Latest / Hydroponics Daily / Cyanide: The Hidden Poison in Almonds, Apples and Bamboo

Transcript

Cyanide: The Hidden Poison in Almonds, Apples and Bamboo · Hydroponics Daily

• 0:00
  Hello and welcome back to Hydroponics Daily, your go-to podcast for everything soilless cultivation.
• 0:06
  This week I was talking to somebody about acorns and they said,
• 0:10
  can you eat acorns? And I said, they were German.
• 0:13
  And I said, well actually, during the First World War, German soldiers used
• 0:17
  to eat acorns and it was a type of ersatz coffee because they couldn't get coffee
• 0:23
  because naval blockades.
• 0:25
  And got me thinking about other types of compounds that
• 0:28
  are poisonous to humans but we still eat
• 0:31
  them and because acorns are mildly toxic
• 0:34
  even but you can eat them you're not going to die from them but they are
• 0:37
  mildly toxic and there are lots of
• 0:40
  plants like this that you're not going to die from but are mildly toxic
• 0:43
  like uncooked potatoes they will
• 0:46
  they've got enzyme inhibitors in them that
• 0:48
  will block you absorbing protein and things like this but one
• 0:51
  of the most interesting is cyanide and people
• 0:55
  are often shocked when they're told that food contains cyanide because we think
• 1:00
  of it as this poison you know it's very much in the Agatha Christie arsenal
• 1:04
  of poisons that people can consume along with arsenic and things like this and
• 1:09
  so just talk about natural sources of cyanide now unlike arsenic which is an element.
• 1:15
  Cyanide is a organic compound which means it contains carbon and nitrogen it's
• 1:21
  a very simple compound on the face of it, just a carbon and nitrogen,
• 1:24
  and a hydrogen gives you hydrogen cyanide.
• 1:27
  But when plants contain it, they're contained into something called cyanogenic glycosides.
• 1:34
  And that means it's just cyanide linked to a sugar molecule or a glucose molecule,
• 1:40
  cyanogenic glycosides, a very fancy way of saying that.
• 1:43
  And it exists in the plant and it doesn't disrupt the cells that it's in,
• 1:48
  because it's kept away from the enzymes that release hydrogen cyanide.
• 1:53
  So the cyanogenic glycoside will be in what's the vacuole of the cells,
• 1:57
  the big balloon inside in the middle of the cell that keeps it turgid,
• 2:01
  and then the enzymes will be in the cytoplasm, the things where the metabolism occurs.
• 2:06
  Now if you break the cells up, you eat it, eat a plant that contains these cyanogen
• 2:12
  containing compounds, and.
• 2:15
  Cyanide containing compounds, sorry. And then it will be the enzymes will mix
• 2:19
  with the cyanogenic glycosides and release hydrogen cyanide,
• 2:23
  giving off a distinctive smell.
• 2:25
  And that distinctive smell is what you would associate with almonds.
• 2:29
  And so the smell of almonds is, so if you smell almonds, that's a warning sign
• 2:34
  that there is cyanide around and the same for, but cyanide is in lots of different
• 2:39
  plants that you may not consider.
• 2:41
  And many of these might come across in hydroponics.
• 2:44
  So I thought I'd talk about it. So the first one being bitter almonds, obviously.
• 2:50
  And I've talked to a lot of plant breeders over the time, and a lot of them
• 2:53
  consider almond breeding to be one of the worst jobs you can have,
• 2:57
  because you consume a lot of almonds trying to find the best almond and breed
• 3:02
  the best almond, because they contain such high levels of cyanide.
• 3:05
  Now almond is in the rose family, and so any of
• 3:07
  the seeds in the rose family will contain a small amount of
• 3:10
  cyanide that includes apples cherries plums
• 3:14
  things like this my son ate a load of
• 3:17
  plum seeds because he's an absolute idiot and i said i said to my wife i better
• 3:22
  take him to hospital to check get him checked out and they're like oh they're
• 3:25
  not blocking his you know his pipes or anything like that i'm like i'm not worried
• 3:28
  about that i'm worried about the cyanide none of the doctors knew about it or
• 3:32
  anything like that so it couldn't have been that big an issue he was fine.
• 3:35
  There's lots of other plants outside of the rose family that contain cyanide as well.
• 3:40
  So cassava is a great example. That is a staple root vegetable.
• 3:44
  Lots of the world's population live on cassava in Africa and South America.
• 3:49
  It's a root vegetable really easy to grow, resistant to a lot of pests and diseases,
• 3:53
  but the bitter varieties contain cyanide and so you have to cook them and you
• 3:58
  have to leach the cyanide out.
• 4:00
  Lima beans in the bean family, they contain cyanide sorghum
• 4:05
  contains hydrogen cyanide as well and so
• 4:08
  you that's one of the big areas of plant breeding in
• 4:11
  north america is to breed various different low
• 4:14
  cyanide variations and lastly bamboo shoots and we think bamboo shoots as being
• 4:20
  this you know nondescript thing that you can eat in chinese food and pandas
• 4:26
  eat it but also contains a large amount of cyanide or a significant amount.
• 4:32
  So we said that you can soak or leach out the cyanide. That's one option.
• 4:36
  And that's commonly done in cassava as well as boiling it.
• 4:39
  That's why you boil bamboo shoots as well and lima beans.
• 4:42
  And then there's other ways like drying and fermentation.
• 4:46
  Traditional methods for making gary, fermented gary.
• 4:50
  Fermented cassava is called gary. And that removes hydrogen cyanide.
