Thesis (M.Sc. (Horticulture)) --University of Limpopo, 2012 / Refer to document / the National Research Foundation

Tea is second only to water as the most consumed beverage in the world due to its health-promoting benefits and characteristic flavor. Even though many botanical teas such as yaupon holly (Ilex vomitoria) and mamaki (Pipturus albidus) are currently available in the tea market, only limited information is available on their polyphenolic contents containing diverse biological activities. Identification of phenolic compounds was performed using advanced analytical technique of mass spectrometry to provide polyphenolic profile of teas. To present fundamental information of phytochemical stability during tea storage, studies to determine the impacts of tea processing, different packaging materials, and various storage conditions on the phytochemical stability were conducted. Ascorbic acid addition and lowering pH successfully decreased the reduction of phenolic compounds by reducing the rate of oxidative degradation while tea pasteurization accelerated oxidative degradation. Glass bottles were most effective to retain higher concentration of polyphenolics. Tea polyphenolics at lower temperature (3 °C) without light exposure were higher retained in each tea. Tea cream, the complex formed by interaction between polyphenolics, caffeine, protein, and metal ions, is highly undesirable in tea industry since it causes haziness and cloudiness in tea infusion as well as deteriorates sensorial properties. Only limited information is available on tea creaming in non-fermented type teas such as green tea, yaupon holly, and mamaki even though many tea creaming compounds are present in these teas. Therefore, studies were conducted to determine the degree of contribution of the tea creaming compounds to tea creaming and to develop novel chemical methods to minimize tea creaming without detrimental effects. Methods applied in the present study defined that hydrophobic interaction was the driving force make tea cream insoluble in the solution. Results obtained by present studies provided fundamental and practical information to the tea industry in terms of phytochemical stability and suggested storage stability of phytochemicals should be considered during processing and storage, since it could be better retained or improved by applying appropriate methods.

Thesis (PhD)--Macquarie University, Division of Society, Culture, Media & Philosophy, Dept. of Media, 2007. / Bibliography: leaves 281-305.

Thesis (MSc Food Sc) (Food Science)--Stellenbosch University, 2008. / The change in aspalathin, iso-orientin, orientin and total polyphenol (TP) content of a commercially produced fermented rooibos (FR) extract was monitored throughout production. Particular attention was paid to the effect of spray-drying on FR and unfermented rooibos (UR) extracts. The quality of commercial, South African rooibos iced teas made with FR extract was also investigated with respect to the aforementioned parameters. Subsequently, the effect of heating and storage on the phenolic composition and colour of experimental iced teas containing respectively FR, UR and nano emulsified unfermented rooibos (NEUR) extracts was investigated. The combined effect of pH (pH 3-7) and storage (5, 30 and 40ºC), as well as high (660 mg/L, 0-7 days at 30ºC; UR only) and low (0.5 mg/L) concentrations of H2O2, was determined on reconstituted FR, UR and NEUR extracts. Finally, eight rooibos iced teas (four variants; unflavoured and lemon-flavoured) were analysed for plant-like, hay-like, rooibos and lemon flavour, as well as astringency, using descriptive sensory analysis. The degree of consumer preference of the flavoured variants was determined using the nine point hedonic scale. In all cases, changes in individual flavonoid content were quantified using HPLC. The TP content of the iced teas and commercial extracts was determined using the Folin-Ciocalteu assay. Browning of the iced teas and reconstituted extracts was monitored spectrophotometrically (420 nm). Aspalathin, iso-orientin and orientin were found to be present after all stages of the FR extract production process. Spray-drying, specifically, also did not reduce the content of these flavonoids, or the TP content, in FR and UR extracts. Despite the relatively good retention during the heating and storage of experimental rooibos iced teas, these flavonoids were either absent or present at extremely low levels in commercial iced teas. The latter suggested that either extremely low quantities of extract, no extract at all or extracts of poor quality, were used for the production of the analysed iced teas. Increased degradation was generally observed for sterilisation treatments compared to pasteurisation whilst losses during storage increased with time. The presence of citric acid, due to its pH-lowering effect, and ascorbic acid, due to its antioxidant activity, was integral to the retention of aspalathin, iso-orientin and orientin during heating, but less so during storage. The UR iced teas generally performed better than their FR counterparts, however, NEUR iced teas exhibited the greatest retention of the aforementioned flavonoids. Heating and storage resulted in browning of most iced teas, whilst the TP content increased slightly or remained unchanged. Phenolic retention in FR and UR extracts decreased with increasing pH and temperature, with concomitant browning. However, between pH 5 and 7, the stability of aspalathin was superior in the NEUR extract formulation. The latter also greatly resisted absorbance changes at pH 3 and 4, despite a loss of aspalathin. The phenolic content of UR extract was immediately reduced by high a concentration of H2O2, however, no significant (P≥0.05) changes in absorbance were detected, suggesting the formation of intermediate, colourless oxidation products. Formulations containing ascorbic acid experienced the greatest reductions. This was attributed to the iron reducing ability of this compound, as reduced iron accelerates the rate of the Fenton reaction. At low levels of H2O2, only the FR extract exhibited a loss of phenolic compounds. The level of iron in this extract was the highest. Despite having the greatest aspalathin and total flavonoid content, lemon flavoured unfermented rooibos iced tea (UF/LEMON) was disliked by consumers. Preference was directed away from the plant-like characteristic of this tea and towards rooibos flavour, characteristic of fermented rooibos iced tea. Iced tea comprising both FR and NEUR extract produced a product that 77% of consumers rated positively. Its slight hay-like flavour did not significantly (P≥0.05) reduce the liking of this product compared to fermented rooibos iced tea.

