Abstract:

Lipase degreasing was carried out as the first step in the production of insoluble dietary fiber from brewer's spent grains. Orthogonal array design was employed to provide a basis for the establishment of a mathematical model predicting the degreasing efficiency as a function of lipase hydrolysis conditions, namely enzyme amount, hydrolysis temperature and length of hydrolysis and the subsequent genetic algorithm optimization of these conditions. The established model displayed an error of 0.0001, indicating high reliability. The optimum values of enzyme amount, hydrolysis temperature and length of hydrolysis were found to be 0.7 g (on the basis of 10 g brewer s spent grains), 39.6 ℃ and 5.6 h, respectively, and the resultant degreasing efficiency reached up to 74.1%. The swelling capacity and water retention capacity of prepared IDF were 6.05 mL/g and 318.2%, respectively.

Key words: insoluble dietary fiber, lipase, BP neural network, genetic algorithm