Thesis (MSc Food Sc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Application of steam treatment to green Cyclopia maculata and C. longifolia to modulate their aroma and flavour profile, without detrimental effects on colour and individual phenolic content, was investigated. Steam treatment (96 °C, atmospheric pressure) of different time periods was applied to the shredded, fresh plant material before drying (STBD; 0, 30, 60, 90 and 120 s) or the herbal tea product after drying (STAD; 0, 1, 2, 3, and 4 min). Steam treatment of 60 s or longer resulted in a significant (p < 0.05) decrease in vegetative (‘green grass’ and ‘hay/dried grass’) and cereal (‘oats/porridge/grains’) aroma and flavour intensities, with an increase in some fruity (‘tropical fruit’ and ‘guava’) and ‘fruity-sweet' aroma intensities. These changes manifested to a greater degree for plant material subjected to STBD, while they were less prominent for C. longifolia compared to C. maculata. Additionally, 19 aroma compounds were instrumentally identified in the volatile fraction of C. maculata infusions prepared from STBD plant material. Of these, seven correlated well with green honeybush vegetative and cereal aroma attributes associated with unsteamed samples. Steaming thus resulted in the rapid loss of some of these highly volatile ‘green’-associated aroma compounds. Steam treatment of more than 60 s, regardless of STBD or STAD, was not detrimental to green colour, and individual phenolic content was not greatly affected. The 30 s STBD treatment of C. maculata, however, led to the rapid loss of green colour and oxidation of phenolic compounds, without considerable aroma improvement. This highlights the need for process control during green honeybush production. Storage stability of steamed (60 s, STBD) and unsteamed green C. maculata was investigated under low (0 °C; moisture impermeable packaging) and normal (25 °C at 60% relative humidity (RH); semi-moisture-permeable sachets) temperature storage conditions (LTS and NTS, respectively) over 6 months and high temperature storage (HTS) conditions (40 °C at 75% RH; semimoisture- permeable sachets) for 1 month. HTS conditions, after 1 month, seemed to emulate changes occurring over 6 months at NTS conditions, with little change detected at LTS conditions. Despite noticeable green colour loss over the respective storage periods at NTS and HTS conditions, individual phenolic compounds were not severely affected. NTS and HTS led to the progressive development of sought-after fermented honeybush sensory attributes, especially in unsteamed samples. These include prominent fruity (‘stewed fruit’, ‘apricot jam’ and ‘marmalade’) aromas and flavours, ‘general sweet’ and ‘fruity-sweet’ aromas and a sweeter taste. The collated descriptive sensory data were used to generate a preliminary sensory wheel for green honeybush aroma, and another for flavour, taste and mouthfeel. The sensory profile of green honeybush was finally described as a dominant vegetative aroma and flavour, prominent sweetassociated and slightly fruity aroma, with sweet and notably bitter tastes and an astringent mouthfeel. By combining the sensory data, it was clear that the major effects of storage outweighed those of steam treatments, suggesting that storage of 3 to 6 months may improve sensory quality, although colour may be slightly compromised. Immediate sensory manipulation and thus improvement, however, may be achieved to a lesser degree in the short term by STBD. / AFRIKAANSE OPSOMMING: Die toepassing van stoombehandeling van groen Cyclopia maculata en C. longifolia vir die modulasie van hul aroma en geur profiel, sonder gepaardgaande nadelige gevolge op kleur en individuele fenoliese inhoud, is ondersoek. Stoombehandeling (96 °C, atmosferiese druk) van verskeie tydstippe is toegepas op die gekerfde, vars plantmateriaal voor droging (SBVD; 0, 30, 60, 90 en 120 s) of die groen teeproduk ná droging (SBND; 0, 1, 2, 3 en 4 min). Stoombehandeling van 60 s of langer het tot 'n betekenisvolle (p < 0.05) afname in vegetatiewe (‘groen gras’ en ‘hooi/gedroogde gras’) en graan (‘hawer/pap/graan’) aroma en geur intensiteite gelei, met 'n toename in sommige vrugtige (‘tropiese vrugte’ en ‘koejawel’) en ‘vrugtige-soet’ aroma intensiteite. Hierdie veranderinge was meer merkbaar in die SBVD behandeling, terwyl C. longifolia minder vatbaar vir hierdie veranderinge was as C. maculata. Daarbenewens is 19 aromaverbindings in die vlugtige fraksie van C. maculata aftreksel voorberei van SBVD plantmateriaal instrumenteel geïdentifiseer. Sewe hiervan het goed gekorreleer met heuningbos vegetatiewe en graan aromas wat verband hou met ongestoomde monsters. Stoombehandeling het dus gelei tot die vinnige verlies van sommige van hierdie baie vlugtige ‘groen’-geassosieërde aromaverbindings. Stoombehandeling vir langer as 60 s, ongeag van SBVD of SBND, het nie die groen kleur en individuele fenoliese inhoud grootliks nadelig beïnvloed nie. ‘n SBVD behandeling van 30 s het egter tot die vinnige verlies van groen kleur en oksidasie van fenoliese verbindings, sonder aansienlike aroma verbetering van C. maculata gelei. Dít beklemtoon die noodsaaklikheid vir prosesbeheer tydens groen heuningbosproduksie. Stabiliteit van gestoomde (60 s, SBVD) en ongestoomde groen C. maculata tydens opberging onder lae (0 °C; vog-ondeurlaatbare verpakking) en normale (25 °C by 60% relatiewe humiditeit (RH); semi-vogdeurlaatbare sakkies) temperatuur opbergingtoestande (LTO en NTO, onderskeidelik) oor 6 maande en hoë temperatuur opbergingtoestande (40 °C by 75% RH; semivogdeurlaatbare sakkies; HTO) vir 1 maand, is ondersoek. HTO het