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

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 submitted in fulfillment of the requirements for the degree Master of Technology: Biomedical Technology In the Faculty of Health and Wellness Sciences At the Cape Peninsula University of Technology, 2012 / Human and experimental animal studies have shown that biomarkers of oxidative damage are elevated in subjects with certain diseases or risk factors. Consequently, it is hypothesized that oxidative stress plays an important role in the pathogenesis of these diseases and that dietary intake of, or supplementation with antioxidants may be protective or be useful therapeutic targets. This study was designed to investigate the modulatory effect of Camellia sinensis (Chinese green tea), Aspalathus linearis (rooibos herbal tea) and the two commercial supplements on the antioxidant status of the liver and kidney of tert-butyl hydroperoxide (t-BHP)-induced oxidative stress male Wistar rats. Rooibos and green tea are beverages well-known for their antioxidant content. Based on the specific beverage consumed, sixty male Wistar rats were randomly assigned into six groups, i.e. fermented rooibos (FRT), unfermented rooibos (URT), Chinese green tea (CGT), rooibos supplement (RTS), Chinese green tea supplement (GTS) and control (CTL). The animals had free access to the respective beverages and standard diet for 10 weeks, while oxidative stress was induced during the last 2 weeks via intraperitoneal injection of 30 μM of t-BHP per 100 g body weight. Among all the beverage and/or supplement preparations, the commercial rooibos supplement had the highest total polyphenol content and antioxidant activity while fermented rooibos, as previously shown, had a lower antioxidant content and potency when compared to its unfermented counterpart. The ability of these beverages and/or supplements to modulate the antioxidant status in tissues was organ specific and varied according to the assessment method. When considering the liver, the intake of unfermented rooibos, Chinese green tea and the commercial rooibos supplement significantly (P<0.05) restored the t-BHP-induced reduction and increased the antioxidant status with regards to oxygen radical absorbance capacity and trolox equivalent antioxidant capacity (TEAC) levels. All the beverages and/or supplements also significantly (P<0.05) enhanced the renal antioxidant capacity as assessed by the TEAC assay. In what may be an indication of decreased oxidative stress, all the beverages were associated with a general decline in activities of the antioxidant enzymes which reached significant levels in renal superoxidase dismutase activity. Generally, the beverages did not impact significantly on lipid peroxidation (LPO) although there were differing trends in the two LPO markers assessed. While thiobarbituric acid reactive substances levels showed a declining trend in both tissues, the conjugated dienes were generally elevated. In conclusion, this study confirms Camellia sinensis and Aspalathus linearis as well as their two supplements as good sources of dietary antioxidants and results demonstrated that rooibos and green tea improved the liver and kidney antioxidant capacity of oxidative stress-induced rats. Their impact on antioxidant status in rats was shown to vary between organs and according to the method of assessment. Hence multi-method, multi-organ assessment may be a more informative approach in in vivo antioxidant studies.

The aim of presented diploma thesis was to characterize baby beverages for early infant feeding. Theoretical part deals with baby foods and beverages including breast milk. Practical part is focused on analysis of active substances in 21 commercially available fruit and herbal instant granular baby beverages and in 3 packaged tea bags for infant and toddler age. To evaluation of antioxidant properties some group parameters were used - total polyphenols, total flavonoids, total antioxidant activity and anthocyanins. All of them were analysed by using spectrophotometrical methods. For identification and quantification of individual phenolic substances was used RP-HPLC/UV-VIS and HPLC/PDA/LC-MS, identification of individual mono- and disaccharides was performed by HPLC/RI. L-ascorbic acid supplemented to some children's drinks was analysed by HPLC-NH2/UV. Protein analysis was performed by Experion microfluidic electrophoresis system (BioRad) and protein concentration was verified by colorimetric method. In general, the highest content of phenolic compounds was shown in tea bags when compared with instant granular beverages that contain mostly added simple carbohydrates. Using contact microbial tests proved immediately after opening and also during manipulation with tea boxes was verified that analysed baby teas are in agreement with strict hygiene requirements for baby beverages.

The process of classification of the raw material, is one of the most important procedures in any tea dryer, being responsible for ensuring a good quality of the final product. Currently, this process in most tea processing companies is usually handled by an expert, who performs the work manually and at his own discretion, which has a number of associated drawbacks. In this work, a solution is proposed that includes the planting, design, development and testing of a prototype that is able to correctly classify photographs corresponding to samples of raw material arrived at a dryer, using intelligence techniques (IA) type supervised for Classification by Artificial Neural Networks and not supervised with K-means Grouping for class preparation. The prototype performed well and is a reliable tool for classifying the raw material slammed into tea dryers.

The end of the year 2007, during the presidential campaign of Republican congressman Ron Paul, was the first time when the modern Tea Party movement appeared on American political scene. In a short period of time the Tea Party became a significant political force that endorsed many successful candidates in 2010 midterm elections and put pressure on established political parties to follow the will of the people. This thesis, written primarily as a political affairs analysis, examines origins of this grassroots movement and its impact on American politics. Put in a broader historical and socio-economic context, this work tries to create a notion of movement's probable future. The thesis is divided into three major parts. First chapter provides an insight into the historical origins of the modern Tea Party movement and also the birth of populism in the United States. The following part looks into the formation of Tea Party and describes the most important organizations connected with the movement and how they influenced its activities. The third part is focused on the most relevant Tea Party protests and in form of a case study assesses its influence on 2010 midterm elections.