Study Of Enzymatic Salted Duck Egg White Preparation Of Albumin Peptides

Bioactive peptide has a high nutrition of value and more functional activities. So it is a popular subject in nutrition now. The egg white of salted duck eggs contains abundance of high quality protein, but it can't be used directly, and is commonly discarded because of its high salt content. That induced serious environment problem and great waste of the high quality protein.This paper researched on the bioactive peptides made from salted duck eggs white which was rich of ovalbumin and was of little commercial value through hydrolyzing by proteases and subsequent membrane filtration to get rid of the extra salt so that the final product could be more useful for human and animals.Firstly, the technology of making ovalbumin peptides was optimized. The enzymatic reaction conditions such as enzyme species, substrate concentration, enzyme concentration, pH, temperature and time of reaction was studied. The optimal conditions of enzymatic treatment was obtained as follows: chose acid proteinase, dilution rate was 1, dosage of enzyme was 3000U/g, pH was 2.5, temperature was 45 ℃, and raction for 6hours.Then the desalting method of the final hydrolyzed product was compared and chosen. The advantage and disadvantage of desalting to the egg white and desalting to the hydrolyzed egg white were evaluated. The membrane filtration technology was chosen to be used for desalting. The results showed that ultra filtration by the molecular mass cutoff 10000 was suitable for egg white, the desalinization rate was 83.81%, and the protein retention was 86.1%. And the nanofiltration and electro dialysis were suitable for hydrolyzed product, the desalinization rate and protein retention of nanofiltration could reach 94.3% and 84.27% using NF-90 at pH=3.2. The desalinization rate and protein retention of electro dialysis could reach 96.69% and 71.4% at pH=4.2.