na 1 maand soortgelyke veranderinge teweeggebring as NTO na 6 maande, terwyl min verandering by LTO bespeur is. Ten spyte van merkbare groen kleur verlies oor die onderskeie tydperke by NTO en HTO is individuele fenoliese verbindings min beinvloed. NTO en HTO het gelei tot die progresiewe ontwikkeling van gesogte sensoriese eienskappe van gefermenteerde heuningbos, veral in ongestoomde monsters. Dit sluit in prominente vrugtige (‘gestoofde vrugte’, ‘appelkooskonfyt’ en ‘marmelade’) aromas en geure , ‘algemene soet’ en ‘vrugtige-soet’ aromas en 'n soeter smaak. Al die beskrywende sensoriese data is saamgestel om 'n voorlopige sensoriese wiel vir groen heuningbos aroma op te stel, asook een vir geur, smaak en mondgevoel. Die sensoriese profiel van groen heuningbos kan beskryf word as 'n oorheersende vegetatiewe aroma en geur, prominente soet-verwante en effens vrugtige aroma, met soet en veral bitter smaak en ‘n vrank mondgevoel. Deur die sensoriese data te kombineer kon duidelik uitgewys word dat die belangrikste gevolge van opberging dié van stoombehandeling oortref. Dit dui daarop dat opberging van 3 tot 6 maande sensoriese kwaliteit kan verbeter, hoewel kleur effens benadeel kan word. In die kort termyn kan onmiddellike sensoriese manipulasie en dus verbetering egter in 'n mindere mate deur SBVD bereik word.

Thesis (MScAgric (Agronomy)--Stellenbosch University, 2008. / Honeybush (Cyclopia spp. Fabaceae) is indigenous to the fynbos botanical biome of the Eastern and Western Cape of South Africa. The increase in the international demand for honeybush tea for health benefits, concern over exploitation of wild populations and the lack of published agronomic information necessitated this study to evaluate different aspects of honeybush propagation. The main objectives of this study were to evaluate the effect of species and cutting position on rooting of cuttings of Cyclopia species using different rooting hormones, to evaluate the effect of an organic plant fertilizer and cutting position on growth and establishment of rooted cuttings and to study the influence of different seed pre-treatments on germination of Cyclopia species. Terminal and sub-terminal cuttings of C. intermedia and C. genistoides treated with different rooting hormones were rooted under day/night temperature controlled glasshouse conditions. Intermittent mist was used as means of moisture supply to the cuttings for 45-60 seconds daily every 30 minutes. C. genistoides rooted significantly better compared to C. intermedia as measured by rooting percentage, number of roots per cutting, length of longest root and mean root length during the summer season. The cutting position had a significant effect on rooting of the cuttings in summer compared to winter and spring season. The interactive effect of species, treatment and cutting position resulted into 86% of rooting in summer from the terminal cuttings of C. genistoides, while only 4% was recorded as the highest rooting percentage in both winter and spring seasons. The highest number of roots and the greatest root length per cutting were obtained with 2 and 4 g L-1 IBA from terminal cuttings of C. genistoides and these hormone concentrations were not significantly different to each other. To evaluate the effect of an organic plant fertilizer and cutting position on plant growth and establishment, rooted cuttings of two Cyclopia species (C. intermedia and C. genistoides) from two cutting positions (terminal and sub-terminal) were transferred to pots (576 cm3) and treated with Nitrosol fertilizer at application rates of 3.33 ml.L-1, 1.67 ml.L-1 and 0 ml.L-1 (control). Cyclopia plantlets were uniformly inoculated once with a symbiotic Rhizobium bacteria to improve the formation of nodules. Nitrosol® at 3.33 ml.L-1 significantly affected fresh and dry plant weight, fresh and dry root weight, number of shoots and nodules per plant compared to either 1.67 ml.L-1 or the control. Relative to species, C. genistoides performed better in terms of fresh and dry plant weight, fresh and dry root weight, and number of shoots and nodules per plant compared to C. intermedia. The origin of the cutting position did not significantly affect the above mentioned parameters. Plant mineral analysis revealed that most of the essential elements increased with increasing Nitrosol® application rates, with C. genistoides having higher levels of mineral elements than C. intermedia. This could be an indication of the differences between the two species in terms of nutrient uptake, utilization and distribution within the plant tissues. In the germination studies, seeds obtained from different seed sources of Cyclopia species were subjected to different pre-sowing treatments. Seed treatments were sulphuric acid (95%), hot water (100°C), water with smoke paper disk, and demineralised water (control). The study revealed that all the treatments had a significant effect on germination with the exception of eight year old seeds obtained from C. subternata (seed source two). Although hot water treatment improved germination compared to smoked paper disk and the control, seeds treated with hot water degenerated rapidly. The highest overall germination (77.33%) was found with one year old seeds compared to other seed sources older than one year. Although smoked paper disks generally did not improve germination compared to the control, in one year old seeds from seed source one, this treatment greatly influenced germination, suggesting that seed age might have influenced germination of these seeds. In terms of germination rate, germination generally started after four days in most treatments.

