Abstract: Proteins were prepared by the combination of various extraction methods based on the method of inducer plus autolysis from waste brewer yeast. The optimum technology processes and parameters were determined by comparison experiments and orthogonal tests. The protein digestibility was measured by a pepsin-trypsin method in vitro. The results indicated that the optimal method of cell-wall broken was inducer plus autolysis plus enzymatic hydrolysis, and the optimal parameters were as follows: temperature 50 ℃, pH 6.0, 40 hours, the neutral protease and the β-glucanase-substrate ratio 25 U/g and 15 U/g respectively. The protein digestibility in vitro was 81.06%.

Key words: waste brewer yeast, protein, enzymatic hydrolysis, extraction technology, in vitro digestibility