Efeito da extrusão termoplástica nas características de viscosidade de pasta, solubilidade e absorção de água de farinhas pré-gelatinizadas de milho e feijão carioca (BRS Pontal)

Abstract

The aim of this study was to evaluate the effect of the thermoplastic extrusion on pasta viscosity characteristics, solubility, water absorption of pregelatinized fl ours with maize and carioca type beans (BRS Pontal). The parameters used in this process were: screw speed (318.2 to 392.9 rpm), initial moisture (10.9 to 21%) and the addition of peeled carioca type beans (4.8 to 55.2%). These parameters were set in levels, by a second order experimental composite rotational design where the response variables studied were water solubility index (WSI), water absorption index (WAI), initial viscosity (V25), maximum viscosity at 95oC (VMax) and fi nal viscosity (FV). In the present study it was observed that higher levels of beans content increased the solubility of extruded fl our, but did not affect signifi cantly the values of water absorption. The fl ours viscosity profi le is consistent with the characteristic of semi-instant products, being dissolved without needing to cook. The optimal points considered to develop pre-gel fl ours were: WSI (13.07%); WAI (5.81 g gel/g dry matter); V25 (436.52 cP); VMax (157.86 cP) and VF (390.26 cP), to a value of desirability of 0.90.