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The effects of green tea, green rooibos and their major flavonoids (EGCG and aspalathin) on testicular cell health in vitroBooysen, Robin Alvin January 2021 (has links)
Philosophiae Doctor - PhD / The testes play a central role in the male reproductive system, as they represent the sites of male sex steroidogenesis and of spermatogenesis. Leydig cells, located at the testicular interstitium, produce predominantly testosterone upon stimulation with either chorionic gonadotropin (CG) or luteinising hormone by a series of enzymatic modifications of cholesterol. Sertoli cells respond to testosterone and follicle stimulating hormone to secrete inhibin and facilitate spermatogenesis by additional activities like maintaining Sertoli cell barrier (SCB) integrity and lactate secretion. Ultimately the Leydig cells, Sertoli cells etc. all work together to confer male fertility. However, infertility occurs globally; leading to the pursuit of treatment, including herbal medicines.
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Development of quality control tools and a taste prediction model for rooibosJolley, Bianca 12 1900 (has links)
Thesis (MScFoodSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: In this study quality control tools were developed for the rooibos industry, primarily to determine the quality of rooibos infusions. A considerable variation between samples of the same quality grade has been noted. As there are no guidelines or procedures in place to help minimise this inconsistency it was important to develop quality control tools, which could confront this problem. Both the sensory characteristics and phenolic composition of rooibos infusions were analysed in order to create and validate these quality control tools.
Descriptive sensory analysis was used for the development of a targeted sensory wheel and sensory lexicon, to be used as quality control tools by the rooibos industry, and to validate the major rooibos sensory profiles. In order to ensure all possible variation was taken into account, 230 fermented rooibos samples were sourced from the Northern Cape and Western Cape areas within South Africa over a 3-year period (2011-2013). The aroma, flavour, taste and mouthfeel attributes found to associate with rooibos sensory quality were validated and assembled into a rooibos sensory wheel, which included the average intensity, as well as the percentage occurrence of each attribute. Two major characteristic sensory profiles prevalent within rooibos, namely the primary and secondary profiles, were identified. Both profiles had a sweet taste and an astringent mouthfeel, however, the primary sensory profile is predominantly made up of “rooibos-woody”, “fynbos-floral” and “honey” aroma notes, while “fruity-sweet”, “caramel” and “apricot” aroma notes are the predominant sensory attributes of the secondary profile.
The predictive value of the phenolic compounds of the infusions towards the taste and mouthfeel attributes (“sweet”, “sour”, “bitter” and “astringent”) was examined using different regression analyses, namely, Pearson’s correlation, partial least squares regression (PLS) and step-wise regression. Correlations between individual phenolic compounds and the taste and mouthfeel attributes were found to be significant, but low. Although a large sample set (N = 260) spanning 5 years (2009-2013) and two production areas (Western Cape and Northern Cape, South Africa) was used, no individual phenolic compounds could be singled out as being responsible for a specific taste or mouthfeel attribute. Furthermore, no difference was found between the phenolic compositions of the infusions based on production area, a trend that was also seen for the sensory characterisation of rooibos infusions. Sorting, a rapid sensory profiling method was evaluated for its potential use as a quality control tool for the rooibos industry. Instructed sorting was shown to successfully determine rooibos sensory quality, especially based on the aroma quality of the infusions. However, determining the quality of the infusion based on flavour quality was more difficult, possibly due to the low sensory attribute intensities. Categorisation of rooibos samples based on the two major aroma profiles i.e. the primary and secondary characteristic profiles, was achieved with uninstructed sorting. The potential of using sorting as a rapid technique to determine both quality and characteristic aroma profiles, was therefore demonstrated, indicating its relevance as another quality control tool to the rooibos industry. / AFRIKAANSE OPSOMMING: Gehaltebeheer hulpmiddels is as deel van hierdie studie vir die rooibosbedryf ontwikkel, hoofsaaklik om die sensoriese kwaliteit van rooibostee te bepaal. Aansienlike verskille is tussen monsters van dieselfde gehaltegraad opgemerk, primêr omdat daar in die wyer rooibosbedryf beperkte riglyne of prosedures in plek is om kwaliteitsverskille effektief te bepaal. Dit is as belangrik geag om gehaltebeheer hulpmiddels te ontwikkel om laasgenoemde probleem aan te spreek. Spesifieke gehaltebeheer hulpmiddels is dus vir hierdie studie ontwikkel en gevalideer deur die sensoriese eienskappe en fenoliese samestelling van rooibostee te analiseer.
Beskrywende sensoriese analise (BSA) is gebruik om ‘n sensoriese wiel en leksikon vir die rooibosbedryf te ontwikkel en te valideer. Om alle moontlike produkvariasie te ondervang, is 230 gefermenteerde rooibos monsters afkomstig van die Noord-Kaap en Wes-Kaap areas in Suid-Afrika oor ‘n tydperk van drie jaar (2011-2013) verkry. Die aroma, geur, smaak en mondgevoel eienskappe wat met rooibos se sensoriese kwaliteit assosieer, is bevestig en uiteindelik gebruik om die sensoriese wiel te ontwikkel. Die gemiddelde intensiteit en persentasie voorkoms van elke eienskap is in die wiel ingesluit. Twee belangrike “karakteristieke” sensoriese profiele wat met rooibos geassosieer word, is geïdentifiseer, nl. die primêre en sekondêre sensoriese profiele. Tipies van beide sensoriese profiele is ‘n kenmerkende soet smaak en vrank mondgevoel, daarenteen bestaan die primêre sensoriese profiel hoofsaaklik uit "rooibos-houtagtige", "fynbos-blomagtige" en "heuning" aromas, terwyl "vrugtige-soet", "karamel" en "appelkoos" aromas die oorheersende sensoriese eienskappe van die sekondêre profiel is.
