Abstract

CIRO VELASQUEZ, HECTOR JOSÉ; LARGO AVILA, STEBAN  and  CASAFUS PIEDRAHITA, HAMED SANTIAGO. RHEOLOGICAL CHARACTERIZATION OF THE CASSAVA ROOT (MANIHOT ESCULENTA CRANTZ)PART ONE: RESPONSE TO UNIDIRECTIONAL COMPRESSION.. Dyna rev.fac.nac.minas [online]. 2007, vol.74, n.151, pp.25-36. ISSN 0012-7353.

The results of the behavior of agricultural products through the determination and analysis of the flow curves of the Cassava (Manihot esculenta crantz) chiroza variety subjected to unidirectional compression are given in this experimental research. The rheological properties such as failure stress, strain until the rupture, toughness and deformability modulus were determined. The cassava samples were subjected to unidirectional compression until the point failure under a constant deformation rate of 1 mm/s and environmental conditions of temperature and relative humidity of 21ºC y 65%, respectively. The rheological tests were evaluated in two loading senses according to the fiber direction of the material (longitudinal and transversal) and two moisture contents levels (raw and dried product). The statistical analyses showed that the rheological behavior of the product depends on the moisture content and the loading direction, indicating that the vegetal material offers a mechanical resistance to the failure ( fracture stress) and toughness or energy density higher in sense longitudinal than transversal. In addition the rigidity to the product expressed by its module of deformability indicates that the product is less rigid as the moisture content of the product diminishes.

Keywords : Cassava, Rheology; Compression test; Mechanical properties; Deformability modulus.

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