Patent NZ-597838-A (NZ)
Title: Production of acid soluble soy protein isolates (”s800”)
Inventor: MEDINA SARAH
IPC: A23J1/14
Filed: 2010-06-30
Abstract: NZ 597838 Disclosed is a method of producing a soy protein product with a protein content of at least about 60 wt% (N x 6.25) d.b., which includes: (a) extracting a soy protein source with water, optionally containing an antioxidant, at a temperature of at least about 1°C to cause solubilisation of soy protein in the soy protein source and to form an aqueous protein solution having a protein content of about 5 to about 50 g/L and a pH of about 1.5 to about 11, (b) separating the aqueous protein solution from residual soy protein source, (c) optionally treating the aqueous protein solution with an adsorbent to remove colour and/or odour compounds from the aqueous protein solution, (d) increasing the protein concentration of the aqueous protein solution to about 50 to about 400 g/L, while maintaining the ionic strength substantially constant by using a selective membrane technique employing a membrane having a molecular weight cut-off of about 3,000 to about 1,000,000 Daltons to provide a concentrated protein solution, (e) optionally diafiltering the concentrated protein solution using water or dilute saline solution, before or after complete concentration thereof using from about 2 to about 40 volumes of diafiltration solution using a membrane having a molecular weight cut-off of about 3,000 to about 1,000,000 Daltons, (f) optionally pasteurizing the concentrated and optionally diafiltered protein solution at a temperature of about 55° to about 70°C for about 30 seconds to about 60 minutes followed optionally by cooling to a temperature of about 20°C to about 35°C, (g) adding calcium salt solution to the concentrated and optionally diafiltered protein solution to a conductivity of about 5 to about 30 mS to cause a precipitate to form in the concentrated protein solution, (h) removing the precipitate from the concentrated protein solution, (i) diluting the clarified concentrated protein solution into about 2 to about 20 volumes of water having a temperature of about 2° to about 90°C, (j) acidifying the resulting solution to a pH of about 1.5 to about 4.4 to produce an acidified clear protein solution, (k) optionally polishing the acidified clear protein solution, (l) increasing the concentration of the acidified clear protein solution to about 50 to about 300 g/L while maintaining the ionic strength substantially constant by using a selective membrane technique using a membrane having a molecular weight cut-off of about 3,000 to about 1,000,000 Daltons to provide a second concentrated protein solution, (m) optionally diafiltering the second concentrated protein solution using water or dilute saline solution, before or after complete concentration thereof using from about 2 to about 40 volumes of diafiltration solution using a membrane having a molecular weight cut-off of about 3,000 to about 1,000,000 Daltons, (n) optionally treating the second concentrated and optionally diafiltered protein solution with an adsorbent to remove colour and/or odour compounds, and (o) optionally drying the second concentrated and optionally diafiltered protein solution to provide a soy protein product having a protein content of at least about 60 wt% (N x 6.25) d.b..