| Hemoglobin is a valuable ingredient of porcine blood. It accounts for two thirds protein of whole blood and more than ninety percent that of blood corpuscle. It is testified that small peptides are suitable for patients with assimilation problems, fit for allergic persons they can prevent from anaphylaxis induced by intact proteins; They are in favor of absorption of mineral nutrition; Some small peptides have immune activity, et al. Iron deficiency and anemia are the most common malnutrition in the world, also grave in China. Heme contains Fe2+, the absorption of which is greater than ferrous salts. Heme-iron is not dependent upon dietary composition and produces little side effects, so it is a perfect hematinic. Peptides would maintain heme in a soluble form within wide pH range (2-12) when peptides and heme co-exist, which can enhance the absorption and bioavailability of heme-iron. Most of porcine hemoglobin is a waste of agricultural and food processing, the investigation on the product of heme-enriched peptides hydrolyzed from porcine hemoglobin can not only converts the waste to the usefulness, but also prevents the harm caused by porcine hemoglobin immediately ejected into circumstance. Therefore, the investigation is greatly ecologically meaningful and economically valuable.In order to find the best conditions of enzymatic hydrolysis, an orthogonal test was adopted to investigate enzyme species, substrate concentration, enzyme concentration and hydrolysis time. Total nitrogen, amino nitrogen, degree of hydrolysis, recycle rate of protein and heme were measured. The results showed that choosing papain or neutral protease, 10% or 8% of substrate concentration, 4000U/g of enzyme concentration, 13h of hydrolysis time, were optimal conditions of enzymatic hydrolysis of porcine hemoglobin.To further improve the effect of enzymatic hydrolysis of porcine hemoglobin, a hydrolysis was conducted by the combinative enzyme of papain and neutral protease. The influences of substrate concentration, proportion of enzymes, pH and temperature on degree of hydrolysis, hemochrome, total nitrogen, recycle rate of protein, aminonitrogen were investigated. The results showed that the influence of substrate concentration was the most obvious, and 8% of substrate concentration was the best level. Both pH7.0 and pH7.5 could be fit for papain and neutral protease, but pH7.5 seemed to be better. The best temperature was 55C, and the proportion of enzymes was the least important factor, which could be determined by the practical instance.In order to explore the application of membrane technology to the clarification and concentration of porcine hemoglobin hydrolysate, the characters of ceramic membrane and ultrafiltration membrane , in the course of clarification and concentration, were investigated, so did the changes of content of peptidic protein, heme, amino nitrogen. It was shown that the effect of ceramic membrane on enzymatic hydrolysate was good, and most of protein, amino nitrogen, heme were acquired. Though a certain loss existed, it could be reduced by increasing the volume of solution to be filtered. The retaining rate of protein by 3500D ultrafiltration was high, and the multiple of concentration on heme was bigger than on amino nitrogen, showing that the application of membrane technology to clarify and condense the enzymatic hydrolysate of porcine hemoglobin was effective.To explore the application area of enzymatic hydrolysate of porcine blood, the best conditions of decolorizing such thing with activated charcoal were investigated. With various temperature, pH, amount of activated charcoal used, time for decolorizing, the effect of decolorizing and loss rate of protein were measured to determine the optimum parameters. The results in the experiment showed that under such conditions as 3.0% of activated charcoal used, pH4, 70C of temperature, 1h of time, the enzymatic hydrolysate of porcine blood were decolorized effectively, and remained high nutritional value.
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