Studies On Preparation Of Collagen And Bioactivities Of Collagen Polypeptide From The Skins Of Aquatic Animals

The whole research study was aimed at investigating the preparation of collagen and bioactivities of collagen polypeptide from the skins of aquatic animals, using the skins of cod, squid and carp as raw materials of experiment. The appropriate protease and condition of hydrolysis was selected to produce collagen polypeptide.First, the study on the extraction and determination of the physicochemical characteristics of collagen from the skins of cod, squid and carp was undertaken. The molecular weight of collagen from the skins of cod, squid and carp determined by SDS-PAGE were 220kDa, 220kDa and 260kDa, respectively. The denaturation temperatures (Td) of these collagens were 24.2℃, 26.8°C and 31.9℃, respectively.Secondly, the different collagen polypeptide was prepared using different condition of enzymic hydrolysis. The collagen polypeptide which possessed radical scavenging properties was prepared under following condition: the alkaline protease Properase E was selected to hydrolyze collagen at pH 9.0, 45℃, 3 h reaction time and enzyme-to-substrate ratio of 1:50. The hydrolysates with a combination of Properase E followed pepsin showed the best radical scavenging activity. For the fragmented hydrolysates by ultratiltration using the ultratiltration membrane that molecular weight cut-off was 10k, 6k and 2kDa, the fractions that molecular weight less than 2kDa had high radical scavenging activity. The yield of collagen polypeptide under different hydrolysis condition was determined. The enzyme-to-substrate ratio was the most important factor that affected the yield. When the collagen was hydrolyzed by Properase E at pH 8.0, 55℃ and enzyme-to-substrate ratio of 4%, the highest yield was achieved.The ACE inhibitory polypeptide was prepared from skin collagen. The pepsin was selected for the proper enzymes to prepare ACE inhibitory polypeptides. The...