Spelling suggestions: "subject:"south africa."" "subject:"south affrica.""
421 |
Microencapsulation and supply of Bifidobacterium lactis DSM 10140 in fermented traditional African beveragesKokott, Shaun January 2004 (has links)
Thesis (MTech (Food Technology))--Cape Technikon, 2004 / Probiotic foods are intended to supply selected viable microorganisms, for
example Lactobacillus acidophilus and Bifidobacterium, to consumers. These
organisms, when consumed at the daily intake of 108
, provide benefits beyond
basic nutrition. Probiotic (AB) foods generally include fermented dairy products
such as yoghurts and cheeses, targeted at the upmarket consumer. However,
due to technical problems associated with the foods and the organism, viable
Bifidobacterium rarely occur in AB foods.
The principle aims of this study were to develop a suitable delivery system for
Bifidobacterium to the consumer, and to supply these living organisms in the
affordable traditional fermented African beverages, amasi and mahewu. This
would provide the benefits of probiotics to the rural African consumer, where
malnutrition and gastrointestinal diseases occur. The organism selected for
this study was Bifidobacterium lactis DSM 10140, commonly associated with AB
starter cultures for yoghurts. The delivery system selected was
microencapsulation of B. lactis using a mixture of the generally recognised as
safe (GRAS) edible gums, gellan and xanthan. Supply vehicles for the
microcapsules to the consumer were amasi and mahewu.
Prior to microencapsulation, rheological studies were undertaken to determine
whether the gellan-xanthan gum mix would provide a suitable support matrix for
microencapsulated B. lactis. This was done using a Paar Physica MGR 300
rotational rheometer with a cone plate 50-2 measuring system. Results
indicated that the hydrated gellan-xanthan gum mix behaved as a
non-Newtonian material, and the flow curve fitted well to the Herschel-Bulkley
model. This demonstrated that the gel was a relatively viscous material with
solid properties. The average yield stress of the gel was 1.515 Pa, indicating
that the gel was stable, and at lower stresses would behave as a solid. The gel
mix would be disrupted by shear stresses associated with mastication and
peristalsis. The minimum viscosity of the gel was constant at temperatures
between 46°C - 61°C. It was concluded from these data that the gel was
suitable for microencapsulation and that microcapsules should only be included
in soft foods, which do not require chewing. Temperatures associated with
microencapsulation, at minimum gel viscosities, were not lethal to B. lactis.
Bifidobacterium lactis cells were incubated under anaerobic conditions (4% H2,
10% CO2, and 86% N2) at 37°C overnight in 250 ml Tryptone-Yeast-Glucose
(TYG) broth, and grown to an 00600 0.9 - 1.1. Cells were harvested and
washed for microencapsulation using centrifugation.
Microencapsulation of the organism was done using a mono-axial extrusion
technique together with a superposed airflow, by manually extruding the
aqueous gum I cell mix through a 27.5 G bevelled needle, fitted on to a 10 ml
syringe. The resultant microdroplets were hardened by free fall into 0.1 M
CaCI2 solution. Microcapsules were separated from the CaCI2 solution by
filtration through Whatman No.1 filter paper. All procedures were carried out in
a laminar flow hood. Results indicated that the method of microencapsulation
used in this study was successful. Using a concentrated inoculum of B. lactis,
high numbers (lOglO 11-12 etu.g-1
) of bacteria were incorporated into the
microcapsules. Therefore the daily intake would be provided by 0.1 g
microcapsules.
The diameter and size distribution of microcapsules were determined by laser
diffractometry. This showed a maximum microcapsule diameter of 2.22 mm
with 50% (w/v) of the microcapsules having a diameter of < 0.637 mm.
Although this represents a considerable size variation, this would not adversely
affect mouthfeel of the beverages, as only 0.1 g microcapsules would be
required to obtain at least 108 B. lactis in any volume of amasi or mahewu.
To enumerate immobilised viable B. lactis, two techniques were compared.
These involved the use of either a pestle and mortar, or high power ultrasound
(HPUS) (20 kHz, 750 W). Results showed that HPUS was superior to the
pestle and mortar technique. A short exposure (15 s) to HPUS disrupted the
matrix releasing all entrapped etus, whereas when using the pestle and mortar
xiii
technique, cells remained partially entrapped in the gel. Therefore the pestle
and mortar technique yielded lower cfu values than expected.
