Browsing by Author "Muller M."
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- ItemComparison of six crossbred lamb types: Sensory, physical and nutritional meat quality characteristics(2003) Hoffman L.C.; Muller M.; Cloete S. W. P. (Schalk Willem Petrus van der Merwe); Schmidt D.The effect of crossbreeding on lamb meat quality was examined on the M. longissimus dorsi and M. semimembranosus of South African lamb breed combinations. The lambs were sired by Dormer (D) and Suffolk (S) rams and born to Merino (M), Dohne Merino (DM) and SA Mutton Merino (SAMM) ewes to give six breed combinations. Ratings of sensory attributes on the M. semimembranosus of the different lamb breed combinations were obtained from a trained descriptive panel. The moisture, total lipids, protein, ash, mineral content and fatty acid composition of the M. semimembranosus were also obtained. Physical parameters measured on the M. longissimus dorsi were: pH48, drip loss, cooking loss and Warner-Bratzler shear force (WBS). Breed did not have a significant effect (P > 0.05) on the sensory quality of lamb, except for D × SAMM lambs which only showed a significantly higher (P ≤ 0.05) initial juiciness compared to S×M. However, breed had a significant effect on pH 48, WBS, protein content and the fatty acid and mineral composition. © 2003 Elsevier Ltd. All rights reserved.
- ItemConsumer expectations, perceptions and purchasing of South African game meat(2005) Hoffman L.C.; Muller M.; Schutte D.W.; Calitz F.J.; Crafford K.The expectations, perceptions and purchasing behaviour of consumers of game meat were Researched by a survey method using a structured, self-administered questionnaire. The sample consisted of 300 South African consumers and included 100 white, 100 coloured and 100 black consumers. It is evident that South African consumers perceive game meat differently than they do the 'traditional' meat types such as beef, mutton/lamb, chicken and pork. They do not consider game meat as a 'regular' type of meat, but rather as an exotic, seasonal product. Furthermore, South African consumers indicated that they are not willing to pay more for game meat than other types of meat. South African consumers indicated that they consider the fat content of meat as an important quality when they purchase meat, as they aspire towards consuming lean meat. This research not only shows that South African consumers are ill-informed regarding the positive attributes of game meat, but also that producers and marketers of game meat are not doing enough to promote game meat. This provides an excellent opportunity for game meat producers and marketers, as game meat is lower in fat than pork, lamb or beef.
- ItemEvaluation of the compositional and functional quality of South African triticale (x Triticosecale Wittmack) cultivars(2011) Manley M.; Snyders F.; McGoverin C.; Fox G.; Muller M.; Kidd M.; Botes W.The baking potential of South African bred triticale (x Triticosecale spp. Wittmack ex A. Camus 1927) cultivars, and the effect of cultivar and environment on baking potential parameters had not previously been studied. At present South African triticale cultivars are used for animal feed as grazing, hay or silage. Seven cultivars harvested over two years from eight localities in the Western Cape region of South Africa were used to examine the baking potential parameters falling number, SDS sedimentation, ash content, particle size index, total protein content and 1000-kernel mass. The quality of the South African bred cultivars compared well with data from cultivars grown in other countries. The triticale cultivars studied here generally had higher ash contents, lower falling numbers and SDS sedimentation values than the bread wheat standard. Significant differences (P<0.05) were observed between cultivars and between localities in each year's harvest, illustrating the effect of genetic as well as environmental factors on the quality of the grain produced. Interactions between cultivars and localities were found to be significant (P<0.05) in all cases.
- ItemImproving the bandwidth of a slotted waveguide array by using a centre-feed configuration(1999) Muller M.; Theron I.P.; Davidson D.B.The use of a centre-feed position (instead of the more conventional end-feed) was investigated to improve the reflection coefficient bandwidth of a slotted waveguide array. The results demonstrated improved bandwidth performance, but at the cost of a degradation in the pattern and a more difficult design procedure.
