Valorization of Canola Meal Proteins Through Acylation with Lauroyl Chloride

Non-reversible structural changes in canola seed protein, during oil extraction process, consequently affect its nutritional and functional value. Valorization of commercial canola meal (CCM) can be achieved through generation of amino acids and converting them into functional molecules. The objective of this study was to generate a mixture of N-acyl amino acids of CCM hydrolysates, to be used as functional molecules with surfactant properties. Ethanol (99%, v/v) pre-treated CCM (45%, w/w protein) was alkali-treated twice (pH 12, 1 h, ambient temperature with mixing) to extract proteins. Acid hydrolysis of the proteins was conducted on the protein extracts using 4 M H2SO4 for 24 h at 110 °C (2.0 mL of acid per 5.0 mg of protein). The protein hydrolysate was N-acylated using lauroyl chloride through Schotten-Baumann reaction (at pH 11), followed by treating with ethanolic NaOH to obtain sodium salt of N-lauroyl amino acids. Selected individual amino acids, abundantly found in canola meal (lysine, leucine and valine), were also acylated and structures were characterized by NMR and FT IR. Alkali-extracted protein fraction contained 46% (w/w) proteins (as N basis, 6.25 conversion factor). Acid hydrolysis resulted in 65% (w/w) recovery of amino acids from the extracted meal protein and contained aspartic acid, glutamic acid, glycine, arginine, proline and leucine in 6.0, 17.3, 4.4, 4.9, 4.7, and 4.4 % (w/w) respectively. The hydrolysate contained approximately 77 % of the total amino acids present in the meal protein fraction and provided a satisfactory quantity of amino acids for further reactions.