Abstract: Nanofiltration membranes (NFM) with molecular weight cut off (MWCO) 160 D and 360 D were used to concentrate and purify corn protein hydrolysate of MW < 5 kD at pH 8.0. The mass transfer efficiencies of peptides, amino acids and sodium ion (Na+) in concentration process and the changes in hydroxyl free radical scavenging activity and antialcoholism activity of corn peptides (CPs) in dialysis process were evaluated. The results showed that although 160 NFM exhibited lower transmission/rejection rates of CPs, amino acids and Na+ as compared to 360 D NFM, the rejection rate of CPs by 160 D NFM was above 88.80% and it provided desalting effect similar to that of 360 D NFM and yielded a desalting efficiency of 94.6% after triple repeated dialysis. Moreover, the activating effect of corn peptides on alcohol dehydrogenase (ADH) was kept very well in 160 D NFM dialysis. In general, 160 D NFM is suitable to be used for the concentration and purification of corn protein hydrolysate and the number of repeated dialysis should be no more than 3.

Key words: nanofiltration (NF), corn peptides, antialcoholism, dialysis, desalination, alcohol dehydrogenase (ADH)