Effect of quinoa flour and zein content on the viscoelastic properties of gluten-free pasta dough

M. SOSA; G. LORENZO; A. CALIFANO

Montevideo

Congreso; "X Congreso Iberoamericano de Ingeniería de Alimentos"; 2015

Laboratorio Tecnológico de Uruguay (LATU)

The substitution of gluten is a great challenge and the majority of gluten-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 vitamin B sources. Particularly, quinoa contains a high protein level and a balanced amino acid profile. Additionally, mixtures of maize prolamin (zein), starch and water can form a dough with properties similar to wheat dough, that could mimic the gluten presence. The objective of this work was to study the viscoelastic properties of gluten-free pasta dough as affected by the content of zein and quinoa flour. A formulation previously optimized was adopted: 51.4% corn starch and 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 were evaluated 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 assays were performed (stress and frequency sweeps). Mechanical spectra data was used to obtain the relaxation spectrum. For all the formulations G´ was greater than G´´, and both moduli slightly increased with frequency. Oscillatory spectra were satisfactorily predicted using Maxwell Generalized model. Increasing quinoa flour or decreasing zein content decreased the elastic properties of the dough (G* at 1Hz decreased from 1.89x10^5 to 9.84x10^4 Pa). Modelling the amplitude data, the critical stress (sigma-cr) for structural breakdown was determined for each formulation. It could be observed that increasing zein content in the dough markedly decreased scr (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 it tended to break at smaller stress values.