Thesis (MTech (Consumer Science: Food and Nutrition))--Cape Peninsula University of Technology, 2011.Includes bibliographical references (leaves 139-156). / Oxidative stress has been implicated in the development of a number of chronic degenerative diseases. These diseases can often be prevented by dietary and lifestyle changes. One major dietary aspect is increasing the intake of plant foods, such as fruit and vegetables as they are rich in the major nutrient and nonnutrient antioxidants. The South African population does not have an adequate intake of fruit and vegetables and many barriers have been noted against increasing the intake of these foods. Other avenues should therefore be sought to increase the antioxidant intake. One such avenue is to use a basic food item consumed often as an antioxidant carrier to increase the antioxidant intake. Much interest has developed in functional foods and their therapeutic effects as well as the use of nutraceuticals in food product development and food fortification. Tea and its polyphenols, due to the antioxidant properties, is a potentially viable option for nutraceutical and functional food use. Rooibos and honeybush herbal teas, native to South Africa, can be potential nutraceutical sources to increase antioxidant levels of food due to their unique polyphenol content. The objective of the study was to increase the total antioxidant capacity (TAC) of a basic food item consumed regularly by most South Africans, such as brown bread through fluid manipulation using rooibos, honeybush and black teas respectively, as the replacement fluid for water in a standardised bread recipe formulation. The TAC of these experimental breads were compared to the TAC of the bread produced with no fluid manipulation (control bread) and a commercially processed bread (reference bread). The experimental breads were prepared using 2% weight per volume (w/v) and 5% (w/v) concentration levels for rooibos, honeybush and black tea respectively. To ascertain the TAC of the experimental breads, the fluorescein(FL)-based oxygen radical absorbance capacity (ORACFL) method was used. The hydrophilic (H)-ORACFL assay was used as the teas contain polyphenols which favour a water environment. The results indicated that the H-ORACFL of the control bread using water as the fluid and the commercial reference bread was significantly different (p < 0.05 for each) to all the experimental bread formulations besides for the 2% (w/v) honeybush experimental bread formulation. The 2% (w/v) honeybush experimental bread formulation was therefore not considered for the consumer acceptance testing. There was no significant difference (p > 0.05) in the H-ORACFL of the 2% (w/v) rooibos and black tea experimental bread formulations, but the H-ORACFL of the 5% (w/v) black tea experimental bread formulation was significantly (p < 0.05) higher than that of the 5% (w/v) rooibos experimental bread formulation. This particular experimental bread formulation had a “golden-orange” colour with a pungent smell due to the increase in rooibos concentration. The 5% (w/v) black tea experimental bread formulation, however, had noted negative sensory attributes of being densely textured with a very dark colour and a pungent and overpowering taste of black tea. These sensory attributes and TAC results lead to the rooibos experimental breads containing 5% (w/v) (as bread A) and 2% (w/v) (as bread B) chosen for the consumer acceptance testing and rooibos being a proudly South African product. The participants (n = 85) of the consumer acceptance testing participated voluntarily and were regular bread consumers. The sample was mostly female (57.6%), in the age group of 18 to 24 years (54.1%), with an education level of between three to four years post-matric/-grade 12 (71.7%) and single, living on their own without children (76.4%). They also represented a sample which had characteristics of a healthy lifestyle. Most participants perceived themselves as being of an optimal body weight (55.2%) and the majority was non-smokers (74.1%), physically active (63.5%), having no family history of chronic disease (69.4%) and not consuming dietary supplements (70.5%). Three sensory attributes of the experimental breads were rated for the acceptance testing and included appearance/colour, flavour/taste and texture/mouthfeel. Both the experimental bread formulations was accepted favourably regarding the above-mentioned sensory attributes. The three liking acceptance categories, ‘neither like nor dislike’ (neutral response), ‘like’ and ‘like very much’ were the most commonly indicated by the participants which also resulted in the experimental breads being rated as fair, good and very good according to the development scores. Although both breads were very similarly scored, there was a trend for bread A to be rated slightly higher regarding the above-mentioned sensory attributes. The acceptance category, ‘like’/good was scored the highest for bread A according to the sensory attributes of appearance/colour (56.5%), flavour/taste (55.3%) and texture/mouthfeel (50.6%). There was no significant association/difference (p > 0.05 for each) between the participants’ demographic characteristics and their overall acceptance of the experimental breads. Most of the participant biographic characteristics also had no significant (p > 0.05 for each) impact on the sensory attribute acceptance of the experimental breads. Although the majority (75%) of the participants consumed rooibos, there was no significant (p > 0.05) association/difference between the participants’ tea consumption and their acceptance of the experimental breads. Although most participants (64%) had no awareness of functional foods, most indicated willingness to purchase foods with added health benefits (93%) and to pay more for foods with added health benefits (73%). These results indicated a general acceptance of bread with functional food characteristics and the possibility of purchasing such products with added health benefits and even at a higher price premium.

Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2006. / Honeybush (Cyclopia spp.) is indigenous to South Africa and consists of more than 20 species of which only a few are used to make a herbal tea with a unique aroma and sweet taste. The aroma of unfermented and fermented honeybush tea differs considerably, indicating that changes take place in the chemical composition of the aroma during the fermentation process. Using a sample enrichment probe (SEP) and gas chromatography-mass spectrometry (GC-MS), the chemical composition of the aroma of unfermented and fermented C. genistoides, was analyzed and the resulting aroma profiles were compared. A total of 74 compounds were identified in the unfermented honeybush aroma, comprising, inter alia, a large number of saturated and unsaturated alcohols, aldehydes and methyl ketones that were found to be either absent, or present in lower relative concentrations, in the aroma of fermented honeybush. Most of these compounds, including 6-methyl-5-hepten-2-one, identified as one of the major constituents of unfermented honeybush, are probably responsible for its grassy, hay-like aroma. In the aroma of fermented honeybush 70 compounds were identified, of which 36 were found to be terpenoids. These compounds are probably responsible for the pleasant sweet aroma of the fermented honeybush. For instance, the major aroma constituent in the fermented honeybush, α-terpineol, is known to have a delicately floral and sweet odour. Other terpenoids occuring in significant quantities in the fermented honeybush, are linalool, cis and trans linalool oxide, nerol, geraniol, 2,6-dimethyl-1,7-octadien-3,6-diol, hexahydrofarnecyl acetone and phytol. These terpenoids are known to have sweet, sweet-woody en floral odours that probably contribute to the overall sweet aroma of the fermented honeybush. In the aroma of the unfermented honeybush a total of 25 terpenoids was identified, of which geranyl acetone, β-ionone, and dihydroactinidiolide are the most significant, since they are present in higher relative concentrations compared to the same terpenoids in the fermented honeybush. These three terpenoids have overall woody and even slightly green odours which contribute to the typical aroma of the unfermented honeybush. The terpenoids present in the aroma of unfermented and fermented honeybush belong to the following compound classes: • Terpenes • Terpene alcohols • Terpene aldehydes • Ketoterpenes • Terpene ethers • Terpene lactones Apart from the terpenoids present in the aroma of unfermented and fermented honeybush, the following classes of compounds are also present: • Aliphatic hydrocarbons (saturated) • Aliphatic alcohols (saturated and unsaturated) • Phenols • Aliphatic aldehydes (saturated and unsaturated) • Aliphatic ketones (saturated and unsaturated) • Aliphatic carboxylic acids (saturated) • Esters (methyl esters, ethyl and higher esters and aromatic esters) • Furane compounds • Lactones The present research was done to compare the chemical composition of the aroma of unfermented and fermented honeybush of one particular species, namely C. genistoides, to obtain an understanding of the evolution and/or disappearance of volatile compounds during fermentation that ultimately could help to identify compounds or compound types and their precursors responsible for its unique sweet aroma.

Thesis (MSc Food Sc )--Stellenbosch University, 2003. / ENGLISH ABSTRACT: Please refer to fulltext for abstract / AFRIKAANSE OPSOMMING: Sien volteks vir opsomming

Thesis (MScFoodSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: In light of the limited and inconsistent supply of good quality honeybush tea, a species-specific sensory profile and the physicochemical characteristics of Cyclopia intermedia (honeybush) tea were determined to ultimately establish the optimum fermentation parameters for this herbal tea on laboratory-scale and to validate these findings on commercial-scale. The characteristic sensory profile of C. intermedia can be described as sweet tasting and slightly astringent with a combination of “fynbos-floral”, “fynbos-sweet”, “fruity” (specifically “apricot jam”, “cooked apple”, “raisin” and “lemon/lemon grass”), “woody”, “caramel/ vanilla” and “honey-like” aromas. The flavour can be described as distinctly “fynbos-floral”, “fynbos-sweet” and “woody”, including hints of “lemon/lemon grass” and “hay/dried grass”. The results of the sensory study were used to create a C. intermedia sensory wheel and lexicon, and an elementary grading system that categorised samples into “good”, “average” and “poor” sensory quality was proposed. Physicochemical parameters, i.e. soluble solids (SS) content, absorbance as a measure of colour, and turbidity, were evaluated as possible rapid predictors of sensory quality. High SS content, absorbance and turbidity correlated strongly with “poor” sensory quality. A linear relationship existed between the physicochemical parameters. The effect of fermentation temperature (70, 80 and 90°C) and time (12, 16, 24, 36, 48 and 60 h) on the sensory and physicochemical characteristics of C. intermedia was determined on laboratory-scale. Increasing fermentation time increased the intensity of positive sensory attributes, while decreasing the intensity of negative sensory attributes. The SS content, colour and turbidity of infusions