Colour reduction in canola protein isolate

Abstract

In the recovery of canola protein isolates from canola oil seeds steps are taken to inhibit the formation of colouring components and to reduce the presence of materials tending to form colouring components, to obtain a lighter and less yellow canola protein isolate.

1 .- 13 . (canceled) 
     
     
         14 . A process of preparing a canola protein isolate from canola oil seed meal, which comprises:
 (a) extracting the canola oil seed meal and to cause solubilization of the protein in the canola oil seed meal to form an aqueous protein solution having a pH of about 5 to about 6.8 by using an aqueous salt solution containing an antioxidant,   (b) separating the aqueous protein solution from residual oil seed meal,   (c) increasing the protein concentration of said aqueous protein solution while maintaining the ionic strength substantially constant by use of a selective membrane technique to provide a concentrated protein solution,   (d) diluting said concentrated protein solution into chilled water having a temperature of below about 15° C. to cause the formation of discrete protein micelles in the aqueous phase,   (e) settling the protein micelles to form an amorphous, sticky, gelatinous, gluten-like protein micellar mass, and   (f) recovering the protein micellar mass from supernatant as said canola protein isolate, the protein micellar mass having a protein content of at least 90 wt % (N×6.25) on a dry weight basis.   
     
     
         15 . The process of  claim 14  wherein said antioxidant is sodium sulfite or ascorbic acid. 
     
     
         16 . The process of  claim 15  wherein said antioxidant is present in said aqueous salt solution in an amount of about 0.01 to about 1 wt %. 
     
     
         17 . The process of  claim 14  wherein said canola oil seed meal is canola oil seed meal which has been air desolventized at a temperature of below about 50° C. to remove residual oil extraction solvent. 
     
     
         18 . The process of  claim 14  wherein said canola oil seed meal is canola oil seed meal which has been desolventized at an elevated temperature below about 100° C. to remove residual oil extraction solvent. 
     
     
         19 . A process of preparing a canola protein solution from canola oil seed meal, which comprises:
 (a) washing said canola oil seed meal with an alcohol,   (b) extracting the washed canola oil seed meal to cause solubilization of the protein in the washed canola oil seed meal to form an aqueous protein solution having a pH of about 5 to about 6.8,   (c) separating the aqueous protein solution from residual oil seed meal,   (d) increasing the protein concentration of said aqueous protein solution while maintaining the ionic straight substantially constant by use of a selective membrane technique to provide a concentrated protein solution,   (e) diluting said concentrated protein solution into chilled water having a temperature of below about 15° C. to cause the formation of discrete protein micelles in the aqueous phase,   (f) settling the protein micelles to form an amorphous, sticky, gelatinous, gluten-like protein micellar mass, and   (g) recovering the protein micellar mass from supernatant as said canola protein isolate, the protein micellar mass having a protein content of at least 90 wt % (N×6.25) on a dry weight basis.   
     
     
         20 . The process of  claim 16  wherein the alcohol is ethanol. 
     
     
         21 . The process of  claim 19  wherein said washing step is effected by dispersing the canola oil seed meal in solvent at a w/v ratio of about 1:3 to about 1:10, stirring the resulting slurry for about 5 to about 60 minutes at a temperature of about 15° to about 45° C., and separating the washed canola oil seed meal from the slurry. 
     
     
         22 . The process of  claim 21  wherein said slurry is stirred for about 15 to about 30 minutes at a temperature of about 30 to about 75° C. 
     
     
         23 . The process of  claim 19  wherein said washing effected a multiple number of times until no additional phenolics and/or visible colour is recovered. 
     
     
         24 . The process of  claim 19  wherein said canola oil seed meal is canola oil seed meal which has been air desolventized at a temperature of below about 50° C. to remove residual oil extraction solvent. 
     
     
         25 . The process of  claim 19  wherein said canola oil seed meal is canola oil seed meal which has been desolventized at an elevated temperature below about 100° C. to remove residual oil extraction solvent. 
     