- ItemMale circumcision for prevention of heterosexual acquisition of HIV in men(2009) Siegfried N.; Muller M.; Deeks J.J.; Volmink J.Background: Male circumcision is defined as the surgical removal of all or part of the foreskin of the penis and may be practiced as part of a religious ritual, as a medical procedure, or as part of a traditional ritual performed as an initiation into manhood. Since the 1980s, over 30 observational studies have suggested a protective effect of male circumcision on HIV acquisition in heterosexual men. In 2002, three randomised controlled trials to assess the efficacy of male circumcision for preventing HIV acquisition in men commenced in Africa. This review evaluates the results of these trials, which analysed the effectiveness and safety of male circumcision for preventing acquisition of HIV in heterosexual men. Objectives: To assess the evidence of an interventional effect of male circumcision for preventing acquisition of HIV-1 and HIV-2 by men through heterosexual intercourse Search strategy: We formulated a comprehensive and exhaustive search strategy in an attempt to identify all relevant studies regardless of language or publication status (published, unpublished, in press, and in progress). In June 2007 we searched the following electronic journal and trial databases: MEDLINE, EMBASE, and CENTRAL. We also searched the electronic conference databases NLM Gateway and AID Search and the trials registers ClinicalTrials.gov and Current Controlled Trials. We contacted researchers and relevant organizations and checked reference lists of all included studies. Selection criteria: Randomised controlled trials of male circumcision versus no circumcision in HIV-negative heterosexual men with HIV incidence as the primary outcome. Data collection and analysis: Two review authors independently assessed study eligibility, extracted data, and graded methodological quality. Data extraction and methodological quality were checked by a third author who resolved differences when these arose. Data were considered clinically homogeneous and meta-analyses and sensitivity analyses were performed. Main results: Three large RCTs of men from the general population were conducted in South Africa (N = 3 274), Uganda (N = 4 996) and Kenya (N = 2 784) between 2002 and 2006. All three trials were stopped early due to significant findings at interim analyses. We combined the survival estimates for all three trials at 12 months and also at 21 or 24 months in a meta-analysis using available case analyses using the random effects model. The resultant incidence risk ratio (IRR) was 0.50 at 12 months with a 95% confidence interval (CI) of 0.34 to 0.72; and 0.46 at 21 or 24 months (95% CI: 0.34 to 0.62). These IRRs can be interpreted as a relative risk reduction of acquiring HIV of 50% at 12 months and 54% at 21 or 24 months following circumcision. There was little statistical heterogeneity between the trial results (χ2 = 0.60; df = 2; p = 0.74 and χ2 = 0.31; df = 2; p = 0.86) with the degree of heterogeneity quantified by the I2 at 0% in both analyses. We investigated the sensitivity of the calculated IRRs and conducted meta-analyses of the reported IRRs, the reported per protocol IRRs, and reported full intention-to-treat analysis. The results obtained did not differ markedly from the available case meta-analysis, with circumcision displaying significant protective effects across all analyses. We conducted a meta-analysis of the secondary outcomes measuring sexual behaviour for the Kenyan and Ugandan trials and found no significant differences between circumcised and uncircumcised men. For the South African trial the mean number of sexual contacts at the 12-month visit was 5.9 in the circumcision group versus 5 in the control group, which was a statistically significant difference (p < 0.001). This difference remained statistically significant at the 21-month visit (7.5 versus 6.4; p = 0.0015). No other significant differences were observed. Incidence of adverse events following the surgical circumcision procedure was low in all three trials. Reporting of methodological quality was variable across the three trials, but overall, the potential for significant biases affecting the trial results was judged to be low to moderate given the large sample sizes of the trials, the balance of possible confounding variables across randomised groups at baseline in all three trials, and the employment of acceptable statistical early stopping rules. Authors' conclusions: There is strong evidence that medical male circumcision reduces the acquisition of HIV by heterosexual men by between 38% and 66% over 24 months. Incidence of adverse events is very low, indicating that male circumcision, when conducted under these conditions, is a safe procedure. Inclusion of male circumcision into current HIV prevention measures guidelines is warranted, with further research required to assess the feasibility, desirability, and cost-effectiveness of implementing the procedure within local contexts. Copyright © 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
