| dc.description.abstract | Inadequate supply of micronutrients causes human h~ealth complications and is a worldwide
problem now referred to as hidden hunger. Beverages from Camellia sinensis are claimed to be
the most widely consumed fluids after water. However it is not known if they contain adequate
,Ie.vels of micronutrients to alleviate hidden hunger problems. The levels of micronutrients in
East African teas are unknown and factors controlling their absorption from the soil remain
obscure. The objective of this study was to assess levels of micronutrients in East African teas, • 0::..local market teas and their infusions, establish if their levels vary with nitrogen fertilizer rates
and plucking intervals and determine if there are variations in micronutrient level in the black
tea of tea clones planted in various geographic locations. The micronutrients Mn, Fe, Zn, Cu
and Se levels from 42 factories in East Africa and effects of grading on the micronutrients
levels in four tea grades were assessed in 'acomplete1y randomized design and two factor
completely randomized design respectively. The effects of nitrogenous fertilizer and plucking
intervals on micronutrient content of clone 6/8 planted in' Timbilil, Sotik Highlands and
Changoi were assessed in a three factor randomized complete block design. The levels of these
minerals were also assessed in black tea of different clones planted in Kangaita, Kipkebe and
Timbilil in a factorial two design randomized in a complete block design replicated three times
under similar agronomic practices. The black tea samples were ashed, acid digested and
extracted for analysis using the AAS. Mn levels were highest while Se levels were lowest.
Mean levels of other micronutrients were in the order Fe>Zn>Cu. Large particle size grades
had more (p:SO.05) micronutrients. Teas from the local market had higher levels of
micronutrients than exported teas and the levels varied significantly (p:S0.05) among the grades.
About 41% and 82% Mn and Cu was extracted in hot water infusion respectively while Fe
extracted was only 17%. A cup of tea from 2.0g tea can contribute 57%, 1.03%, 0.65%, 2.0%
and 2.85% of Mn, Fe, Zn, Cu and Se respectively of daily minimum requirement. Thus consumption of more than two cups of tea per day can supply daily requirements of Mn.
However adequate daily supply of other micronutrients must be supplied by other foods. All the
micronutrients significantly (p:S0.05) varied with location of production. Mn and Se levels were
not significantly (p:S0.05) affected by increasing rates of nitrogenous fertilizer, Fe and Zn
significantly (p:S0.05) increased while Cu levels significantly (p:S0.05) reduced. Plucking
intervals did not significantly (p:SO.05) affect the micronutrient content of the resultant black
teas. Different clones showed varied (p:SO.OS) micronutrient content when planted in a single
location under similar agronomic practices and did not follow a similar pattern when the clones
were planted in different locations. To increase micronutrient levels in tea, it is necessary to
optimize nitrogen fertilizer rates and use suitable clones for different geographic locations. | en_US |