The survival of microencapsulated B. lactis, in 1 M sodium phosphate buffer,
was studied as a possible means of supply of microcapsules to industry for
incorporation into foods. Microcapsules were stored in the buffer for 21 days at
either 4°C or 22°C. Results showed that cell viability was not significantly
reduced (p>0.05) at either temperature after 21 days. Hence this form of
storage could be used to deliver viable immobilised B. lactis to the food
industry.
In order to assess the survival of immobilised B. lactis in the GIT, the
microcapsules were incubated at 37°C over a period of 240 min in simulated
gastric juice (SGJ) (pH 1.5). Viable counts were performed by sampling at
regular intervals. A similar study was done in simulated bile and pancreatic
juices (BPJ) (pH 6.5). In SGJ, it was demonstrated that there was a significant
reduction (3 log cycles) (p<0.05) of free cells after 240 min. However, this
trend was not noted for microencapsulated B. lactis. Therefore, the gellanxanthan
gel matrix protected B. lactis from the lethal effect of SGJ. In BPJ, no
significant difference (p>0.05) was noted for surviving fractions of both
immobilised and free B. lactis.
Commercial pasteurised amasi (pH 4.4) and mahewu (pH 3.5) were selected as
the supply vehicles for the microencapsulated B. lactis. Known numbers of
viable microencapsulated and free B. lactis cells were added to both beverages.
For most samples, incubation was at either 4°C or 22°C for 21 days in the
presence of atmospheric oxygen. In addition, free cells were incubated
anaerobically at 22°C. As oxygen is limiting in the microcapsules, these were
not incubated under anaerobic conditions. The survival I shelf-life studies of
commercial amasi indicated no significant difference (p>0.05) in survival rate
between immobilised and free B. lactis cells. The reduction noted for viable
counts of immobilised or free B. lactis cells was approximately 1.5 log cycles.
Even so, after 21 days viable immobilised B. lactis (1010 0.1 g'l microcapsules)
remained in excess of the daily intake 108
, whereas in the free B. lactis cells,
the viable count declined to 106 mr1
. Statistical analyses showed that
temperature or oxygen presence had little effect on the survival of both
immobilised or free B. lactis cells (p>O.05). In mahewu, decline in viability of
cells was observed for most samples. However microencapsulation enhanced
cell survival at both 4°C and 22°C when compared to free cells. The decrease
in viable B. lactis free cells occurred more rapidly (3 log cycles) in mahewu,
than in amasi, at both 4°C and 22°C. Throughout the shelf-life studies it was
apparent that viable B. lactis cell numbers did not increase. This was
advantageous as metabolites associated with B. lactis growth would have
adversely altered the taste of both amasi and mahewu.
Sensory evaluation of the traditional fermented African beverages, enriched
with either viable immobilised or free B. lactis, was done in order to determine
consumer response to the product. An analytically trained 12-member taste
panel analysed the beverages for colour, texture, and taste. The triangle taste
test procedure was used. No differences were detected with regard to texture,
and colour of the fermented beverages containing immobilised B. lactis.
However, in the fermented beverages containing free cells, a change in
viscosity was noted. There was a significant difference (p<O.05) recorded in
flavour for both amasi and mahewu containing free B. lactis cells. In the two
fermented beverages enriched with immobilised cells, significant (p<O.05)
flavour differences were detected in mahewu. However, this was not observed
in the amasi samples containing immobilised B. lactis. Therefore, in order to
retain the sensory properties of amasi, B. lactis should be supplied in
microcapsules. In mahewu, although flavour differences noted were not
unpleasant to the panellists, results from this study indicate that the use of
commercial flavoured mahewu should be considered as a supply vehicle for
microencapsulated B. lactis.
Overall, this study demonstrated that immobilisation of B. lactis in
gellan-xanthan gum is possible. Microcapsules produced contained high
numbers of viable B. lactis, and were suitable for incorporation into soft foods.
