Soluble canola protein isolate production ("nutratein")

Abstract

Canola protein isolates are provided which contain both albumin and globulin protein fractions that are soluble, transparent and heat stable in an acidic aqueous environment. The canola protein isolates are completely soluble in water at low pH, low in phytic acid and useful in products for human consumption, pet foods and aquaculture.

1 . A method of producing a canola protein isolate having a canola protein content of at least about 90 wt % (N×6.25) d.b., which comprises:
 (a) extracting canola oil seed meal at a temperature of at least about 5° C. to cause solubilization of canola protein from the meal and to form an aqueous protein solution having a protein content of about 5 to about 40 g/L and a pH of about 5 to about 6.8,   (b) separating the aqueous protein solution from the spent oil seed meal,   (c) increasing the protein concentration of the aqueous protein solution to about 50 to about 250 g/L while maintaining the ionic strength substantially constant by using a selective membrane technique to provide a first concentrated protein solution,   (d) optionally diafiltering the first concentrated protein solution,   (e) adding calcium salt solution to the first concentrated and optionally diafiltered protein solution to a conductivity of about 15 to about 25 mS to cause a precipitate to form in the first concentrated protein solution,   (f) removing the precipitate from the first concentrated protein solution,   (g) diluting the clarified first concentrated protein solution with about 2 to about 20 volumes of water having a temperature of about 2° to about 90° C.,   (h) acidifying the resulting solution to a pH of about 2.5 to about 4.0 to produce an acidified clear protein solution,   (i) increasing the concentration of the acidified clear protein solution to about 50 to about 200 g/L while maintaining the ionic strength substantially constant by using a selective membrane technique to provide a second concentrated protein solution,   (j) optionally diafiltering the second concentrated protein solution, and   (k) optionally drying the second concentrated protein solution to provide a canola protein isolate having a protein content of at least about 90 wt % (N×6.25) d.b.   
   
   
       2 . The method claimed in  claim 1  wherein the calcium salt is calcium chloride. 
   
   
       3 . The method claimed in  claim 2  wherein sufficient calcium chloride solution is added to the concentrated and optionally diafiltered protein solution to provide a solution having a conductivity of about 17 to about 20 mS. 
   
   
       4 . The method claimed in  claim 1  wherein the first concentrated protein solution is diluted with about 10 to about 15 volumes of water. 
   
   
       5 . The method claimed in  claim 1  wherein the resulting solution is acidified to a pH of about 3 to about 3.5. 
   
   
       6 . A method of producing a canola protein isolate having a canola protein content of at least about 90 wt % (N×6.25) d.b., which comprises:
 (a) extracting canola oil seed meal at a temperature of at least about 5° C. to cause solubilization of canola protein from the meal and to form an aqueous canola protein solution having a protein content of about 5 to about 40 g/L and a pH of about 5 to about 6.8,   (b) separating the aqueous canola protein solution from the oil seed meal,   (c) adding calcium salt solution to the aqueous protein solution to a conductivity of about 15 to about 25 mS to cause a precipitate to form in the concentrated protein solution,   (d) removing the precipitate from the aqueous canola protein solution,   (e) increasing the protein concentration of the aqueous protein solution to about 50 to about 250 g/L while retaining the ionic strength substantially constant by using a selective membrane technique to provide a first concentrated protein solution,   (f) optionally diafiltering the first concentrated protein solution,   (g) diluting the first concentrated protein solution with about 2 to about 20 volumes of water having a temperature of about 2° to about 90° C.,   (h) acidifying the resulting solution to a pH of about 2.5 to about 4.0 to produce an acidified clear protein solution,   (i) increasing the concentration of the acidified clear protein solution to about 50 to about 250 g/L while maintaining the ionic strength substantially constant by using a selective membrane technique to provide a second concentrated protein solution,   (j) optionally diafiltering the second concentration protein solution, and   (k) optionally drying the second concentrated protein solution to provide a canola protein isolate having a protein content of at least about 90 wt % (N×6.25) d.b.   
   
   
       7 . The method claimed in  claim 6  wherein the calcium salt is calcium chloride. 
   
   
       8 . The method claimed in  claim 7  wherein sufficient calcium chloride solution is added to the aqueous protein solution to a conductivity of about 17 to about 20 mS. 
   
