Abstract: Based on one-factor-at-a-time experiments, process optimization for zein extraction using L-cysteine treatment followed by ultrasonic-assisted extraction was performed using an orthogonal array design. Zein extraction yield was investigated with respect to L-cysteine amount, ratio of liquid to material, ultrasonic treatment time, temperature and pH. The optimal process conditions for zein extraction were achieved as follows: L-cysteine amount 0.65%, ratio of liquid to material 7:1, ultrasonic treatment time 1.5 h, temperature 40 ℃, and pH 5.0. Under these conditions, the yield and purity of zein were 89.06% and 92.51%, respectively.

Key words: L-cysteine, zein, extraction