Study On Collagen From Body Wall And Lipid From Visceral Of Starfish(Asterina Pectinifera)

Starfish what maks a great harm to the coastal economic shellfish aquaculture is the ocean common echinoderms and rich in resources,but ferity,specially with oysters,scallops and abalone Marine products for food.We can turn waste into wealth with the development and utilization of starfish effectively.This thesis investigated the fat from Asterina visceral and the pepsin-soluble collagen(PSC)prepared from the body wall of Asterina,for starfish's processing and utilization.The basic nutrient components were analyzed and determined in different parts of Asterina pectinifera(the whole body,the body wall and viscera).PSC were extracted from the body wall of Asterina with yield of 6.11%;Glycines of PSC from the mantle of abalone were 32.9%.Hydroxylation ratios of proline(HDP)in PSC from abalone were 45.5%.The maximum absorption wavelength of PSC in the near ultraviolet region was 232 nm;SDS-PAGE showed that PSC from the body wall of Asterina had two a chain,The molecular masses of the collagen subunits were about 140 kDa;Native collagen gave a characteristic CD(circular dichroism)spectrum with a positive extreme at 220 nm and a negative peak appeared at 196 nm,which was typical of the collagen triple-helix structure.The denaturation temperature(Td)of PSC from the body wall of Asterina was about 23.0?.PSC from the body wall of Asterina had a poor oil absorbency(15.7%)and rich emulsion(98.9%).Asterina pectinifera visceral was hydrolyzed by four proteases including neutral protease,alkali protease,papain and trypsin,respectively.The results showed the optimum conditions hydrolyzed by neutral protease when solid-liquid ratio at 1:4,pH at 7.0,temperature at 45?,and hydrolysis time at 3 h.The optimum conditions hydrolyzed by alkali protease when solid-liquid ratio at 1:4,pH at 8.0,temperature at 45?,and hydrolysis time at 3.5 h.The optimum conditions hydrolyzed by papain when solid-liquid ratio at 1:4,pH at 7.5,temperature at 50?,and hydrolysis time at 3 h.The optimum conditions hydrolyzed by trypsin when solid-liquid ratio at 1:3,pH at 8.0,temperature at 45?,and hydrolysis time at 3 h.The optimum conditions of the Asterina visceral lipid recovering were that:neutral protease when solid-liquid ratio at 1:5,pH at 7.0,temperature at 50?,and hydrolysis time at 3 h;alkali protease when solid-liquid ratio at 1:5,pH at 8.0,temperature at 55?,and hydrolysis time at 3 h;papain when solid-liquid ratio at 1:5,pH at 7.0,temperature at 50?,and hydrolysis time at 3 h;trypsin when solid-liquid ratio at 1:5,pH at 8.0,temperature at 45?,and hydrolysis time at 3 h.The results showed that enzyme-assisted aqueous extraction allowed recovering 6.86%?6.11%?8.0%and 5.5%of Asterina visceral lipid from the sample hydrolyzed by neutral protease,alkali protease,papain and trypsin,respectively.PUFA was the chief component which accounts for approximately 40.83%-50.45%of the total fatty acid.Eicosapentaenoic acid(EPA)and docosahexaenoic acid(DHA)together composed about 27.83%-36.62%of the total fatty acid.