Die korrelasie tussen die fenoliese verbindings en die smaak en mondgevoel eienskappe van rooibos ("soet", "suur", "bitter" en "vrankheid") is ondersoek met behulp van verskillende tipe regressieontledings, nl. Pearson se korrelasie, gedeeltelike kleinstekwadrate regressie (PLS) en stapsgewyse regressie. Korrelasies tussen individuele fenoliese verbindings en die smaak en mondgevoel eienskappe was laag, maar steeds betekenisvol. Alhoewel die uitgebreide stel monsters (N = 260) verteenwoordigend was van vyf oesjare (2009-2013) en twee produksiegebiede (Wes-Kaap en Noord-Kaap, Suid-Afrika), kon geen individuele fenoliese verbindings uitgesonder word as betekenisvolle voorspellers van spesifieke smaak of mondgevoel eienskappe nie. Verder is daar ook geen verskil tussen die verskillende produksie-areas wat betref fenoliese samestelling gevind nie. Soortgelyke resultate is bevind vir die sensoriese karakterisering van rooibostee.
Sortering, 'n vinnige sensoriese profileringsmetode, is geëvalueer vir sy potensiële gebruik as 'n gehaltebeheer hulpmiddel vir die rooibosbedryf. Gestrukteerde sortering was suksesvol om rooibos se sensoriese kwaliteit, veral die algemene aroma kwaliteit van rooibos, te bepaal. Hierdie profileringsmetode was egter nie so suksesvol om rooibos se algemene geur, smaak en mondgevoeleienskappe te bepaal nie. Hierdie tendens kan moontlik toegeskryf word aan die betekenisvolle laer intensiteite van laasgenoemde sensoriese eienskappe. Die kategorisering van die rooibos monsters op grond van hul karakteristieke primêre en sekondêre sensoriese profiele is suksesvol deur middel van ongestrukteerde sortering bepaal. In die geheel gesien is die potensiaal van die sorteringstegniek as ‘n vinnige metode om die algemene sensoriese kwaliteit, asook die karakteristieke aroma profiele van rooibos te bepaal, dus bewys. Hierdie vinnige sensoriese profileringstegniek hou dus besliste voordele in vir die rooibosbedryf as dit kom by sensoriese gehaltebeheer.
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Antimikrobielle Wirksamkeit von Rooibos (Aspalathus linearis) und Hopfen (Humulus lupulus) auf lebensmittelrelevante MikroorganismenKühnast, Karin 14 April 2015 (has links)
Die antimikrobielle Wirkung eines Pflanzenextraktes aus fermentiertem Rooibos (Aspalathus linearis) und eines Extraktes aus Hopfen (Humulus lupulus) auf Milchsäurebildner (Lactobacillus spp., Carnobacterium spp., Leuconostoc carnosum), Verderbniserreger (Bacillus spp., Brochothrix spp., Pseudomonas fluorescens) und pathogene Mikroorganismen (Listeria monocytogenes, Salmonella Enteritidis) wird unter In-vitro-Bedingungen über einen Lagerungszeitraum von 28 Tagen bei Temperaturen von 10 °C und 25 °C untersucht. In den sich anschließenden Challengeversuchen wird evaluiert, ob sich die antimikrobiellen Wirkungen beider Pflanzenextrakte gegen Listeria monocytogenes auf die Lebensmittelmatrix Rotschmierkäse übertragen lassen. Mögliche herstellungsbedingte und sensorische Probleme aufgrund der Anwendung der Pflanzenextrakte im Lebensmittel „Weichkäse“ werden erörtert.
Die Ausgangskeimzahl beträgt je Keim 102–103 KbE/ml. Der Rooibosextrakt wird in einer Konzentration von 5 mg/ml zugesetzt und der Hopfenextrakt in einer Konzentration von 30 µg/ml.
Unter In-vitro-Bedingungen ist eine statistisch abgesicherte bakteriostatische Wirkung des Rooibosextraktes auf Listeria monocytogenes bei einer Lagerungstemperatur von 10 °C in den ersten 14 Tagen nachweisbar. Die Reduzierung der Verderbniserreger in den ersten 24 Stunden nach Zugabe des Rooibosextraktes bei beiden Lagerungstemperaturen bzw. der Milchsäurebildner bei 25 °C ist statistisch nicht abzusichern und bei den weiteren Probenahmen nicht mehr darstellbar. Der Rooibosextrakt hat keine nachweisbare antibakterielle Wirkung auf Salmonella Enteritidis.
Alle grampositiven Testkeime lassen sich durch die Zugabe des Hopfenextaktes statistisch signifikant in ihrem Wachstum beeinflussen. Eine antibakterielle Aktivität des Hopfens zeigt sich bei Listeria monocytogenes in einer verlängerten lag-Phase und anschließendem bakteriostatischen Effekt bei 10 °C. Der Hopfenextrakt hat keinerlei Wirkung auf die gramnegativen Teststämme Pseudomonas fluorescens und Salmonella Enteritidis.
Der Extrakt aus Hopfen zeigt auch in der Lebensmittelmatrix Rotschmierekäse eine signifikante Wachstumshemmung auf Listeria monocytogenes. Der Extrakt aus fermentierten Rooibos zeigt keinen antilisteriellen Effekt. Beide Pflanzenextrakte beeinflussen leicht die sensorischen Eigenschaften der Käse, die Käsereifung nicht.
Erstmals liegen antibakterielle In-vitro-Studien der getesteten Pflanzenextrakte gegen lebensmittelrelevante Mikroorganismen über 28 Tage vor. Eine Anwendung von Pflanzenextrakten als antimikrobieller Lebensmittelzusatz ist erst nach entsprechender Validierung im jeweiligen Einzelprodukt möglich.
