Enzymatic pretreatment of jojoba seeds to facilitate oil extraction

A short enzymatic pretreatment of crushed jojoba seeds enabled centrifugal extraction of more than 25% of the oil contained within the seed matrix. Commercially available hydrolytic enzymes, including glucanases and proteases, were selected on the basis of their capability to release soluble sugars and proteins and then examined for their effect on release of the oil from the seed particles. Pectinases and xylanases led to a release of 5-15% of the total sugars within the seeds, and enabled extraction of 10-15% of the oil. Treatment with proteases released 10-15% of the protein contained in the seeds, but was significantly more effective in releasing 25% of free oil. Only proteases activity caused the entrapment of about 60% of the oil in the form of extremely stable emulsion. Several denaturing treatments of the seed matrix were performed to prevent the formation or destabilize the emulsion phase. Autoclaving the seeds to denature proteins in their matrix yielded more than 50% release of the oil. Similar treatment of the dense emulsion to denature its proteins released more than 25% of the oil from the emulsion phase. Denaturation and precipitation of seed proteins by 10% w/v of trichloroacetic acid released more than 55% of the oil. The results indicate that amphipathic (hydrophobic-hydrophilic and surface active) proteins are responsible for the formation and stabilization of the dense emulsion phase which counteracts efficient extraction of the oil.