title: Extrusion of Rice, Bean and Corn Starches: Extrudate Structure and Molecular Changes in Amylose and Amylopectin.
abstract: The objective of this study was to evaluate the effects of starch source and amylose content on the expansion ratio, density, and texture of expanded extrudates, as well as to investigate the structural and molecular changes that occur in starch granules as a function of extrusion. The starches employed were rice starches (8%, 20%, and 32% amylose), carioca bean starch (35% amylose), and Hylon V®corn starch (55% amylose). The extrudates from rice starches containing 20% and 32% amylose exhibited the highest expansion ratio, while, extrudates from Hylon V®corn starch containing 55% amylose exhibited the lowest expansion ratio. The hardness values of the extrudates with 55% amylose were twice those of the extrudates with 20%, 32%, and 35% amylose. An additional finding was that although the amylopectin promoted the expansion of the gelatinized starch matrix, it failed to strengthen and sustain the walls of the extrudate bubbles during expansion.
authors: Dept. of Agroindustrial Science and Technology, Federal Univ. of Pelotas, 96010-900, Pelotas, RS, Brazil.
authors: Nathan Levien
authors: NL
authors: Vanier
authors: Dept. of Food Science and Nutrition, Univ. of Minnesota, St Paul, Minn, U.S.A.
authors: Varatharajan
authors: V
authors: Vamadevan
authors: Dept. of Agroindustrial Science and Technology, Federal Univ. of Pelotas, 96010-900, Pelotas, RS, Brazil.
authors: Graziella Pinheiro
authors: GP
authors: Bruni
authors: Dept. of Agroindustrial Science and Technology, Federal Univ. of Pelotas, 96010-900, Pelotas, RS, Brazil.
authors: Cristiano Dietrich
authors: CD
authors: Ferreira
authors: Dept. of Agroindustrial Science and Technology, Federal Univ. of Pelotas, 96010-900, Pelotas, RS, Brazil.
authors: Vânia Zanella
authors: VZ
authors: Pinto
authors: Dept. of Food Science and Nutrition, Univ. of Minnesota, St Paul, Minn, U.S.A.
authors: Koushik
authors: K
authors: Seetharaman
authors: Dept. of Agroindustrial Science and Technology, Federal Univ. of Pelotas, 96010-900, Pelotas, RS, Brazil.
authors: Elessandra da Rosa
authors: ED
authors: Zavareze
authors: Dept. of Agroindustrial Science and Technology, Federal Univ. of Pelotas, 96010-900, Pelotas, RS, Brazil.
authors: Moacir Cardoso
authors: MC
authors: Elias
authors: Healthy Processed Foods Research Unit, WRRC, ARS, United States Dept. of Agriculture, 800 Buchanan Street, Albany, Calif, 94710, U.S.A.
authors: Jose De J
authors: JJ
authors: Berrios
mesh_terms: D000687:Amylopectin / Q000032:analysis*; D000688:Amylose / Q000032:analysis*; D007887:Fabaceae / Q000737:chemistry*; D005504:Food Analysis; D005780:Gelatin / Q000737:chemistry; D015394:Molecular Structure; D012275:Oryza / Q000737:chemistry*; D013213:Starch / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry*
chemical_list: D005780:Gelatin; D013213:Starch; D000688:Amylose; D000687:Amylopectin
keywords: amylose; crystallinity; morphology; starch extrusion; texture