Effect of Enzyme-Assisted Extraction on Structural and Functional Properties of Palm Kernel Protein

Palm kernel seed is massively produced in Malaysia and conferred a complete amino acid profile, sufficient for an average adult. To harvest this protein, enzyme extraction was introduced. The extraction was performed in an aqueous environment using protease and carbohydrase in alkaline and acidic conditions, and their effect on structural and functional properties of the protein was evaluated. Increasing the extraction time and enzyme concentration leads to increased protein extraction until a plateau was reached. Specifically, 5% Viscozyme L extraction for 1 h was found to be the most effective condition increasing the extracted protein content from 0.19% to 0.50%. Enzyme hydrolysis was found to significantly affect the protein structural property where cellulase caused the loss of hydrophobic amino acids, while Viscozyme L and papain caused protein aggregation. Due to the change in structural property, a decrease in the emulsifying activity index and an increase in the emulsifying stability of the protein extracted with the aid of enzymes were observed. This suggests the possibility of the extracted protein being used as an emulsifier or stabilizer of a food hydrocolloid system.