being made fran soy bean protein, others are from blood fibrin, and some 

 are being made frcan fish proteins such as those of tuna or mackerel. Pro- 

 teins to be used for the preparation of hydrolysates for human consiomption 

 must meet certain standards of purity. Specifications have been established 

 for various proteins limiting the amount of moisture, fat and ash that 

 may be jsresent. A typical example of acceptable material was given in the 

 section on methods of manufacture under pix>teins. 



Methods of manufacture 



Protein hydrolysates are at present being manufactured by the acid 

 hydrolysis and the enzymatic digestion methods. The acid hydrolysis m^hod 

 yields a product which has a reduced tryptophane content and the customairy 

 practice is to supplement the preparation with the sjnithetic form of the 

 amino acid, tryptophane. Since the synthetic tryptophane is only 50 per- 

 cent active biologically, it is necessary to add double the amount required 

 to bring the tryptophane content up to the level that was present in the 

 original protein from which the hydrolysate was prepared. Since the 

 amino acid tryptophane is compairatively expensive, this required supple- 

 mentation adds considerably to the cost of the finished product. 



Enzymatic hydrolysis is usually carried out by subjecting a solution 

 of the protein (casein is most widely employed) to the action of the enzymes 

 present in the ground tissue of mammal pancreas. The digestion is allowed 

 to proceed until the proteins are reduced largely to amino acids and to a 

 lesser extent to small polypeptides. If the final product is to be used 

 intravenously, extreme care must be taken to avoid the formation of pyrogens 

 during the processing. Pyrogens are substances, presumkbly carbohydrate 

 in nature and formed by bacterial action, which ^en injected into the blood 

 stream cause undesirable reactions and an increase in body temperature. 



Economics of manufacture 



Protein hydrolysates are being widely used in medicine. Both oral 

 and parenteral preparations enjoy a large market. However, the supply of 

 these products appears to be more than adequate for the demand with can- 

 petition at present between more than two dozen different market prepa- 

 rations. The cost of the raw protein material, even though seemingly ex- 

 pensive when viewed by itself, actually represents only a fraction of the 

 cost of the finished articlei For example, the hydrolysate solutions 

 when marketed usually contain only five percent of the hydrolyzed pro- 

 tein, but because of the expense involved in the extensive testing, both 

 laboratory and clinical, in addition to high marketing and promotion ex- 

 penses, the final coat bears little relation to the cost of the basic 

 ingredients . 



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