Influence of the dehydration process on active compounds of okara during its fractionation

Okara (residue of the soymilk manufacture) is rich in proteins, fibres and. lipids. It also contains isoflavones that possess health-promoting properties. A new method has been developed for the valorization of fibres from okara by hydrolysis of insoluble proteins with a protease and removal of the oil. Three different processes were investigated: the first one involved delipidation and drying prior to proteolysis and led to the highest content of fibre (80%) in the final product. The second used proteolysis on crude okara followed by solvent delipidation-dehydration and gave an intermediate content of fibre (75%). The last process was totally enzymatic (proteolysis and lipolysis) and gave the lowest content of fibre in the final product (50%). Fibre water-holding capacity was correlated to the total dietary fibre content of each sample. It was preferable to use crude okara for hydrolysis, since oven-drying during the process decreased the water-holding capacity and modified the isoflavone profile of okara. (c) 2005 Society of Chemical Industry.