title: Extrusion Conditions and Amylose Content Affect Physicochemical Properties of Extrudates Obtained from Brown Rice Grains.
abstract: The utilization of whole grains in food formulations is nowadays recommended. Extrusion cooking allows obtaining precooked cereal products and a wide range of ready-to-eat foods. Two rice varieties having different amylose content (Fortuna 16% and Paso 144, 27%) were extruded using a Brabender single screw extruder. Factorial experimental design was used to study the effects of extrusion temperature (160, 175, and 190°C) and grits moisture content (14%, 16.5%, and 19%) on extrudate properties. Specific mechanical energy consumption (SMEC), radial expansion (E), specific volume (SV), water absorption (WA), and solubility (S) were determined on each extrudate sample. In general, Fortuna variety showed higher values of SMEC and S (703-409 versus 637-407 J/g; 33.0-21.0 versus 20.1-11.0%, resp.) than those of Paso 144; on the contrary SV (8.64-3.47 versus 8.27-4.53 mL/g) and WA tended to be lower (7.7-5.1 versus 8.4-6.6 mL/g). Both varieties showed similar values of expansion rate (3.60-2.18). Physical characteristics depended on extrusion conditions and rice variety used. The degree of cooking reached by Paso rice samples was lower than that obtained for Fortuna. It is suggested that the presence of germ and bran interfered with the cooking process, decreasing friction level and broadening residence time distribution.
authors.affiliation: Instituto de Tecnología de Alimentos, Universidad Nacional del Litoral, 1 de Mayo 3250, 3000 Santa Fe, Argentina.
authors.forename: Rolando José
authors.initials: RJ
authors.lastname: González
authors.affiliation: Instituto de la Grasa (CSIC), Avenida Padre García Tejero 4, 41012 Seville, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Pastor Cavada
authors.affiliation: Instituto de la Grasa (CSIC), Avenida Padre García Tejero 4, 41012 Seville, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Vioque Peña
authors.affiliation: Instituto de Tecnología de Alimentos, Universidad Nacional del Litoral, 1 de Mayo 3250, 3000 Santa Fe, Argentina.
authors.forename: Roberto Luis
authors.initials: RL
authors.lastname: Torres
authors.affiliation: Instituto de Tecnología de Alimentos, Universidad Nacional del Litoral, 1 de Mayo 3250, 3000 Santa Fe, Argentina.
authors.forename: Dardo Mario
authors.initials: DM
authors.lastname: De Greef
authors.affiliation: Instituto de Tecnología de Alimentos, Universidad Nacional del Litoral, 1 de Mayo 3250, 3000 Santa Fe, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avenida Rivadavia 1917, 1033 Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Silvina Rosa
authors.initials: SR
authors.lastname: Drago