Thesis (MSc)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (MScFoodSc)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (M. Sc. (Medical Sciences)) -- University of Limpopo, 2020 / This study investigated the effect of rooibos tea on human sperm in vitro. Semen samples from 50 healthy men and 50 patients were treated with aqueous extracts of fermented rooibos (0 µg/ml, 0.10 µg/ml, 1.0 µg/ml, 10 µg/ml, 100 μg/ml) and unfermented rooibos (0 µg/ml, 0.15 µg/ml, 1.5 µg/ml, 15 µg/ml, 150 μg/ml) for one hour at 37ºC. Thereafter, sperm parameters were analysed. Exposure to unfermented rooibos had no effect on sperm motility, vitality and DNA fragmentation in both groups (P>0.05). However, this treatment significantly increased the production of reactive oxygen species, thus influencing the acrosome reaction, and demonstrated a decrease in mitochondrial membrane potential in the donor group (P<0.05). Treatment with fermented rooibos increased progressive motility in the donor group (P<0.05) but had no effect on sperm vitality, reactive oxygen species and the acrosome reaction in either group (P>0.05). A decrease in mitochondrial membrane potential and DNA fragmentation was observed in the donor group and the patient group (P<0.05). Rooibos tea maintains certain sperm functional parameters, and this may positively affect fertility rate. / National Research Foundation (NRF)

Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2015. / Rooibos iced tea (RIT), as one of the products of Rooibos is fast becoming very popular as a beverage in society due to the benefits of the phenolic compounds that are associated with this herbal tea. Some of the commercially available products have been found to contain, if any, lower contents of the major phenolic compounds, namely aspalathin and its oxidation products, iso-orientin and orientin. Their presence is considered as indicators of a good quality product. The purpose of this study was to investigate the effect of ultraviolet-C (UV-C) light as an alternative treatment to heat treatment on the shelf life, pH, phenolic composition, colour and microorganisms associated with Rooibos. Two formulations of RIT were used in order to determine the efficacy of the UV-C on the shelf life whilst three formulations were used for the physicochemical analysis. Only one formulation was used for inoculation with three spoilage bacteria, yeast and mould spoilage microorganisms namely; Escherichia coli K12, Staphylococcus aureus, Salmonella sp., Saccharomyces cerevisiae and Cladosporium sp. The UV-C dosages of 0, 918, 1 836, 2 754 and 3 672 J.l -1 were used to treat the RIT using a pilot-scale UV-C system with a turbulent flow at a constant flow rate of 4000 l.hr-1 . A log count of 4 log10 was considered the limit for the spoilage growth since it is the average log10 afternormal pasteurisation. The use of UV-C treatment was found to have significantly (p1) effect on the overall colour difference of the RIT in formulations A, B, and C. All the spoilage microorganisms were significantly reduced by UV-C dosage to less than 4 log10 except the Cladosporium sp. The S. cerevisiae was the most sensitive microorganism whilst Cladosporium sp. was the most resistant. The effect of UV-C on the spoilage microorganism followed the sequence: S. cerevisiae>Salmonella sp.>S. aureus>E. coli K12>Cladosporium sp. This study indicated that microbiological reduction was achieved as a function of increasing UV-C dosage. In order to achieve the highest log10 reduction, the highest UV-C dosage of 3 672 J.l-1 may be used. However, the dosage may need to be increased in order to achieve the desired results in the treatment of Cladosporium sp. It can thus be concluded from the above investigations that UV-C dosage treatment of 3 672 J.l-1 is optimum in the non-thermal treatment of RIT / South African Association for Food Science & Technology Cape Peninsula University of Technology Bursary

