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I analyse smallholder tea producer experiences of dual-certification to Fairtrade and Organic Voluntary Private Standards (VPSs). Dual-certification represented a gold-standard in pro-development certifications, implying alignment between the standards and producer priorities. Yet certification required smallholders to implement two different and challenging standards simultaneously, and the smallholder category was heterogeneous. Gaps in knowledge persisted regarding smallholder implementation of dual-certification in South Indian tea. The main contribution of this research was empirical, investigating 1) reasons for the extension of dual-certification, 2) implications for export-market access and 3) conflicts of practice with norms among tea farmers. I adopted an agricultural marketing network scope to tether Global Value Chain analytical tools into producer contexts. This maintained the connection of producers with global tea buyers and global standards, contributing to understanding the exercises of power by institutions. This research examined the context of South Indian tea, identifying tea production and marketing networks of industry actors, local institutions, industry conventions and Fairtrade-Organic governance. The use of secondary data was complimented by qualitative techniques. I used a case study approach, recruiting one Fairtrade-Organic, dual-certified producer group and one non-certified producer group of smallholders. I sampled key power nodes in networks to generate interview data with key agents including farmers, producer group managers, tea buyers, standard setters and background institution informants. I held 40 interviews with 60 participants during 7 months in South India and the UK.Global Value Chain analysis represented the founding framework that considered standards as governing production and trade in certified commodities. GVC approaches analysed the distribution of benefits and market access between actors in GVCs. Powerful lead firms controlled chain coordination, shaped competition, market access and costs of compliance. The sociological redefinition of power led to standards theorised as legitimated conceptions of the good, the fair and the environmental, with attention turning to producer accounts of governance and standards. The thesis contributes to a growing literature highlighting agency, governmentality, and powers of institutions, in GVCs. Global standards were expressions of fragmented power in governmentality. I analysed accounts of the extension of dual-certification, attendant changes to market access and performances of implementation, seeing through farmers‘ eyes. I derived from data 3 empirical contributions. Firstly, producer institutions and gatekeepers exercised power by affecting smallholder certifications. Yet smallholders were purposeful agents who drove their certification statuses. Secondly, certification did not define market access; quality remained paramount. Fairtrade-Organic standards carried definitions of quality that were intangible, taking the ascertainment of leaf quality from the hands of farmers. Finally, smallholder agent behaviours were analysed as negotiations of Fairtrade-Organic and tea industry valuations of good tea practices. Standards were not pre-defined, bringing compliance costs; rather, Fairtrade-Organic existed in, was constituted by, smallholder performances. Attempts to enhance the legitimacy of FLO governance by aligning standards with producer priorities involved producer regional forums. Alignment was skewed by FLO‘s failure to distinguish smallholder from plantation priorities. This parallels a pro-market pragmatism about the future of Fairtrade.

Thesis (M.Sc. (Chemistry)) -- University of Limpopo, 2016 / In this study, antioxidant activity methodologies were evaluated in terms of analytical performances. The total antioxidant activity from Athrixia phylicoides leaves (Bush tea) determined using 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH•) method, cupric ion reducing power (CUPRAC) method and cyclic voltammetry (CV). Folin-Ciocalteu method was used to quantify total phenolic content (TPC) in Athrixia phylicoides leaves. The influence of chemical and physical parameters on the total phenolic content and antioxidant activity determination were investigated. Results from direct sample and crude sample were compared. Antioxidant activity and phenolic content from Athrixia phylicoides leaves were compared with those from commercialised green tea, black tea and rooibos tea using two chosen antioxidant capacity method with acceptable characteristics. Results from the evaluation of the methods demonstrated excellent recoveries (99 to 103%) consistently, good linearity within the calibration concentration range (R2 = 0.997) and repeatable low coefficient of variation < 5% were indicative of good precision except for CV method. The average total antioxidant activity of various extracts of Athrixia phylicoides leaves ranged from 0.039 to 0.122 mg/mL (EC50), 0.031 to 0.233 mg/mL (EC50) and 339 to 429 mV (anodic potential) for DPPH method, CUPRAC method and CV method, respectively. The total antioxidant activity values for each Athrixia phylicoides samples determined by CUPRAC method were higher than the values produced by DPPH and CV methods. The highest antioxidant activities in the DPPH and CUPRAC methods were found in water extracts (direct sample). However, concentrated samples for DPPH method and CV gave a different trend with the methanol extract (crude sample) displaying the highest antioxidant capacity. Increasing the infusion time only increased total antioxidant activity determined by CUPRAC method, whilst DPPH and CV methods had the highest antioxidant activity in the lowest infusion time (3 min). Even though the results are inconclusive with regard to the effect of solid to solvent ratio effect on the total antioxidant activity, 1:150 ratio and 1:100 ratio extracts for both CUPRAC and DPPH methods and for CV gave the highest antioxidant capacities, respectively. The total antioxidant activities in pure antioxidant standards and in the teas were ranked in the following order by both CUPRAC and DPPH methods: Quercetin > catechin > Trolox and Chinese green tea > Joko black tea > Athrixia phylicoides leaves > Laager rooibos tea, respectively. Comparative study showed the necessity of employing more than one method, as each method for the same sample yielded different results. CUPRAC and DPPH methods displayed higher sensitivity and repeatability as compared to the CV method with poor precision.