decreased with increasing fermentation time, while the SS content and turbidity of infusions increased with increasing fermentation temperature. Fermentation at 90°C for 36 h on laboratory-scale produced C. intermedia with the best sensory properties, while preserving the SS content and colour of infusions. Fermentation at 70°C and 80°C required longer fermentation times for development of positive sensory attributes. Fermentation at 90°C was subsequently validated on commercial-scale. Laboratory-scale fermentation of the same batches of plant material was also carried out concurrently to allow direct comparison of the scale of fermentation on tea quality. Commercial-scale fermentation, despite increased variability as a result of increased batch volumes and heating difficulties, produced C. intermedia of “good” sensory quality after 24 and 36 h of fermentation. Increasing fermentation time had little effect on the SS content and colour of infusions of tea produced on commercial-scale, but turbidity increased significantly after 36 h. Thus, to produce C. intermedia with consistently good quality on commercial-scale, fermentation at 90°C for 24 to 36 h is recommended. Increasing fermentation time past 48 h should be avoided to prevent turbidity and the development of sensory attributes characteristic of over-fermented tea. However, due to the large variability of commercial-scale honeybush tea production, it is recommended that each batch be monitored between 24 and 36 h to determine when optimum fermentation has been obtained. / AFRIKAANSE OPSOMMING: Beperkte en wisselvallige beskikbaarheid van goeie gehalte heuningbostee noodsaak die optimisering van fermentasie parameters vir Cyclopia intermedia. Optimisering van fermentation parameters is op laboratorium skaal gedoen, gevolg deur validasie van die parameters op kommersiële skaal. Vooraf is die spesie-spesifieke sensoriese profiel en die fisies-chemiese eienskappe van C. intermedia tee bepaal. Die kenmerkende sensoriese profiel van C. intermedia kan beskryf word as soet en effens vrank met 'n kombinasie van "fynbos-blomagtige", "fynbos-soet", "vrugtige" (spesifiek "appelkooskonfyt", "gekookte appel", "rosyntjie” en “suurlemoen/sitroen gras"), "houtagtige", "karamel/vanilla" en "heuningagtige" aromas. Die smaak kan beskryf word as "fynbos-blomagtig", "fynbos-soet" en "houtagtig", met 'n tikkie "suurlemoen/sitroen gras" en "hooi/gedroogde gras". Die resultate van die sensoriese studie is gebruik om 'n C. intermedia sensoriese wiel en leksikon, asook 'n basiese graderingstelsel wat tee monsters in "goeie", "gemiddelde" en "swak" sensoriese kwaliteit klassifiseer, te ontwikkel. Fisies-chemiese parameters: oplosbare vastestof (SS) inhoud; absorbansie as 'n maatstaf van kleur; en troebelheid, is geëvalueer as moontlike indikasies van sensoriese kwaliteit. Hoë SS inhoud, absorbansie en troebelheid waardes het sterk met "swak" sensoriese kwaliteit gekorreleer. 'n Lineêre verwantskap bestaan tussen die fisies-chemiese parameters en kwaliteit. Die effek van fermentasie temperatuur (70, 80 en 90°C) en -tyd (12, 16, 24, 36, 48 en 60 h) op die sensoriese en fisies-chemiese eienskappe van C. intermedia is op laboratorium skaal bepaal. Verlenging van fermentasie tyd het die intensiteit van die positiewe sensoriese eienskappe verhoog, terwyl dit die intensiteit van negatiewe sensoriese eienskappe verminder het. Die SS inhoud, kleur en troebelheid van die tee het met verlengde fermentasie tyd afgeneem, terwyl die SS inhoud en troebelheid met verhoging van fermentasie temperatuur toegeneem het. Fermentasie by 90°C vir 36 h op laboratorium skaal het tee met die beste sensoriese eienskappe geproduseer, met behoud van die SS inhoud en kleur. Fermentasie by 70°C en 80°C het 'n langer fermentasie tyd vir die ontwikkeling van positiewe sensoriese eienskappe vereis. Fermentasie by 90°C is daaropvolgens op kommersiële skaal uitgevoer, met gelyktydige laboratorium skaal fermentasie van dieselfde plantmateriaal lotte om die direkte effek van die skaal van fermentasie op tee kwaliteit te bepaal. Kommersiële fermentasie, ten spyte van verhoogde wisselvalligheid as gevolg van groot volumes tee en probleme met verhitting, het tee van "goeie" sensoriese kwaliteit na fermentasie periodes van 24 en 36 h geproduseer. Verlenging van fermentasie tyd het min uitwerking op die SS inhoud en kleur van kommersiel gefermenteerde tea gehad, maar troebelheid het beduidend na 36 h toegeneem. Fermentasie by 90°C vir 24 - 36 h word gevolglik aanbeveel om tee met goeie gehalte op kommersiële skaal te produseer. Fermentasie vir langer as 48 h moet vermy word om troebelheid te voorkom en die ontwikkeling van sensoriese eienskappe kenmerkend van oor-gefermenteerde tee te vermy. As gevolg van faktore wat groot variasie in kommersiële skaal heuningbostee produksie kan teweegbring, word aanbeveel dat elke produksielot tussen 24 en 36 h gemonitor word om die optimum fermentasie tyd te bepaal.

Thesis (MSc Food Sc) (Food Science)--University of Stellenbosch, 2005. / Near infrared spectroscopy (NIRS) and UV/Vis spectrophotometric methods were investigated as rapid and/or more economical methods to quantify the major monomeric phenolic compounds, soluble solid content (SSC), total polyphenol content (TPC) and total antioxidant activity (TAA) of green rooibos and Cyclopia genistoides.