The gel matrix significantly protected viable cells from harsh conditions
associated with SGJ. Although the surviving fraction of immobilised cells,
when compared to free cells, was not improved in amasi samples, it is
recommended that for technological reasons associated with production of
amasi, microencapsulation should be used. In mahewu, microencapsulation
enhanced B. lactis survival at both 4°C and 22°C. Therefore immobilisation of
B. lactis in mahewu is necessary in order to maintain the daily intake.
Immobilised B. lactis should be incorporated into both beverages after
fermentation, and pasteurisation.
|
422 |
Americans in South Africa, 1784-1870Booth, Alan R. January 1964 (has links)
Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / This study discusses the course and consequences of Americans -- traders, whalers, explorers and missionaries -- in South Africa between 1784 and 1870. Sources for the study included logbooks, personal and business papers of merchants and ship captains, colonial records, and missionary letters. Research was carried on in libraries and archives in the United States and Great Britain.
Yankee whalers found by the late eighteenth century that South African waters, especially in the vicinity of Walvis and Delagoa Bays, abounded with right whales. The whalers' activities in Cape waters included not only conventional trade at Cape Town and Simons Town, but also considerable trade and intercourse with Africans along the coasts.
The trade of Americans with South Africa began as the result of their quest for new world markets prompted by the withdrawal of trade advantages by Great Britain after the American Revolution. The Cape of Good Hope came to be valued by merchants as a place where a general cargo might be sold and another loaded for markets either in the Orient, the West Indies, or the United States. Located on a major trade route, the Cape was valued as a place where information on world markets could be obtained. American trade was discouraged and frequently interrupted by British and Dutch regulatory acts and discriminatory duties. But after the early thirties, with the rise of the American glove, shoe and tanning industries, the importation of hides and skins from South Africa firmly established the trade. With the rise of the wool trade by the late forties, commercial relations were further strengthened. Thereafter, while the Cape continued to be a limited market, it was conditions in America which primarily influenced the commerce: the American Civil War and various United States tariff acts determined the quantity and character of the staple Cape export to America, wool.
Missionaries from the American Board arrived in South Africa in 1835. Motivated largely by the millenarian tradition, they came to preach the gospel and save "heathen" souls before the Second Coming. Their early efforts were unsuccessful. The Interior Mission to Mzilikazi was plagued by sickness, and finally withdrew after the Boer attack on Mosega in 1837. In Natal, after a more encouraging start with Dingaan's Zulus, the Maritime Mission was again forced to flee after the massacre of the trekboers in February, 1838. Two missionaries remained in South Africa, and by 1839 they had returned to Natal. The growth of the Mission over the next three decades was steady but moderate, marred in part by the missionaries' prejudices and conservative attitudes toward African customs and education. Gradually more tolerant attitudes began to prevail among the missionaries, with the resultant strengthening of the Mission. Churches were formed and became self-supporting, and by 1870 there were African pastors in the field. By the thirties, the sum total of American involvement had brought sharp reaction from Cape Europeans. American munitions smuggling to the Zulus was a cause of concern, and there were fears that American trading and missionary activity in Natal signified colonial ambitions there on the part of the United States. It was an American merchant ship in Port Natal which finally prompted Governor Napier's decision in 1841 to reoccupy Natal. American consuls in South Africa were relatively inactive until the American Civil War, when the Alabama captured a Union merchantman in Table Bay. Ensuing complications, including a supposed American territorial violation at Angra Pequena, clouded American-British relations until the Geneva Arbitration award in 1872. / 2031-01-01
|
423 |
Masisebenzisane = Let us work together / Let us work togetherGeerdts, Penelope January 1991 (has links)
No description available.
|
424 |
What is a credit union?Cape Credit Union League January 1900 (has links)
A credit union is a self-help financial co-operative where people, who are united by a Common Bond, agree to save money together and, to make loans to one another at low rates of interest. The common bond is the most important characteristic of a credit union because credit unions are founded on trust and unless members already have something in common, they have no basis for trusting one another. The purpose of the common bond is to protect members' interests and members' funds. It also fosters a spirit commitment and co-operation.
