Browsing Department of Chemistry by Title
Now showing items 38-57 of 323
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Challenges of maintaining tea quality
(2016)Tea (Camellia sinensis (L.) O. Kuntze) is an important cash crop contributing to economic wellbeing and wealth in many developing countries. The crop creates employment opportunities and development in the rural areas ... -
The changes in black tea quality due to variations of plucking standard and fermentation time
(Elsevier, 1998)Catechin levels in green leaf, total theaflavins, brightness, thearubigins, colour, flavour index and sensory evaluation decrease with coarse plucking standard in clone 6/8. The sum of Group I volatile flavour compounds ... -
The changes in black tea quality due to variations of plucking standard and fermentation time
(Elsevier, 1998-04)Catechin levels in green leaf, total theaflavins, brightness, thearubigins, colour, flavour index and sensory evaluation decrease with coarse plucking standard in clone 6/8. The sum of Group I volatile flavour compounds ... -
Changes in soil chemical properties and leaf nutrients content in tea due to nitrogen fertilizer rates and application intervals.
(Tea Research Foundation of Kenya, 2010)Tea (Camellia sinensis (L.) O. Kuntze) plant, requires much more nitrogen than most of the other nutrients for its growth, development and sustainability of harvestable crop. Soil as a resource of plant nutrients, cannot ... -
Changes in soil properties following conversion of forests into intensively managed Camellia sinensis L. plantations along a chronosequence.
(International Society of Tea Science, 2012)Tea in Kenya was introduced in the beginning of the 20th Century, although commercial cultivation commenced in 1924. The total acreage of tea plantations has steadily increased and currently covers approx. 0.15 million ha, ... -
Changes in the chemical and sensory quality parameters of black tea due to variations of fermentation time and temperature
(Elsevier, 2001-12-31)The changes in theaflavins and residual catechin compositions, thearubigins TRSI and TRSII, sensory characteristics of total colour, brightness and briskness of black tea were investigated. It was demonstrated that the ... -
Changes in the Composition of Elements in Non-Aerated Green Teas Processed from Seedling Tea (Camellia sinensis) Due to Variations in Nitrogenous Fertilizer Rates and Seasons.
(International Journal of Tea Science Vol 13, No. 1&2 (2017) : 80-93, 2017)Soil nutrients are lost to the plant with harvested crop in tea production with most ending up as minerals and contribute to human nutrition upon tea consumption. Production of non-aerated green tea in Kenya has been low. ... -
Changes in the Composition of Elements in Non-Aerated Green Teas Processed from Seedling Tea (Camellia sinensis) Due to Variations in Nitrogenous Fertilizer Rates and Seasons.
(International Journal of Tea Science, 2017)Soil nutrients are lost to the plant with harvested crop in tea production with most ending up as minerals and contribute to human nutrition upon tea consumption. Production of non-aerated green tea in Kenya has been low. ... -
Changes in theaflavin composition and astringency during black tea fermentation
(Elsevier, 1994-01-01)Both theaflavins and sensory evaluations vary in a quadratic manner with fermentation duration in the process of black tea manufacture. The rate of formation of total (Flavognost) theaflavins varies with clones, and within ... -
Changes in thearubigin fractions and theaflavin levels due to variations in processing conditions and their influence on black tea liquor brightness and total colour
(Elsevier, 2004-03-30)Increase in coarser plucking standards significantly (P< 0.05) depressed levels of theaflavin (TF; μmol/g), total colour and brightness (spectrophotometer) of black tea. But total thearubigins (TR) TRSI, TRSII and ... -
Chemical constituents of Ocimum kilimandscharicum Guerke acclimatized in Kakamega Forest, Kenya
(Chemical Society of Ethiopia, 2019)The genus Ocimum belongs to the Lamiaceae family and is made of almost 200 species of herbs and shrubs which have potential medicinal properties. The species are native to the tropical and temperate climate zones around ... -
Chemical extraction to assess the bioavailability of chlorobenzenes in soil with different aging periods
(Springer-Verlag, 2011-12-01)Bioavailability is mainly influenced by aging and desorption of contaminants in soil. The purpose of this study was to investigate the desorption kinetics of chlorobenzenes (CBs) in soil and to investigate whether chemical ... -
The chemotypic variation of Sceletium tortuosum alkaloids and commercial product formulations
(Elservier, 2012)Commercial production and trade in Sceletium tortuosum and its products is on the rise due to an increase in consumer demand. Mesembrine-type alkaloids are the main active compounds responsible for the therapeutic properties ... -
The chemotypic variation of Sceletium tortuosum alkaloids and commercial product formulations
(Pergamon, 2012)Commercial production and trade in Sceletium tortuosum and its products is on the rise due to an increase in consumer demand. Mesembrine-type alkaloids are the main active compounds responsible for the therapeutic properties ... -
Chimie Minérale 1
(2011-02-01)Le cours commence par un examen attentif du tableau périodique des éléments et de la façon dont il est organisé. La connaissance du tableau permet de saisir facilement et rapidement les concepts et les propriétés de la ... -
Chinchona Alkaloid from Dendrosenecio kilimanjari subsp. cottonii
(Georg Thieme Verlag Stuttgart· New York, 1997-02)Investigation of the Tanzanian Dendrosenecio kilimanjari subsp. cottonii resulted in the isolation of the cinchona alkaloid, cinchonidine (2). Conversion of cinchonidine to deoxy-cinchonidine was achieved in high yield ... -
Chlorophyll meter use on field grown tea: 1. The optimum leaf age and measuring positions on a leaf blade.
(Tea Research Foundation of Kenya, 2000)In a field experiment conducted in Kenya, a Hydro N-tester chlorophyll meter was used to determine the optimum age and reading position for the measurement of chlorophyll in leaves of tea (clone 6/8). Meter readings were ... -
Clonal plain black tea quality parameters responses of hard physical withered leaf to rehydration and fermentation durations
(2016-04-16)Hard physical withers in tea processing result in reduced plain black tea quality parameters, but improve flavoury black tea quality. Chemical withers with minimal moisture loss improve plain black tea quality parameters. ... -
Clonal variation in the individual theaflavin levels and their impact on astringency and sensory evaluations
(Elsevier, 1995-01-01)Clonal variation in the individual theaflavin levels and their impact on astringency and sensory evaluations -
Clonal Variations in the Response of Hard Physically Withered Leaf to Rehydration Following Long Chemical Wither Durations
(International Journal of Tea Science Vol 13, No. 1&2 (2017) : 72-79, 2017)Long chemical wither durations and hard physical wither reduce the quality of plain black tea, through reduction in total theaflavins production while encouraging thearubigins formation. Such quality reduction may vary ...