Abstract: Nelumbo nucifera Gaertn is rich in protein and amino acid,and poor in fat. Studies showed that peptides from protein can be absorbed easily and have new activities. In this study the protein of Nelumbo nucifera Gaertn was hydrolyzed into peptides with proteinase produced by microorganism, and the index, degree of hydrolysis (DH%) was used to optimize the conditions of Nelumbo nucifera Gaertn fermentation by Bacillus subtilis. The poly peptides from fermented Nelumbo nucifera Gaertn with different concentrations were fractionated by Sephadex G-25 gel chromatography, and the scavenging capacity to hydroxyl free radical of each peak was detected. The results showed that under the conditions of Nelumbo nucifera Gaertn powder 4%, wheat bran 1%, inoculation 5%size, 37 ℃, 120 r/min and 48 h, the degree of hydrolysis reaches 49.2%, and the scavenging capacity to hydroxyl free radical is 65.6%. Absorption peak 3 by Sephadex G-25 gel chromatography had the highest scavenging capacity to hydroxyl free radical, 85.2%. It is suggested that peptides derived from Nelumbo nucifera Gaertn possess high scavenging capacity to hydroxyl free radical, which can be used as a potential source of antioxidant ingredients for food and pharmaceutical industry.

Key words: Nelumbo nucifera Gaertn, fermentation, bioactivity peptides, gel chromatography, antioxidation