Modification of insoluble dietary fibres in soya bean okara and their physicochemical properties

The changes in physicochemical and physiological properties of modified soluble dietary fibre (mSDF) in the okara using enzymatic [cellulase/substrates ratio of 2.0-6.0% (w/w) at 50 degrees C for 90-150 min], chemical [water bath of 1-3 h, water bath temperature of 50-90 degrees C, Na2HPO4 concentration of 0.1-0.9% and sample/reagent radio (S/R) of 1:40-1:60 (w/v)] and physical (homogenised once or twice under the optimal cellulase treatment condition) treatments were evaluated. The mSDF yield with chemical treatment (57.16%) was significantly (P < 0.05) higher than that of physical treatment [homogenisation once (16.54%) or twice (42.02%)] in combination with cellulase treatment. All treatments improved swelling capacity of mSDF and promoted bile acid-and cholesterol-absorption capacity, but enzymatic and chemical treatments decreased the total reducing power of mSDF, except homogenisation-cellulase treatment (141.74 mu M TE g(-1)). Therefore, homogenisation-cellulase treatment may be the appropriate method to improve the SDF proportion and ameliorate the functionality of okara.