Biofortification of Beta-carotene in Cassava Enhances Provitamin A Content and Shelf Life
Findings of a new study in sub-Saharan Africa have indicated that
biofortification of beta-carotene concentrations in cassava storage roots
significantly increased provitamin A in the cultivars. This may mark an
important milestone in addressing the region's challenge with vitamin A
deficiency. The result is published in Plant Biotechnology Journal.
Food and Agricultural Organization (FAO) reports that vitamin A deficiency
is a pervasive major health issue affecting an estimated 47% of preschool
children in sub-Saharan Africa. This deficiency is attributed to increased
incidence of blindness and suppressed immunity leading to enhanced
The study found that storage roots from three top-performing transgenic
lines grown under glasshouse conditions accumulated carotenoids of between
40 and 60 ?g/g dry weight, representing a 20-to 30-fold increase, compared
to roots harvested from a non-transgenic control. The study discovered that
85 to 90 per cent of these carotenoids accumulated as all-trans-â-carotene,
the most nutritionally efficacious carotenoid.
Interestingly, the researchers found that accumulation of carotenoids was
accompanied by a five-time reduction in postharvest physiological
deterioration of storage roots suggesting that increased carotenoid
concentrations prolong shelf life of harvested storage roots. The short
shelf life of cassava storage roots has profoundly constrained sub-Saharan
African farmers' ability to transport harvested cassava storage roots from
rural production areas to urban markets limiting the plant's potential as a
cash crop for most farmers in the region.
The study also showed that cassava biofortification increases concentrations
of soluble sugars and triacylglycerols but reduces starch content in the
This was part of a project that drew partnership between the University of
Nebraska-Lincoln and the National Root Crops Research Institute to conduct
the first government-approved confined field trial of a genetically modified
crop in Nigeria.