The total mineral ion concentration of Rooibos Tea was determined using ICP-OES. Significant concentrations of Na, K, Mg, Ca, P were found, and trace levels of Al, Fe, Mo, Sr, Zn, Ba, Cu and Pb detected. Protocatechuic acid, aspalathin and rutin were identified in Rooibos tea infusions analysed with HPLC. Analysis of tea samples by Ion Chromatography showed the presence of Cr and S042- ions. Rooibos Tea liquor had a pH of 4.6 once equilibrium had been reached. Partition coefficients (1.0 - 1.4 mm sieving fraction) for Na+, K+, Mg2+, protocatechuic acid, aspalathin, rutin, S042- and Cl were determined for infusions at 80 C using a graphical and a successive extraction method. A total mineral content method was also used to determine the partition coefficients for the mineral ions. The Na+, K+, Mg2+,SO42-, H2P04- (as P) and Cl ions as well as protocatechuic acid, aspalathin and rutin all displayed first order behavior, allowing the determination of infusion rate constants. The particle size effect was investigated at 80 C. All the mineral ions showed an increase in infusion rate constant with decreasing particle size, protocatechuic acid and aspalathin showed no trend, while the rutin infusion rate constant was independent of particle size. Calcium uptake by the leaf was observed, this was more pronounced with the smaller particle sizes. Infusion rate constants and hence diffusion coefficients were determined for the nine species for temperatures ranging from 45 to 90 C. These diffusion coefficients for the mineral ions were compared with those for the respective species in aqueous media to give hindrance factors, which were of the order of 102. Except for Cl, all hindrance factors increased with an increase in temperature. The infusion rate constants for all the species at the various temperatures were fitted to an Arrhenius equation and activation energies of infusion determined. The values were lower than those predicted theoretically. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998

Thesis (MTech(Food and Nutrition))--Cape Peninsula University of Technology, 2010 / Oxidative stress had been linked to the development of certain chronic diseases, but can be delayed or prevented by the consumption of dietary antioxidants. Fruits, vegetables, wholegrains and beverages, such as, teas are the major dietary antioxidant contributors. The majority of South Africans do not consume adequate daily servings of fruits and vegetables, neither sufficient minimally processed grains nor wholegrains. One way to incorporate antioxidants in the South African diet is by adding antioxidant-rich foods or beverages to recipes as ingredients. The objective of this study was to determine the effect on the total antioxidant capacity (TAC) of substituting water with rooibos herbal tea in soup recipe formulations. Rooibos is a proudly South African beverage rich in antioxidants. Soup is a readily available and relatively inexpensive meal item regularly consumed during the winter months in South Africa. Three popularly consumed soups in the City of Cape Town Metropolitan Municipality namely chunky vegetable, butternut and chicken noodle were selected for the experimental study. The water in each of the soup recipe formulations (control) was substituted with fermented and unfermented / “green” rooibos (experimental recipe formulations). The study was of comparative nature as the results (i.e. the TAC as the factor investigated) of three different soup recipe formulations on fluid manipulations of each (with fermented and unfermented rooibos) was compared to the control soup recipe formulations of each (no fluid manipulation). The results (i.e. the TAC) of the three prepared control and experimental soup recipe formulations were also compared to that of the raw soup mixtures of each of the soup recipe formulations to determine the effect of thermal processing on each. The main variable identified in the preparation of the soup recipe formulations that may impact the TAC (the dependent variable) and needed to be controlled was the heat application. Other variables that may influence the results were the soup recipe formulation ingredients, the prepreparation of the raw ingredients, the standing time of ingredients before use and the equipment used. Before determination of the heat applications and the fixed time allocations of the soup recipe formulations to ensure recipe standardisation, the pre-preparation procedures of the raw recipe ingredients were also standardised.

