Protein hydrolysates enriched in peptides having a carboxy terminal proline residue

Abstract

A method of enzymatically producing a protein hydrolysate from a protein substrate is described, wherein a proline-specific endoprotease or a composition containing a proline-specific endoprotease and optionally a subtilisin or a metallo endoprotease, and other enzymes such as carboxypeptidases, is used to produce a protein hydrolysate enriched in peptide fragments having a carboxy-terminal proline residue. Such protein hydrolysates may be used as such or to reduce bitterness in foods nutritionally supplemented by protein hydrolysates, as well as to produce hydrolysate-containing foodstuffs having low antigenicity.

1 - 21 . (canceled) 
     
     
         22 . An enzyme composition comprising a proline-specific endoprotease, the composition being capable of producing a protein hydrolysate comprising peptides, wherein the molar fraction of peptides (%) carrying a carboxy terminal proline is at least two times the molar fraction (%) of proline in the protein 
     
     
         23 . The enzyme composition according to  claim 22 , wherein the composition further comprises is a serine or a metalloendoprotease or a combination of serine and metalloendoproteases. 
     
     
         24 . (canceled) 
     
     
         25 . The enzyme composition according to  claim 23 , wherein the composition further comprises at least subtilisin and carboxypeptidase. 
     
     
         26 . A method of enzymatically producing a protein hydrolysate from a protein substrate, which method comprises incubating the protein substrate with a proline specific endoprotease and one or more other endoprotease(s), either sequentially or concomitantly, in amounts sufficient to produce a protein hydrolysate which comprises peptides, wherein the molar fraction (%) of peptides carrying a carboxy terminal proline is more than two times the molar fraction (%) of proline in the protein substrate used to generate the protein hydrolysate. 
     
     
         27 . The method according to  claim 26 , wherein said incubating with the proline specific endoprotease is performed sequentially to incubating with the other endoprotease(s). 
     
     
         28 . The method according to  claim 26 , wherein said incubating with the proline specific endoprotease is performed concomitantly to incubating with the other endoprotease(s). 
     
     
         29 . The method according to  claim 26 , wherein the proline specific endoprotease has a pH optimum below 7. 
     
     
         30 . The method according to  claim 26 , wherein the other endoprotease(s) is a serine or a metalloendoprotease or a combination of serine and metalloendoproteases. 
     
     
         31 . The method according to  claim 30 , wherein the other endoprotease(s) is a combination of subtilisin and carboxypeptidase. 
     
     
         32 . The method according to  claim 26  further comprising recovering the protein hydrolysate without ultrafiltration or microfiltration. 
     
     
         33 . The method according to  claim 26 , wherein the molar fraction (%) of peptides carrying a carboxy terminal proline in the protein hydrolysate is more than three times the molar fraction (%) of proline in the protein substrate. 
     
     
         34 . The method according to  claim 26 , wherein the proline specific endoprotease is employed at at least 150 milli-units per gram protein substrate. 
     
     
         35 . The method according to  claim 26 , wherein the average length of peptides is from 3 to 9 amino acids. 
     
     
         36 . The method according to  claim 26 , wherein at least 10% of the protein substrate is hydrolyzed into peptides having molecular masses from 400 to 2000 Dalton. 
     
     
         37 . The method according to  claim 26 , wherein the molar fraction of peptides carrying a carboxy terminal proline is from 30 to 70%. 
     
     
         38 . The method according to  claim 26 , wherein the protein substrate is whey and the molar fraction of peptides carrying a carboxy terminal proline is at least 8%. 
     
     
         39 . The method according to  claim 26 , wherein the protein substrate is casein and the molar fraction of peptides carrying a carboxy terminal proline is at least 25%. 
     
     
         40 . The method according to  claim 26 , wherein the protein substrate is soy and the molar fraction of peptides carrying a carboxy terminal proline is at least 20%. 
     
     
         41 . The method according to  claim 26 , wherein the protein substrate is gluten and the molar fraction of peptides carrying a carboxy terminal proline is at least 20%. 
     
     
         42 . The method according to  claim 26 , wherein the protein substrate is barley and the molar fraction of peptides carrying a carboxy terminal proline is at least 20%.