0 ± 0.02 μL of distilled water was added. The pan was hermetically sealed and equilibrated at room temperature for 24h, then heated at the rate of 10 °C/min from 15 to 110 °C with an empty sealed pan as a reference. Parameters including onset (T0), peak (Tp), conclusion (Tc) and enthalpy (δH) were determined. Temperature at which storage modulus increased, storage modulus at the end of

heating (G′h) and storage modulus at the end of cooling (G′c) were measured with a Paar Physica Controlled Stress Rheometer (MCR 300, Gaz, Austria), buy Epacadostat equipped with parallel plate geometry. Measurements were made in the linear viscoelastic region determined in tests of constant frequency and variable amplitude. Strain and frequency were set at 0.01% and 1 Hz, respectively. The temperature of the bottom plate was controlled with a Peltier system (Viscotherm VT2, Paar Physica, Gaz, Austria), and liquid paraffin was applied to the sample’s exposed surface to prevent water evaporation. Native and extruded amaranth flour aqueous suspension selleck inhibitor (0.20 g wt) were heated from 20 °C to 90 °C at a rate of 10 °C/min, kept at 90 °C for 10 min (sufficient time to allow the storage modulus equilibrium), then cooled to 20 °C at

10 °C/min and held for 10 min at this temperature. All analyses were carried out in at least duplicate and data expressed as mean ± standard deviation employing the Statistica version7.1 software (Statsoft Inc., Tulsa, OK, USA). The proximate composition, on a dry

basis, of the native and extruded amaranth flours are depicted in Table 1. The results obtained for native flours are in agreement with those reported by previous studies on the same amaranth variety: protein at around 15 g/100 g (the nitrogen factor used was 5.85 according Selleck Gemcitabine to Berghofer & Schoenlechner, 2002), and lipid of around 7 g/100 g (Capriles, Coelho, Matias, & Arêas, 2006). Starch, fiber and ash amounts were also in accordance with Capriles et al. (2006) and Mendonça et al. (2009). The extruded flour compositions were similar to those of native flour. Thus, both mild and severe extrusion process did not significantly affect the composition of the flours. Although vitamin and mineral amounts were not determined in the present study, according to Cheftel (1986), the thermoplastic extrusion process did not reduce these nutrients. Hunter color values (L∗, a∗, b∗) of flours are shown in Table 2. Many reactions take place during extrusion cooking that may affect color. The color observed in extruded products might be due to caramelization or the Maillard reaction (Cheftel, 1986). Lysine and other amino acids present in the raw material probably react with the reducing sugars, favored by the processing conditions, which lead to darkening of the extruded products (Gutkoski & El-Dash, 1999). Luminosity (L∗ value) was decreased by the extrusion process whereas a∗ and b∗ values were increased, findings which are consistent with those of Ilo, Liu, and Berghofer (1999).