Efeito da concentração de transglutaminase microbiana e do tempo de extrusão nas propriedades tecnológicas de massas glúten-free funcionais.

Abstract

This work aims to study the effect of microbial transglutaminase concentration and extrusion time on the technological properties of functional gluten-free doughs, produced with red rice and white quinoa wholemeal flours. The textural and rheological properties of the doughs were evaluated and the physical, technological and functional properties, before and after cooking, were determined. Rice and quinoa flours were obtained by grinding in a disk mill. The pastas were produced based on wholegrain red rice flour, 10% white quinoa wholemeal flour, 10% sweet powder, 3% psyllium, 30% water and transglutaminase enzyme concentrations varying by 0.5%, 1 .0% and 1.5%. Three extrusion times were used: 5.10 and 15 minutes, according to a factorial design of 22 with 3 central points to test linear effects. The dough samples were analyzed for cooking quality, texture profile, rheological properties, color and bioactive compounds, and the levels of phenolic compounds were quantified. A longer extrusion time and lower MTgase content provided greater starch solubilization and a weakening of the dough's protein network, resulting in greater cooking loss and lower moisture content. The firmness of the doughs was affected by the longer extrusion time, since the high shear stress and temperature favor the formation of a strengthened starch network. The behavior of the curves in the rheology study indicates that the masses present a typical behavior of pseudoplastic materials, with a characteristic that is predominantly more elastic than viscous and the product structure resembles a gel. The reddish color (+a*) was noticed in samples with lower concentration of MTgase, due to the predominance of the reddish pigment in the red rice flour. The mean interaction between MTgase and extrusion time, referring to the samples from the central point of the study, resulted in greater breaking of bonds and greater phenolic accessibility in the samples. The extrusion time and the concentration of MTgase influence the cooking, physical, rheological and functional properties of the doughs.