EFFECT OF QUINOA FLOUR AND ZEIN CONTENT ON THE VISCOELASTIC PROPERTIES OF GLUTEN-FREE PASTA DOUGH

M. SOSA; G. LORENZO; A. CALIFANO

Congreso; CIBIA X Innova 2015; 2015

The substitution of gluten is a great challenge and the majority ofgluten-free products available on the market are based on starches. Currently,food manufacturers are investing in the use of whole grains (corn, sorghum,amaranth and quinoa), since most of these are excellent fiber, iron, and vitaminB sources. Particularly, quinoa contains a high protein level and a balancedamino acid profile. Additionally, mixtures of maize prolamin (zein), starch andwater can form a dough with properties similar to wheat dough, that could mimicthe gluten presence. The objective of this work was to study the viscoelasticproperties of gluten-free pasta dough as affected by the content of zein andquinoa flour. A formulation previously optimized was adopted: 51.4% corn starchand corn flour, 6.6% dry-egg proteins, 2.5% of xanthan/locust bean gums mixture,2.6% sunflower oil, 1.1% NaCl and water. Three levels of quinoa flour wereevaluated replacing corn flour (0%, 5.14%, 10.3%), and three levels of zein,partially replacing dry-egg (0% ,2.2%,4.4%). Small amplitude oscillatory assayswere performed (stress and frequency sweeps). Mechanical spectra data was usedto obtain the relaxation spectrum. For all the formulations G? was greater thanG??, and both moduli slightly increased with frequency. Oscillatory spectrawere satisfactorily predicted using Maxwell Generalized model. Increasingquinoa flour or decreasing zein content decreased the elastic properties of thedough (G* at 1Hz decreased from 1.89x105 to 9.84x104 Pa).Modelling the amplitude data, the critical stress (σcr) forstructural breakdown was determined for each formulation. It could be observedthat increasing zein content in the dough markedly decreased σcr(from 1029.0 to 371.2 Pa), while non-significant effect was observed for quinoa,thus, although dough matrices became more elastic with the presence of zein ittended to break at smaller stress values.