- ItemPhysical and sensory meat quality of South African Black ostriches (Struthio camelus var. domesticus), Zimbabwean Blue ostriches (Struthio camelus australis) and their hybrid(2008) Hoffman L.C.; Muller M.; Cloete S.W.P.; Brand M.Meat derived from three genotypes of ostrich, resulting from breeding South African Black (Black) ostriches and Zimbabwean Blue (Blue) ostriches as well as their hybrid, was analysed for physical and sensory quality. Ostriches of a commercially standard slaughter age of 14 months, raised under the same environment were used. The pH24 was the highest in the pure Blue genotype and therefore meat from this genotype was the darkest and the percentage drip loss and cooking loss the lowest. When comparing the pure Blue genotype to the pure Black genotype, 70% of the muscles had a higher pH24, 50% of the muscles were redder and significantly less saturated in colour, 67% of the muscles had a lower percentage drip loss and 50% of the muscles had a lower percentage cooking loss. No significant genotypic differences were found regarding the instrumental toughness, nor the sensory attributes of the meat. © 2007 Elsevier Ltd. All rights reserved.
- ItemPhysical, sensory and consumer analysis of eating quality and appearance of pear genotypes among South African consumers(2011) Steyn W.J.; Manning N.; Muller M.; Human J.P.The Agricultural Research Council (ARC) Infruitec-Nietvoorbij, South Africa, aims to breed new European pear cultivars with a local as well as export market potential. They are focused on a range of blushed cultivars from early to late season that do not lose their red skin colour in high temperature conditions. Important eating quality characteristics that are used as selection criteria are high sugar content (sweet taste) and a strong pear flavour. We used descriptive sensory analysis, consumer preference and physical maturity measurements to determine the preference of pear appearance and taste among South African pear consumers. Our research showed that yellow, green and lightly coloured blushed pears were preferred and important sensory attributes were pear flavour, sweet taste, melting character, juiciness and a soft texture. Good flavour and texture are the most important positive attributes. Mealiness and hardness were the main negative attributes. Hence, it appears that the ARC breeding objectives are very well aligned with the preference of South African consumers. The findings were also consistent with international studies that indicated high pear flavour, sweetness, melting texture and juiciness as the most preferred sensory attributes in European pears. Therefore, preference studies can be conducted locally on new cultivars for the export market. Considering the preference for lighter red blush, breeders may find that new cultivars that accumulate more red pigment and are therefore less prone to colour loss may have a lower preference among consumers.
- ItemSecundum atrial septal defects - A review of 75 patients(2000) Muller M.; Kerkhof M.; Van der Merwe P.-L.Secundum atrial septal defect (ASD) is the most common type of ASD within the spectrum of congenital cardiac abnormalities in children. In this retrospective study the data on 75 patients with a pure secundum ASD were analysed. The male/female ratio was 1:1.3. This is less than the reported male/female ratio of 1:2. The symptoms most often found were shortness of breath, cough and susceptibility to fatigue. An ejection systolic heart murmur was found in the majority of the patients. A fixed split second heart sound was only found in 49% of patients. This could have been the result of incomplete documentation, inexperienced clinicians, a fast heart rate or the fact that a split second heart sound is not always present in patients with ASDs. On the chest radiograph the majority of patients presented with right ventricular enlargement, right atrial enlargement and increased pulmonary blood flow. A relatively unexpected finding on echocardiography was left atrial enlargement. This is usually caused by volume overload in the presence of large ASDs. Another unexpected finding was the high number of left QRS-axis deviations (10%) and indeterminate QRS- axis deviations, left rotation (7%) present on the electrocardiogram. This finding is much higher than the reported 3.8% of left QRS-axis deviation present in patients with secundum ASDs. The only explanation for this phenomenon is that during the embryological development of the atrial septum, not only does a secundum ASD develop, but the endocardial cushion becomes involved, giving rise to abnormal conductive pathways.