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The inoculum ecology of Botrytis cinerea in Rooibos nurseriesSpies, Christoffel, F. J. (Christoffel Frederik Jakobus) 04 1900 (has links)
Thesis (MScAgric)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Grey mould, caused by Botrytis cinerea, is the most important foliar disease of rooibos
seedlings. Although the disease is primarily controlled with applications of fungicides, the
improvement of cultural methods of disease management should lessen this dependence on
chemical control. Such improvements would, however, not be possible without knowledge of
the inoculum sources and dispersal of the pathogen. The aim of this study was to investigate
the inoculum ecology of B. cinerea in rooibos nurseries in order to identify primary sources of
inoculum and to improve the environmentally friendly management of the disease.
The study was conducted in four nurseries over two production seasons (March to July
2003 and 2004). Levels of airborne inoculum of B. cinerea were monitored on a monthly basis
inside and around the nurseries with spore traps. Samples of plant material and organic debris
were taken in the corresponding areas to determine the incidence of plant material infected by
the pathogen and the incidences of grey mould in the nurseries were recorded. Low numbers
of B. cinerea colonies were observed on the spore traps. Similar levels of airborne inoculum
were observed inside and around the nurseries. The incidence of plant material yielding B.
cinerea was higher outside the nurseries than inside, indicating the importance of such
materials as potential sources of inoculum. Since patterns of airborne inoculum observed in
this study confirmed reports of the local dispersal of B. cinerea, the removal of possible hosts
outside the nurseries could aid in the management of grey mould in rooibos nurseries.
Resistance to dicarboximide fungicides is a genetically stable trait in B. cinerea, and
therefore has the potential to be used as a phenotypic marker. This marker can be used to gain
knowledge on the dispersal of B. cinerea inoculum inside and outside rooibos nurseries.
Isolates of B. cinerea collected from the air and from plant material in and around four rooibos
nurseries were assessed for resistance to iprodione at 1 and 3 μg/ml a.i. Some of the isolates
showed resistance to iprodione at 1 μg/ml a.i. However, none of the isolates showed resistance
at 3 μg/ml a.i. iprodione. The initial incidence of dicarboximide-resistance at the nurseries was
slightly higher than expected. As the season progressed, the incidence of iprodione-resistant
isolates decreased towards May, after which an increase was observed towards July. A
relatively high percentage of isolates collected outside the nurseries was found to be dicarboximide-resistant. Two of the nurseries had a significant higher incidence of resistant
isolates on plant material collected inside, than on plant material collected outside the nursery.
However, when looking at resistance levels of airborne isolates, no significant differences were
found in the incidence of resistant isolates sampled inside and outside the four nurseries. The
data indicated the importance of organic debris and seed-borne infections in the survival and
dispersal of dicarboximide-resistant isolates of the pathogen.
With the current emphasis on organic agriculture the knowledge gained in this study
presents valuable possibilities of improving the cultural management of grey mould in rooibos
nurseries. / AFRIKAANSE OPSOMMING: Vaalvrot, veroorsaak deur Botrytis cinerea, is die belangrikste bo-grondse siekte van
rooibossaailinge. Alhoewel die beheer van die siekte hoofsaaklik op die gebruik van
fungisiede berus, behoort die verbetering van verbouingspraktyke hierdie afhanklikheid van
chemiese beheer te verminder. Sulke verbeteringe sal egter slegs moontlik wees indien
voldoende kennis van die inokulumbronne en verspreiding van die patogeen beskikbaar is. Die
doel van hierdie ondersoek was om die inokulum ekologie van B. cinerea in rooibos kwekerye
te ondersoek sodat primêre inokulumbronne opgespoor en omgewingsvriendelike
siektebestuurspraktyke verbeter kan word.
Die ondersoek is in vier kwekerye oor twee produksie seisoene (Maart tot Julie 2003 en
2004) uitgevoer. Vlakke van luggedraagde inokulum van B. cinerea is op ’n maandelikse basis
met behulp van spoorvangers binne en buite die kwekerye gemonitor. Monsters van
plantmateriaal en organiese materiaal is in ooreenstemmende areas geneem om die voorkoms
van B. cinerea geïnfekteerde plantmateriaal vas te stel en die voorkoms van vaalvrot in die
kwekerye is aangeteken. Min B. cinerea kolonies is op die spoorvangers waargeneem.
Soortgelyke vlakke van luggedraagde inokulum is binne en buite die kwekerye waargeneem.
Die hoër voorkoms van B. cinerea geïnfekteerde plantmateriaal buite die kwekerye as binne,
dui op die belang van sulke materiaal as potensiële inokulumbronne. Aangesien die patrone
van luggedraagde inokulum, soos waargeneem in hierdie ondersoek, ander berigte van B.
cinerea se beperkte verspreidingsvermoë bevestig, kan die verwydering van moontlike
alternatiewe gashere buite die kwekerye die bestuur van die siekte binne die kwekerye
verbeter.
Weerstand teen dikarboksimied fungisiede is ’n geneties-stabiele kenmerk in B. cinerea
en het daarom potensiaal om as ’n fenotipiese merker gebruik te word. Hierdie merker kan
gebruik word om kennis aangaande die verspreiding van B. cinerea in en om rooibos kwekerye
in te samel. Botrytis cinerea isolate in lug en op plantmateriaal in en om vier rooibos
kwekerye is gedurende 2003 en 2004 versamel. Die isolate is vir weerstandbiedendheid teen
iprodioon by konsentrasies van 1 en 3 μg/ml aktiewe bestandeel (a.b.) getoets. Isolate met
weerstand teen 1 μg/ml a.b. iprodioon is waargeneem, maar nie teen 3 μg/ml nie. Die aanvanklike voorkoms van dikarboksimiedweerstand by die kwekerye was hoër as verwag.
