Department of Chemistry: Recent submissions
Now showing items 301-320 of 326
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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 ... -
Influence of region of production on clonal black tea chemical characteristics
(2008-05-01)Production of black tea from the same vegetatively propagated (VP) cultivars, in Kenya and Malawi, shows variations in both chemical composition and quality. Whereas it is possible to produce black teas with similar ... -
Correlation of theaflavins content and valuations of Kenyan black teas
(John Wiley & Sons, Ltd, 1986-05-01)Correlation between theaflavins content and tasters' valuations of Kenyan black teas generally give positive but statistically non-significant correlation coefficients. In 105 correlations using 12 samples each, only ... -
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 ... -
Flavanol composition and caffeine content of green leaf as quality potential indicators of Kenyan black teas
(1997)The Ñavanol composition and ca† eine content of green tea leaf, black tea quality parameters of theaÑavins, thearubigins, liquor brightness and total colour varied more among clones than with time of the year. In green ... -
The relationship between some chemical parameters and sensory evaluations for plain black tea (Camellia sinensis) produced in Kenya and comparison with simila...
(Elsevier, 2006-08-31)Reliable and accurately measurable chemical parameters that can be used to estimate black tea quality are desirable in trade, research and breeding programmes. Using plain Kenyan black tea from 11 cultivars, which gave ... -
Enhanced degradation of 14 C-HCB in two tropical clay soils using multiple anaerobic–aerobic cycles
(2013-02-28)The aim of the study was to induce and enhance the degradation of hexachlorobenzene (HCB), a highly-chlorinated persistent organic pollutant, in two ecologically different tropical soils: a paddy soil (PS) and a non-paddy ... -
Immobilization of chlorobenzenes in soil using wheat straw biochar
(American Chemical Society, 2013-04-25)Biochar has shown great potential for immobilizing organic contaminants in soil. In this study, pentachlorobenzene (PeCB), 1, 2, 4, 5-tetrachlorobenzene (1, 2, 4, 5-TeCB), and 1, 2, 4-trichlorobenzene (1, 2, 4-TCB) ... -
Effects of pH and metal ions on oxytetracycline sorption to maize-straw-derived biochar
(Elsevier, 2013-05-30)Biochars produced from biomass residues have been recognized as effective sorbents to hydrophobic compounds, but knowledge on sorption of antibiotics to biochar and its mechanisms are still inadequate. Sorption of ... -
Isolation and characterization of a toxic metal-tolerant Phenanthrene-degrader Sphingobium sp. in a two-liquid-phase partitioning bioreactor (TPPB)
(2013-10-01)A phenanthrene-degrading strain PHE3, identified as the genus of Sphingobium, was isolated using a two-liquid-phase partitioning bioreactor. More than 96% of the initial amount (up to 100 mg l− 1 silicone oil) of ... -
Tenax extraction for exploring rate-limiting factors in methyl-β-cyclodextrin enhanced anaerobic biodegradation of PAHs under denitrifying conditions in a red paddy...
(Elsevier, 2014-01-15)The effectiveness of anaerobic bioremediation systems for PAH-contaminated soil may be constrained by low contaminants bioaccessibility due to limited aqueous solubility and lack of suitable electron acceptors. Information ... -
Remediation of organochlorine pesticides (OCPs) contaminated site by successive methyl-β-cyclodextrin (MCD) and sunflower oil enhanced soil washing–portulaca...
(Pergamon, 2014-06-30)An innovative ex situ soil washing technology was developed in this study to remediate organochlorine pesticides (OCPs)-contaminated site. Elevated temperature (50 C) combined with ultrasonication (35 kHz, 30 min) at ... -
Role of cosubstrate and bioaccessibility played in the enhanced anaerobic biodegradation of organochlorine pesticides (OCPs) in a paddy soil by nitrate and methyl...
(Springer Berlin Heidelberg, 2014-07-01)Abstract The present study was conducted to investigate the anaerobic biodegradation potential of biostimulation by nitrate (KNO 3) and methyl-β-cyclodextrin (MCD) addition on an aged organochlorine pesticide ... -
Evaluation of soil washing process with carboxymethyl-β-cyclodextrin and carboxymethyl chitosan for recovery of PAHs/heavy metals/fluorine from metallurgic plant...
(Elsevier, 2014-08-01)Abstract Polycyclic aromatic hydrocarbons (PAHs)/heavy metals/fluorine (F) mixed- contaminated sites caused by abandoned metallurgic plants are receiving wide attention. To address the associated environmental problems, ... -
Evaluation of enhanced soil washing process and phytoremediation with maize oil, carboxymethyl-β-cyclodextrin, and vetiver grass for the recovery of organochlorin...
(Academic Press, 2014-08-01)Abstract An innovative ex situ soil washing technology was developed in this study to remediate organochlorine pesticides (OCPs) and heavy metals in a mixed contaminated site. Elevated temperature (60 C) combined with ... -
Response surface methodology to understand the anaerobic biodegradation of organochlorine pesticides (OCPs) in contaminated soil—significance of nitrate conce...
(2014-09-01)Abstract Purpose Problems associated with Organochlorine pesticide (OCP)-contaminated soils have received wide attention. To understand the anaerobic biodegradation process constraints, innovative mathematical analysis ... -
Does powder and granular activated carbon perform equally in immobilizing chlorobenzenes in soil?
(Royal Society of Chemistry, 2015)The objective of this study is to compare the efficacies of powder activated carbon (PAC) and granular activated carbon (GAC) as amendments for the immobilization of volatile compounds in soil. Soil artificially-spiked ... -
Enhanced soil washing process for the remediation of PBDEs/Pb/Cd-contaminated electronic waste site with carboxymethyl chitosan in a sunflower oil–water solven...
(2015-02-01)Abstract An innovative ex situ soil washing technology was developed to remediate polybrominated diphenyl ethers (PBDEs) and heavy metals in an electronic waste site. Elevated temperature (50° C) in combination with ... -
Effect of anthropogenic activities on the water quality of Amala and Nyangores tributaries of River Mara in Kenya
(2015-10-30)Abstract Mau Forest in the upper reaches of the Mara River basin has recently undergone increased forest destruction followed by human settlement and agricultural activities. These anthropogenic activities may be ... -
The interactive biotic and abiotic processes of DDT transformation under dissimilatory iron-reducing conditions
(Pergamon, 2015-11-30)Abstract The objective of the study was to elucidate the biotic and abiotic processes under dissimilatory iron reducing conditions involved in reductive dechlorination and iron reduction. DDT transformation was ...