Optimization of germination process of cowpea by response surface methodology

Abstract

The effect of soaking time, germination time and temperature on the nutrient content, oligosaccharides and trypsin inhibitor activity in cowpea was evaluated by response surface methodology. All the three processing variables affected nutrient content, oligosaccharides and trypsin inhibitor activity. Optimization was based on conditions that maximized reduction in oligosaccharides and trypsin inhibitor activity and minimized total solids losses. Optimum conditions for germination of cowpea were: soaking time = 8 h, germination time = 52 h and germination temperature = 25 °C and under these conditions the predicted values using a polynominal equation for total solids loss, protein, fat and ash contents were 7.71, 23.30, 1.48 and 2.29 (% dry basis), respectively. The trypsin inhibitor level was 4.28 mg/g dry solids. The values for raffinose, stachyose and sucrose were 0.90, 1.96 and 3.61 (% dry basis), respectively. Good agreement was found between experimental values obtained at optimum process conditions and predicted values.