Enzymatic Hydrolysis Of Porcine Hemoglobin And Antioxidant Activity Of Its Hydrolysate

China is a big meat process country and has an abundant byproduct blood in which only porcine blood can generate 1.3 million tons annually. Animal blood is richly containing hemoglobin in the blood cells which represents 70-80% of the protein content of blood and also includes contains hematin. However, due to the taste and the color only a little blood was consumed directly by people and the other larger amounts was used as feedstuff. Further more, blood is still can not be digested and absorbed easily for the problem of low bioavailability. This work used hemoglobin as resources, researching optimal conditions and some intrinsic mechanisms of enzymatic hydrolysis of hemoglobin, decoloring the hydrolysate and extracting hematin, valuing the flavor and antioxidant activity of the hydrolysate and the decolorized for supporting the theory and technology of enzymic hydrolysis of hemoglobin, decolorization, extraction of hematin, and utilization of the product.The composition of porcine hemoglobin showed it had high content of protein, low content of fat and low calorie. Therefore, porcine hemoglobin was a good substrate for hydrolysis. Hemoglobin was hydrolyzed by one protease just obtaining relatively low protein regovery (PR). Freeze, ultrasonic and homogenization can hemolyze blood cells and increase PR of hydrolysis for 5-7%. Both of the enzyme admixtures, Pancreatin and Protamex (PP) as well as Pancreatin and Flavourzyme (PF), hydrolyzed hemoglobin got high PR about 95%. And moreover, the hydrolysates had no bitter taste. The both of the enzyme admixtures had specificity for terminal a variety of hydrophobic amino acids and thus reduced the bitter taste of the product. The Q value of the hydrolysate was in agreement with the results of taste, so the Q rule can be direct the practice. During hydrolysis of hemoglobin by the both enzyme admixtures, the product aggregated leading to decrease PR.Though adsorbent can adsorb pigment it was not critical factor for decoloring. pH significantly influence the result of decolorization. Pigments flocculated and precipitated between themselves during process leading to decolorization. Pigment formed clathrate hydrates for the sake of hydrophobic interaction and further aggregated to bigger clathrate hydrates which can be removed by centrifuge. Decolorization reduced the hydrophobicity of peptides and improved the flavor of product. Hydrolysis and decolorization can promote the nutritional value of hemoglobin. Freeze can enrich and concentrate hematin.The hydrolysate and its decolorized of PF and PP had DPPH radical scavenging activity, reducing power and ferrous ion chelating activity, and the activity of the former hydrolysate was stronger than that of the latter. No relativity between the degree of hydrolysis and the above mentioned antioxidant activity which can be depressed by decolorization. In contrast, copper ion chelating activity, which can be improved by decolorization, of the hydrolysate of PF was weaker that of PP.The hydrolysate and its decolorized of PF and PP restrained lipid peroxidation in the linoleic acid system, and the antioxidant activity, which was also can be depressed by decolorization, was increased with increasing concentration of the products. The decolorized of PF inhibited lipid peroxidation in Chinese Cantonese sausage, but the activity had no relation to the concentration. At higher concentration of 4%, the decolorized of PF decreased the acid value of Chinese Cantonese sausage. The activity of inhibiting lipid peroxidation and decreasing acid value of powder of spray-dried was stronger than that of liquid hydrolysate possibly due to generated new material possessing antioxidant activity.The average hydrophobicity of hydrolysate coming from PF and PP was reduced after decolorization, and the antioxidant activity of the both decolorized decreased with decreasing the hydrophobicity. No relativity was found between antioxidant activity and molecular weight of peptides; the antioxidant activity of peptide should mainly determined by amino acid composition and cube configuration. The effect of hydrophobic amino acid on constituting and maintaining the cube configuration was more important than that of hydrophilic amino acid, and so the hydrophobic amino acid influenced deeper the antioxidant activity of peptide than hydrophilic amino acid. Three categories peptides separated from hydrolysate of hemoglobin had different antioxidant activity, among which, the antioxidant activity of basic peptide was strongest, acidic peptide took second place and the neutral was weakest.