Cassava Roots

The traded root is a tapered, starch-filled organ with a thin outer periderm and a thicker cortex enclosing the starchy parenchyma, plus a central fibrous strand. The peel fractions and the flesh separate readily, which is why peeling is the first operation in almost every processing route and why peel accumulates as a distinct residual stream at processing sites.

Cassava varieties are grouped in trade as sweet or bitter types. The distinction is not a flavour note but a compositional one: it reflects how much cyanogenic glycoside the root carries, and it governs which processing route a lot must take before it can be eaten. Buyers therefore care about type as well as about size and soundness.

Cassava is among the most perishable of the starchy staples. Within a very short time of lifting, the root begins post-harvest physiological deterioration — a vascular discolouration, spreading from wounds and from the cut end, that renders the flesh unacceptable well before any microbial rot takes hold. Microbial spoilage then follows. Mechanical damage during lifting accelerates both, because deterioration starts at wounds.

There is no equivalent of the potato store for fresh cassava at commercial scale. The practical response is speed: roots move from field to processing within a narrow window, and the trade is organised around proximity rather than around storage. Where fresh roots are sold, chains are short and local. Drying, starch extraction, and fermentation all serve to convert a perishable root into a stable, transportable product.

Cassava roots naturally contain cyanogenic glycosides, and it is a settled point of food science that these must be reduced by adequate processing before the root is consumed. This is not an incidental quality matter — it is the reason cassava processing exists in the forms it does. Peeling, grating, soaking, fermenting, pressing, drying, and cooking, used in the combinations traditional to each product, are the operations by which the raw root becomes food.

How much processing a lot needs depends on the variety type, and bitter types are handled through more thorough routes than sweet ones. AgricultureID states this at reference level only: it publishes no compositional limits and no processing procedures, because both are matters for national food-safety authorities and for the applicable food standard, not for an encyclopaedia entry.

Cassava supports several genuinely distinct pathways from the same root. Wet processing extracts starch, which serves food and a wide range of industrial users. Fermented and dried food routes produce gari and related granular and flour products, particularly across West Africa. Drying and chipping produces a stable chip traded for feed compounding and for fermentation feedstock, including ethanol. Peel, generated in volume wherever roots are processed, is a residual stream that is put to feed use rather than simply discarded.

• Food — fermented and dried products such as gari, and starch for food use
• Industrial — native and modified starch for non-food users
• Feed — dried chips and pellets, and processing residues
• Energy — fermentation feedstock for ethanol production

Fresh cassava is not graded through anything like the elaborate national standards applied to cereals. Buyers at a processing gate assess root size and shape, freedom from mechanical damage, absence of vascular streaking, and the time elapsed since lifting — with the last of these often decisive. Starch factories additionally value dry matter, since it determines how much product a delivery yields, and reject consignments that have waited too long.

Because the fresh root travels poorly, international trade in cassava is dominated by derived products rather than by the commodity described on this page. Statistics for "cassava" in trade data usually refer to dried, chipped, or starch forms; the fresh root itself moves in local and regional chains.