>Magister Scientiae - MSc / The aim of this study was to investigate the presence of Salmonella in the tea processing environment, to identify and detect potential virulence genes isolated from Salmonella in the tea, and to determine the antibiotic resistance levels of Salmonella isolated from fermented Rooibos. / National Research Foundation (NRF)

Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Aspalathus linearis is a leguminous shrub native to the Cedarberg Mountains in the Western Cape, of which the leaves and stems are used for the preparation of rooibos tea. Over the past few decades, rooibos tea and other related products have gained popularity due to their health promoting properties. These beneficial properties can partly be ascribed to the phenolic constituents that are trapped within the cellulolytic plant material of the tea leaves as glycoconjugated aroma and phenolic compounds. Although many fungal species are known for their efficient hydrolysis of plant material, fungal enzymes have not been evaluated for the bioprocessing of rooibos tea to improve its commercial value. It was the objective of this study to identify a specific cocktail of microbial enzymes to enhance the maceration of the rooibos plant material, while retaining the antioxidant content. During this study, 11 fungal species known for the production of hydrolytic enzymes, as well as 12 species isolated from rooibos tea products, were screened for their potential to improve aroma development and/or increased extraction of soluble matter and/or antioxidants from rooibos tea material. After culturing in Potato Dextrose medium, the crude enzyme extracts of the 23 isolates were evaluated on spent rooibos tea for enhanced extraction of soluble solids (SS) and/or total polyphenols (TP). Nine strains increased the yield in SS (improvement varying from 3% to 42%), while 14 strains yielded higher levels of TP (increase varying from 1% to 36%). Little improvement in colour development from green (unfermented) rooibos tea was observed, but the enzyme extracts from Pleurotus ostreatus var. florida, Lentinula edodes, Aspergillus oryzae, Aspergillus tubingensis, Paecilomyces variotti and Trichoderma reesei improved the aroma development from green tea to some extent. Ten-fold concentrated enzyme extracts from four of these isolates were able to release at least an additional 10% in SS from the green tea. The crude enzyme extracts prepared from three food-grade strains, i.e. Aspergillus oryzae, Lentinula edodes and Pleurotus ostreatus var.florida, contained relatively high levels of endoglucanase, xylanase and pectinase activities. Eight different culture media were evaluated for optimal hydrolase and laecase production by these food-grade fungi. MYPG proved to be the best growth medium, while 1% spent grain, 1% wheat straw and 1% pineapple peel gave the best induction of xylanase, cellulase, pectinase and laecase activities for L. edodes. When cultured in the Yeast Peptone (YP) medium + 1% wheat straw, the L. edodes enzyme cocktail showed the best improvement in both the aroma and colour development of green tea and may be considered for shortening of the fermentation time required for green tea processing. Traditional open-air fermentation of rooibos tea can take up to -1-6hours, which results in a significant loss in antioxidants and therefore also in its pharmaceutical and nutraceutical value. The Rhizopus oryzae cocktail prepared in YP + 1% wheat straw showed potential for the development of a quick-draw fermented tea made by infusion, where there is improved colour release and more than 20% improved extraction of soluble solids without a loss in the TP content. When cultured in Potato Dextrose medium, the L. edodes cocktail can be used for aroma and colour development from green tea, while the R. oryzae cocktail can be used for increasing the antioxidant content in rooibos extracts from green or fermented tea. This was confirmed with small-scale industrial treatments of fermented tea where