A carrot with a white center

November 16, 2019

What you see: A carrot with a white core
What it is: A perfectly fine, two-toned carrot
Eat or toss: Eat! 

 

The story:

This carrot offers a lovely lesson in xylem and phloem tissue. As you may remember from grade school science class, the xylem (which is white in this carrot), delivers water and minerals from the soil to the rest of the plant. The outer phloem tissue (in this case, the orange area) ferries sugars generated by photosynthesis to the root. 

 

The sugar-moving phloem tissue is, not surprisingly, sweeter than the inner xylem tissue.  In the carrots we’re accustomed to eating in the United States, both the xylem and phloem are usually orange, though they may be different shades of orange, even in the same carrot.

 

So why is xylem in the carrot pictured above white?  Irwin Goldman, a horticulture professor at the University of Wisconsin-Madison, said that genetics, and to a lesser degree, environmental conditions like soil, water and temperature, can cause such a dramatic color difference between the two carrot regions. 


“You can have a gene that gives you a dark phloem and a different gene that gives you a lighter xylem,” he said. “They’re separately controlled.” 
 
Ultimately, the amount and type of carotenoid pigments that a carrot produces will affect just how orange it is. As mammals and carrot eaters, we value carotenoids because our bodies can use some of them to make Vitamin A. 
 
So, there’s nothing unsafe about this funky colored carrot, but is it less nutritious? Actually, yes. Goldman notes that you’ll only get provitamin A activity in the pigmented part of this carrot. 

 

Photo courtesy of Daniel Yoder with Johnny's Selected Seeds
 
SOURCES
Irwin Goldman. Horticulture professor. University of Wisconsin-Madison.

What Are Carotenoids? Live Science. Jessie Szalay October 15, 2015
Xylem. Britannica.
Phloem. Britannica

Daniel Yoder. Research Technician. Johnny’s Selected Seeds.

The Carrot Root Explained. World Carrot Museum.
Beta Carotene and Carrots. World Carrot Museum.

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© 2019 by Eat Or Toss.

Content may not be duplicated without express written permission from EatOrToss.com. All information posted on this blog is thoroughly researched, but is provided for reference and entertainment purposes only. For medical advice, please consult a doctor. Please see our terms