The study, by researchers from Tuskegee University in Alabama, targeted at finding a way to incorporate natural and fresh antioxidants into the diets of astronauts while traveling in space.
They grew 18 different varieties of hydroponic carrots using two different methods of nutrient delivery.
Growing carrots hydroponically cultivates the vegetables by placing the roots in liquid nutrient solutions rather than in soil.
Among all foods, carrots have the highest carotenoid content.
They also contain a natural pigment known for provitamin A and have been associated with protection against cancer, cardiovascular diseases, cataracts and macular degeneration as well as enhancing the immune response.
Astronauts can be exposed to elevated levels of radiation, which might put them at risk for some types of cancer.
Researchers believe that the addition of unprocessed carrots to their diets may help reduce the negative effects of radiation and cancer development.
The hydroponically grown carrots were issued nutrients in two different methods.
One method is the nutrient film technique (NFT), in which the roots were exposed to a nutrient solution within a plastic film trough.
The second method is the microporous tube membrane system (MTMS), in which nutrient tubes were embedded into Turface-a material similar to crushed clay- where the carrots were planted.
All carrots were harvested 70 days after planting. They were tested for moisture, fat and carotene content as well as color and texture.
Consumer testing also occurred to test the acceptability of the hydroponic carrots.
This group evaluated color, crunchiness, sweetness, fibrousness, blandness and overall preference of the 18 different carrot types grown using NFT and MTMS.
The study concluded that hydroponic carrots grown using the MTMS method were most appealing to consumers due to their color and more carrot-like appearance.
According to lead researcher A.C. Bovell-Benjamin, "The Nevis-F carrot cultivar grown using the NFT method had the highest carotenoid content and acceptability among consumers, and therefore, it will be the most likely choice for inclusion in NASA's food system."