Rapeseed meal from pressing of rapeseed oil was hydrothermally decompd. in 20% (m/m) aq. suspension. The meal was rich in protein, hemicellulose and cellulose components. The decompn. proceeded in subcrit. water under batch conditions. To optimize the hydrothermal process, the Doehlert array was used. According to a quadratic model, an optimum yield of soluble protein, amino acids and monosaccharides 20.3% (194.5 degrees C, 3.7 min), 19.8% (212 degrees C, 26.3 min) and 7.6% (245.1 degrees C, 28.6 min), resp., was predicted.