Studies On The Enzymatic Preparation Of Antioxidative Peptides From Sea Cucumber

The sea cucumber had the advantages of low fat, high protein, which had beenseen as health food and nutrition food. Sea cucumber was eaten for its edible musclebands and body wall, and the remaining tissues and organs were discarded. However,these discarded by-products can become a good source of protein and active products.The number of sea cucumber species worldwide was about1,250, among which onlyabout40kinds could be edible. Most of the sea cucumbers were underutilized becauseof poor taste, but their protein content was not lower than that of edible sea cucumber,which could also be a good source of protein.This paper explored the protease enzymolysis optimum process conditions ofStichopus horrens by-products (visceral protein) and the low value sea cucumberAcaudina leucoprocta respectively, including enzyme screening, single factorexperiment design and the center combination experimental design method, the degreeof hydrolysis, DPPH radical scavenging activity (DRSA value) and Vitamin CEquivalent Antioxidant Capacity (VCEAC value) as an index, The amino acidcomposition and molecular weight distribution of enzymolysis products obtained byoptimal conditions were determined. The enzymolysis products were separated,through ultrafiltration, and the antioxidant activities of each composition weredetermined.1. Research on Enzymatic Hydrolysis of Stichopus horrens visceral1) The sea cucumber (Stichopus horrens) visceral was hydrolyzed with one of fiveproteases (Alcalase, Protamex, Flavourzyme, Neutrase, and Papain) in order togenerate peptides with a highest degree of hydrolysis (DH) or antioxidant capacity.The antioxidant activity of hydrolysates was measured by ABTS and DPPH method.Protamex hydrolysate was found to have the greatest DH and DPPH radicalscavenging activity (DRSA), Papain hydrolysate was found to have the greatestVitamin C Equivalent Antioxidant Capacity (VCEAC) by ABTS method.2) Single factor experimental design and central composite design were used tooptimize the conditions for enyzmatic hydrolysis of Stichopus horrens visceral proteinby Protamex. The results revealed that the optimum enzymatic condition for hydrolysiswas found to be: temperature52.18oC, pH6.69, enzyme dosage2.5g/100g, andreaction time10h. Under these conditions, DH was48.6542%. Central compositedesign was used to optimize the conditions for enyzmatic hydrolysis of Stichopushorrens visceral protein by Protamex. The results revealed that the optimum enzymatic condition for hydrolysis was found to be: temperature47.63oC, pH6.49, enzymedosage1.75g/100g, and reaction time5.63h. Under these conditions, DRSA was50.80%. Central composite design was used to optimize the conditions for enyzmatichydrolysis of Stichopus horrens visceral protein by Papain. The results revealed thatthe optimum enzymatic condition for hydrolysis was found to be: temperature50.19oC,pH8, enzyme dosage2.5g/100g, and reaction time9h. Under these conditions,VCEAC was0.2533μmol/g.3) The enzymolysis products obtained by optimal conditions mostly focused onthe molecular weight of the below2000Da. The enzymolysis products of Stichopushorrens visceral obtained by optimal conditions with degree of hydrolysis, DRSA andVCEAC value as an index, the proportion of the molecular weight under2000Da,respectively,94.12%,90.08%and99.52%. From raw material amino acid compositionanalysis result of protein and enzyme solution product, the enzyme solution before andafter enzymolysis of amino acids in amino acid composition basically remainunchanged, the kind and content of the enzyme solution without change of amino acids,and make the protein chain segment fracture into smaller peptides.2. Research on Enzymatic Hydrolysis of Acaudina leucoprocta1) The sea cucumber (Acaudina leucoprocta) was hydrolyzed with one of fiveproteases (Alcalase, Protamex, Flavourzyme, Neutrase, and Papain) in order togenerate peptides with a highest degree of hydrolysis (DH) or antioxidant capacity.The antioxidant activity of hydrolysates was measured by ABTS and DPPH method.Alcalase hydrolysate was found to have the greatest DH and DPPH radical scavengingactivity (DRSA), Papain hydrolysate was found to have the greatest Vitamin CEquivalent Antioxidant Capacity (VCEAC) by ABTS method.2) Single factor experimental design and central composite design were used tooptimize the conditions for enyzmatic hydrolysis of Acaudina leucoprocta protein byAlcalase. The results revealed that the optimum enzymatic condition for hydrolysiswas found to be: temperature60oC, pH7.63, enzyme dosage2.5g/100g, and reactiontime3.81h. Under these conditions, DH was52.44%. Central composite design wasused to optimize the conditions for enyzmatic hydrolysis of Acaudina leucoproctaprotein by Papain. The results revealed that the optimum enzymatic condition forhydrolysis was found to be: temperature60oC, pH6.28, enzyme dosage2.16g/100g,and reaction time5h. Under these conditions, DRSA was43.099%. Centralcomposite design was used to optimize the conditions for enyzmatic hydrolysis ofAcaudina leucoprocta protein by Alcalase. The results revealed that the optimumenzymatic condition for hydrolysis was found to be: temperature60oC, pH8.28, enzyme dosage2.5g/100g, and reaction time10h. Under these conditions, VCEACwas0.21203μmol/g.3) The enzymolysis products obtained by optimal conditions mostly focused onthe molecular weight of the below2000Da. The enzymolysis products of Acaudinaleucoprocta obtained by optimal conditions with degree of hydrolysis, DRSA andVCEAC value as an index, the proportion of the molecular weight under2000Da,respectively,98.55%,97.05%and94.85%. From raw material amino acid compositionanalysis result of protein and enzyme solution product, the enzyme solution before andafter enzymolysis of amino acids in amino acid composition basically remainunchanged, the kind and content of the enzyme solution without change of amino acids,and make the protein chain segment fracture into smaller peptides.