Hierdie vlak het egter gedaal met die verloop van die seisoen tot in Mei, waarna ’n toename tot
in Julie waargeneem is. Die persentasie dikarboksimied-weerstandbiedende isolate buite die
kwekerye was relatief hoog. In twee van die kwekerye was die voorkoms van
weerstandbiedende isolate op plantmateriaal in die kwekerye betekenisvol hoër as op
plantmateriaal buite die kwekerye. Daar was egter geen betekenisvolle verskille in die
voorkoms van luggedraagde weerstandbiedende isolate nie, ongeag van die kwekery of posisie.
Die data dui op die belang van organiese materiaal en saadgedraagde infeksies in die oorlewing
en verspreiding van dikarboksimied-weerstandbiedende isolate van die patogeen.
Met die huidige klem op organiese landbou bied die inligting wat in hierdie ondersoek
versamel is moontlike praktyke wat geïmplementeer kan word om die beheer van vaalvrot in
kwekerye met behulp van verbouingspraktyke te verbeter.
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Anti-microbial activity of rooibos tea (Aspalathus linearis) on food spoilage organisms and potenial pathogensSchepers, Sonette 12 1900 (has links)
Thesis (MSc Food Sc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT:Aspalafhus linearis is an indigenous fynbos plant cultivated in the Clanwilliam area
of the Western Cape, South Africa. The rooibos tea that is prepared from this
plant, has become popular worldwide mainly due to the alleged health properties.
Studies on the anti-microbial properties of green, black and oolong teas have
shown that these teas have strong anti-microbial activity against a wide range of
microbes. No studies have been done on the anti-microbial activity of rooibos tea
and the aim of this study was to determine what impact rooibos tea extracts would
have on the growth of different food spoilage and potential pathogenic microbes.
Water and ethyl acetate extracts of fermented and unfermented rooibos tea
were used to determine the inhibitory effect on the growth of an Escherichia coli
strain. The E. coli culture was grown in tea-MRS with either added fermented or
unfermented rooibos tea extracts. Both the water and ethyl acetate extracts
showed a strong inhibitory effect against the E. coli strain in that there was a
decrease in the final bacterial cell density (Nmax)(from 0.59 00 to 0.25 00) and
the maximum specific growth rate (~max)(from 1.12 h-1 to 0.20 h-1) and an increase
in the doubling time (~) (from 0.59 h to 1.80 h) and lag time (tlag)(from 4.81 h to
6.60 h) as the concentration of the soluble solids of the tea extracts was increased
from 0.5 to 5.0 g.r1
. Furthermore, it was found that the fermented rooibos tea had
a much stronger inhibitory effect (69% decrease in growth at 5.0 g.r1 soluble
solids) compared to the unfermented rooibos tea extracts (35.1% decrease in
growth at 5.0 g.r1 soluble solids). The resulting data indicated that rooibos tea had
a very strong inhibitory effect on the growth of the E. coli strain. It was also found
that the water extracts of rooibos tea showed a stronger inhibitory effect on the
growth of the E. coli than the ethyl acetate extracts, indicating that the antimicrobial
activity of rooibos tea is not exclusively due to the polyphenolic content -
individual compounds. It was also determined that the rooibos tea water extracts
showed a bacteriostatic action against the E. coli strain in that as soon as the tea
is no longer part of the growth medium, the E. coli resumed a normal growth
pattern. The data obtained showed that the inhibitory effect of rooibos tea water
extracts (69% decrease in growth) against the growth of E. coli was more
pronounced than that found when black tea water extracts (25.7% decrease in
growth) at the same concentrations were used.Rooibos tea water extracts (0.5 - 5.0 g.r1) of fermented and unfermented
tea were also used to determine the inhibitory effect on other food spoilage
microbes and potential pathogens. Strains of Staphylococcus aureus, Bacillus
cereus, Listeria monocytogenes, Streptococcus mutans, Saccharomyces
cerevisiae and Zygosaccharomyces rouxii were grown in the presence of
fermented and unfermented rooibos tea water extracts. The effect that fermented
rooibos tea had on the growth of all the microbes tested was in the following order:
Staph. aureus (90.8% decrease in growth) > L. monocytogenes (89.2% decrease
in growth) > Strep. mutans (84.1% decrease in growth) > B. cereus (80.3%
decrease in growth) > Sacch. cerevisiae (77.7% decrease in growth) > E. coli
(69.0% decrease in growth). The rooibos tea clearly had an inhibitory effect on the
growth of all the microbes, with the exception of the Z. rouxii strain where the
presence of the tea water extracts was found to enhance the growth.
The inhibitory effect of rooibos tea on the growth of these microbes was
shown by changes in the growth parameters with Nmax and IJmaxshowing
decreases, while the ld and tlagincreased as the concentration of the tea soluble
solids was increased. As with E. coli, the fermented rooibos tea water extracts
showed the stronger inhibitory effect on the growth of the various microbes.
The data obtained in this study suggests that rooibos tea is not effective as
an anti-microbial agent against all yeast species, but will strongly retard the growth
of specific Gram-positive and Gram-negative bacteria. As long as rooibos tea is
present, strong anti-microbial activity will be observed at a cup of tea concentration
of 2.5 g.r1 soluble solids. These results may be of value to support the health
claims associated with rooibos tea and may in the future lead to the use of rooibos
tea as a "natural" food preservative. / AFRIKAANSE OPSOMMING:Aspalathus linearis is 'n inheemse fynbosplant wat gekultiveer word in die
Clanwilliam area van die Wes Kaap, Suid-Afrika. Rooibostee, wat gemaak word
van hierdie plante, het baie gewild geword wereldwyd a.g.v. die
gesondheidsaspekte van hierdie tee. Studies toon dat groen, swart en oolong tee
sterk anti-mikrobiese aktiwiteit het teen 'n wye reeks mikrobes. Aangesien daar
voorheen geen studies gedoen is op die anti-mikrobiese aktiwiteit van rooibostee
nie, was die doel van hierdie studie om die effek van rooibostee te bepaal op die
groei van verskillende voedselbederwers en potensiele patogeniese mikrobes.