• 4:56
  I've never tried gary. Has anyone ever eaten some gary? If you have, then let me know.
• 5:01
  Be interested. can you make hydroponic gary let's have
• 5:04
  a look see if anyone's growing hydroponic cassava turns out
• 5:07
  people have done it and it's mainly for young seedlings it's
• 5:10
  a really good way method of getting young seedlings ready for
• 5:12
  planting out in the field interestingly gary i
• 5:15
  have seen gary before because there's this this
• 5:19
  instagram and it's west african
• 5:22
  cuisine these are they live in italy and they they make
• 5:26
  like boiled sheep's head and then
• 5:29
  they have this like big sloppy mess that goes with it
• 5:31
  they eat with it with their hands and i think that is
• 5:34
  gary i always send these videos to my
• 5:37
  colleagues josie and matthew because josie's
• 5:40
  italian and these are these are italian i was
• 5:43
  like oh authentic italian food she screams this
• 5:46
  is not italian food yeah this bright orange
• 5:49
  like gelatinous material and i always wondered what it
• 5:52
  was and it turns out that's gary fermented cassava
• 5:55
  to remove hydrogen cyanide you knew i'm
• 5:58
  gonna go and try some i'm gonna get some gary from my local world food
• 6:02
  shop and try it just for the podcast we've said that it it's anything in the
• 6:06
  rose family contains cyanide cherry laurel where you have to be really careful
• 6:11
  when you're pruning cherry laurels in your garden or anywhere else because when
• 6:14
  the leaves are crushed they release massive levels of cyanide now this is not
• 6:18
  an edible plant cherry laurel,
• 6:20
  and you can be overcome with these fumes, especially if you put it in the back
• 6:26
  of a van or a truck and then drove off, you could get very high levels of cyanide.
• 6:30
  If you think that's not true, then get a leaf of cyanide.
• 6:35
  A leaf of cherry laurel, crush it up, put it under a glass, and put any insect
• 6:42
  in there with it, and the insect will die from cyanide poisoning. It's that toxic.
• 6:47
  And that's what it's there for. It's there to prevent herbivory.
• 6:50
  It's an anti-herbivory compound, and it's a very powerful, gaseous one, not a liquid.
• 6:56
  I said apples, apple seeds. There's a theory that a cup of apple seeds is enough
• 7:00
  to kill a human. I read once that a.
• 7:04
  Two scientists had a bet, and one of them said you couldn't die from cyanide
• 7:08
  poisoning from a cup of apple seeds.
• 7:09
  The other one said you could, and then one of them ate it, and he died.
• 7:13
  I can't find reference to that, so that might be an apocryphal,
• 7:16
  a false story that's just funny and interesting.
• 7:20
  There's obviously the story of Alan Turing, the famous computer scientist who
• 7:25
  apparently ate an apple laced with cyanide as suicide, and that's where Apple
• 7:31
  gets its logo from, the computer brand.
• 7:32
  Whether that's true or not is very much
• 7:35
  up for debate and also Oppenheimer the
• 7:39
  story that Oppenheimer tried to poison one of his university
• 7:42
  lecturers with a cyanide laced apple is also very much debatable but it is in
• 7:48
  the film Oppenheimer this is not the natural levels of cyanide obviously in
• 7:53
  an apple but these are additional levels added to it so cyanide it's one of
• 7:59
  these infamous chemicals that's
• 8:02
  we think of as being a poison, but it's also natural, probably has some good
• 8:06
  effects in very small amounts on your gut flora and things like this,
• 8:10
  but very, very small amounts.
• 8:12
  Cyanide was used for a time as a sort of soil fumigant, plant fumigant,
• 8:16
  but we'd never use nowadays as always better alternatives because of its effects
• 8:21
  on human metabolism and plant metabolism.
• 8:24
  It's not something you should use.
• 8:27
  There's far better alternatives for soil and grow media sterilization such as
• 8:32
  ozone, steam, lime sulfur, even hydrogen peroxide's better really.
• 8:38
  So don't use cyanide for that.
• 8:42
  But certainly one you should consider, especially if you're growing plants in
• 8:46
  the rose family and you're cutting up, like if you imagine you were growing
• 8:49
  hydroponic cherry laurels and you were pruning them every day in your grow room,
• 8:53
  you might get exposed to large levels of cyanide potentially.
• 8:56
  Something to look out for, especially you're growing plants in the rose family or
• 8:59
  cassava or bamboo okay well
• 9:02
  sorghum i've grown sorghum last couple of years i tried to
• 9:05
  grow a frost tolerant variety of
• 9:07
  sorghum from north america didn't go very well they
• 9:11
  all died off due to frost so they can't be that frost tolerant
• 9:14
  unfortunately sorghum is an interesting one because it's also
• 9:16
  a c4 plant not sure if i've talked about c4
• 9:19
  plants on the podcast if i have
• 9:22
  then fantastic if i haven't i'll probably
• 9:25
  do an episode on it tomorrow because it's really interesting okay just
• 9:29
  check my notes and it looks like I haven't recorded a podcast about c4
• 9:32
  plants so I'll do that tomorrow because
• 9:35
  that's really interesting and you grow these plants slightly differently to
• 9:39
  most types of plants what we call c3 plants so I'll give you a full in-depth
• 9:44
  episode about c4 plants and how you supercharge their growth in hydroponics
• 9:48
  plants like sorghum and maize these are all c4 plants Okay,
• 9:53
  thank you very much for listening. Until tomorrow, goodbye.