enlarged as present trends appear to indicate, then the possibility of 

 using salmon milt more extensively seems excellent. This use will be 

 dealt with more fully under the section of this repxsrt devoted to a dis- 

 cussion of amino acid production from salmon cannery waste. 



Protein Hydrolysates 



Chenical nature 



Protein hydrolysates, as the name implies, are a mixture of sub- 

 stances, mainly amino acids, resulting from the hydrolysis of proteins. 

 This hydrolysis can be accomplished by several well known methods. Pro- 

 teins can be hydrolyzed by digestion at a suitable temperature with acid, 

 alkali, or enzymes. Each method possesses certain advantages and disad- 

 vantages. Digestion with acid causes destruction of tryptophane, an essen- 

 tial amino acid, which if lost during processing, must be added to the 

 hydrolysate before the material would be considered nutritionally adequate. 

 Hydrolysis of proteins with alakli causes a racemization of most of the 

 amino acids resulting in a hydrolysate of much lower nutritional value. 

 Enzymatic hydrolysis of proteins results in a product of excellent nu- 

 tritive characteristics, but the process must be carried out under care- 

 fully controlled conditions. The complete hydrolysis of proteins by en- 

 zymes without the concomitant formation of pyrogens — substances that are 

 dangerous in parenteral or intravenous solutions — is difficult if not im- 

 possible to accomplish without resorting to very expensive processing pro- 

 cedures. 



Uses 



Protein hydrolysates are used in medicine for feeding patients vrtio 

 cannot or should not take the whole protein. Hydrolysates are administered 

 both parenterally and orally. Parenteral administration is used with 

 patients unable to ingest protein because of gastro- intestinal disease or 

 gastric surgery, and in bum and fracture cases where sufficient piotein 

 cannot be eaten. Hydrolysates for intravenous injection must be very 

 carefully produced to be free from pyrogens and antigens while oral prepa- 

 rations need not meet such rigid standards of purity. 



Protein hydrolysates are also used to some extent in the preparation 

 of microbiological culture media and for the production of antibiotics and 

 other substances. 



In addition to the uses described above, protein hydrolysates also 

 have been used to add a "meaty" flavor to various foods, such as soup 

 mixes and soup stocks. 



Present sources of raw material. 



At the present time the majority of the protein hydrolysate products 

 are prepared from ctsein and lactalburain. 5ome of these preparations are 



Ik 



