Improved recovery of protein from soy grit by enzyme-assisted alkaline extraction

Abstract Recovery of protein from soy grit, its functional properties and possibility for the reduction of time of conventional alkaline extraction by the assistance of enzymes were studied. Enzymatic treatment was performed by commercial preparations of cellulase (NS22086), xylanase (NS22083) and pectinase (Vinozym) (applied separately or in combination) as well as by commercial carbohydrases cocktail (Enzyme complex, NS22119). Three different extractions were investigated - alkaline (at pH 8 for 1 h, 2 h or 3 h), enzyme-assisted aqueous (at pH 5.5 for 3 hours) and enzyme-assisted alkaline extractions (enzymatic extraction for 1 h followed by alkaline extraction for 1 h or 2 h) at 50 ˚C and solid:liquid ratio 1:10 (w/v). The highest enhancement of recovery of protein was achieved by pretreatment of soy grit with enzyme cocktails. Treatment with Enzyme complex followed by 1 h alkaline extraction increased protein yield for 21% compared to 2 h alkaline extraction. Treatment by combination of individual cellulase, xylanase and pectinase followed by 2 h alkaline extraction enhanced protein yield for 13% in comparison to 3 h alkaline extraction. So, reduced time of alkaline extraction was attained by the assistance of carbohydrases cocktails with even positive effect on protein yield. In addition, protein from enzyme-assisted alkaline extraction exhibited ameliorated solubility, emulsifying and whipping properties compared to alkaline extracted protein.