The preparation of Pure Jojoba Oil requires pre-treatment of jojoba seeds, including cleaning, impurity removal, crushing and rolling, steaming and drying. The cleaned jojoba seeds are sent to the crusher to reduce their particle size, increase their specific surface area, and rupture part of the cell membrane. Rolling can be carried out after crushing, or directly rolling without crushing. Rolling sheet not only has a mechanical destruction effect on the structure of seeds, but also can shorten the mutual diffusion distance of solvent and oil during extraction, and reduce the internal resistance of seed sheet to the diffusion of solvent and oil molecules. Steaming and drying can improve the permeability of the cell membranes that are not damaged during the crushing process through the action of water vapor and temperature. The tiny oil droplets in the seeds that were originally emulsified by the protein but not dispersed. After steaming and drying, the protein is denatured and solidified by heat, which destroys the emulsified state and makes it easier for the small oil droplets to aggregate, and the larger oil is separated from the seeds. drop. Steaming causes water to bind to replace part of the oil on the surface of the solid material, and produces considerable oleophobicity, reducing the affinity of the oil with the surface of the solid material in the seed.
This effect increases the oil yield during pressing. The temperature of steaming and drying is generally 105-120 °C, and the time is 80-120 minutes. It is better to control the moisture of the seeds after steaming and drying to 2%-5%. The seeds used for extraction do not need to be steamed. The extraction and separation of oil includes three methods: pressing method, solvent extraction method and supercritical CO2 extraction method. 1. Pressing method: The process is simple, but the oil production rate is low, and the residual oil in the residue is high. Generally, only 80% to 90% of the oil can be squeezed out. 2. Solvent extraction method: The extraction rate can reach more than 97%, but due to the use of solvent circulation, there are problems of solvent recovery, loss and anti-pollution, fire prevention and explosion-proof, and the equipment requirements are relatively high. The most effective solvent extraction method is continuous countercurrent operation. The type and nature of the solvent have a great influence on the extraction efficiency. . The extraction temperature has little effect on the oil yield, but will affect the color of the oil. Therefore, low boiling point solvents (60~90℃) should be used as far as possible to avoid deepening of oil color. The extraction time is not necessarily as long as possible, and the yield improvement after about 120 min is very limited.