   
       9 . The method claimed in  claim 6  wherein the first concentrated protein solution is diluted with about 10 to about 15 volumes of water. 
   
   
       10 . The method claimed in  claim 6  wherein the resulting solution is acidified to a pH of about 3 to about 3.5. 
   
   
       11 . A method of producing a canola protein isolate having a canola protein content of at least about 90 wt % (N×6.25) d.b., which comprises:
 (a) extracting canola oil seed meal at a temperature of at least about 5° C. to cause solubilization of canola protein from the meal and to form an aqueous protein solution having a protein content of about 5 to about 40 g/L and a pH of about 5 to about 6.8,   (b) separating the aqueous protein solution from the spent oil seed meal,   (c) increasing the protein concentration of the aqueous protein solution to about 50 g/L or less while maintaining the ionic strength substantially constant by using a selective membrane technique to provide a partially concentrated protein solution,   (d) adding calcium salt solution to the partially concentrated protein solution to a conductivity of about 15 to about 25 mS to cause a precipitate to form in the partially concentrated protein solution,   (e) removing the precipitate from the partially concentrated protein solution,   (f) further increasing the protein concentration of the partially concentrated protein solution to about 50 to about 250 g/L while maintaining the ionic strength substantially constant by using a selective membrane technique to provide a first concentrated protein solution,   (g) optionally diafiltering the first concentrated protein solution,   (h) diluting the first concentrated protein solution with about 2 to about 20 volumes of water having a temperature of about 2° to about 90° C.,   (i) acidifying the resulting solution to a pH of about 2.5 to about 4.0 to produce an acidified clear protein solution,   (j) increasing the concentration of the acidified clear protein solution to about 50 to about 250 g/L while maintaining the ionic strength substantially constant by using a selective membrane technique to provide a second concentrated protein solution,   (k) optionally diafiltering the second concentrated protein solution, and   (l) optionally drying the second concentrated protein solution to provide a canola protein isolate having a protein content of at least about 90 wt % (N×6.25) d.b.   
   
   
       12 . The method claimed in  claim 11  wherein the calcium salt is calcium chloride. 
   
   
       13 . The method claimed in  claim 12  wherein sufficient calcium chloride solution is added to the aqueous protein solution to a conductivity of about 17 to about 20 mS. 
   
   
       14 . The method claimed in  claim 11  wherein the first concentrated protein solution is diluted with about 10 to about 15 volumes of water. 
   
   
       15 . The method claimed in  claim 11  wherein the resulting solution is acidified to a pH of about 3 to about 3.5. 
   
   
       16 . A method of producing a canola protein isolate having a canola protein content of at least about 90 wt % (N×6.25) d.b., which comprises:
 (a) extracting canola seed meal with an aqueous solution of a calcium salt at a temperature of at least about 5° C. to cause solubilization of canola protein from the meal and to form an aqueous canola protein solution having a protein content of about 5 to about 40 g/L and a pH of about 5 to about 6.8,   (b) separating the aqueous protein solution from the oil seed meal,   (c) diluting the aqueous protein solution with about 0.5 to about 10 volume of water having a temperature of about 2° to about 90° C.,   (d) acidifying the resulting diluted canola protein solution to a pH of about 2.5 to about 4 to produce an acidified clear protein solution,   (e) increasing the concentration of the acidified clear protein solution to about 50 to about 250 g/L while maintaining the ionic strength substantially constant by using a selective membrane technique to provide a concentrated protein solution,   (f) optionally diafiltering the concentrated protein solution,   (g) optionally drying the concentrated solution to provide a canola protein isolate having a protein content of at least about 90 wt % (N×6.25) d.b.   
   
   
       17 . The method claimed in  claim 16  wherein the calcium salt is calcium chloride. 
   
   
       18 . The method of  claim 17  wherein the aqueous solution of calcium salt herein has a concentration of less than 1.0 M. 
   
   
       19 . The method of  claim 18  wherein the aqueous solution of calcium salt has a concentration of about 0.10 to about 0.55 M. 
   
   
       20 . The method claimed in  claim 16  wherein the resulting solution is acidified to a pH of about 3 to about 3.5. 
   