Thesis (PhD(FoodSc))--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Potential beneficial and/or adverse modulatory effects of polyphenol-enriched extracts of rooibos (Aspalathus linearis) and honeybush (Cyclopia spp.) on the antioxidant homeostasis in the liver were investigated. Phase II metabolism of aspalathin and mangiferin, the major polyphenols of rooibos and honeybush respectively, was assessed for potential glucuronidation and sulphation. Glucuronidation resulted in a loss of antioxidant activity for aspalathin and mangiferin in post-column HPLC-DAD-DPPH• and HPLC-DAD-ABTS•+ assays and also a decreased activity of iron chelating properties of mangiferin in the FRAP assay. Two independent studies for 28 and 90 days with polyphenol-enriched extracts (PEEs) of unfermented rooibos [Aspalathus linearis (PER)] and honeybush [Cyclopia. subternata (PECsub) and C. genistoides (PECgen)] in male Fischer rats were conducted to assess possible beneficial and/or adverse biological effects. PECgen was only included in the 28 day study. PEEs were characterised by in vitro antioxidant assays and HPLC analysis. The importance of detailed chemical characterization of rooibos and honeybush when investigating biological effects in vivo is clear as distinctive biological effects and major differences in compositions were evident. Biological parameters included were serum chemical parameters, activities of selected antioxidant enzymes, levels of glutathione and the modulation of expression of oxidative stress and antioxidant defense related genes in the liver. Sub-chronic (90 days) exposure of rats to PER and PECsub both adversely affected iron absorption significantly (P<0.05) and significantly (P<0.05) and markedly lowered levels of reduced glutathione (GSH) in the liver. The high levels of polyphenol intake were implicated and interaction with glutathione was postulated to occur via catechol o-quinone conjugations with GSH. This was also implicated in the significantly (P<0.05) increased activity of glutathione reductase (GR) following 28 days. These findings suggest that PEEs from rooibos and honeybush have the potential to alter the glutathione homeostasis, which could contribute to oxidative status in the liver. PECsub resulted in alterations in the liver biliary system which was manifested as significantly (P<0.05) increased serum total bilirubin (Tbili) and alkaline phosphatase (ALP), depending on the age of the rats, level of total polyphenols and duration of exposure. The expression of a number of oxidative stress and antioxidant defense related genes were differentially altered by the PEEs of rooibos and honeybush in rat liver and further indicated potential oxidative stress. Modulatory effects of PEEs on expression of 84 of these genes in rat liver were assessed with a quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) array and provided additional insights into the possible adverse and protective effects of rooibos and honeybush. Further investigation on total polyphenol dose levels and time of exposure in the application of PEEs of rooibos and honeybush as dietary supplements and functional foods is recommended and will also be of value in anticipated regulatory requirements for future substantiation of safety and efficacy. / AFRIKAANSE OPSOMMING: Die moontlike voordelige en/of nadelige modulerende effekte van polifenol-verrykde ekstrakte van rooibos (Aspalathus linearis) en heuningbos (Cyclopia spp.) op die antioksidant homeostasis in die lewer is ondersoek. Die fase II metaboliete van aspalatien en mangiferin, die hoof verbindings in rooibos en heuningbos onderskeidelik, is ondersoek t.o.v. glukuronidering en sulfonering. Glukuronidasie het gelei tot n verlies in antioksidant aktiwiteit van aspalatien en mangiferin soos bepaal in post-kolom HPLC-DAD-DPPH• en HPLC-DADABTS•+ toetse, asook verminderde interaksie met yster van mangiferin in die FRAP toets. Twee onafhanklike studies van 28 en 90 dae is onderneem met polifenol-verrykde ekstrakte (PVEs) van ongefermenteerde rooibos [Aspalathus linearis (PVR)] en heuningbos [Cyclopia. subternata (PVCsub) and C. genistoides (PVCgen)] in manlike Fisher rotte om die moontlike voordelige en/of nadelige biologiese effekte te ondersoek. PECgen was slegs in die 28 dae studie ingesluit. PVEs is gekarrakteriseer deur in vitro antioksidant en HPLC analises. Die belang van chemiese karaktirisering van rooibos en heuningbos tydens ondersoeke na biologiese aktiwiteit is duidelik aangesien verskeie en variërende biologiese aktiwiteite en verskille in die komposisie in die huidige studie gesien is. Die biologiese parameters wat ondersoek is om die effek van die PVEs te bepaal het serum kliniese parameters, aktiwiteit van geselekteerde ensieme, glutatioon en evaluering van die ekspressie van oksidatiewe en antioksidant verwante gene in die lewer, ingesluit. Sub-kroniese (90 dae) blootstelling van rotte aan PVR en PVCgen het yster absorpsie negatief beïnvloed. Die beduidende (P<0.05) verlaagde vlak van gereduseerde glutatioon in die lewer was toegeskryf aan die hoë vlakke van polifenole ingeneem tydens die studie en word moontlik veroorsaak deur n spesifieke katekol o-konjugasie van GSH. Hierdie interaksie was ook moontlik die oorsaak van n beduidende (P<0.05) toename in die aktiwiteit van glutatioon reduktase. Dié bevindinge het moontlike implikasies t.o.v die glutatioon homeostase en is n moontlike indikase dat PVEs van rooibos kan bydra tot oksidatiewe stres. PVCsub het veranderinge in die lewer gal-sisteem tot gevolg gehad aangesien daar n beduidende (P<0.05) verhoging in die serum totale bilirubin en alkalien fosfaat was. Hierdie veranderinge is beïnvloed deur die ouderdom, vlakke van die totale polifenole en die periode van blootstelling. Die uitdrukking van oksidatiewe en antioksidant verwante gene is op verskillende maniere beïnvloed deur die PVEs van rooibos en heuningbos in rot lewer and dien as n verdere indikasie van onderliggende oksidatiewe stres. Die modulerende effekte van PVEs op geenuitdrukking het gelei tot additionele insig aangaande die moontlike skadelike of beskermende eienskappe van PVEs vir gebruik as kruie produkte of dieet aanvullings. Die indikasies van moontlike oksidatiewe stres was duidelik van biologiese parameters en modulering van geenuitdrukking in die lewer, en vereis verdere ondersoek na die polifenool dosis en periode van toediening voordat PVEs van rooibos en heuningbos as funksionele voedsel produkte gebruik word. Hierdie ondersoek sowel as toekomstige ondersoeke in hierdie verband sal van waarde wees vir regulatoriese vereistes omtrent die veiligheid en effektiwiteit van rooibos en heuningbos kruie produkte.

