Application of Response Surface Methodology and Central Composite Design for the Optimization of Tiger Nut (Cyperus esculentus L.) Flour Production

The Response Surface Methodology (RSM) involving three factors five level central composite design (CCD) was employed at design constrains of 46.590C ≤ X1 ≤ 63.410C; 11.32 hours ≤ X2 ≤ 14.59 hours and 31.91 hours ≤ X3 ≤ 52.09 hours, to optimize the selected process variables for the production of tiger nut flour. The objective of this study was to locate the best combination of drying temperature (X1), drying time (X2) and post-sprouting sampling time (X3) that will give optimum quality tiger nut flour. Regression models and response surface plots were developed and their adequacy tested by examining the coefficient of determination (R2, R2 adjusted) analysis of variance (ANOVA), lack-of-fit test and analysis of residual. The result showed models with 80.30% to 96.07% R2,76.75% to 95.36% R2 adjusted, 7.38 to 228 F calculated and insignificant lack-of-fit, as proof of model adequacy. The result of the composite desirability function showed the optimum levels for the production of tiger nut flour to be 56.440C drying temperature, 12.03 hours drying time and 43.53 hours post-sprouting sampling time with resultant of 2.75% moisture content, 21.75% protein, 2.66 x 10-3kg/s flowrate and 496mg/100g vitamin C content.Keyword: Response surface, central composite design, optimization, tiger nut flour