RESPONSE SURFACE METHODOLOGY TO OPTIMIZE THE PRECOOKING TIME AND DRYING TEMPERATURE IN PRECOOKED FONIO PROCESSING.

Fonio (Digitaria exilis) is a traditional cereal, mainly processed and marketed as precooked fonio of which processing yield is very low in spite of its nutritional and economic importance in many poor rural communities of Africa. Response Surface Methodology (RSM) is a set of statistical and mathematical methods used to develop, improve, and optimize of the processes. In the present study, Response Surface Methodology (RSM) was used to analyze the effects of precooking time and drying temperature on physical (size distribution and whiteness) and functional (hydration capacity and viscosity) characteristics of precooked fonio, the most popular derived product from fonio grains in West Africa. The aim was to optimize precooked fonio process. Fourteen samples of precooked fonio were produced by varying precooking time (15-90 min) and drying temperature (50-100 °C). Results showed that all the measured responses were significantly (p < 0.05) affected by the precooking time. The interaction of two variables had a significant effect upon the peak viscosity. Increase in precooking time was followed by an increase in particle size and hydration capacity, while whiteness and peak viscosity decreased. Optimal processing conditions generated from the models was precooking time, 35.44 min, and drying temperature, 86.54 °C, with a global desirability of 0.80. [ABSTRACT FROM AUTHOR]