Resumo

VELASQUEZ-BARRETO, Frank F.  e  VELEZMORO, Carmen. Rheological and viscoelastic properties of Andean tubers starches. Scientia Agropecuaria [online]. 2018, vol.9, n.2, pp.189-197. ISSN 2077-9917.  http://dx.doi.org/10.17268/sci.agropecu.2018.02.03.

The aim of this work was to determine the physicochemical characteristics, rheological and viscoelastic properties of Andean tubers starches. Tubers of mashua (Tropaeolum tuberosum Ruiz & Pavón), oca (Oxalis tuberosa M.) and olluco (Ullucus tuberosum C.) from the district of Paucará (Huancavelica, Peru) were used. The starches were extracted by sedimentation, sieving, washing, and drying at 40 °C for 48 h in an oven. The physochemical properties of the tubers, starch yield, apparent amylose content (AA), and the rheological, and viscoelastic properties of the starches pastes were determined. The AA was between 21.13% and 26.13%. The mashua, oca and olluco pastes presented a thixotropic and pseudoplastic behavior (n < 1). Pastes of the three starches showed more elastic behavior than viscous behavior (G' > G") and the complex viscosity (η*) was greater than mashua and olluco starch pastes. The mashua, oca and olluco starch pastes showed a deviation from the Cox-Merz rule. The results showed that mashua, oca and olluco starch pastes were a thixotropic and pseudoplastic behavior and had a more elastic behavior and the mashua starch pastes showed a higher complex and apparent viscosity.

Palavras-chave : Rheological properties; viscoelastic properties; Andean tubers starches; thixotropic fluid; Cox-Merz rule.

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