Thesis (MSc. (Chemistry)) -- University of Limpopo, 2016 / In this study, antioxidant activity methodologies were evaluated in terms of analytical performances. The total antioxidant activity from Athrixia phylicoides leaves (Bush tea) determined using 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH•) method, cupric ion reducing power (CUPRAC) method and cyclic voltammetry (CV). Folin-Ciocalteu method was used to quantify total phenolic content (TPC) in Athrixia phylicoides leaves. The influence of chemical and physical parameters on the total phenolic content and antioxidant activity determination were investigated. Results from direct sample and crude sample were compared. Antioxidant activity and phenolic content from Athrixia phylicoides leaves were compared with those from commercialised green tea, black tea and rooibos tea using two chosen antioxidant capacity method with acceptable characteristics. Results from the evaluation of the methods demonstrated excellent recoveries (99 to 103%) consistently, good linearity within the calibration concentration range (R2 = 0.997) and repeatable low coefficient of variation < 5% were indicative of good precision except for CV method. The average total antioxidant activity of various extracts of Athrixia phylicoides leaves ranged from 0.039 to 0.122 mg/mL (EC50), 0.031 to 0.233 mg/mL (EC50) and 339 to 429 mV (anodic potential) for DPPH method, CUPRAC method and CV method, respectively. The total antioxidant activity values for each Athrixia phylicoides samples determined by CUPRAC method were higher than the values produced by DPPH and CV methods. The highest antioxidant activities in the DPPH and CUPRAC methods were found in water extracts (direct sample). However, concentrated samples for DPPH method and CV gave a different trend with the methanol extract (crude sample) displaying the highest antioxidant capacity. Increasing the infusion time only increased total antioxidant activity determined by CUPRAC method, whilst DPPH and CV methods had the highest antioxidant activity in the lowest infusion time (3 min). Even though the results are inconclusive with regard to the effect of solid to solvent ratio effect on the total antioxidant activity, 1:150 ratio and 1:100 ratio extracts for both CUPRAC and DPPH methods and for CV gave the highest antioxidant capacities, respectively. The total antioxidant activities in pure antioxidant standards and in the teas were ranked in the following order by both CUPRAC and DPPH methods: Quercetin > catechin > Trolox and Chinese green tea > Joko black tea > Athrixia phylicoides leaves > Laager rooibos tea, respectively. Comparative study showed the necessity of employing more than one method, as each method for the same sample yielded different results. CUPRAC and DPPH methods displayed higher sensitivity and repeatability as compared to the CV method with poor precision.

Objetivo: Evaluar los factores asociados al diagnóstico tardío en menores de 18 años atendidos en el INSN en Lima, Perú entre 2017 y 2019. Diseño: El tipo de diseño de estudio es observacional transversal analítico.

