Effect of chia (Sativa hispanica L.) and hydrocolloids on the rheology of gluten-free doughs based on chestnut flour

The rheological characterisation of chestnut flour doughs with chia flour at 4.0 g/100 g flour basis and a hydrocolloid (guar gum, hydroxypropyl methyl cellulose (HPMC) or tragacanth gum) at different concentrations (0.5,1.0, 1.5, 2.0 g/100 g, fb.) was carried out at 30 degrees C using a controlled stress rheometer. Previously, the mixing behaviour was determined using Mixolab (R) apparatus. Measurements of shear (0.01-10 s(-1)), oscillatory (1-100 rad s(-1) at 0.1% strain), creep-recovery (loading of 50 Pa for 60 s) and temperature sweep (30-100 degrees C) were performed. The simultaneous presence of chia and hydrocolloids modified significantly the theological properties of doughs. Apparent viscosity at constant shear rate and storage and loss moduli at constant angular frequency decreased with increasing hydrocolloid content, except for tragacanth gum which loss modulus exhibited a reverse trend. Creep-recovery data showed that doughs elasticity improved with the presence of guar (65.9%), HPMC (64.8%) or tragacanth (45.8%) at 1.0, 2.0 and 1.0 (g/100 g, f.b.), respectively. Flow curves, mechanical spectra and creep-recovery curves obtained experimentally were satisfactorily fitted using Cross, power and Burgers models, respectively. Gelatinization temperatures decreased with increasing additive content for all systems. (C) 2012 Elsevier Ltd. All rights reserved.