Rheological description of the interaction of xyloglucan and starches: effect of the amylose content in starches
2015
de Freitas, Rilton Alves | Woehl, Marco Aurélio | Kaminski, Gabriel A.T. | da Silva, Renata | Sierakowski, Maria Rita
Starches’ rheological properties can be improved in association with other hydrocolloids in order to expand their industrial applications. Xyloglucan (XG) was mixed with starches and heated until complete starch gelatinization. Using the rheological tan delta (G”/G’) measurement and iodine-XG competition assay, an ideal proportion of 5:1 for interaction between high-amylose cornstarch and the XG was determined. The starch-amylose synergism was found to be related to the amount of amylose. For yam and high-amylose cornstarch, the G”/G’ declined from 0.075 to 0.073 (p < 0.05) and from 0.138 to 0.101 (p > 0.05), respectively, for the starch and hydrocolloid–starch mixture. For amylopectin-rich samples, cassava, normal, and waxy cornstarches, where the reaction is antagonistic, the G”/G increased from 0.390 to 0.865 (p < 0.05), 0.100 to 0.210 (p > 0.05), and 0.446 to 6.740 (p < 0.05), respectively, for starch and hydrocolloid–starch mixture. These synergistic interactions can be used by industries to manufacture products with the desired rheological properties.
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