How to Make Vegetable Oil?

Vegetable oil has wide variety of uses when it comes to food for example it is used in making cooking oil, mayonnaise, salad dressing, and many more. Also, it is involved in the production of non-food substances such as fatty acids, soaps, resin, detergents, varnish, lubricants and plastic. With technology people have greatly shifted from traditional extraction processes which were tedious, slow, and quite messy to modern extraction methods. Increased market demand also contributed much to this revolutionary shift and today you can extract vegetable oil from your home and use it in making detergents or sell it to other manufacturing companies.

The standard cooking oil bottle contains 99% of vegetable oil and this oil is extracted from various plants (commonly referred as seeds) such as sunflower, safflower, sesame, cotton and palm kernel. The oil is also extracted from nuts such as peanut, almond, walnut and soybeans. Few vegetable oils do not need heavy processing procedures for example peanut and olive can be cold-processed that extracts a light, tasty oil that can help in your cooking. However, this process may not be sufficient for most vegetable oils since it may leave some substances in the oil making it look dirty and have a bitter taste. That is why vegetable oils need to be extracted using highly specialized machines that will ensure the seeds undergo the all necessary stages to produce the best quality.

 

Cleaning

The first stage of vegetable oil making involves seed cleaning and grinding, magnets are passed over the seeds to remove traces of metal, their outer material is then removed. The skinless nuts or seeds are now ground into rough substances so as to increase the surface area for efficient pressing. Groove rollers are now used to crush the coarse seeds up to a certain level of evenness. The even meal is heated to allow for oil extraction. Also, as the oil is produced it comes with out impurities that are removed as the process continues.

Pressing

The heated substance is directed inside a screw press which continuously raises the pressure and oil is pressed out from slots within the barrel of vegetable oil machine where it is easily recovered. However, this stage is best for seeds that have huge amounts of oils, those with little oil do not undergo this stage.

Extraction Using additional Solvents

After the oil has been obtained from the press, an oil cake remains which is now processed again using the solvent extraction method to maximize the yield. Hexane is now used to dissolve the oil from the oil cake that is obtained through the distillation process.

Eliminating Solvent Impurities

90% of the remaining solvent evaporates and is collected for recycling. A stripping column is used to retrieve what remains and it is boiled using steam and the light hexane moves upwards as it condenses and collected.

Refining

Refining is aimed at removing undesirable colors, bitterness and odor. During the refining stage, the oil is heated between 40 to 85 degree Celsius and mixed an alkaline substance for example sodium carbonate. It is then cleaned to remove soap substances, they are then treated with heated water of about 188-206 degrees Celsius. Phosphatides precipitate while the dregs are extracted by centrifuge. Oil used for cooking, particularly vegetable oil is bleached by use of activated carbon which filters it and absorbs some pigmented materials. For vegetable oil designed for salad dressing, the oil is chilled and filtered to extract waxes and this ensures it does not solidify when put in a refrigerator.