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Cassava chips

November 10, 2012

Cassava or manioc (Manihot esculenta, Euphorbiaceae) is the world’s easiest crop to grow. Simply cut the leggy branches into 30 cm sticks and plant them in the soil. The tuberous roots can be harvested after 9-18 months. Cassava chips are similar in taste to potato chips.

This is how we make cassava chips at Dokmai Garden: Peel and wash the tubers to remove the bulk cyanide. Slice the tubers as thin as you can and then throw the slices into a wok with hot soybean oil. After being fried until yellow transfer them to a piece of cardboard to remove excess oil and add salt.

This is a nice tropical snack straight from your monsoon garden. Enjoy the chips with a cold beer and a good friend.

Avoid using large tubers. This is an ideal size.

The best chips are made from thin slices separated from each other before being fried in hot oil.

Since cassava can survive dry conditions, it grows very well here in Chiang Mai and in Esan, making Thailand a major exporter of cassava. Hundreds of millions of tonnes/year are produced worldwide as pig feed or tapioca.

The word ‘cassava’ comes from the West Indian Taino language. ‘Manioc’ is derived from the Tupi language of coastal Brazil.

The plant is protected from hungry animals by the compound linamarin, which looks like a glucose sugar with a cyanide ion attached. Linamarin can release cyanide gas when digested. Cyanide chokes cells by inhibiting the mitochondrial enzyme cytochrome c oxidase. Although there are 99 species of the genus Manihot, all native to tropical and warm America, Manihot esculenta is the most important species for cooking. Like in the species ‘apple’ there are many different cultivars of cassava. The ‘sweet’ (non bitter) ones contain lower concentrations of linamarin, and this linamarin is mostly located to the peel.

Are the chips safe to eat in spite of the cyanide? The NSW Food Authority in Australia recommends consumers not to eat more than 100 g of cassava chips a day. Since levels of cyanide vary a lot due to cultivar (15-400 mg HCN/kg fresh cassava), the limit is set to make sure that even if you eat the most cyanide rich chips you would still be OK. Some ‘sweet’ cassava may only contain 2% of the cyanide content in bitter strains.

A risk assessment has been made by Food standards Australia New Zealand (2008): “Two hundred grams of cassava chips is considered to be a reasonable and possible dietary intake for a 20 kg child in a two hour eating session. Hence 200 g of chips eaten by a 20 kg child equates to 160 mg (8 mg/kg bw) linamarin (or 0.15 mg/kg bw available HCN)”. The deadly dose is 60 times higher (9 mg HCN/kg body weight), i.e. it would be dangerous if the child manages to swallow 12 kg (120 bags) in two hours.

Cyanogenic glycosides can be found in marzipan, bamboo shoots and cherries too. Variation in food ingredients is a recipe for joy and health.

Text: Eric Danell

Photo: Eric Danell & Anna Kiss

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5 Comments leave one →
  1. November 11, 2012 7:42 AM

    Please tell us about other ways to eat Cassava, just in case we run out of beer or friends to share with.
    Also FAO expects very high prices for food late in 2013 due to crops failures in the USA & elsewhere resulting from Global Warming. To help avoid famine shouldn’t we be asking landholders to grow as much food as possible in the coming year and turn weedscapes and lawns into fields of food?
    If so what would you suggest, Cassava maybe or perhaps Maize?

    • November 11, 2012 9:13 PM

      Absolutely, there is plenty of land around Chiang Mai which is crowded with south American mimosas and hardly anything else. Cassava is an excellent choice due to simple growing techniques, modest water and soil requirements, ability to withstand many insects and a potato-like taste.

      As to recipes, do anything with it you would do with potato. I shall try some more recipes and keep you updated.

      Breadfruit is another simple crop, but more adapted to hot (15°C and up) and moist climate.

      Eric

    • November 15, 2012 11:54 PM

      Dear Ricky,

      We tried making pressed cassava, similar to that of pressed potatoes. As it turns out, boiling the cassava for a long time brings out a fragrance of burnt sugar, which is appealing for making dessert but not for a main course. When we tried to press the pieces of cassava they turned out to be very hard, and clogged the holes. The small amount we managed to press was very tasty though, with a gravy from making Swedish meatballs.

      Eric and Zak

  2. November 11, 2012 9:01 AM

    I want to be clear about the ‘peel and wash the tubers to remove the bulk cyanide.” Exactly how is this done? It implies that the cyanide is concentrated on the outside of the tuber and that a rinse with water will get rid of most of it. Is this true?

    Cassava grows well in Hawaii, but as far as i know it is not grown commercially, but as an ornamental.

    • November 11, 2012 9:15 PM

      If you have a ‘sweet’, i.e. a non-bitter variety, then the majority of cyanide is located in the peel. Remove it and wash the surface and you should be OK.

      Cheers, Eric

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