Optimization of water extraction of naturally emulsified oil from maize germ

•A DOE-based strategy was adopted for water extraction of maize germ oil bodies.•Taguchi method was applied to pre-test a large number of process parameters.•Modelling/optimization of extraction process by using Response Surface Methodology.•The proposed model can adequately describe the process performance.•Oil bodies yield of 99.30 ± 0.56% is the highest reported in the literature.

A design of experiments-based experimental strategy is proposed to develop an effective and rapid water extraction process for maximizing the yield of naturally-emulsified oil based on oil bodies from maize germ. Orthogonal array (D9) of Taguchi, the signal-to-noise ratio, the main effects, and the analysis of variance (ANOVA) were adopted to pre-test the process parameters (germ flour particle size (dp), water-to-solid ratio (w), pH and extraction time (t)) for their effect on the extraction yield (Y) and the diameter of oil droplets (d3.2). Water extraction of emulsified oil from germ flour of dp < 0.85 mm at pH 9.0 was optimized using response surface methodology and central composite design (independent variables: w, t, and n for number of cycles). The quadratic model fitted well to Y. The extraction yield of emulsified oil of 99.30 ± 0.56% (w = 3:1 g/g, t = 14 min, n = 5) is the highest reported in the literature.