Precoppe, Marcelo ORCID: 0000-0002-7937-5782 (2021) Roller press construction guide. Manual. CGIAR Research Program on Roots, Tubers and Bananas, London, University of Greenwich.

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Abstract

Cassava (Manihot esculenta Crantz) is a perennial root crop native to South America and the main source of calories for many people living in sub-Saharan Africa. However, two days after harvest, the cassava roots become unsuitable for human consumption. To extend its shelf-life, the roots need to be processed into flour; a dried product that is used as the basis for many dishes. To process cassava into flour, the roots are peeled, grated, pressed, pulverized, dried, and milled. From those steps, drying is the most energy-intensive one. Therefore, dewatering before drying is an important step that results in significant energy savings. Dewatering is the step where water is removed by mechanical means instead of by evaporation. Cassava dewatering can be considered as an expression operation, a separation process where the water is expelled from the wet cassava mash by pressure. In sub-Saharan African countries cassava dewatering is done using presses. Those presses usually have a perforated cage and a top piston. The mash, obtained by grating the roots, are placed in bags, and those bags are piled inside the cage one on top of the other. When the press is full, the piston is slowly lowered, squeezing the material, and forcing the water out, through the bags and the perforations in the cage. After pressing, the piston is raised and the bags containing the press cake are removed to be pulverized. This kind of presses are popular because of their simplicity and low cost, but it has three major drawbacks: work drudgery, inconsistent reduction in moisture, and low throughput. Those drawbacks are associated with the fact that those presses operate in batches, instead of continuously. Continuous presses are used widely for the expression of fruit juices and oils from various oilseeds. They require less labour than batch operated presses, have higher throughput and their operation is more consistent. However, continuously operated dewatering equipment suitable to cassava processing centres in sub-Saharan Africa is not available. Therefore, the objective of this working paper is to provide instructions on how to build a simple and low-cost continuously operated cassava dewatering equipment.

Item Type:	Monograph (Manual)
Additional Information:	This RTB Working Paper is intended to disseminate research and practices about production and utilization of roots, tubers and bananas and to encourage debate and exchange of ideas. The views expressed in the papers are those of the author and do not necessarily reflect the official position of RTB, CGIAR or the publishing institution.
Uncontrolled Keywords:	dewatering; pressing; cassava
Subjects:	S Agriculture > S Agriculture (General) T Technology > TJ Mechanical engineering and machinery
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science Faculty of Engineering & Science > Natural Resources Institute Faculty of Engineering & Science > Natural Resources Institute > Food Science and Marketing Economics
Related URLs:	Organisation
Last Modified:	16 Feb 2024 08:51
URI:	http://gala.gre.ac.uk/id/eprint/35131

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