A Dissertation 2019
Indigenous leafy vegetables are important in human diet as they supply a number of
important nutrients for human health. A cross-sectional study was carried out at
Chamwino District (Mzula and Chinoje villages), Dodoma to assess the effect of
drying and cooking on nutrients composition of selected indigenous leafy vegetables.
A total of 120 randomly selected participants were interviewed using pretested
structured questionnaires with the main focus on vegetable production, processing and
storage practices. For laboratory analysis, three commonly consumed varieties of
indigenous leafy vegetables namely ''Amaranthus'' (Amaranthus hybridus), ''Jute
mallow'' (Corchorus olitorius L.) and ''Spider flower'' (Cleome gynadra L.) were
selected from each village and divided into three groups; uncooked (fresh) to serve as
control samples, the dried-cooked samples and fresh-cooked samples. The samples
were analysed for β-carotene by using Ultra Violet Visible Spectrophotometer;
Vitamin C by titration method and minerals (iron, calcium and zinc) by Atomic flame
emission Spectrophotometer. The results showed that the concentration of β-carotene
in indigenous leafy vegetables ranges from 328 - 179 μg/ g, vitamin C (89 - 23 mg/100
g), iron (46 - 27 g/100 g), calcium (62 - 31 g/100 g) and zinc (45 - 13 g/100 g). Sun-
drying and cooking had significant (p<0.05) impact in reduction of micronutrients in
the selected vegetables. The β-carotene was reduced by 64 % in sun - dried and by 90% in
dried cooked vegetables; Vitamin C was reduced by 33% in sun - dried and by 64 % in dried
cooked; Iron was reduced by 34% in sun - dried and by 57 % in cooked dried, calcium by 21%
in sun - dried and by 65 % in cooked dried. The highest percentage retention of β-carotene
was seen in Corchorus olitorius L. (36%), Vitamin C in Amaranthus hybridus L.
(67%), Zinc in Amaranthus hybridus L. (92%), Calcium in Cleome gynadra L. (79%)
and Iron in Amaranthus hybridus L. (65%). The results from the present study.