the L. edodes YP + wheat straw cocktail improved the release in SS by more than 10% and the R. oryzae yP + wheat straw cocktail increased the yield in SS by more than 30% and the TP by more than 20%. / AFRIKAANSE OPSOMMING: Aspalathus linearis is 'n fynbosplant inheems aan die Sederberge in die Wes-Kaap, waarvan die blare en stingels vir die voorbereiding van rooibostee gebruik word. Die afgelope paar dekades het die gewildheid van rooibostee en verwante produkte aansienlik toegeneem weens die gesondheidsvoordele wat dit inhou. Hierdie voordelige eienskappe kan toegeskryf word aan die fenoliese komponente wat binne die sellulolitiese plantweefsel van die teeblare as gekonjugeerde geur- en fenoliese verbindings vasgevang is. Alhoewel verskeie swamspesies vir hul doeltreffende degradering van plantmateriaal bekend is, is fungale ensieme nog nie geëvalueer vir die prosessering van rooibostee om die kommersiële waarde daarvan te verbeter nie. Die doelwit van hierdie studie was om 'n spesifieke kombinasie van mikrobiese hidrolitiese ensieme te identifiseer wat die maserasie van rooibos plantmateriaal sal verhoog met behoud van die anti-oksidant inhoud. Tydens hierdie studie is 11 swamspesies wat bekend is vir die produksie van hidrolitiese ensieme, asook 12 swamspecies wat vanaf rooibostee produkte geïsoleer is, geëvalueer vir hul potensiaalom geurontwikkeling en/of ekstraksie van oplosbare stowwe en/of anti-oksidante vanuit rooibostee materiaal te verbeter. Die kru ensiemekstrakte van die 23 isolate, wat ID Aartappel-Dextrose medium opgegroei is, is op oorskot rooibostee geëvalueer vir verhoogde ekstraksie van oplosbare vastestowwe (SS) en/of totale polifenole (TP). Nege rasse het die opbrengs van oplosbare vastestowwe verhoog (verbetering tussen 3% en 42%), terwyl 14 rasse die totale polifenoliese vlakke laat toeneem het (tot so hoog as 36%). Baie min verbetering in kleurontwikkeling van groen (ongefermenteerde) rooibostee is waargeneem, maar ensiemekstrakte van Pleurotus ostreatus var. florida, Lentinula edodes, Aspergillus oryzae, Aspergillus tubingensis, Paecilomyces variotti en Trichoderma reesei, het wel die aroma ontwikkeling vanaf groen tee tot 'n mate verbeter. Tienvoudig gekonsentereerde ekstrakte van vier van hierdie isolate het 'n verbetering van meer as 10% in die ekstraksie van opgeloste vastestowwe uit groen tee tot gevolg gehad. Die ensiemekstrakte van drie swarnme bekend vir hul gebruik in die voedselindustrie, nl. A. oryzae, L. edodes and P. ostreatus var. florida, het relatief hoë vlakke van endoglukanase, xylanase en pektinase aktiwiteit getoon. Agt verskillende kultuur-media is vir die optimale produksie van hidrolitiese and lakkase ensieme vanaf hierdie voedsel-graad swarnme geëvalueer. MYPG was die beste groeimedium vir L. edodes, -terwyl 1% koringstrooi, 1% oorskot graan en 1% pynappelskil die beste induksie van xylanase, pektinase, endoglukanase en lakkase aktiwiteite vir hierdie organisme getoon het. Lentinula edodes opgegroei in YP medium + 1% koringstrooi, het die beste verbetering in aroma en kleur getoon vanaf groen tee getoon. Hierdie ekstrak kan dus moontlik gebruik word vir die verkorting van die fermentasietyd wat vir groen tee benodig word. Ope-lug fermentasie van groen tee duur gewoonlik tot 16 uur en lei tot 'n aansienlike verlies in antioksidant-inhoud. Die R. oryzae ekstrak het die beste potensiaal vir die vervaardiging van 'n "quick-draw" tee getoon met 'n goeie kleurvrystelling sonder enige verlies in SS en TP opbrengs. Wanneer die swamme in Aartappel-Dextrose medium opggegroei word, kan die L. edodes ensiemekstrak vir aroma en kleurontwikkeling van groen tee aangewend word, terwyl die R. oryzae ensiemekstrak vir die verhoging van die antioksidant-inhoud in rooibos ekstrakte van groen tee of gefermenteerde tee gebruik kan word. Dit is bevestig met die kleinskaalse behandeling van gefermenteerde tee waar die L. edodes YP + 1% koringstrooi ensiemekstrak die vrystelling van SS met meer as 30% en die TP met meer as 20% verbeter het.

