Characterization of the agglomeration of roasted shredded cassava (Manihot esculenta crantz) roots

Roasted and granulated cassava roots flour, known as 'rale' in the south of Mozambique, is a common meal in sub-Saharan Africa and is consumed reconstituted with hot or cold water. In this work, analysis of rale was carried out with the aim of understanding what determines the agglomeration properties. Rale is agglomerated roasted cassava flour with about 95% of starch gelatinized. The pre-gelatinized and agglomerated cassava gives cold swelling as well as a resistance against disintegration when heated. The softness of swollen agglomerated granules is temperature dependent. Microscopy of rale agglomerates shows that the granulation is formed by partial swelled starch granules bound together by retrograded leached AM. A physical model of rale consisting of glass beads agglomerated by drying with an AP or AM solution showed that particles with retrograded AM were resistant to disintegration in water at 90 degrees C while glass beads agglomerated with AP did not show comparable heat resistance. Thus it was concluded that the leaching and retrogradation of AM is essential to obtain the rale agglomeration and functionality.