What you see: You bite into a carrot and the center is tough, woody or fibrous. In the carrot pictured above, the center was impossible to chew, but the carrot flesh around it was fine. (It’s a weird photo we know; sorry, not sorry.)
What it is: The carrot is overmature; it’s toughening its core for the next phase of its life.
Eat or toss: The texture will probably be such that you won’t want to eat the center, but you can certainly eat around the tough area.
Overmature carrots can get woody
Wait too long to harvest carrots and the center of the root can toughen up. Once such a carrot arrives on your plate, this makes for an unpleasant texture, but the rest of the carrot is still fine to eat.
At the center of the carrot, xylem tissue ferries water and nutrients from the soil to the rest of the plant. (Sometimes carrot xylem tissue can even be a different color from the rest of the carrot, like this.)
As most vegetables mature, they become less tender and more fibrous (consider the difference between baby asparagus and woody-bottomed, overmature asparagus). It’s almost like they’re trading their baby fat for muscle. As they age, they bulk up with a carbohydrate called lignin. When it’s not making your food too tough to chew, lignin helps trees stand up, helps keep microbial invaders at bay and generally acts as a backbone for the plant world. Lignin is also an insoluble dietary fiber that’s good for our digestive tracts, at least when it’s ingested in quantities small enough that you don’t spit out your too-tough food.
The carrot’s xylem toughens as it ages
Maturing carrots toughen up the xylem tissue more so than other areas of the root–it’s preparing for a big job.
As it gets older and older, explained Penelope Perkins-Veazie, a horticultural science professor at North Carolina State University, “there’s some signaling going on there that basically says, ‘Okay, I want my xylem to get lignified to give it strength.’ And usually it’s because what you’re trying to do is get your xylem ready to transport a lot of water.”
The carrot, she said, is reinforcing its root to better support a proliferation of growth of the carrot plant above ground.
Lignin can also cause white to develop on the surface of carrots
You’ve also seen lignin if you’ve ever noticed a white film that won’t wash away on the surface of baby carrots or carrots you’ve peeled and cut yourself. While a white patch from simple dehydration will go away with a water rinse, if the white comes from lignin–which arrived to help heal the carrot’s cut surface–the white won’t wash off. That said, a patch of wound-healing lignin on a carrot’s exterior isn’t enough to change the texture of the carrot and it will still taste fine.
SOURCES:
- Penelope Perkins-Veazie. Horticultural science professor. North Carolina State University. Interview and email correspondence August 2024.
- Irwin Goldman. Horticulture professor. University of Wisconsin-Madison.
- Carrot (Daucus Carota). UC Davis, Vegetable Research and Information Center Home Vegetable Gardening. Accessed June 2024.
- Carrots. Illinois Extension – Home Vegetable Gardening. University of Illinois Urbana-Champaign. Accessed June 2024.
- Quality attributes of fresh carrots stored under modified atmospheres. Kamran Nadeem. Masters Thesis. University of Tennessee, Knoxville TRACE: Tennessee Research Research and Creative Exchange.
- Is all dietary fiber the same. Kathlene Riggs. Utah State University Extension. Aug. 19, 2011. Accessed June 2024.
- The Effect of Lignin on Biodegradability. Tom Richard. Cornell Composting. Science and Engineering. Cornell University.
- Comparison of storage and lignin accumulation characteristics between two types of snow pea. Xuerui Li, Jinxiang Wang, Yunhui Qu, Yiping Li, Yasmin Humaira, Sajjad Muhammad, Hongmei Pu, Lijuan Yu, Hong Li. Plos One. Published: July 1, 2022.
- Ahmed Khadr, Yahui Wang, Feng Que, Tong Li, Zhisheng Xu, Aisheng Xiong, Exogenous abscisic acid suppresses the lignification and changes the growth, root anatomical structure and related gene profiles of carrot, Acta Biochimica et Biophysica Sinica, Volume 52, Issue 1, January 2020, Pages 97–100, https://doi.org/10.1093/abbs/gmz138
- Que F, Wang GL, Feng K, et al. Hypoxia enhances lignification and affects the anatomical structure in hydroponic cultivation of carrot taproot. Plant Cell Reports. 2018 Jul;37(7):1021-1032. DOI: 10.1007/s00299-018-2288-3. PMID: 29680943.
- Ascorbic Acid Treatments For Preventing Lignification On Ready-To-Use Carrot Rezzan Kasım* , M.Ufuk Kasım Kocaeli University, Graduate School of Natural and Applied Sciences, Vocational School of Arslanbey, 41285 Kartepe/Kocaeli-Turkey. Turkish Journal of Agricultural and Natural Sciences Special Issue: 2, 2014.
- Nitric oxide regulates the lignification and carotenoid biosynthesis of postharvest carrot (Daucus carota L.) Miao Sun, Tao Yang, Xuan-Huan Qiao, Peng Zhao, Zhi-Peng Zhu, Guang-Long Wang, Lin-Lin Xu, Ai-Sheng Xiong. Postharvest Biology and Technology. Volume 207, January 2024.
- Que, F., Hou, XL., Wang, GL. et al. Advances in research on the carrot, an important root vegetable in the Apiaceae family. Hortic Res 6, 69 (2019). https://doi.org/10.1038/s41438-019-0150-6
- Mechanism of Surface White Discoloration of Peeled (Minimally Processed) Carrots During Storage LUIS CISNEROS-ZEVALLOS, MIKAL E. SALTVEIT, and JOHN M. KROCHTA. JOURNAL OF FOOD SCIENCE-Volume 60, No. 2, 1995.
