Vitamin A is widely recognised to be important for sight, development, immunity and cell differentiation. Vitamin A deficiency is prevalent in many developing countries, particularly African and South American nations.
Biofortification of foods with vitamin A precursors is therefore an important element of combatting the widespread deficiency levels.
“Biofortification with provitamin A carotenoids is a food-based strategy to combat vitamin A deficiency. Biofortified crops have been selectively bred to have a greater carotenoid content, with special emphasis on beta- carotene, and are being disseminated in many African countries,” explained the researchers writing in .
The effect of storage (sometimes at high ambient temperatures) and cooking on these biofortified foods is therefore critical in delivering final products containing adequate carotenoid levels, the researchers led by Professor Sherry Tanumihardjo suggested.
Therefore development of fortified maize and eggs which retain their carotenoid levels after storage and cooking may be key in improving vitamin A status in poorer nations.
“Understanding provitamin A retention is important for assessing efficacy of biofortified foods,” Tanumihardjo and colleagues noted.
Retention is key
When high beta-cryptoxanthin (BCX) maize flour was cooked into various foods (porridge, tortillas, puffs, muffins), researchers achieved high retention levels of provitamin A carotenoids. In some cases exceeded the value in the raw flour due to release of carotenoids from the food matrix.
The best and worst levels of carotenoid retention were for whole-grain maize flour made into porridge (112%) and sifted flour made into deep-fried cornmeal puffs (known as ‘hush-puppies’) (67%), reported the research team led by the University of Wisconsin.
The scientists also fed high BCX biofortified flour to hens to produce high BC eggs. Provitamin A compounds eggs showed a resilience to various cooking methods, retaining all of their carotenoids when fried, microwaved or hard-boiled, although 15% of carotenoids were lost by scrambling.
“It is noteworthy that biofortified maize and eggs retained >80% provitamin A carotenoids with cooking, given that both of these foods are not widely consumed in the raw state,” noted study leader Professor Sherry Tanumihardjo.
The researchers also examined nutrient degradation in two types of biofortified maize flour (high-xanthophyll (HX) and high beta-carotene (HBC)) during long-term (12-month) storage at different temperatures. The examined retention of lutein plus zeaxthanin, beta-carotene and beta-cryptoxanthin.
In cold storage (-20 degrees Celsius (deg C)), HX flour had retained 100% of all of individual carotenoids, while the HBC flour conserved around 90%.
At 37 degress C – typical ambient temperature in sub-Saharan African and South American households – the flour lost around 80-95% of the carotenoids
Source: ACS Omega
Volume 2, issue 10, Pages 7320-8, doi: 10.1021/acsomega.7b01202
“Retention of Carotenoids in Biofortified Maize Flour and β‑Cryptoxanthin-Enhanced Eggs after Household Cooking”
Authors: Margaret Sowa, Sherry A. Tanumihardjo et al