Thesis (MScMedSc)--Stellenbosch University, 2012. / Includes bibliography / ENGLISH ABSTRACT: Obesity is a major source of morbidity and mortality worldwide. More than 1.5 billion individuals over the age of 20 years are overweight, with more than 500 million of these individuals being obese. Obesity increases the risk of developing cardiovascular disease, type 2 diabetes and certain types of cancer. Recently, a number of plant extracts have been shown to possess anti-obesity properties in vitro and in various animal models of obesity. The aim of this study was to investigate the effect of a hot water fermented extract of Cyclopia maculata, a South African herbal tea more commonly referred to as honeybush, on lipogenesis and lipolysis in 3T3-L1 pre-adipocytes and adipocytes. To investigate the effect of C. maculata extract on adipogenesis, 3T3-L1 preadipocytes were differentiated in adipogenesis inducing media containing various concentrations. The optimal concentration was determined by screening concentrations ranging from 0 to 1,600 μg/ml. 3T3-L1 pre-adipocytes were differentiated with TNFα or unsupplemented adipogenesis inducing media as positive and negative controls, respectively. Intracellular lipid accumulation was measured by using the Oil O Red stain and a commercial triglyceride assay kit. Cell viability was measured using the 3-(4,5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) and adenosine tri-phosphate (ATP) assays. The expression of PPARγ, C/EBPα, SREBP-1 and PPARα was assessed by Western blot analysis, while the expression of the secreted proteins leptin and adiponectin was assessed by ELISA. The effect of C. maculata extract on lipolysis was investigated by differentiating 3T3-L1 pre-adipocytes in adipogenesis inducing and adipogenesis maintenance media for 8 days until they were mature adipocytes, and thereafter treating with C. maculata extract for 24 hours. The optimal concentration was determined by screening concentrations ranging from 0 to 1,600 μg/ml. Isoproteronol or unsupplemented adipogenesis maintenance media was used as positive and negative controls, respectively. Intracellular lipid break down was measured by using the Oil O Red stain, while glycerol release, a marker of lipolysis, was measured using a commercial kit. Cell viability was measured using the MTT and ATP assays. The expression of HSL and perilipin was assessed by Western blot analysis, while the expression of secreted proteins leptin and adiponectin was assessed by ELISA. Treatment with the C. maculata extract, at most of the concentrations tested, decreased intracellular lipid accumulation in pre-adipocytes. The Oil O Red and the intracellular triglyceride assay, in combination with the cell viability assays, showed that 80 μg/ml optimally reduced intracellular lipid without affecting cell viability. Western blot analysis showed that differentiation of 3T3-L1 adipocytes in the presence of 80 μg/ml of the C. maculata extract decreased the expression of PPARγ2, a key adipogenenic transcription factor, 1.8-fold (p=0.006). PPARγ2 was observed at a smaller size than expected and further studies are needed. The results of the C/EBPα, SREBP-1 and PPARα Western blots were not included in this study and are recommended to be further optimized to reduce non-specific binding. ELISA results showed a significant increase in the secretion of the adipokines, adiponectin (>10-fold, p<0.001) and leptin (1.5-fold, p=0.002). The C. maculata extract was better than the positive control, TNFα, at inhibiting adipogenesis. A concentration of 80 μg/ml of the C. maculata extract maximally induced lipolysis, without affecting cell viability. Western blot analysis showed non-specific binding, and are recommended to be further optimized to reduce non-specific binding. Western blot analysis also showed that acute treatment (24 hours) of mature 3T3-L1 adipocytes with 80 μg/ml increased the expression of the lipolytic protein, HSL (1.6-fold, p=0.025). Perilipin Western blot was not included due to non-specific binding. ELISA results showed an increase in adiponectin (1.5-fold, p=0.015) and leptin (1.2-fold, p=0.067) secretion. Similar results were obtained after treatment with the C. maculata extract or the positive control, isoproteronol. This study shows that treatment of 3T3-L1 pre-adipocytes and adipocytes with 80 μg/ml of C. maculata plant extract inhibits adipogenesis and induces adipolysis, without causing cytotoxicity. A major limitation of the current study is that it was conducted in an in vitro model and does not represent the complexity of obesity as it occurs in humans. However, despite this, we believe that these results are promising and provide support for future in vivo studies to substantiate these preliminary findings. The results of this study is aligned with the Department of Science and Technology’s Ten Year Innovation Plan and the “Farmer to Pharma” value chain that aims to improve our bio-economy by developing our indigenous resources. Moreover, this type of initiative will be able to stimulate job creation, while being able to utilize the very rich South African indigenous knowledge. / AFRIKAANSE OPSOMMING: Vetsug is 'n groot