Cassava

Manihot esculenta was domesticated in the Amazon Basin of South America approximately 8,000 to 10,000 years ago.

• Originated in the southwestern Amazon Basin, in the region of modern-day Brazil, Bolivia, and Peru
• Domesticated by Indigenous peoples of the Amazon who developed the complex processing techniques needed to detoxify the roots
• Spread throughout tropical America in pre-Columbian times
• Portuguese traders introduced cassava to Africa in the 1500s, where it became a dietary cornerstone
• Reached Asia (India, Indonesia) in the 1700s via Portuguese and Spanish colonial trade
• Today, Nigeria is the world's largest producer (over 60 million tonnes annually)
• The genus Manihot contains approximately 100 species, mostly native to the neotropics
• The species epithet "esculenta" means "edible" — ironic for a plant whose raw roots are toxic
• Cassava was so important to the Tikuna people of the Amazon that their word for it, "mandioca," became the plant's name in Portuguese

Manihot esculenta is a deciduous, perennial shrub typically grown as an annual.

Plant:
• Erect, branching shrub, 1 to 3 meters tall
• Stems vary in color from green to gray to brown

Leaves:
• Palmately lobed, typically 3 to 7 deep lobes
• 10 to 20 cm across, on long petioles (10 to 30 cm)
• Dark green above, pale green below
• Some varieties have red or purple-tinted petioles and young leaves

Storage roots (the edible portion):
• Enlarged, fusiform (spindle-shaped) to cylindrical, typically 15 to 50 cm long and 5 to 15 cm in diameter
• Brown, rough, bark-like skin
• White to pale yellow flesh, very starchy
• No defined harvest time — can be left in the ground for months and harvested as needed
• Each plant produces 5 to 15 storage roots weighing 1 to 5+ kg total

Flowers:
• Small, greenish-yellow, unisexual
• Male and female flowers on the same plant (monoecious)
• Borne in open panicles

Seeds:
• Large, elliptical, mottled gray-brown
• Contain high levels of cyanogenic glycosides
• Used for breeding but not eaten

Cassava roots are primarily a calorie source but provide some nutrients.

Per 100 g boiled cassava (no fat added):
• Energy: approximately 112 kcal
• Carbohydrates: 27 g (predominantly starch — very high)
• Protein: 1.4 g — low protein content is a nutritional concern
• Fat: 0.3 g
• Vitamin C: 20 mg (33% DV)
• Folate: 27 mcg
• Potassium: 271 mg
• Magnesium: 21 mg
• Thiamin: significant

Nutritional concerns:
• Very low protein content (1 to 2%) — diets heavily dependent on cassava can lead to protein deficiency
• Low in essential micronutrients compared to other staples
• Biofortified varieties with enhanced vitamin A (yellow cassava) are being developed
• Contains resistant starch — may have prebiotic benefits

Tapioca nutrition:
• Almost pure carbohydrate starch
• Very low in protein, fat, and micronutrients
• Commonly used as a gluten-free flour alternative

RAW CASSAVA IS TOXIC — it contains dangerous cyanogenic glycosides.

• Contains linamarin and lotaustralin — cyanogenic glycosides that release hydrogen cyanide (HCN) when plant tissue is damaged or digested
• Hydrogen cyanide is a potent metabolic poison — it blocks cellular respiration by inhibiting cytochrome c oxidase
• "Bitter" cassava varieties contain 50 to 400 mg HCN per kg of fresh root — potentially LETHAL
• "Sweet" cassava varieties contain less than 50 mg HCN per kg — safer but still require cooking
• Symptoms of cyanide poisoning: headache, dizziness, nausea, vomiting, rapid breathing, rapid heart rate, convulsions, and death
• Chronic exposure to sub-lethal cyanide levels causes konzo (a paralytic neurological disease) and tropical ataxic neuropathy
• Traditional processing methods (grating, fermenting, pressing, roasting, boiling) effectively remove most cyanide
• Cassava must NEVER be eaten raw
• Properly processed cassava products (tapioca, gari, farinha) are safe

Cassava is a tropical crop that thrives in poor soils and harsh conditions.

Planting:
• Plant stem cuttings (stakes) 10 to 20 cm long, pushed into the soil
• Plant at the start of the rainy season
• Space 80 to 120 cm apart
• Requires 8 to 24 months for roots to reach full size

Site:
• Tolerates extremely poor, acidic, drought-prone soils — grows where few other crops survive
• Full sun
• Tropical temperatures (25 to 35°C)
• Drought-tolerant once established

Care:
• Minimal weeding required after the first 3 months
• No fertilizer required in most traditional systems
• Very resistant to pests and diseases

Harvest:
• Roots can be harvested 8 to 24 months after planting
• Harvest by pulling the stem and digging around the base
• Roots deteriorate rapidly after harvest (within 2 to 3 days) — must be processed promptly
• Can be left in the ground as a living food storage system

Traditional detoxification:
• Peeling (most cyanide is in the skin)
• Grating or pounding to break cell walls and release the enzyme that breaks down cyanogenic glycosides
• Fermenting (2 to 5 days) to allow enzymatic hydrolysis
• Pressing to remove toxic juice
• Roasting, drying, or cooking to drive off residual HCN
• These steps reduce cyanide to safe levels

Culinary uses (all properly processed):
• Boiled or fried like potatoes — the simplest preparation
• Tapioca pearls — the basis for tapioca pudding and bubble tea
• Gari — West African fermented, roasted cassava granules eaten as a staple
• Fufu — pounded cassava eaten with soups (West Africa)
• Farinha — Brazilian toasted cassava flour
• Casabe — Caribbean flatbread made from cassava flour
• Boba pearls — the chewy spheres in bubble tea are made from tapioca starch
• Cassava fries — popular in Latin America
• Bammy — Jamaican cassava flatbread
• Tapioca flour — gluten-free baking
• Cassava cake — Filipino dessert
• Fermented products: chicha, various African fermented foods

Industrial uses:
• Tapioca starch — used in food processing, textiles, paper, and adhesives
• Bioethanol production
• Animal feed from processing residues
• Biodegradable packaging materials