Water- en etielasetaat-ekstrakte van gefermenteerde en ongefermenteerde
rooibos tee is gebruik om die inhiberende effek op die groei van Escherichia coli te
bepaal. Escherichia coli is gegroei in tee-MRS met bygevoegde gefermenteerde
of ongefermenteerde rooibostee-ekstrakte. Seide die water- en etielasetaatekstrakte
van rooibostee het 'n sterk inhiberende effek gewys teen E. coli en dit
word gestaaf deur 'n afname in die finale bakteriese seldigtheid (Nmax)(vanaf 0.59
00 tot 0.25 00) en die maksimum spesifieke groeitempo (lJmax) (vanaf 1.12 h-1 tot
0.20 h-1) en 'n toename in die verdubbelingstyd (~) (vanaf 0.59 h tot 1.80 h) en die
sloerfase (tlag)(vanaf 4.81 h tot 6.60 h) 5005 wat die konsentrasie van oplosbare
vastestowwe van die tee toeneem van 0.5 tot 5.0 g.r1
. Verder is daar gevind dat
die gefermenteerde rooibostee 'n baie sterker inhiberende effek het (69% afname
in groei by 5.0 g.r1 oplosbare vastestowwe) in vergelyking met die
ongefermenteerde rooibostee-ekstrakte (35.1% afname in groei by 5.0 g.r1
oplosbare vastestowwe). Die resultate van die data dui aan dat rooibos tee 'n
baie sterk inhiberende effek het op die groei van die E. coli spesie. Die waterekstrakte
van rooibostee het 'n sterker inhibisie getoon teen die groei van E. coli
as die etielasetaat-ekstrakte, wat aandui dat die anti-mikrobiese aktiwiteit van
rooibostee nie eksklusief toegeskryf kan word aan die polifenoliese samestelling
nie. Daar is ook gevind dat rooibostee water-ekstrakte 'n bakteriostatiese effek
het teen E. coli, want sodra die tee ekstrakte nie meer teenwoordig is in die
groeimedium nie, hervat E. coli normale groei. Die data wys ook dat die
inhiberende effek van rooibostee water-ekstrakte (69.0% afname in goei) teen E.
coli baie sterker is as die van swart tee water-ekstrakte (25.7% afname in groei) by
dieselfde konsentrasies.Rooibostee water-ekstrakte (0.5 - 5.0 g.r1) van gefermenteerde en
ongefermenteerde rooibostee is ook gebruik om die inhiberende effek te bepaal
teen ander voedselbederwers en potensiele patogene. Spesies van
Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Streptococcus
mutans, Saccharomyces cerevisiae en Zygosaccharomyces rouxii is gegroei in die
teenwoordigheid van gefermenteerde en ongefermenteerde rooibostee waterekstrakte.
Die effek wat gefermenteerde rooibostee het op die groei van die
getoetste mikrobes is 5005 volg: Staph. aureus (90.8% afname in groei) > L.
monocytogenes (89.2% afname in groei) > Strep. mutans (84.1% afname in groei)
> B. cereus (80.3% afname in groei) > Sacch. cerevisiae (77.7% afname in groei)
> E. coli (69.0% afname in groei). Rooibostee het 'n duidelike inhiberende effek
gehad teen al die organismes, behalwe teen Z. rouxii spes ie, waar die
teenwoordigheid van rooibostee die groei van die organisme bevorder het.
Die inhiberende effek van rooibostee teen die groei van hierdie mikrobes
word ondersteun deur die groei parameters waar die Nmaxen IJmaxafgeneem het
terwyl die ~ en tlagtoegeneem het 5005 wat die konsentrasie van die oplosbare
vastestowwe toeneem. Die gefermenteerde rooibostee water-ekstrakte het ook 'n
sterker inhiberende effek op die groei van die verskillende mikrobes net 5005 met
E. coli.
Die data wat verkry is van hierdie studie dui aan dat rooibostee nie effektief
sal wees as 'n anti-mikrobiese middel teen aile gis spesies nie, maar dit sal die
groei van spesifieke Gram-positiewe en Gram-negatiewe bakterie sterk vertraag.
So lank as wat rooibostee teenwoordig is, sal sterk anti-mikrobiese aktiwiteit
waargeneem word by 'n koppie-tee konsentrasie van 2.5 g.r1 oplosbare
vastestowwe. Hierdie resultate kan help om die gesondheidseienskappe
geassosieer met rooibostee te ondersteun en help om die gebruik van rooibostee
as 'n "natuurlike" preserveermiddel te bevorder.
