Modification of the functional and structural properties of amaranth starch by fluidised bed and extrusion heating processes

GONZALEZ, R., CARRARA, C. , TOSI, E., AÑÓN, M.C., PILOSOF, A.

LEBENSMITTEL-WISSENSCHAFT UND-TECHNOLOGIE-FOOD SCIENCE AND TECHNOLOGY

Año: 2007 vol. 40 p. 136 - 143

0023-6438

AbstractToday amaranth is a promising food source yet its technological properties are not well known. The modification of some properties ofan amaranth starch-rich fraction by a controlled heating is studied. This fraction was obtained by the differential milling of Amaranthuscruentus grains.Tests were performed by both fluidized bed and extrusion heating, according to a factorial experimental design of two variables:temperature and moisture, at three levels 150–170–200 1C and 120–160–200 g/kg wb, respectively. Effects were evaluated by the ANOVAmethod. As responses, solubility and water absorption, amylographic and dynamic rheological properties, crystallinity, granularintegrity and resistant starch content were evaluated. Flours obtained from samples heated by fluidized bed gave aqueous dispersionswith high consistencies when cooked, and they had low solubility in water and preserved part of the starch crystalline structure. Floursobtained from extrusion-heated samples gave very high solubility in water but had lower consistency of the aqueous dispersions whencooked, and they showed a complete loss of the crystalline and granular structure.By applying each of the two heating processes, it was possible to modify, according to selected targets, the amaranth starch-richfraction, what would allow to obtain pre-cooked amaranth flours with a wide range of hydration and rheological properties.r 2005 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.