Impact of total solid content and extraction pH on enzyme-aided recovery of protein from defatted rapeseed (Brassica rapa L.) press cake and physicochemical properties of the protein fractions.
Pectinase treatment was used to facilitate protein recovery from defatted rapeseed (Brassica rapa) cold-pressing residue in water-lean conditions and without pH adjustment. Effect of extraction pH on protein yield and physiochemical properties of the protein concentrates was assessed. Enzymatic hydrolysis of carbohydrates was feasible at high (40%) solid content and improved protein recovery at pH 6. Comparable protein yields (40-41% of total protein) from enzyme-aided water extraction (pH 6) and nonenzymatic alkaline extraction (pH10) at 10% solid content suggested that after enzymatic treatment, rapeseed protein could be extracted without exposure to alkali. However, water extraction required dilute conditions, whereas alkaline extraction was feasible also at 20% solid content. The water extracts possessed better protein solubility, higher ζ-potential, and smaller particle size than isoelectric precipitates from alkaline extraction, indicating higher dispersion stability. This is suggested to be mediated by electrostatic interactions between proteins and pectic carbohydrates in the water extracts.
VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
Katariina
K
Rommi
VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
Dilek
D
Ercili-Cura
VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
Terhi K
TK
Hakala
VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
Emilia
E
Nordlund
VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
Kaisa
K
Poutanen
VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
Raija
R
Lantto
D055162:Biocatalysis; D029741:Brassica rapa / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D011096:Polygalacturonase / Q000737:chemistry*; D012995:Solubility; D014866:Waste Products / Q000032:analysis
D010940:Plant Proteins; D014866:Waste Products; D011096:Polygalacturonase
anionic carbohydrates; isoelectric precipitation; pectinase treatment; protein extraction; protein solubility