Potato protein isolates

Abstract

The present invention relates to a process for obtaining a potato protein fraction using a specific absorbent. Specifically, the invention relates to the carrier material, which comprises a specific polymeric material, functionalised with suitable ligands. By the use of a functionalised support carrier according to the present invention, a potato protein fraction can be obtained with higher effectiveness.

1 . A process for the isolation of a native potato protein fraction from potato juice, comprising the steps of
 a) adjusting the pH of the potato juice to 4.0-6.5;   b) contacting the potato juice with a functionalised support carrier having pores wherein at least 90% of the pores have a pore diameter between 10 and 200 nm, and wherein the carrier is functionalised with a hydrophobic, mixed-mode ligand having a pKa of 2.5-5 which ligand is coupled to the carrier through an S- or O-atom;   c) desorbing the potato protein fraction from the functionalised support carrier by elution; and   d) optionally concentrating and/or drying the potato protein fraction.   
     
     
         2 . A process according to  claim 1 , wherein elution is carried out at a pH between 5.7 and 8.9. 
     
     
         3 . A process according to  claim 2 , wherein the potato protein fraction is a patatin fraction. 
     
     
         4 . A process according to  claim 1 , wherein elution is carried out at a pH above 9 or below 3. 
     
     
         5 . A process according to  claim 4 , wherein the potato protein fraction is a protease inhibitor fraction. 
     
     
         6 . A process according to  claim 1 ,
 wherein elution is carried out with an aqueous buffer.   
     
     
         7 . A process according to  claim 1 ,
 wherein the mixed-mode ligand is chosen from the group of substituted benzoic acids, salicylic acids, nicotinic acids and naphthoic acids, whereby substitution is at an available ring position with a (CH2)n-XH group, with n=0-4 and X=S.   
     
     
         8 . A process according to  claim 1 , wherein the support carrier is a porous synthetic polymer, a porous polysaccharide, a porous inorganic material, or any combination thereof. 
     
     
         9 . A process according to  claim 1 , wherein the hydrophobic, mixed-mode ligand is attached to the support carrier through a spacer that links to the support carrier through an O or S-atom and that does not comprise nitrogen-containing functional groups. 
     
     
         10 . A process according to  claim 1 , wherein the pH of the potato juice is adjusted with acid and/or base. 
     
     
         11 . A process according to  claim 1 , wherein the potato juice has undergone a pretreatment comprising absorption of contaminants to a layered silicate and/or activated carbon and/or a flocculation. 
     
     
         12 . A native potato protein fraction obtainable by a process according to  claim 1 .