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United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: Vitamin a Equivalence of Carotenoids from Cassava in Women

Location: Immunity and Disease Prevention Research Unit

2013 Annual Report


1a.Objectives (from AD-416):
Biofortification of staple food crops is a promising strategy for increasing dietary Vitamin A intake and improving Vitamin A status in populations at risk of deficiency. The purpose of this study is to determine the Vitamin A equivalence of carotenoids in high-carotenoid varieties of cassava. #2. The additional purpose of this study is to determine the Vitamin A equivalence of carotenoids in high-carotenoid varieties of cassava gari.


1b.Approach (from AD-416):
We plan to conduct a single site Phase II intervention study in healthy adult women. Women will serve as their own controls, and will be fed three treatments in random order: a single meal of white, non-biofortified low-carotenoid cassava with oil, a similar meal of bio-fortified cassava that is high in carotenoids without oil, and a similar meal of bio-fortified cassava with oil. Carotenoids and vitamin A will be measured in the triacylglycerol-rich lipoprotein (TRL) fraction of plasma by standard methods involving ultracentrifugation (to concentrate the TRL fraction) followed by reversed-phase HPLC using electrochemical detection. We plan to collect sufficient data to identify the times of the first appearance and peak concentrations of retinol, retinyl esters, alpha-carotene (AC), beta-carotene (BC), beta-carotene isomers (BCI) and cryptoxanthin (CX) in TRL when a single meal containing moderately high amounts of carotenoids from bio-fortified cassava is fed to healthy adult women. We will use these data to determine the vitamin A equivalency of bio-fortified cassava in adult women. Documents Trust with Harvestplus. Log 43059. #2. Garification detoxifies cassava and increases its palatability, but destroys carotenoids in the process. We plan to compare the effects of two fermentation times (3 and 4 days), two roasting temperatures, and several sequential roasting times on the retention of carotenoids in gari made from three different biofortified cultivars of cassava. The goals of this project, henceforth called the ‘Gari project’, are to:.
1)develop standardized procedures for making gari from biofortified cassava that will decrease variability between preparations and thus enhance our ability to identify differences in methods and cultivars that result in higher carotenoid concentrations: and.
2)to identify the cultivar and garification treatment that has the highest carotenoid concentration after garification.


3.Progress Report:

This is the final report for project which was terminated in May, 2013. The research relates to objective 3 of the inhouse project, “Examine the absorption of B-cryptoxanthin (CX) from supplements and foods, its contribution to vitamin A stores, and the impact of CX, other carotenoids and vitamin A on immune function". Biofortified cassava, which was developed to combat vitamin A deficiency in Africa, contains moderate amounts of beta-carotene. We estimated the effectiveness of biofortified cassava for increasing beta-carotene and vitamin A concentrations in ten healthy adult women. Data from this human study were combined with cassava consumption data from countries in Africa where cassava is a staple food, to model the daily vitamin A intake and cyanide exposure of women in Africa. If biofortified cassava completely replaced white cassava in the diet, it could meet recommended vitamin A intakes for the following percentages of individuals from 6 African countries: Angola (95%), Central African Republic (95%), Congo (~100%), Ghana (99%), Mozambique (99%), and Nigeria (92%). Cyanide exposure was negligible. Our research demonstrated that consumption of biofortified cassava, processed to maintain beta-carotene and remove cyanide, can potentially increase vitamin A concentrations in African populations and other areas of the world where cassava is a staple crop. Currently, collaborators (HarvestPlus and the International Institute of Tropical Agriculture) are distributing vitamin A cassava to combat vitamin A deficiency in Nigeria, and were granted £30 million to develop and deliver six biofortified crops, including biofortified cassava, to millions of farmers in Africa and Asia.

Biofortified cassava lost substantial amounts of carotenoids when it was converted to gari. Most carotenoid losses occurred during roasting. Fermentation time and pH had little effect on carotenoids or cyanide concentrations.


Last Modified: 8/22/2014
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