Preparation Of Scallop Antioxidant Peptides By Papain Immobilized On Mesoporous Materials

With the increasing demand for the functional foods and health care products,the antioxidant peptides coming from marine organisms and their processingby-products hold tremendous potential in the development of functional foods, basedon its capability to remove free radicals and chelate metal ions, its safe edibility andits low cost of production. Scallop is important marine mollusk of our country. Withits abundant resources and variable health care functions, it is the significant sourceof marine bioactive peptides. Mesoporous materials become great system for enzymeimmobilization because of its highly ordered open-framework structure andrelatively large specific surface area. Here, the home-made mesoporous materialswere adopted to immobilize papain and applied immobilized enzyme to processscallop proteins to generate anti-oxidative peptides, in order to provide reference forproduction of highly valued marine active polypeptide. Using home-mademesoporous material MCM-41to generate immobilized enzymes and analyzed thecharacteristics of immobilized enzymes and the optimum condition for enzymolysis.Taken together, the immobilized enzyme membrane reactor was applied to generatemarine active polypeptides.The contribution of this paper including:First, mesoporous material MCM-41with the free hydroxyl groups in its poreswere prepared, employed the electronic microscope and Fourier infrared spectrum tocharacterize the materials, and accomplished amino and hydroxyl modification ofMCM-41, synthesized the large MCM-41mesoporous materials with a diameter ofapproximately80μm, well spherical structure, and pore distribution of its tunnels.Second, the immobilization of papain on MCM-41, N-MCM-41, C-MCM-41and L-MCM-41were studied. With enzyme activity as indicator, the capability ofL-MCM-41to immobilize the enzyme is much better than the other materials wasfounded. The activity recovery of immobilized papain can reach82.79%. L-MCM-41 was chosen as carrier and confirmed the optimal conditions through orthogonal tests(the quality ratio between enzyme and mesoporous material is1:0.25, pH7.6, theconcentration of pentanediol is1%, and the concentration of activator is40mmol/Lhomocysteine and2mmol/L EDTA). Based on the characteristics of the immobilizedenzyme, its optimal enzymatic condition is: pH7.0and at the temperature of70°C.This will provide technical support for the industrial application of L-MCM-41immobilized enzyme in the mollusk polypeptide enzymolysis.Third, the techniques of generating antioxidant peptides through digestingscallop proteins by protease were optimized. With clearance rate of OH and DPPHas indicators, the time of enzymolysis reduced from16h to7h, shortening theexperimental period and improving the efficiency. Through testing the antioxidantactivity of different molecular weight peptide hydrolysised by free protease andimmobilized protease, it concluded that the peptide with a molecular weight less than1kDa possess the strongest antioxidant activity with a strongest capability ofremoving OH (IC50=1.87mg/mL) and DPPH (IC50=0.77mg/mL);Thus, the scallop antioxidant peptides generated by papain immobilized onL-MCM-41possessed a higher anti-oxidative activity, providing reference for thefurther industrial production.