RHEOLOGICAL PROPERTIES OF RICE–SOYBEAN PROTEIN COMPOSITE FLOURS ASSESSED BY MIXOLAB AND ULTRASOUND

Abstract

ABSTRACTThe rheological behavior of gluten‐free composite flours formulated with rice flour and increasing amounts of soybean protein (SP) isolate (0–2%, w/w, flour blend basis) in the presence and absence of transglutaminase (1%, w/w) was assessed using two complementary approaches, the Mixolab device and ultrasonic measurements. Dough was subjected to dual mechanical and thermal constraints, namely mechanical changes due to mixing and heating in the Mixolab and in parallel measurements of ultrasonic attenuation and velocity were performed at two different temperatures (25 and 65C). Main differences were observed during the mixing process, where SPs and transglutaminase induced an important increase of the dough consistency. Results from ultrasonic measurements were in accordance with those obtained with the Mixolab device, both approaches being able to assess the empirical rheological behavior of gluten‐free matrixes and even to detect the effects induced by protein ingredients and processing aid.PRACTICAL APPLICATIONSTwo complementary approaches, the Mixolab device and ultrasonic measurements, are proposed for assessing rheological behavior of gluten‐free doughs. Mixolab provides information of gluten‐free dough empirical rheology following the dough physicochemical changes associated with dual mechanical shear stress and temperature constraint. Ultrasound also may be used to determine consistency changes in gluten‐free dough, resulting in an interesting potential for future development of a quality control system intended for the industrial production process of dough. Consequently, Mixolab and ultrasounds could be regarded as promising tools in order to investigate rice flour dough properties and the changes induced by other ingredients and processing aids.