Prevent Itching While Peeling Purple Yam / Ube

While peeling purple yam / ube for the maja recipe, I felt a mixture of uncomfortable skin itchiness. After, I immediately washed my hands with soap and water. The itchiness persisted for about 15 minutes after washing.

purple yam slice

I learned later that acidic solution like vinegar, calamansi juice and lemon are effective for immediate relief.

I asked Mr. Web, “How to prevent skin from getting itchy while peeling ube?” I got no answer. The yam should be cooked well to eradicate the harmful substance. It could cause harm when eaten raw or insufficiently cooked.

I got hint, the substance that causes itchiness is degraded by heat.

Perhaps the culprit substance is more concentrated near the peel. Remember that nutrients are more concentrated near the peel. The same might apply to harmful substances.  I got a piece of raw purple yam. I rubbed the center part to my right arm. I got a piece of skin and rubbed it to my left arm. The left arm felt intense itch while the right arm almost felt nothing. It is really concentrated near the peel. Perhaps dipping in hot water for few minutes is going to solve the problem.

arm with purple yam stains

I prepared four chunks of raw ube. I got a casserole with water and bring it to slow boiling. I dipped the first chunk for one minute, the second for two minutes, the third for three minutes and the fourth for four minutes. Then I got peels from each chunks and rubbed each to different parts of my left arm. I felt a minimal and negligible itchiness. I noticed no difference among four chunks.


update as of May 2017

I recommend blanching or completely cooking the root prior to peeling.


Thanks to Dr. Pri Bandara for mentioning the saponin. I did a little digging myself and found out:

Yam contains diosgenin saponin and dioscorine alkaloid. Toxic compounds that can be removed by washing, boiling and cooling. It was also mentioned that high level of alkaloids causes itchiness and bitterness.

Source:
Tropical Agricultural Research & Extension 15(1): 2012

PROXIMATE ANALYSIS AND PHYTOCHEMICAL AND MINERAL CONSTITUENTS IN FOUR CULTIVARS OF YAMS AND TUBER CROPS IN SRI LANKA
Senanayake SA, Ranaweera KKDS, Bamunuarachchi A and Gunaratne A 1Department of Food Science and Technology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka Department of Agriculture, University of Sabaragamuwa, Belihuloya, Sri Lanka

Article accepted: 22 March 2011


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9 Comments

  • My stomach is covered in a painful rash after handling taro root i mistaked them for cassavas or yucca. I was shirtless while peeling and my stomach rested against water from my counter top. Just then I began to itch. My arms, my stomach. Open blisters got holes and bled. All over over my lower stomach, sides. It felt like my skin was burning off. I felt hot, itchy, burning sensation, rawness. This began hours ago at about nine pm its now almost two am and im afraid, but its subsiding. :'(

  • To avoid the itch: in the Caribbean we rub our hands with cooking oil before peeling all the tubers and Voila!…itch free. Try it out..

    • thanks! Thant’s a very nice suggestions

  • Tooth paste gave me 90% some relief of yam etching. Lemon and vinegar did nothing.

  • Water makes it worse… Its the Calcium Oxate in the Yams… stay dry while cutting!

    • That’s a terrible experience. I am also sensitive to Taro. I use gloves when cleaning Taro cormes to avoid itchy skin. I have found leaves and stems to be worse. The itch is reported to be caused by saponin (a glycoside that makes the corms slippery) but I haven’t looked for scientific reports confirming this. Cook corms (yams) well then they are perfectly OK to eat. I now eat only a very small amount of the traditional Sri Lankan curry made with young leaves & stem because I find a minor irritation of my throat after eating it. I have no problem with yams.

    • Calcium oxalate is very unlikely to be the cause of the itch. It is likely to be the saponin or other compounds. These researchers report two: uracil and glycol-protein taro lectin (Bioorg Med Chem Lett. 2015 Oct 15;25(20):4382-6. doi: 10.1016/j.bmcl.2015.09.023. Epub 2015 Sep 11.)

      • thanks for the update!

  • Thanks for posting this! My daughter and I just had a similar reaction to Yellow Ñame Root (a similar wild yam) and it had me freaking out. You went beyond the call of duty using yourself as a test subject. 🙂

    I’m not sure why this doesn’t show up in more searches online, or how many people have this reaction (maybe similar to some people having reactions to mango skin), but thanks again for posting.

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