Thesis (MSc) -- University of Stellenbosch, 2005. / ENGLISH ABSTRACT: The Rooibos tea plant (Aspalathus linearis) is indigenous to South Africa and occurs only in the Western Cape's Cedarberg region. Rooibos tea is produced from the leaves and fine stems of the plant. The tea is normally prepared by brewing the leaves and consuming the liquor. However, the Rooibos plant is not only used to prepare tea; the plant extracts are also used in various neutraceutical and pharmaceutical products, including health drinks, iced tea, soaps and moisturising creams. Although the tea plant contains native enzymes responsible for the colour and aroma development of Rooibos tea, the disruption and maceration of the plant material during processing is insufficient to allow these enzymes proper access to the substrates responsible for Rooibos tea's characteristics. The current processing of Rooibos tea is also time consuming and is done under uncontrolled conditions, leading to unnecessary loss in aroma and antioxidant content. The addition of enzymes could improve the maceration of the plant material, shorten the processing time and improve the extraction of aroma, colour and antioxidant components. During this study, 16 commercially available microbial enzymes were evaluated on three different Rooibos substrates for the improvement of aroma and colour development, as well as the extraction of soluble solids (SS) and total polyphenols (TP). Thirteen enzymes were evaluated on spent tea for the enhanced extraction of soluble solids and to determine the best candidates for further evaluation on fermented and green Rooibos tea. Seven of the enzymes improved the yield in SS from spent tea. Up to 232% improvement was obtained, depending on the type of enzyme and dosage applied. The best six enzyme preparations were further evaluated on fermented Rooibos tea. For Depol™ 670L at 20 ul/g tea, the laboratory treatment increased the yield in SS by 44%, while small-scale industrial simulations increased the SS by 26%. However, an increase in the yield in SS was usually accompanied by a decrease in the %TP/SS ratio, indicating that mainly inactive compounds were extracted. Based on the results with the commercial enzymes, twelve "synthetic" enzyme cocktails, consisting of different combinations of commercial enzymes were designed, of which three cocktails released increased amounts of SS without decreasing the %TP/SS ratio significantly. Thirteen enzymes were evaluated on dried and freshly cut green Rooibos tea, with three enzymes (Depol™ 670L, Pectinex Ultra SP-L and Depol™ 692L) increasing the yield in SS between 21% and 66%, and the TP content between 11% and 47%. Laccase was the best candidate in improving colour development from green tea, with the improvement being slightly better at 50°C than at 40°C. All the "synthetic" cocktails containing laccase improved the colour extract of all three substrates evaluated, but also significantly decreased the TP and antioxidant content. However, lower dosages of laccase resulted in colour development with little loss in the antioxidant content. Due to the promising results obtained with the treatments of Rooibos tea with laccases, it was decided to clone and express the laccase gene (lacA) of Pleurotus ostreatus into Aspergillus niger. The gene was successfully transformed into A. niger, but the expression of the recombinant gene was not effective. / AFRIKAANSE OPSOMMING: Die Rooibostee plant (Aspalathus linearisi is inheems tot Suid-Afrika en kom slegs in die Sederberg-omgewing in die Wes-Kaap voor. Rooibostee word van die blare en fyn stingels van die plant geproduseer. Die tee word normaalweg voorberei deur die blare in kookwater te laat trek en dan die aftreksel te drink. Die Rooibos plant word nie net gebruik om tee te maak nie; die tee ekstrak word ook gebruik vir verskeie neutraseutiese en farmaseutiese produkte, insluitende gesondheidsdrankies, ystee, seep en bevogtigingsrome. Ten spyte daarvan dat die teeplant sy eie ensieme vir die kleur en aroma ontwikkeling van Rooibostee bevat, is die verbreking en maserasie van die plantmateriaal tydens prosessering onvoldoende om die ensieme genoeg toe gang tot die substrate verantwoordelik vir die kenmerkende eienskappe van Rooibostee te gee. Die huidige prosessering van Rooibostee is ook tydrowend en geskied onder onbeheerde toestande, wat tot 'n onnodige verlies in aroma en antioksidante lei. Die toevoeging van ensieme kan die afbraak van die plantmateriaal verbeter, die behandelingsproses verkort en die aroma, kleur en antioksidant inhoud van ekstrakte verbeter. Tydens hierdie studie is 16 kommersieel-beskikbare mikrobiese ensieme op drie verskillende Rooibos substrate vir die verbetering van aroma, kleur en ekstraksie van oplosbare vastestowwe (SS) en totale polifenole (TP) getoets. Dertien ensieme is op oorskot tee vir die verbeterde ekstraksie van oplosbare vastestowwe geevalueer, waama die beste kandidate vir evaluering op gefermenteerde en ongefermenteeede Rooibostee gekies is. Sewe ensieme het die SS vanaf oorskot tee verhoog. Tot 232% verhoging is waargeneem, afhangende van die tipe ensiem en die dosis wat gebruik is. Die beste ensiern preparate IS verder op gefermenteerde Rooibostee geevalueer, Labarotoriurn behandelings met Depol™ 670L teen 20 ul/g tee het die SS inhoud met 44% verhoog, terwyl die kleinskaalse industriele simulasie die SS inhoud met 26% verhoog het. 