EFFECT OF EXTRUSION PARAMETERS IN THE CHARACTERISTICS OF PASTA VISCOSITY AND WATER ABSORPTION INDEX OF PRE COOKED PASTA PREPARED BY MIXED FLOUR OF BROWN RICE AND MAIZE OBTAINED BY EXTRUSION COOKING

摘要

The effect of the variables moisture, temperature and formulation was studied in the characteristics of paste viscosity and water absorption index (WAI) in pre cooked pastas made from mixed flour of brown rice and maize, by extrusion cooking. The experimental design was elaborated to verify the effect of three substitutions levels of maize flour (20, 30 and 40%), three levels of moisture (30, 35 and 40%) and three temperatures on the high pressure zone (70, 80 and 90°C), resulting in 20 treatments. The results showed that the initial viscosity at 25°C was not affected by any extrusion variables. Although, the maximum viscosity was negatively affected by moisture and formulation (% of maize flour), and the final viscosity also was negatively affected by all studied parameters. The water absorption index, as the initial viscosity, was not affected by the values of the variables. Therefore, the production of pre cooked pasta by extrusion cooking requires cares necessary to get a complete, resistant product and with a good final yield.