Sweet potato (Ipomoea batatas)
is one of the most important, versatile and unexploited crops in Kenya. The
crop is well adapted to smallholder farming systems, inexpensive to produce,
relatively drought tolerant and gives high yields even with minimum inputs.
Although widely produced in Kenya, sweet potato remains primarily a subsistence
crop. Lack of organized marketing, limited consumer interest and low value
addition activities are some of the factors that have contributed to low
commercialization of the crop. The overall objective of the current study was
to investigate the suitability of incorporating sweet potato leaves into the
roots to produce nutritious sweet potato flakes with high vitamin A and protein
content. Sweet potato roots were cured to increase the endogenous amylase
enzyme and then washed and pre-cooked to enable starch hydrolysis to increase
sweetness of the flakes and then heated to boiling to enable mashing. Dried
sweet potato leaves powder was then added to the mash sweet potato roots at
varying percentages and then dried using single drum drier. Addition of sweet
potato leaves was found to significantly (p < 0.05) increase protein content
from 6.6% protein to 15.40% when the leaves constituted 50% of the flakes. Beta
carotene content of the flakes decreased from 7986 μg/100g when no leaves were
added to 3979 μg/100g when the leaves constituted 50% of the flakes. The
addition of the leaves reduced the overall acceptability. Colour was the most
adversely affected while texture was the least affected by the addition of
sweet potato leaves. However, all the flakes with up to 30% leaves were
acceptable to the panelists with respect to colour, taste, texture and overall
acceptability. Incorporating sweet potato leaves into the roots can therefore
improve sweet potato protein and hence improve nutrition and value addition of
root-based products such as flakes and flour.
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