'n Verhoging in SS het egter gewoonlik met 'n afname in die %TP/SS verhouding gepaard gegaan, wat aandui dat hoofsaaklik onaktiewe stowwe vrygestel IS. Na aanleiding van die resultate met die kommersiele ensieme, is twaalf "sintetiese" ensiemmengsels met verskillende ensiemkombinasies getoets, waarvan drie mengsels ook meer SS vrygestel het met byna geen verlaging in die %TP/SS verhouding nie. Dertien ensieme was op gedroogde en vars gekerfde groen Rooibostee getoets met drie ensieme (Depol™ 670L, Pectinex Ultra SP-L en Depol™ 692L) wat die SS met tussen 21% en 66%, en die TP inhoud met tussen 11% en 47% verhoog het. Lakkase was die beste kandidaat vir die verbetering van kleur ontwikkeling by groen Rooibostee met die verbetering effens beter by 50°C as by 40°C. Al die "sintetiese" ensiem mengsels wat lakkase bevat het, het die kleur by al die verskillende substrate verbeter, maar het ook die TP en antioksidant inhoud aansienlik verlaag. Laer lakkase dosisse het goeie kleurontwikkeling tot gevolg gehad met minimale verlies in die antioksidant inhoud. Vanwee die goeie resultate wat met die lakkase behandelings verkry is, is daar besluit om die lakkase geen (lacA) van Pleurotus ostreatus te kloneer en in Aspergillus niger uit te druk. Die geen is suksesvol in A. niger getransformeer, maar die uitdrukking daarvan was nie effektief nie.

<p>&nbsp / </p> <p align="left"><font face="Times New Roman">Aspalathus linearis (A. linearis), </font><font face="Times New Roman">commonly known as Rooibos tea or Red bush tea and </font><i><font face="Times New Roman">amellia sinensis (C. sinensis) </font></i><font face="Times New Roman">or Black tea are beverages that are consumed throughout the</font><font face="Times New Roman">world. These teas possess antioxidant, immunomodulating and anti-cancer actions. The aim</font> <font face="Times New Roman">of this study was to use <i>in vitro </i>assays to screen Rooibos and Black tea for endocrine</font> <font face="Times New Roman">modulation. </font><font face="Times New Roman">The immune modulating effects of Rooibos and Black tea were investigated using an <i>in vitro</i></font> <font face="Times New Roman">whole blood culture (WBC) assay. Unstimulated WBCs treated with Rooibos tea secreted</font> <font face="Times New Roman">higher levels of IL-6, IL-10 and IFN<font lang="JA">&gamma / </font>than cultures treated with DMSO control. Rooibos treatment of stimulated WBCs resulted in higher IL-6, lower IL-10 and no effect on IFN&gamma / </font><font face="Times New Roman">secretion compared to DMSO treated stimulated WBC. Black tea treatment of stimulated</font> <font face="Times New Roman">WBC resulted in decreased IL-6, IL-10 and IFN<font lang="JA">&gamma / </font>secretion compared to the DMSO treated</font> <font face="Times New Roman">stimulated WBC. </font><font face="Times New Roman">Extracts of Rooibos and Black tea were assessed for phytoestrogens using quantitative </font><font face="Times New Roman">estrogen ELISAs. Both teas contain phytoestrogens. The quantitative ELISAs showed that </font><font face="Times New Roman">Rooibos tea contained significantly lower estrone (E1), estradiol (E2) and estriol (E3) levels </font><font face="Times New Roman">than Black tea. The effects of Rooibos and Black tea on proliferation of the estrogen</font> <font face="Times New Roman">dependant MCF-7 cell line was determined to further characterise the phytoestrogenic</font> <font face="Times New Roman">properties of the teas. Both Rooibos and Black tea extracts caused a significant inhibition of</font> <font face="Times New Roman">MCF-7 proliferation. </font><font face="Times New Roman">This study shows that Rooibos tea and Black tea are beverages that can either stimulate or </font><font face="Times New Roman">suppress the immune system. Also, both teas contain significant levels of phytoestrogens as </font><font face="Times New Roman">determined by quantitative ELISAs. The current study confirms previous reports showing </font><font face="Times New Roman">inhibition of growth in breast cancer cell lines by phytoestrogens. The findings extend </font><font face="Times New Roman">related observations on the anti-carcinogenic potential of the two teas.</font></p>