oorsaak van morbiditeit en mortaliteit wêreldwyd. Tans is meer as 1,5 miljard mense oor die ouderdom van 20 jaar oorgewig, met meer as 500 miljoen van hierdie individue wat vetsugtig is. Vetsug verhoog die risiko vir die ontwikkeling van kardiovaskulêre siekte, tipe 2 diabetes en sekere soorte kanker. Onlangs het 'n aantal plantekstrakte anti-vetsug eienskappe in vitro en in verskeie dier modelle van vetsug getoon. Die doel van hierdie studie was om die effek van die Cyclopia maculata, 'n Suid-Afrikaanse kruie-tee, meer algemeen bekend as heuningbos, op lipogenese en lipolise in 3T3-L1 pre-adiposiete en adiposiete te ondersoek. Vir die ondersoek, is 3T3-L1 pre-adiposiete gedifferensieer in ‘n adipogeneseinduserende media met verskillende konsentrasies van ‘n warm water ekstrak van gefermenteerde C. maculata. Die optimale konsentrasie van C. maculata ekstrak is bepaal deur die selle met verskeie konsentrasies te behandel wat gewissel het van 0 tot 1600 mg / mL. 3T3-L1 pre-adiposiete is met adipogenese-induserende media gedifferensieer met of sonder TNFα supplementasie wat as positiewe en negatiewe kontrole, onderskeidelik gedien het. Intrasellulêre lipied-versameling is gemeet deur middel van Oil O Red kleuring en trigliseried-inhoud is bepaal deur 'n kommersiële kit. Sel-lewensvatbaarheid is bepaal deur 3-(4,5-Dimetielthiazol-2- yl)-2,5-difenieltetrazolium bromied (MTT) en adenosien tri-fosfaat (ATP) assays. Die PPARγ, C/EBPα, SREBP-1 and PPARα proteïen uitdrukking is deur middel van Western-blot analise bepaal, terwyl die gesekreteerde proteïene, leptien en adiponektien, deur ELISA bepaal is. Die effek van C. maculata ekstrak op lipolise is ondersoek deur 3T3-L1 preadiposiete in adipogenese-induserende media te differensieer waarna die selle vir ‘n verdere 8 dae in adipogenese-onderhoud media gekultuur is totdat hulle volwasse adiposiete bereik het, voordat die adiposiete behandel is met C. maculata ekstrak vir 24 uur. Die optimale konsentrasie C. maculata ekstrak is bepaal deur die selle met verskeie konsentrasies te behandel wat gewissel het van 0 tot 1600 mg/ml. Adipogenese-onderhoud media met of sonder isoproterenol is onderskeidelik gebruik as die positiewe en negatiewe kontroles. Intrasellulêre lipied afbraak is deur middel van Oil O Red gemeet, terwyl vry gliserol, 'n merker van lipolise, deur ‘n kommersiële kit bepaal is. Sel-lewensvatbaarheid is bepaal deur MTT en ATP assays. Die uitdrukking van HSL is deur middel van Western-blot analise bepaal, terwyl die uitdrukking van die gesekreteerde proteïene, leptien en adiponektien, deur ELISA gemeet is. Ek stel voor dat die perilipin Western blots verder geoptimaliseer word om sodoende nie-spesifieke binding te verminder. Behandeling met C. maculata ekstrak het intrasellulêre lipied-akkumulasie in die pre-adiposiete verminder, by die meeste van die konsentrasies wat getoets is. Die Oil O Red en die intrasellulêre trigliseried toetse, in kombinasie met die sellewensvatbaarheid assays, het getoon dat 80 mg/ml C. maculata ekstrak intrasellulêre lipied optimaal verminder sonder om die sel-lewensvatbaarheid te affekteer. Western blot analise het getoon dat die differensiasie van 3T3-L1 adiposiete in die teenwoordigheid van 80 mg/ml C. maculata ekstrak die uitdrukking van PPARγ2, 'n sleutel adipogenetiese transkripsie faktor, 1.8-voudig (p=0.006) verlaag. PPARy2 is waargeneem by a kleiner grootte as verwag en verdere ondersoek word benodig. Ek stel voor dat die C/EBPα, PPARα en SREBP- 1 Western blots verder geoptimaliseer word om sodoende nie-spesifieke binding te verminder. ELISA resultate het 'n beduidende toename in die sekresie van die adipokines, adiponektien (>10-voudig, p <0.001) en leptien (1.5-voudig, p= 0.002) getoon. Cyclopia maculata ekstrak was beter as die positiewe kontrole, TNFα, om adipogenese te inhibeer. Teen ‘n konsentrasie van 80 mg/ml het C. Maculata ekstrak lipolise maksimaal geïnduseer, sonder om sel-lewensvatbaarheid te beinvloed. ELISA resultate het 'n toename in adiponektien (1.5-voudig, p = 0.015) en leptien (1.2-voudig, p = 0,067) sekresie getoon. Soortgelyke resultate is verkry met die positiewe kontrole, isoproteronol, as met C. maculata ekstrak behandeling. Hierdie studie het getoon dat die behandeling van 3T3-L1 pre-adiposiete en adiposiete met 80 mg/ml C. maculata ekstrak adipogenese inhibeer en adipolise induseer, sonder enige sitotoksisiteit. 'n Beperking van die huidige studie is dat dit in 'n in vitro model gedoen is wat nie die kompleksiteit van vetsug in die mens weerspieël nie. Ten spyte daarvan is resultate belowend en ondersteun dit toekomstige in vivo studies om hierdie voorlopige bevindinge te staaf. Bewys dat ‘n water ekstrak van gefermenteerde C. maculata anti-vetsug eienskappe het kan groot ekonomiese gevolge vir die heuningbos industrie inhou. Die resultate van hierdie studie is in lyn met die Departement van Wetenskap en Tegnologie se tien jaar Innovasie Plan en die "Farm Pharma" waardeketting wat daarop gemik is om ons bio-ekonomie te verbeter deur die ontwikkeling van ons inheemse hulpbronne. Daarbenewens sal hierdie tipe inisiatief potensieel werkskepping stimuleer, terwyl dit die ryk Suid-Afrikaans inheemse kennis aanwend.