Soyflakes and soybrokens were enzymatically hydrolyzed using a mixed-activity crude enzyme prior to extraction of oil using hexane. To enhance oil availability and extractability, a second order response surface methodology was used to obtain optimal process conditions for soyflakes and soybrokens of 24.6% and 24.7% wet mass basis (wb) moisture during hydrolysis, 14.2% and 7.1% volume per weight of the sample (v/w) enzyme concentration, and 13.3 and 13.9 h hydrolysis time, respectively. Enzymatic hydrolysis significantly increased the extraction rates. The enzymatic hydrolysis reduced the extraction time for over 99% extraction from 28 h to 14 h in soyflakes and from 32 h to 21 h in soybrokens under the optimum process conditions. Mathematical models were developed to describe the extraction kinetics of both enzymatically hydrolyzed and unhydrolyzed soyflakes and soybrokens. Observed experimental oil extraction data fitted well with the developed mathematical models. (c) 2007 Elsevier Ltd. All rights reserved.