioreactor could handle so as to reduce neutralisation costs and acclimatise the microbes to lower pH's. The lowest operational pH reached was 5,1 with a COD removal of over 90%. This has a considerable impact on the economic aspects of the winery waste water treatment process as neutralisation of the waste water will not be necessary before introducing it to the UASB bioreactor.