dedicated to my parents
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Weight losses of Green tea and Rooibos tea in an aquatic environment : The importance of leaching when estimating decomposition rates / Viktförluster av Grönt te och Rooibos te i vattenmiljö : Vikten av urlakning vid estimering av nedbrytningshastigheterEdwartz, Johannes January 2018 (has links)
Leaching is one of the major processes occurring when organic litter is decomposed and is often completed within a few days when litter enters aquatic environments. It is important that leaching is addressed when studying microbial and invertebrate decomposition rates in order to avoid overestimations. The traditional litter bag method that has been used to measure decomposition rates in both terrestrial and aquatic environments has in recent years been challenged by the new and widely adopted tea bag index (TBI). Both methods, however, fail to bring a standardized methodology for separating and recognizing weight losses of litter due to leaching and biotic decomposition. Through a field experiment in two streams with different water discharge, this study has focused on exploring the leaching phase and post-leaching phase of the tea products used in TBI. The results unveiled that 20% of rooibos tea’s and 44% of green tea’s initial weight was lost to leaching within three days (72 hours) of the experiment. After the 72nd hour, both teas remained in a stabilized phase until the end of the experiment (120 hours). Water discharge had no significant effect on neither of the tea-weights during or after the leaching phase. This study recommends that weight loss through the leaching phase are taken into account in future studies and advocate the development of an updated TBI protocol where leaching losses are recognized. If not, overestimations of active decomposition rates will be made and may result in compromised conclusions. / Urlakning är en av de viktigaste processerna som uppstår vid nedbrytning av organiskt material och är ofta slutfört inom några dagar när materialet befinner sig i vattenmiljöer. Det är viktigt att den urlakade massan beräknas när studier fokuserade på nedbrytningshastigeter av mikrober och evertebrater genomförs, detta för att undvika en överestimering av den biotiska aktiviteten. Den traditionella metoden, där torkade växtdelar i påsar, har använts för att mäta nedbrytningshastigheter i både mark- och vattenmiljöer har under de senaste åren utmanats av det nya och allmänt accepterade tepåse-indexet (TBI). Båda metoderna misslyckas dock med att implementera en standardiserad metodik för att separera och uppskatta materialets viktförluster genom urlakning och biotisk nedbrytning. Genom ett fältexperiment i två vattendrag med olika vattenföring har denna studie fokuserat på att undersöka urlakningsfasen och den stabiliserade perioden efter urlakningen hos teprodukterna som används i TBI. Resultaten avslöjade att 20% av rooibos tes och 44% av grönt tes ursprungliga vikt förloras genom urlakning inom tre dagar (72 timmar) av experimentet. Efter den 72:a timmen förblev båda teerna i en stabiliserad fas till slutet av experimentet (120 timmar). Vattenflöde hade ingen signifikant effekt på någon av tetypernas vikter, varken för perioden under eller efter urlakningsfasen. Denna studie rekommenderar att viktminskning genom urlakningsfasen beaktas i framtida studier och förespråkar utvecklingen av ett uppdaterat TBI-protokoll för att inkludera urlakningens påverkan. Om inte, kommer överskattningar av aktiva nedbrytningshastigheter att göras och kan leda till äventyrade slutsatser.
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The use of rooibos (Aspalathus linearis) and honeybush (Cyclopia spp.) as wood alternative in red winemakingDe Wet, Alet 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Wine knowledge has increased drastically in recent years with the aid of scientific experimentation. The producers of wine have increasingly incorporated new wine knowledge into the marketing and innovation of wine products. In parallel with the above, the consumer market has become more aware of winemaking practices and their influence on consumer health. The use of alternative methods and additives in wine are means by which producers have been able to create innovative wine products.
This study focused on the addition of rooibos (Aspalathus linearis) and honeybush (Cyclopia spp.) plant material to red wine. Consumer liking, as well as descriptive sensory analysis (DSA) of different red wines made from a range of cultivars with the addition of rooibos and honeybush plant material, was investigated. Another aim of the study was to observe the effect of oxygen addition to red wines treated with rooibos and honeybush plant material.
The consumer studies included a number of events where wines treated with rooibos and honeybush material were compared with other commercial wines. The results could not clearly indicate whether consumers liked or disliked the wine products with added rooibos and honeybush plant material. Further refinement of wines with the addition of rooibos and honeybush can serve as topics for future research. Focus on the potential health benefits which can be added to wine from rooibos and honeybush plant material, as a result of inherent antioxidants within both these species, may serve as a novel research topic. The DSA panels identified aroma descriptors that could be related to the addition of wood and leaf or only rooibos and honeybush wood to wine.
The addition of oxygen to wines treated with rooibos and honeybush plant material indicated that aromas associated with these treatments are relatively stable in wine undergoing oxidation. This could possibly pave the way for future research on the topic of low sulphur dioxide containing wines. As a result of this study, a commercial wine product called “Rooibos wine” was developed and became available in retail. Further research on this topic and the impact of the addition of rooibos and honeybush material to wine may be of great benefit for the production of innovative wines with unique aroma profiles. / AFRIKAANSE OPSOMMING: Kennis oor wyn het oor die afgelope paar jaar vooruitgegaan met behulp van wetenskaplike eksperimentering. Wynprodusente sluit toenemend nuwe wynkennis in die bemarking en innovering van wynprodukte in. Parallel hiermee het die verbruikersmark baie meer bewus geword van wynbereidingspraktyke en die invloed daarvan op verbruikersgesondheid. Die gebruik van alternatiewe metodes en byvoegings in wyn is maniere waarop produsente innoverende wynprodukte kan skep.
Hierdie studie het gefokus op die byvoeging van rooibos (Aspalathus linearis) en heuningbos (Cyclopia spp.) plantmateriaal by rooiwyn. Verbruikers se voorkeur, sowel as die beskrywende sensoriese analise (descriptive sensory analysis [DSA]) van diverse rooi wyn kultivars waarby rooibos en heuningbos plantmateriaal gevoeg is, is geanaliseer. Nóg ’n doelwit van die studie was om die effek van suurstofbyvoeging by rooiwyne wat met rooibos en heuningbos plantmateriaal behandel is waar te neem.
Vir die verbruikerstudies is geleenthede aangebied waar wyne wat met rooibos en heuningbos materiaal behandel is met kommersiële wyne vergelyk is. Die resultate kon nie duidelik aandui of die verbruikers gehou het of nie van wynprodukte wat met rooibos en heuningbos behandel is. Verdere verfyning van wyne met bygevoegde rooibos en heuningbos kan as onderwerpe vir toekomstige navorsing dien. Die verhoogde gesondheidvoordele van wyn wat met rooibos en heuningbos plantmateriaal behandel is as gevolg van die inherente anti-oksidante eie aan die spesies, kan dien as fokus vir ʼn nuwe navorsingstema. Die DSA-panele het beskrywende terme vir aromas geïdentifiseer wat verband kan hou met die byvoeging van die hout/blaar of slegs die rooibos- en heuningboshout by die wyn.