- ItemSensory and preference testing of selected beef muscles infused with a phosphate and lactate blend(2008) Hoffman L.C.; Muller M.; Vermaak A.Consumers expect beef products to be juicy and tender. In the present investigation four beef muscles, i.e. Biceps femoris (BF), Longissimus lumborum (LL), Rectus femoris (RF) and Semitendinosus (ST), were infused with a blend consisting of sodium and potassium salts, di- and triphosphates and lactates. The muscles were stored at 4 °C for 24 h, followed by storage at -18 °C until the descriptive sensory analysis could be performed on all four muscles. BF and LL were also subjected to consumer sensory analysis to determine the overall degree of liking. The infused and non-infused samples did not differ significantly with regard to aroma and flavour. The infused samples were significantly more juicy and tender than the untreated samples. Although the infused samples were rated significantly higher in salty taste than the untreated samples, both treatments illustrated a relatively low mean value for saltiness. Both the infused LL and BF samples illustrated a high degree of liking. Therefore, the infusion of beef muscles with a blend containing phosphates and lactates could be applied successfully to enhance the sensory attributes of beef. © 2008 Elsevier Ltd. All rights reserved.
- ItemSensory characterization of rooibos tea and the development of a rooibos sensory wheel and lexicon(2012-02-22) Koch I.S.; Muller M.; Joubert E.; van der Rijst M.; Naes T.Rooibos samples were collected throughout the 2009 harvesting season from different geographic areas in the Western Cape, South Africa, and from different producers to capture as much potential variation in rooibos sensory characteristics as possible. The quality (i.e. the appearance of the leaves, and the color and flavor of the infusion) of 69 samples was evaluated by expert graders, and samples were grouped into four quality grades. Using descriptive analysis sensory profiles of the rooibos samples were developed and 121 aroma, flavor, taste, and mouthfeel descriptors were generated. A rooibos sensory wheel was created by selecting 27 flavor, taste and mouthfeel attributes and grouping these terms together to form a logical, convenient and user-friendly overview of the sensory descriptors associated with rooibos. The most frequently occurring descriptors were selected to compile a rooibos sensory lexicon of 14 flavor, taste and mouthfeel attributes along with a definition and reference standard for each term. It was found that the term "characteristic" rooibos flavor may be described as a combination of honey, woody and herbal-floral notes with a slightly sweet taste and subtle astringency. Also, differences in the sensory characteristics between and within different quality grades were established with low-quality tea often being associated with green, hay-like and musty flavors and a bitter or sour taste. High-quality tea was generally associated with pleasant rooibos attributes including honey, woody, floral and caramel notes and a sweet taste. This research is a first step towards the broader objective of standardizing the sensory terminology of rooibos tea. © 2011 Elsevier Ltd.
- ItemThe retail of South African game meat: Current trade and marketing trends(2004) Hoffman L.C.; Muller M.; De Schutte W.; Crafford K.The purchasing and marketing of game meat by supermarkets and butcheries in the Western Cape Province of South Africa was researched by the survey method. Two supermarket groups in South Africa indicated that they do market game meat, and springbok (Antidorcas marsupialis) was the species that most supermarkets sold. Both supermarket groups indicated that they would sell more game meat if available. They also mentioned that a central marketing structure would facilitate the sale of game meat and ensure consistent quality. Thirteen of the twenty butcheries that sell game meat were also in favour of a central marketing structure. The butcheries indicated that consumers are not adequately informed about the health benefits and cooking methods of game meat. Some of the meat buyers at butcheries were ignorant of the qualities of meat that are important when purchasing game meat. It is evident that game meat marketers should exercise stricter control over the quality of game meat, and that supermarkets and butcheries are not promoting game meat extensively enough.