Insolubilization contribution

Soybean concentrate production involves the removal of soluble carbohydrates, peptides, phytates, ash, and substances contributing undesirable flavors from defatted flakes after solvent extraction of the oil. Typical concentrate production processes include moist heat treatment to insolubilize proteins, followed by aqueous extraction of soluble constituents aqueous alcohol extraction and dilute aqueous acid extraction at pH 4.5. 

Irreversible insolubilization of proteins may occur mainly through formation of both intermolecular disulfide and hydrophobic bonds. The product can be quite different depending on the relative contribution of these two types of bonds. The hydrophobic bonds are formed among the hydrophobic amino acid side chains contributed by valine, leucine, isoleucine, phenylalanine, etc. 

Enzymes best retain their activity on insolubilization when hydrophilic rather than hydrophobic matrices are used. Although many non-carbohydrate matrices have been employed, the hydrophilic nature of polysaccharides must be a major feature contributing to their widespread use for enzyme insolubilization. Presumably, the hydroxyl groups of the polysaccharide resemble water molecules sufficiently to provide the enzyme to be attached with an environment suited to its stability. 

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