Die aromas in wyn wat met rooibos en heuningbos behandel is, is gevind om relatief stabiel te bly tydens oksidasie. Dit kan moontlik die weg baan vir toekomstige navorsing oor lae swaweldioksied-bevattende wyne. As gevolg van hierdie studie is ‘n kommersiële wynproduk, genaamd “Rooiboswyn”, ontwikkel en is dit in die handel beskikbaar. Verdere navorsing oor hierdie onderwerp en die impak van die byvoeging van rooibos en heuningbos materiaal by wyn sal moontlik van groot voordeel wees vir die produksie van innoverende wyne met unieke aroma profiele.
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Development and evaluation of a food frequency questionnaire to assess daily total flavonoid intake using a rooibos intervention study modelVenter, Irma 03 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: A comprehensive food frequency questionnaire (FFQ) was developed to assess the daily total
flavonoid intake over the past fortnight within a 14-week intervention that consisted of four periods
to determine the effect of rooibos consumption on oxidative stress in adults (n=40) at intermediate
to high coronary heart disease (CHD) risk. Within the intervention the comprehensive FFQ validity
(against six estimated dietary records and biomarkers), reproducibility (on administrations in the
washout and control periods six weeks apart as these periods had similar flavonoid intake
restrictions) and responsiveness (across the four intervention periods of changed dietary
conditions) was evaluated. The baseline period dietary record and FFQ dietary sources found to
contribute most to the participants’ daily total flavonoid intake, considering the percentage
contribution, and the between-person variation in intake, considering the stepwise multiple
regression analysis, formed the food list of the resultant abbreviated FFQ. The validity,
reproducibility and responsiveness of the latter were also evaluated within the intervention and its
validity (against dietary records) and reproducibility (on re-administration two weeks apart) in an
additional group (n=90) being at low and intermediate CHD risk to evaluate its external strength.
The validity and reproducibility evaluations of the comprehensive and abbreviated FFQs in the
intervention and abbreviated FFQ within the additional group comprised paired difference tests (to
establish the ability to estimate group intakes), correlation coefficients (to establish the ability to
rank individual participants), category agreement and gross misclassification next to the weighted
kappa statistic (to establish the ability to classify the participants into tertiles and quintiles of intake)
and Bland-Altman plots (as representation of the limits of agreement between the two dietary
assessment methods). Correlation coefficients were also used for biomarker validity evaluations in
the baseline period. The repeated measures analysis of variance (ANOVA) (Bonferroni correction)
was used for the responsiveness evaluations of the comprehensive and abbreviated FFQs across
the intervention periods alongside that of the biomarkers as evidence for the changed dietary
conditions.
The study demonstrated that the comprehensive FFQ could be modified to a format with a brief
food list as few items contributed appreciably to the total flavonoid intake and of which most also
contributed to the between-person intake variability. The comprehensive and moreover the
abbreviated FFQ in the validity evaluations provided sufficiently accurate daily total flavonoid intake
estimates. They could determine the intake at group level in correspondence with that of the
dietary records. The participant intakes could additionally be categorized and in particular ranked
greatly alike to the dietary record intakes. The Bland-Altman plots revealed proportional bias
regarding overestimation at the higher intake level. The reproducibility also appeared to be greatly
satisfactory although seasonal fruit exclusions from the abbreviated FFQ food list may hamper its
repeated administration. Both FFQs also confirmed the changed total flavonoid intakes across the
intervention periods in relation to changes in the expected direction concerning the plasma total
polyphenol, conjugated diene and thiobarbituric acid reactive substance concentrations. / AFRIKAANSE OPSOMMING: ‘n Omvattende voedsel frekwensie vraelys (VFV) is ontwikkel om die daaglikse totale flavonoïed
inname oor twee agtereenvolgende weke te beraam te midde van ‘n 14-week intervensie. Die
intervensie het uit vier periodes bestaan wat die effek van rooibosinname op oksidatiewe stres in
volwassenes (n=40), met ‘n intermediêre tot hoë koronêre hartsiekte (KHS) risiko, bepaal het.
Binne die intervensie is die geldigheid (teen ses geskatte dieetrekords en biochemiese merkers),
herhaalbaarheid (op aanwending ses weke uitmekaar in die uitwas en kontrole intervensie
periodes met dieselfde flavonoïed inname bepalings) en waarneembaarheid (oor vier intervensie
periodes van veranderde dieet bepalings) van die omvattende VFV geëvalueer. Die dieetbronne in
die basislyn periode dieetrekords en vraelyste wat die meeste tot die deelnemers se daaglikse
totale flavonoïed inname (baseer op die persentasie bydrae) en die tussen-persoon variasie in
inname (baseer op die stapsgewyse meervuldige regressie analise) bygedra het, het die
voedsellys van die voortvloeiende verkorte VFV gevorm. Die geldigheid, herhaalbaarheid en
waarneembaarheid van dié VFV is binne die intervensie geëvalueer en die geldigheid (teen
dieetrekords) en herhaalbaarheid (heradministrasie twee weke later) daarvan in ‘n verdere groep
(n=90) met lae en intermediêre KHS risiko as evaluasie van die eksterne vermoë van die VFV.
Die geldigheid en herhaalbaarheid evaluasies van die omvattende en verkorte VFV in die
intervensie en die verkorte VFV in die verdere groep het bestaan uit gepaarde verskil toetse
(bepaling van die groepinname skattingsvermoë), korrelasie koëffisiënte (bepaling van individuele
deelnemer rangorde skattingsvermoë), kategorie ooreenstemming en erge wanklassifikasie naas
die aangepaste kappa statistiek (bepaling van die vermoë om die deelnemer innames in derdes en
vyfdes te klassifiseer) en die Bland-Altman karterings (verteenwoordiging van
ooreenstemmingslimiete tussen die twee dieetinname metodes). Korrelasie koëffisiënte is ook
gebruik vir biochemiese merker geldigheid evaluasies in die basislyn periode. Die herhaalde
metings analise van variansie (ANOVA) (Bonferroni regstelling) is gebruik om die
waarneembaarheid evaluasies van die omvattende en verkorte VFV oor die intervensie periodes
naas dit van die biochemiese merkers te evalueer as bewys van die veranderde dieet bepalings.
