CFD assisted investigation of mechanical juice extraction from cassava leaves and characterization of the products.

Cassava is grown because of its starchy roots, but the leaves being rich in protein are mostly underutilized. For protein recovery, mechanical juice extraction from cassava leaves and the extraction process was evaluated using computational fluid dynamics (CFD) simulation. The influence of input variables such as nozzle diameter and rotational speed of the screw was investigated in relation to process efficiency. The highest green juice extraction yield (81.0%) from cassava leaves and dry matter of press cake (61.3%) were achieved by using 4 mm nozzle diameter and 18 rpm screw speed. The protein content of the cassava leaves, press cake, juice sediment, and juice supernatant was found to be 31.5%, 27.7%, 26.2%, and 12.4%, respectively. The crude protein, cellulose, hemicellulose, lignin, and total phenolic content mainly accumulated in the press cake. The screw pressing concentrated the amino acids in the press cake and the juice sediment.

Detoxification of Cassava Leaves by Thermal, Sodium Bicarbonate, Enzymatic, and Ultrasonic Treatments.

Cassava leaves are a valuable source of protein but the cyanogenic potential limits their use as food and feed. Four different treatments were investigated to detoxify cassava leaves. Thermal (55 °C for 6 hr), sodium bicarbonate (0.4% NaHCO3 , 55 °C for 6 hr), enzymatic (0.32% Multifect® GC Extra, 4 hr), and ultrasonic treatments (500 W, 35 kHz, 55 °C, 0.25 hr) reduced the total cyanide (µg HCN equivalents per g fresh leaf or ppm) content by 90%, 93%, 82%, and 84% while the cyanide content reduction in the respective controls was 85%, 90%, 79%, and 84%, respectively. The sodium bicarbonate treatment was found to be the most effective treatment. Therefore, it was further optimized by varying time and temperature. A significant effect on the cyanide content was observed by changing the incubation time while no significant effect of temperature was noticed. Nevertheless, extended incubation time during sodium bicarbonate treatment reduced ascorbic acid content by 7% and 39% when leaves were incubated with sodium bicarbonate for 0.5 hr and 48 hr, respectively. PRACTICAL APPLICATION: Cyanogenic glucosides are the major toxic compound in cassava leaves, which limits their use as food and feed. The methods proposed in this study can be used to detoxify cassava leaves, which are generally considered as an inferior by-product. Hence, detoxified cassava leaves may contribute to fulfil world protein demand in an eco-sustainable way.