Theanine is a free, non-protein amino acid found in Camellia sinensis (tea) leaves. It is the main amino acid component in tea and contributes 1 to 2% of the dry weight of tea leaves. The content of amino acids is a key green tea quality parameter. High grade teas contain high amounts of theanine. It is responsible for the sweet, brothy umami taste of green tea. To date there is no international standard method for the analysis of theanine in tea samples. Several methods with different advantages and disadvantages have been reported but most of them are unsuitable for routine quality control analysis in commercial tea samples. In this study, a high performance liquid chromatography (HPLC) method with evaporative light scattering detection for the determination of theanine in tea samples has been developed. Chromatographic separation of theanine was achieved by reverse phase HPLC using a phenyl-hexyl column and isocratic water elution within 8 minutes. The method requires no sample derivatization and includes simple sample clean-up. Applying the same chromatographic conditions to a widely available C18 column, separation of theanine was achieved within 10 minutes. The successful application of the C18 column renders this method widely applicable. The method is linear over several orders of magnitude and the LOD are 11.53 and 10.83 μg/ml and the LOQ are 39.44 and 35.10 μg/ml for the phenyl-hexyl and C18 column, respectively. Simple but effective sample preparation and polyvinylpolypyrrolidone pre-treatment, along with the short analysis time facilitates high sample throughput (~40 samples can be prepared in an 8 hour day with overnight analysis by HPLCELSD). The method is selective, precise, accurate and practical for the quantification of theanine in tea extracts and was successfully used to determine theanine content in a variety of tea samples. The sensitivity and simplicity of this method renders it suitable for use in routine theanine analysis in quality control laboratories. Green tea, a simple refreshing beverage, has been believed to have therapeutic uses for centuries. Scientists have recognized that the wide range of physiological functions of green tea is due to the presence of catechins. An increasing body of evidence is showing that methylated forms of catechins have potent inhibitory activities to allergies. In addition to the methylated catechins, another relative novel group of catechins exists, namely digallated catechins. The medicinal value of these compounds is not yet known, but it is reasonable to speculate that the antioxidant capacity of digallated catechins will be superior to that of epigallocatechin gallate due to the 3 additional hydroxyl groups provided by the second gallic acid moiety. In this study reverse phase UPLC/ESI-MS/MS was effectively applied to investigate the presence of digallated and methylated catechins in crude tea extract. Low abundance catechins (-)-epigallocatechin-(O-3”-methyl) gallate ([M + H]+, m/z 473) and (-)-epicatechin-3-(O-3”-methyl) gallate ([M + H]+, m/z 457) were successfully detected at 31.9 and 37.5 minutes, respectively. The 2 digallated catechins investigated could not be detected, possibly due to being present at concentrations below the limit of detection. Compared to conventional HPLC/ESI-MS/MS, increased resolution and sensitivity, 80% less use of solvent and significantly reduced analysis times were observed. / Dissertation (MSc)--University of Pretoria, 2009. / Biochemistry / unrestricted

Thesis (M.F.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / This paper deals with the ideas involved in the work in the Masters of Fine Arts Thesis Exhibition. The images and environments I create are basically functional objects, yet I utilize the metaphor of nature to bring into play much deeper and more complex meaning. The functional qualities signify human presence and human involvement, and set the stage for the ritualistic and ceremonial aspects of the work to come through. Images of nature speak of adaptation and conflict, growth and blossoming. Images of nature point to a basic sense of beauty and harmony that has gotten lost in our modern world. I hope, through my work, to make people take more time in looking at their surroundings, and to create out of common experiences such as a cup of tea, an aesthetic experience instead. / 2031-01-01

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Demand for tea is increasingly driven by its reported antioxidative properties. To ascertain such efficacy, the antioxidative activity (AA) of freshly brewed commercially available full-leaf white, green, oolong, and black tea was determined using a dynamic method. Various amounts (w/v) of tea were brewed at different temperatures for a constant period of time. The AA was calculated based on the ability of the brew to quench hydroxyl-radicals as quantified by chemiluminescence detection. Black tea had the strongest radical scavenging ability followed by green tea. Their AA was far greater than those of the other two types of tea tested. This efficacy finally eroded on serial dilution to a tea concentration of 0.15625 X 10-4 g/mL. The significant data clearly substantiate the sound premise that tea, particularly black tea, is unique in its dramatic ability to counter the adverse onslaught of radicals that are known contributors to human morbidity and mortality.

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