Studies On The Physical Character Of Collagen Of A Kind Of Sea Cucumber And Some Bioactivities Of The Peptides From The Collagen

The components of a low value sea cucumber(Paracaudina chinens var.) , extraction of collagen from the sea cucumber, and its properties , the conditions of the enzymatic hydrolysis and purification, and some bioactivities of the peptides from collagen of the sea cucumber were researched.Three different methods were applied in extracting collagen from sea cucumber according to the properties of the sea cucumber collagen. The experimental results show that it can't obtain collagen with acid. And it has an obvious difference with other marine animals that the sea cucumber collagen is difficult to be obtained by pepsin extraction method when it performed at low temperature. Extraction method with pepsin and hot water were applied to obtain the collagen. Extraction yield of collagen was 29.2% and 27.4% respectively. The result shows that it hasn't significant difference of the two methods from the view of yield, but pepsin extraction method is time-consuming. So hot water extraction method is established to the extracting collagen from the sea cucumber.There is certain difference of the properties of the collagen extracted by different methods. The viscosity of collagen solution is increased by increase of its concentration and decrease of temperature. However the viscosity of hot water-soluble collagen is higher than that of pepsin-soluble collagen.To hydrolyze the sea cucumber collagen, four proteases are used as follows:3942 neutral proteinase, trypsin, papain, bromelain. The results indicate that 3942 neutral proteinase and bromelain have a stronger hydrolytic activity to the collagen. 3942 neutral proteinase has broad-spectrum hydrolytic property and it make against the separation and purification of the hydrolysate. Moreover bromelian has certain specificity and mainly hydrolyzes the Lys-, Arg-, Phe- and Tyr- carboxyl end ofproteins peptide and amide. So bromelian is choosed to apply in the experiment.The conditions for the hydrolytic reaction are determined by the orthogonal test based on the single-facter test of the hydrolysis of the sea cucumber collagen. The conditions are optimized through the detection of the activity of scavenging Or' by hydrolysate. The results show that the optimal reactive temperature, enzyme dosage, concentration of substrate, pH and time is : 40°C, 0.8%, 18mg/100ml, pH5.2, 4h, respectively. And it is about 52.20% of the scavenging ratio on O2" of the hydrolysate prepared at this condition.The activity of scavenging (V and -OH by hydrolysate of sea cucumber collagen is detected by PR self-oxidize method and salicylic acid method. And the hydrolysate is separated and purified using the ultrafiltrate and Sephadex G-25. The result shows that the high active components are mainly peptides of low molecular weight. The mixture of peptides is passed through Sephadex G-25 after ultrafiltrate, and four elution peaks are obtained. There is almost no peptides in peaklll and peaklV. There is certain activity of scavenging radical of peaki and peakll .The scavenging ratio on O2-" and OH is 3.86% and 29.20% respectively, and the scavenging ratio on OH is 58.42% and 75.41% , respectively.The rabbit liver mitochondria free radical damage model is applied to further study of its activity. The result shows that the peptides from sea cucumber collagen can prevent the damage of rabbit liver and the mitochondria.