Optimization of Roasting Parameters for <i>Parkia biglobosa</i> Oilcake to Obtain a Coffee Substitute (Response Surface Methodology)

<i>Parkia biglobosa</i> is a non-wood forest product whose seeds contain an oil with interesting characteristics. Extracting this oil by pressing will produce a large quantity of oil cake. However, these cakes are not recovered and therefore constitute waste. This study therefore set out to transform this cake into a coffee substitute, using response surface methodology to optimise roasting conditions. The time and temperature varied from 10 to 20 minutes and from 190°C to 210°C respectively. Statistical analysis reveals that they have a significant influence on the response parameters (colour difference, polyphenol content and antioxidant activity) at the 95% confidence level. Colour difference, phenolic compound content and antioxidant activity increased from 32.499 to 54.608, from 53.406 mg/g to 79.036 mg/g and from 78.583% to 91.305% respectively. Roasting conditions (time and temperature) had an impact on phenolic compound content and antioxidant activity. This study revealed that antioxidant activity was correlated with polyphenol content, insofar as a decrease in polyphenol content with temperature led to a drop in antioxidant activity. So to produce the <i>Parkia</i> substitute with high nutritional potential, the response parameters must reach their maximum values. Under these experimental conditions, the optimum roasting parameters are 203°C for 12 minutes, resulting in a colour difference of 49.190, a polyphenol content of 73.949 mg/g and an antioxidant activity of 86.021%.