Fresh cassava roots are transformed into shelf stable raw materials (flours and extracted starches). Chemical composition (moisture, protein, lipid, fibre and amylose content, cyanide contents), dry matter, starch extraction yields, particle size distribution and whiteness index are some of the quality characteristic requirements for selection of varieties in breeding programs, and raw materials for industrial processes. Starch yields ranges 20–35%, and vary with genotype. The crude protein (1–2%) and crude fat (∼1%) are considered minor components of cassava and are indicative of the poor nutritional quality. The cumulative of particles passing finer than sieve (D90) is commonly selected for industrial applications because it yields a large proportion of flour in the range 90–96% finer particle than sieve size. The amylose is the main genetic trait for categorising starches into waxy, semi-waxy, normal/regular and high amylose types when amylose content is 0–2, 3–15, 16–35, and > 35% of the total starch, respectively. Additionally, amylose is basic criteria for blending flours of different botanical sources. Cassava varieties are classified as sweet and bitter varieties when cyanide values are in the range 15–50 and 50–400 ppm, respectively. The a* (redness-greenness) and b* (yellowish) are considered as impurities in white fleshed cassava.
Part of the book: Cassava