|
425 |
Will the expanded audit report model proposed by IAASB reduce the expectation gap in South Africa?Maseko, Kwena Nicholas January 2016 (has links)
In 2013 the International Auditing and Assurance Standards Board (IAASB) proposed the revision of the international auditing standard on the audit report (ISA 700) to meet the information needs of the users of audited financial statements. The purpose of this research was to investigate whether the International Standards Assurance and Accounting Board’s (IAASB) revised International Standard on Auditing (ISA 700) would reduce the expectation gap. It focused on the expectation gap investigation in three areas, namely: responsibilities of auditors, reliability of audited financial statements and decision-making usefulness of audited financial statements. A differential testing instrument was used in the study and completed by research subjects that comprised auditors, bankers and shareholders. Non-parametric Kruskal-Wallis H test and non-parametric Mann-Whitney test were used to analyse the data. The results of the study showed that despite the audit report modifications, expectation gap remained persistent with regard to auditors’ responsibilities. On the positive front, the study showed that the revised ISA 700 resulted in users finding audited financial statements reliable and useful for decision-making purposes.
|
426 |
A feasibility study in the development of an off-line PLC based robot control systemBryson, Craig Weir January 1990 (has links)
A project report submitted to the Faculty of Engineering, in partial fulfilment of the requirements for the degree of Master of Science in Engineering, University of the Witwatersrand. Johannesburg 1990. / Robotics are becoming a more prominent force in the
industrial environment, and research is being concentrated
on control rather than on the robot. The feasibility of a
substitute, off-line, plc based control system was
investigated. Many advantages are associated with an
off-line system, as well as the large financial saving (at
the most 50% that of the existing controller) .
A PLC with discrete 1/0 modules and a fast counting module
were used. Open loop control was looked at, with optical
encoders used for position control. Overshoot of the DC
motors consistently occurred, and other external factors
ensured the unpredictability and instability of open loop
control.
It was concluded that closed loop control was necessary to
ensure accurate positioning and speed control. PLC modules
Were investigated, and an axis control system (not yet
commercially available) was found to ideally suit the
purpose of servo/encoder control. This system makes use of
speed and position feedback signals, essential for accurate
terminal Control of the robot. / MT2017
|
427 |
Analysing the relevance of public service broadcasting in the South African television sector for the digital dispensationGongxeka, Nomonde January 2016 (has links)
A research report submitted to the Faculty of Humanities, of the
University of Witwatersrand, in partial fulfilment of the
requirements for the Degree of Master of Arts in ICT Policy
and Regulation
October 2016 / In the current era of the digital television (TV) broadcasting dispensation, the relevance of the Public Service Broadcasting (PSB) mandate in South Africa remains critical, to inform and build democracy in the public interest. Recent debates with regard to the relevance and retention of PSB in the digital era seem to suggest that there are divergent views in this regard. These debates gave rise to this study.
The study aimed to assess and reconfigure the role of the South African Broadcasting Corporation (SABC) in carrying the public broadcasting mandate in the digital era. Furthermore, the study explored how the PSB remit can be repositioned to meet the needs of South African citizens in the 21st century. In addition, this study investigated the evolution of public service broadcasting policy and the role played by the Department of Communications (DoC), the policy maker in informing policy. The study seeks to ascertain whether the policy direction provided by the DoC is in actual fact in sync with the developments taking place in the TV broadcasting sector.
This research followed a qualitative research approach, by exploring the relevance of PSB in the digital era and also by examining South Africa’s 3-tier broadcasting system, with a particular focus on the SABC. The research analysed the SABC (PSBs), MultiChoice (pay-TV licensee), e.tv (Free-to-Air commercial licensee) and Association of Community Television in South Africa (ACT-South Africa), a body representing Community TV licensees, in their attempts to discharge the PSB remit in the digital era. The qualitative paradigm aided in the process of describing and understanding the research topic.
