What is tapioca

Tapioca is a starch extracted from cassava root (Manihot esculenta Crantz). Cassava species, also known as yucca, manioc and tapioca, is native to the northeast region of Brazil, but its use spread throughout South America. The cassava plant was carried by Portuguese and Spanish explorers to most of the West Indies and Africa and Asia. All the parts of the crop are useful either for human consumption (young leaves and roots) or for feeding animal ¹. The plant grows in poor soil and is relatively drought resistant; the tubers are rich in carbohydrates and the leaves contain some protein. Cassava species tolerates drought and has been considered as a well adapted crop facing climate change which could position it as one of the best alternatives for providing food for the rapidly growing world population in future ². Cassava is a dietary staple for more than 600 million people globally ³. Cassava root has many uses. The roots are processed into tapioca flour, tapioca starch and other end products (chips, flakes, biofuel, textile, and glue) ⁴. Although tapioca is a staple food for millions of people in tropical countries, it is devoid of nutrition and low in food energy. The uses of the cassava roots are constrained by some factors. They are perishable; require rapid utilization after harvest and contain sometimes detrimental levels of cyanogenic glycoside ⁵.

Cassava contains cyanogenic glucosides (linamarin and lotaustralin) that are released as hydrogen cyanide, which are thought to protect the plants from insects and other animals ⁶. For human consumption, the cassava plants need to be detoxified, usually by soaking, drying in the sun, boiling, fermentation, or grating with roasting ⁷. These processes allow the cyanogenic glucosides to be released, but depend upon traditional practices, time taken and the availability of water. Neurotoxicity is associated with incompletely detoxified cassava, although the exact mechanisms by which these compounds cause neurological damage is unclear. The toxicity of cyanide is reduced by its transformation to thiocyanate or cyanate, which requires sulphur donors, often limited in malnutrition. Two neurological conditions are mainly associated with bitter cassava: a myeloneuropathy and konzo. The myeloneuropathy manifests as a slowly evolving bilateral sensory polyneuropathy, optic atrophy and sensorineural deafness, and sensory ataxia, is seen in adults (particularly elderly) who have a solely cassava diet ⁸. Konzo is a condition with selective upper motor neuron damage, manifesting as an acute or subacute onset of an irreversible, non-progressive, and symmetrical spastic paraparesis or quadriparesis ⁹. The disease konzo has no cure ¹⁰. Prevention measures such as proper cassava processing, i.e., detoxification of cassava roots before their consumption. Konzo is found in remote poor regions, often occurring as epidemics in times of drought, famine, and war, when the usual detoxifying preparation of cassava are not followed. One country with the highest prevalence of this paralysis is the Democratic Republic of Congo, where konzo can affect up to 5 percent of people in some villages ¹¹. All children in konzo-harboring villages – even without physical symptoms – showed poorer memory than children from konzo-free villages. Those in konzo villages additionally lagged in visual-spatial aptitude and in mental processing. These results suggest that even without physical manifestations from cassava toxins, some children suffer damage and the overall burden of cassava-related brain impact may have been underestimated. Besides myeloneuropathy and konzo, cassava is associated with other neurological disorders. For example, cassava consumption is associated with epilepsy across Africa ¹² and behavioural and emotional problems in Kenyan children ¹³; but it is unclear whether this is a marker of poverty and thus associated with other risk factors, or a result of neurotoxicity. Konzo can be prevented with appropriate preparation of cassava, but it remains unclear whether consumption of cassava has any subtle neurotoxic effects. In view of the reliance of many poor people in many parts of the world on cassava as a staple food, scientists need to determine the full extent of cassava’s effect on the central nervous system (CNS).

Cassava-derived food products (e.g. tapioca flour or starch) are increasingly exported for snack production, animal feed and used as thickening agents in food industries. It is therefore critical to understand the potential neurotoxic properties and the extent of neurodevelopmental risk associated with this staple.

Tapioca flour is naturally gluten free. In developed countries, tapioca starch (flour) is used as a thickening agent in various manufactured foods. In addition to its use for culinary purposes, cassava finds application in industrial products such as an adhesive for laundry purposes, for manufacturing paper, alcohol, butanol, dextrin, adhesive tape, textile sizing, and glue ¹⁴.

Commercially, the tapioca starch is processed into several forms: hot soluble powder, meal, pre-cooked fine/coarse flakes, rectangular sticks, and spherical “pearls”. Pearls are the most widely available shape; sizes range from about 1 mm to 8 mm in diameter, with 2–3 mm being the most common.

Flakes, sticks, and pearls must be soaked well before cooking, in order to rehydrate, absorbing water up to twice their volume. After rehydration, tapioca products become leathery and swollen. Processed tapioca is usually white, but sticks and pearls may be colored. Traditionally, the most common color applied to tapioca has been brown, but recently pastel colors have been available. Tapioca pearls are generally opaque when raw, but become translucent when cooked in boiling water.

Brazil in South America, Thailand in Asia, and Nigeria in Africa are the world’s largest producers of cassava. Currently, Thailand accounts for about 60 percent of worldwide exports.

Figure 1. Cassava

Figure 2. Tapioca pearls

Tapioca nutrition

Tapioca predominantly consists of carbohydrates, with each cup containing 26 grams for a total of 100 calories; it is very low in saturated fat, protein and sodium. It has no significant essential vitamins or dietary minerals ¹⁵. One serving of tapioca pudding contains no dietary fiber, a small amount of oleic acid, and no omega-3 or omega-6 fatty acids ¹⁵.

Table 1. Tapioca starch (finely tapioca ground flour) nutrition facts

[Source ¹⁵]

Table 2. Tapioca flour nutrition facts

[Source ¹⁵]

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