     
         26 .- 54 . (canceled) 
     
     
         55 . A process of preparing a canola protein isolate from canola oil seed meal, which comprises:
 (a) extracting the canola oil seed meal to cause solubilization of the protein in the canola oil seed meal to form an aqueous protein solution having a pH of about 5 to about 6.8,   (b) separating the aqueous protein solution from the residual oil seed meal,   (c) increasing the protein concentration of said aqueous protein solution while maintaining the ionic strength substantially constant by use of a selective membrane technique to form a concentrated protein solution,   (d) diluting said concentrated protein solution into chilled water having a temperature below about 15° C. to cause the formation of discrete protein micelles in the aqueous phase,   (e) settling the protein micelles to form an amorphous, sticky, gelatinous, gluten-like protein micellar mass,   (f) separating the protein micellar mass from supernatant,   (g) drying the protein micellar mass to provide a canola protein isolate having a protein content of at least 90 wt % (N×6.25) on a dry weight basis, and   (h) extracting said canola protein isolate with an aqueous alcoholic solution.   
     
     
         56 . The process of  claim 55  wherein said aqueous alcoholic solution is an aqueous ethanol solution having a volume ratio of ethanol:water of about 2:1 to about 1:2. 
     
     
         57 . The process of  claim 55  wherein said extraction step is effected by dispersing the canola protein isolate in the aqueous alcoholic solution in an amount of about 5 to about 25 wt %, mixing the resulting slurry for about 30 to about 60 minutes, and separating the extracted canola protein isolate from the slurry. 
     
     
         58 . The process of  claim 55  wherein said extraction step is repeated until no additional phenolics and/or invisible colourants are removed from the canola protein isolate. 
     
     
         59 . A process of preparing a canola protein isolate from canola oil seed meal, which comprises:
 (a) extracting the canola oil seed meal to cause solubilization of the protein in the canola oil seed meal to form an aqueous protein solution having a pH of about 5 to about 6.8,   (b) separating the aqueous protein solution from residual oil seed meal,   (c) increasing the protein concentration of said aqueous protein solution while maintaining the ionic strength substantially constant by use of a selective membrane technique to provide a concentrated protein solution,   (d) pasteurizing the concentrated protein solution to form a pasteurized protein solution,   (e) diluting the pasteurized protein solution into chilled water having a temperature below about 15° C. to cause the formation of discrete protein micelles in the aqueous phase,   (f) settling the protein micelles to form an amorphous, sticky, gelatinous, gluten-like protein micellar mass, and   (g) recovering the protein micellar mass from supernatant as said canola protein isolate, the protein micellar mass having a protein content of at least 90 wt % (N×6.25) on a dry weight basis.   
     
     
         60 . The process of  claim 59  wherein said pasteurization is effected by heating the concentrated protein solution at a temperature of about 55° to about 70° C. for about 10 to about 15 minutes. 
     
     
         61 . The process of  claim 60  wherein said concentrated protein solution is heated at a temperature of about 60° to about 65° C. for about 10 minutes. 
     
     
         62 . A process of preparing a canola protein isolate from canola oil seed, which comprises:
 (a) treating canola oil seeds to inactivate myrosinases contained in the oil seeds to produce treated oil seeds,   (b) processing said oil seeds to remove canola oil therefrom and produce a canola oil seed meal,   (c) extracting the canola oil seed to cause solubilization of the protein in the canola oil seed to form an aqueous solution having a pH of about 5 to about 6.8,   (d) separating the aqueous protein solution from residual oil seed meal,   (e) increasing the protein concentration of said aqueous protein solution which maintaining the ionic strength substantially constant by use of a selective membrane technique to provide a concentrated protein solution,   (f) diluting the concentrated protein solution into chilled water having a temperature below about 15° C. to cause formation of discrete protein micelles in the aqueous phase,   (g) settling the protein micelles to form an amorphous, sticky, gelatinous, gluten-like protein micellar mass, and   (h) recovering the protein micellar mass from supernatant, the protein micellar mass having a protein content of at least 90 wt % of (N×6.25) on a dry weight basis.   
     
     
         63 . The process of  claim 62  wherein the canola oil seed meal is air-desolventized at a temperature below about 50° C. to remove residual oil extraction solvent prior to said extracting step. 
     
     
         64 . The process of  claim 62  wherein the canola oil seed is desolventized at an elevated temperature below about 100° C. to remove residual oil extraction solvent prior to said extracting step.