The main findings of this study revealed that the PSB mandate still has relevance in the digital era, however weak this may be. The multi-channel and the competitive TV broadcasting landscape will deplete the commercial advertising market share, on which the SABC heavily relies for revenue income. Secondly, the SABC’s mandate can never be upheld unless appropriate funding is secured by government. Lastly, the findings reveal that the DoC has regressed in providing policy and prescriptions and that there is thus a policy vacuum in the implementation of the PSB mandate. / MT2017
|
428 |
Implementation and outcomes of the Expanded Public Works Programme (EPWP) in MabopaneMogagabe, Caroline January 2017 (has links)
Thesis presented in partial fulfilment for the degree of Master of Management (in the field of Public Sector Monitoring and Evaluation) to the Faculty of Commerce, Law, and Management, University of the Witwatersrand, 2016 / 22 years into the democracy, South Africa is still struggling with unemployment. Issues such as poor education outcomes, high disease burden, uneven public service performance, corruption and others have been listed amongst issues the country is facing however; poverty and inequality have been identified as the two main challenges facing the country (The National planning commission, 2012). This research attempted to understand unemployment and how the EPWP addresses the unemployment issues at a local level. The EPWP intends to provide temporary employment and provide training to its beneficiaries through skills programmes, learnership and artisan development. The skills and training provided intend to enhance the beneficiaries’ chances of being employable on other projects after exiting the EPWP (EPWP, 2016)
Between 1994 and 2014 white labour force has increased with 9 percent, Indian/Asian labour force increased with 45 percent, 5 percent increase of coloured work force and a 95 percent hike of black African labour force (Stats SA, 2014). According to the National planning commission (2012) South Africa has made a remarkable transition from apartheid into democracy. The high growth experienced by the black African ethnic group has been attributed to the number of interventions implemented by the government to eradicate inequality such as Affirmative Action Act (AA). From the stats provided, one is able to deduce that the government has been able to make progress in terms of decreasing inequality and therefore needs to develop employment creation strategies to address unemployment.
The literature review conducted in this study indicates a link between unemployment, economic growth, apartheid and skills development. Apartheid has not been pursued as an attribute as strategies to overcome it have become pre-eminent. This research utilised the qualitative strategy and cross-sectional research design. Semi-structured interviews were conducted with interview schedule as a guiding tool for basic questions, the researcher asked further questions when required to do so. / XL2018
|
429 |
Data charges, delivery dependability, geographical distance, product risk and information quallity as predictors of online purchase intention in the South African retail sectorLuthuli, Menelisi Minenhle January 2017 (has links)
A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy, School of Economic and Business Sciences, 2017 / The continuous growth of e-commerce has led to a keen interest in the uptake of online shopping. This phenomenon is even more prevalent in developed western countries. However, penetration has taken place at a lessor rate in developing countries in most parts of Africa including South Africa. Apart from infrastructural capability and adequate online store reputation, the success of online shopping fundamentally rests upon e-tailers who are able to capture consumers by understanding what variables drive them to shop online. Although several studies have explored factors that drive online purchase intention, few have explored variables of interest as done in this present study. More specifically, this sort of research is scarce within the South African general merchandise online retail sector. This study aims to determine whether data charges, delivery dependability, geographical distance, product risk and information quality have any influence on consumers‘ online purchase intention. The conceptual model adopted in this study selected data charges, delivery dependability, geographical distance, product risk and information quality as predictor variables, online shopping satisfaction and trust as mediating variables and online purchase intention as the outcome variable. This is a quantitative study whereby 20 000 online survey questionnaires were distributed to a base of two renowned South African online retailers who predominately specialize in general merchandise. Of those distributed, 924 were complete and thus deemed useable by the researcher. The findings support all eight proposed hypotheses, therefore indicating that the aforementioned variables indeed influence online purchase intention at varying levels of significance. The study seeks to contribute new contextual knowledge, adding to the existing literature linked to online retailing and to contribute new empirical and theoretical findings. The research findings highlight new insights to marketing practitioners who, with better understanding of consumer decision making theory, will be able to create strategies that can be employed to influence consumers‘ online purchase intention in the South African general merchandise online retail sector.
Keywords: E-commerce, online shopping, purchase intention, general merchandise retail. / GR2018
|
430 |
Adults learning to write: exploring alternatives to functional writingSher, Alison 04 October 2011 (has links)
MA, School of Literature and Language Studies, Faculty of Humanities, University of the Witwatersrand, 2003
|
Page generated in 0.0761 seconds