   
       21 . A method of producing a canola protein isolate having a protein content of at least about 90 wt % (N×6.25) d.b., which comprises:
 (a) extracting canola oil seed meal at a temperature of at least about 5° C. to cause solubilization of canola protein from the meal and to form an aqueous protein solution having a protein content of about 5 to about 40 g/L and a pH of about 5 to about 6.8,   (b) separating the aqueous protein solution from the spent oil seed meal,   (c) increasing the protein concentration of the aqueous protein solution to about 50 g/L or less while maintaining the ionic strength substantially constant by using a selective membrane technique to provide a partially concentrated protein solution,   (d) adding calcium salt solution to the partially concentrated protein solution to a conductivity of about 15 to about 25 mS to cause a precipitate to form in the partially concentrated protein solution,   (e) removing the precipitate from the partially concentrated protein solution,   (f) diluting the partially concentrated protein solution with about 0.5 to about 20 volumes of water having a temperature of about 2 to about 90° C.,   (g) acidifying the resulting solution to a pH of about 2.5 to about 4.0 to produce an acidified clear protein solution,   (h) increasing the protein concentration of the acidified canola protein solution to about 50 to about 250 g/L while maintaining the ionic strength substantially constant by using a selective membrane technique to provide a concentrated protein solution,   (i) optionally diafiltering the concentrated protein solution, and   (j) optionally drying the concentrated protein solution to provide a canola protein isolate having a protein content of at least about 90 wt % (N×6.25) d.b.   
   
   
       22 . The method claimed in  claim 21  wherein the calcium salt is calcium chloride. 
   
   
       23 . The method claimed in  claim 22  wherein sufficient calcium chloride solution is added to the aqueous protein solution to a conductivity of about 17 to about 20 mS. 
   
   
       24 . The method claimed in  claim 21  wherein the resulting solution is acidified to a pH of about 3 to about 3.5. 
   
   
       25 . A method of producing a canola protein isolate having a canola protein content of at least about 90 wt % (N×6.25) d.b., which comprises:
 (a) extracting canola oil seed meal at a temperature of about 5° C. to cause solubilization of canola protein from the meal and to form an aqueous canola protein solution having a protein content of about 5 to about 40 g/L and a pH of about 5 to about 6.8,   (b) separating the aqueous canola protein solution from the oil seed meal,   (c) adding calcium salt solution to the aqueous protein solution to a conductivity of about 15 to about 25 mS to cause a precipitate to form in the concentrated protein solution,   (d) removing the precipitate from the aqueous canola protein solution,   (e) diluting the aqueous canola protein solution with about 0.5 to about 10 volumes of water having a temperature of about 2° to about 90° C.,   (f) acidifying the resulting aqueous solution to a pH of about 2.5 to 4.0 to produce an acidified clear protein solution,   (g) increasing the concentration of the acidified clear protein solution to about 50 to about 250 g/L while maintaining the ionic strength substantially constant by using a selective membrane technique to provide a concentrated protein solution,   (h) optionally diafiltering the concentrated protein solution, and   (i) optionally drying the concentrated protein solution to provide a canola protein isolate having a protein content of at least about 90 wt % (N×6.25) d.b.   
   
   
       26 . The method claimed in  claim 25  wherein the calcium salt is calcium chloride. 
   
   
       27 . The method claimed in  claim 26  wherein sufficient calcium chloride solution is added to the aqueous protein solution to a conductivity of about 17 to about 20 mS. 
   
   
       28 . The method claimed in  claim 25  wherein the resulting solution is acidified to a pH of about 3 to about 3.5. 
   
   
       29 . A canola protein isolate having a protein content of at least about 90 wt % (N×6.25) d.b. containing both albumin and globulin fractions of the canola protein and which is soluble in an acidic aqueous environment. 
   
   
       30 . The canola protein isolate of  claim 29  wherein the acidic aqueous environment is a beverage having a pH ranging from about 2.5 to about 5. 
   
   
       31 . The canola protein isolate of  claim 29  having a phytic acid content of less than about 1.5% by weight. 
   
   
       32 . The canola protein isolate of  claim 29  having a protein content of at least about 100 wt % (N×6.25) d.b.