Chaya cooking water / consuming raw with acid fruit

Plants Chaya
#1

Hi, I am new to this forum and the website is an AMAZING resource. I live in Australia and we have a small food forest plant nursery. I have three questions regarding chaya:
1.) Is the cooking water safe to consume?
2. I found a bunch of recipes of aqua fresca that include RAW chaya leaves but always either lime juice, orange juice or /and pineapple. Do the acids somehow bind to the hydrocyanic acid and render them safe or is it more about the quantity?
3.) Is there an upper daily limit for consuming the COOKED leaves?

By the way, we are growing chaya very small scale in our backyard in a warm, temperate coastal, frost-free climate, roughly in the area of the Myall lakes. It grows fine but can not be harvested year-round, and we do not get that insane growth other people report. Our next trial will be growing it in our main garden, a poorly drained clay pit. I’ll let you know how that goes!

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#2

Hi Nicola,

We’re so glad that you have found valuable resources on ECHOcommunity and ECHO Conversations!

You have asked some very important questions that we at ECHO have been asked before, but we are not always able to fully answer. I hope that I can shed some light and perhaps we can work together to find someone with a lab who can help us better understand these important considerations about chaya processing and safe consumption!

In an earlier chaya post on this platform I shared some of the chemical breakdown of linamarin (the major cyanogenic glucoside in chaya and cassava). Chaya (Cnidoscolus aconitifolius ) and Cassava (Manihot esculenta) contain the same major cyanogenic glycoside and there has been a lot of research about cassava processing techniques. Linamarase, the enzyme that removes the cyanide compound from the cyanogenic glycoside becomes active in water and is located in the plant tissue itself. So when the plant cell is disrupted, this enzyme can act on the glycoside. The cyanohydrin will stay in the water until conditions allow for it to off-gas as HCN (Montagnac et al., 2009; figure 1). These conditions are a pH greater than 4 and a temperature of 30°C (86°F).

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  1. When boiling chaya leaves, allow the vapors to be released because the cyanide off-gasses as HCN. Normally that means leaving the lid off during cooking and making sure to cook chaya leaves in a well-ventilated area. We can’t be positive, though, without testing, that there is no CN content in the cooking water. In the past we have used cyantesmo strips to detect HCN from processing chaya (Motis, 2016, ; Hepler et al., 2018) but it is qualitative and it cannot detect aqueous forms of CH (only HCN). To know confidently, we would need to test the cooking water in a laboratory.

  2. In conversations with several network members over the years, I have heard similarly of people consuming raw chaya with citrus to make a juice/smoothy. We can’t prove the effectiveness of this process for decreasing the CN content without laboratory testing, but pulverization makes chemical sense for increased release of CN as there is water in plant cells that after pulverizing, would interact with the linamarase enzyme and increase the interaction between the enzyme and glucoside. Lowering the pH too much makes me a bit concerned about inactivating the linamarase, but it seems to be common practice in some regions. There has been some research into using chaya as part of poultry feed. At ECHO, we do often feed it to our fowl (chickens and ducks) and have not seen any negative side effects yet. Possibly because the leaf cell walls are crushed in the chickens’ crops and the volatile toxins (HCN) released before digestion occurs.

  3. Great question! In a previous post, someone asked specifically about oxalates (an antinutrient) found in chaya which would likely be the secondary limiting factor to consumption after the cyanogenic glycoside. I asked a nutritionist to answer the question and you can find her response on that forum thread here.

Please let us know how your next trail performs and if you learn anything else about processing for safe consumption!

Reference:

Hepler, D., A. Hing, S. Kauffman, T. Lau, M. Ziegler, R. Schaeffer, and K. Witt 2018. For How Long Should Chaya Leaves be Boiled? . ECHO Development Notes no. 141

Motis, T. 2016. Cyantesmo Paper for Detecting Cyanide. ECHO Development Notes no. 130

Montagnac, J.A., C.R. Davis, and S.A. Tanumihardjo. 2009. Processing Techniques to Reduce Toxicity and Antinutrients of Cassava for use as a Staple Food. Comprehensive reviews in food science and food safety. 8:17-27.

Research article abstracts on chaya leaf meal fed to poultry:

Donkoh, A. Kese, A.G., and C.C. Atuahene. 1990 Chemical composition of chaya leaf meal (Cnidoscolus aconitifolius (Mill.) Johnston) and availability of its amino acids to chicks. Animal Feed Science and Technology 30 (issues 1-2): 155-162 URL: https://www.sciencedirect.com/science/article/pii/037784019090059H 4

Kese, A.G., Donkoh, A., Atuahene, C.C. and C. Nkansah. 1989. Evaluation of methods of processing chaya leaf meal (CLM) in terms of chemical composition and on performance and physiological parameters of chicks. Nigerian Journal of Animal Production Vol 16 No. 1 URL: https://www.ajol.info/index.php/njap/article/view/124422 4

#3

This question is very important when it comes to chaya consumption. I would say while both chaya and cassava leaves are very important vegetables, let’s just also be careful on consuming raw versions. I have distributed a lot of chaya plants in Zimbabwe and reports I get make me feel that it is important to ensure that people are well trained in cooking. Chaya.

Many people in this corner of the world like to use herbs for self treating mild and sometimes severe illnesses. Use of most herbs is by boiling in water and drinking the resultant tea.
Now, many people have reported positive outcomes from using chaya as a cooked vegetable which made others to believe that it can be used the same way as they use other herbs. I think this can be dangerous. Some people explained resultant symptoms that made me suspect they had had to much HCN in their blood, I would therefore be VERY cautious on drinking chaya water.

In countries where cassava is used as a vegetable, cassava leaves are pounded in a pestle and motor until it’s almost a paste. It’s then boiled in a lot of water for many hours and many times mixed with meat and boils together.

The pot is not closed and the place has to be well ventilated. What I notice on this way of cooking chaya is;

  1. A LOT of water is added and I think this is to dilute the HCN in the water for steaming it out
  2. It’s boiled for a Very long time ( like 4 to 6 hrs) to get the gas to come out
  3. It’s boiled in a place with very good ventilation so that fumes have no chance of accumulating in a closed area
  4. Boiling with meat ( the N in amino acids help denature the HCN)

I have grown chaya and observed my own farm animals eat chaya. In the early days. Goats would not eat fresh green chaya but would wait till the leaves turn yellowish then they would start eating, as time went by however, they started eating even green leaves. I saw this same behavior also in range chickens.

I have a number of people who have said they feed their rabbits green chaya and they see no problem. Others have had problems with wild hare eating their chaya

I know I have said a lot of different observations here and not related to treatment of chaya using pH, it’s because I am not well versed in that

I hope this information helps

#4

Dear Nicola and Margaret,

We enjoy having you around Echo Community. Warm welcome.

#5

I have no idea about Chaya. I might have seen it but not know if it can be consumed. I just want to say few about Casava as vegetable. I grew up eating it. Superb food. Great for digestion…its’s cooked with palm oil, or groundnut paste.
Caution: Don’t let cassava peels be eaten by goats beloved. I lost 2 goats. There is no remedy!