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 mortality.

The study found that storage roots from three top-performing transgenic lines grown under glasshouse conditions accumulated carotenoids of between 40 and 60 μg/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-β-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 roots.

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. 

Read the research article for more details.