Die studie het aangedui dat die omvattende VFV gewysig kon word tot ‘n formaat met ‘n verkorte
voedsellys omdat slegs ‘n aantal items merkbaar tot die totale flavonoïed inname bygedra het en
die meeste hiervan ook tot die tussen-persoon variasie in inname. Die omvattende en die verkorte
VFV het in die geldigheid evaluasies daarvan voldoende akkurate daaglikse totale flavonoïed
inname skattings opgelewer omdat groep innames bepaal kon word in ooreenstemming met dit
verkry van die dieetrekords en die deelnemer innames bykomend kategoriseer en in besonder
grootliks eenders rangeer kon word as met hul dieetrekord innames. ‘n Proporsionele oorskatting
by die hoër inname vlakke is wel vir al twee getoon in die Bland-Altman karterings. Die
herhaalbaarheid was ook grootliks aanvaarbaar, alhoewel seisoenale vrugte uitsluitings in die
verkorte VFV voedsellys die heruitvoering kan bemoeilik. Al twee vraelyste kon ook die
veranderinge in die daaglikse totale flavonoïed inname oor die intervensie periodes bevestig in
ooreenstemming met veranderinge in die verwagte rigting van die plasma totale polifenool,
konjugaat diëne en tiobarbituursuur reaktiewe stof konsentrasies.
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Effect of Rooibos preparation on the total polyphenol content and antioxidant capacity of herbal tea and its consumer characteristicsPiek, Hannelise January 2016 (has links)
Thesis (MTech (Consumer Science: Food and Nutrition))--Cape Peninsula University of Technology, 2016. / Background: The different types and forms of rooibos and the ways in which it is prepared and
flavoured for consumption influences its total polyphenol content and total antioxidant capacity
(TAC) and hence depends on its consumer practices.
Design: Phase 1 of the study entailed the selection and preparation of different rooibos types
and forms; rooibos brewed for different times; and with different household and commercially
added flavourings to determine the total polyphenol content, TAC, flavonol and flavanol content;
and subsequent identification of the optimal cup of rooibos based on the first two biochemical
parameters. For Phase 2 a questionnaire was used to obtain information on the profile of the
adult rooibos herbal tea consumer, as well as of those consuming the optimal cup of rooibos.
Results: The following prepared rooibos samples delivered the higher biochemical parameter
content: green / unfermented (type representative); green / unfermented leaves and powdered
extract (form representatives); that brewed for 10 minutes or longer; and those with added
honey. The optimal cup of rooibos was identified as the one brewed for 10 minutes or longer.
The older respondents and those with a lower level of education consumed a higher daily
amount of rooibos (p < 0.05) and those who brewed rooibos in a teapot consumed the optimal
cup (p < 0.05). However, very few respondents consumed the advised number of cups per day
(< 1%) and the identified optimal cup (15.9%).
Conclusions: Rooibos consumers in this study did not consume it in sufficient amounts and did
not brew it for long enough to fully gain from its attributed health benefits.
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Radioprotective effects of rooibos herbal tea on the developing central nervous system of wistar ratsAlrtemi, Milod M Ahmed January 2018 (has links)
Magister Scientiae - MSc / Background: Early postnatal radiation exposure from environmental, diagnostic or therapeutic
sources is potentially deleterious to the developing nervous system resulting in oxidative stress,
structural damage, altered neurochemistry, DNA damage, inflammatory stresses as well as
correlating cognitive impairment during adult life. Numerous studies in literature have
investigated the radioprotective effects of medicinal plants and beverages. However, only a few
studies have focused on the radioprotective effects of rooibos, an indigenous South African
herbal tea, well known for its many acclaimed health benefits.
Aims: This study was done to investigate the diverse radioprotective potential of fermented
Rooibos herbal tea (FRHT) consumed ad libitum by pregnant rats on the adult offspring rats
exposed to a once-off 6 Gy dose of gamma irradiation on postnatal day 3.
Methods: Twenty-four (24) adult female rats were equally divided into four groups (6 per
group) as control (NS), radiation (X), tea (RT) and their combination. On PND 30, offspring rats
were subjected to neurobehavioural assessment for open field and novel object recognition
parameters and later sacrificed, the brain tissues removed and processed for histological,
immunohistochemical and neurochemical analyses, using standard techniques.
Results: Pre-treatment with FRHT showed overall protection against radiation-induced
distortions in offspring rats by significantly improving exploratory activity, the frequency of
central square entry, rearing episodes, cumulative freezing time and memory retention as
indicated by a relatively higher recognition index. FRHT was also found to significantly improve
the antioxidant defence mechanisms in the offspring rats by reversing lowered FRAP levels,
increasing superoxide dismutase and catalase enzyme activities and reducing lipid peroxidation.
Histological and immunohistochemical analyses showed that morphological alterations were
generally attenuated in the RTX group and the high number of caspase-3 and Glial fibrillary
acidic protein (GFAP)-positive cells was significantly reduced, indicating protective effects
against apoptosis and gliosis.
Conclusion: Taken together, our findings tend to suggest that the potential radioprotective
effects of FRHT are multimodal, possibly executed through the anti-apoptotic, antioxidative,
anti-gliosis and other mechanisms, as observed in this study, and this is often attributed to the
high polyphenol content in Rooibos tea.
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