Development of films based on quinoa (Chenopodium quinoa, Willdenow) starch

The filmogenic solutions (FS) composed of quinoa starch (4.0 g/100 mL) were prepared, containing various concentrations of glycerol (GC; 16.6-33.4g glycerol/100 g of quinoa starch, dry weight basis) and alkaline pH values (9.7-11.3). To obtain quinoa starch films (QSF), the FS were dried using different temperature/time combinations (T degrees C/h) denoted as the drying conditions (DC; 30 degrees C/20 h-50 C/5 h). The influence of GC, pH and DC on the mechanical properties and solubility of QSF was evaluated using response surface methodology (RSM). According to the statistical analyses, the optimized conditions corresponded to 21.2 g of glycerol/100 g of quinoa starch, a pH value of 10.7 and 36 degrees C/14 h for the DC. The films produced under these conditions exhibited superior mechanical properties (7.05 +/- 0.37 N puncture force, 7.56 +/- 0.95 MPa tensile strength, and 58.14% +/- 3.16 elongation at break), low solubility (15.9%), and optimal barrier properties (WVP of 0.204 +/- 0.012 g mm m(-2) h(-1) kPa(-1) and oxygen permeability of 4.34 +/- 1.03 cm(3) mu m m(-2) d(-1) kPa). (C) 2010 Elsevier Ltd. All rights reserved.