Most cooking oils are organic because they originate from
natural plants such as peanuts, safflowers, groundnuts, sunflower, among other
vegetable oils. Cooking oils are liquid at room temperature, and they are at
times employed in making salad dressing, drying food materials and also added
in preparation of food that is being processed.
Since immemorial, many people in different parts of the world attempted several methods to get oil from plants. Most of them used fire, sun, oven, among other techniques for purposes of obtaining cooking oil from plant products. Since then, there has been technological development, and this has led most industries to produce large quantities of cooking oil.
Raw materials used in the production of cooking oil
As earlier mentioned, cooking oil is mostly generated from a source of plants, for instance, seeds, germ, and nuts. Some of the special flavoring seeds that are used to produce cooking oil are not limited to palm kernel, cotton, grape seed, sunflower, sesame, and safflower. On the other hand, nuts used in cooking oil production include peanut, walnut oils, almond, and soybean. They are others that come from extracting oil from the fruit flesh of a plant. For example, coconut oil, olive oil, and palm oil. Others are removed from an embryo(germ) of a plant such as corn oil.
Manufacturing Process of Cooking Oil
Cooking oils like peanut, sunflower oils, olive and coconut oils are usually cold-pressed. Here, the technique involves minimal processing and therefore generates a flavorful, light oil which is favorable for cooking. Nonetheless, the majority of sources of oil are inconvenient for cold processing because they can lead to the production of harmful elements in the cooking oil. The end product that will be produced will be dark, odiferous or even have a bitter-tasting. Therefore, these oils usually go through several and vigorous procedures to produce safe products.
Manufacturing of cooking oil involves the following procedures:
1. Cleaning and Grinding
Here, the plant oil seeds are usually passed through several magnets to eliminate any form of metal prior to being deskinned, stripped or even dehulled of extraneous material. If the plant oil source is from cottonseed, its ginned seeds have to be stripped and dehulled. Milling is always done to corn to separate the germ from the kernel.
After stripping off the nuts or seeds, they are then ground to form a course meal to offer a more grinding area for it to be pressed fast. To obtain perfect consistency during grinding, hammer mills or mechanized rollers are usually employed to crush these materials. Thereafter, the course meal is heated at a high temperature to enhance oil extraction. More oil is produced here but the unfortunate thing is that it also comes with more impurities. Therefore, these impurities have to be eliminated here for it to suit human consumption.
After the course meal has been heated properly, it is then passed over the screw press which consequently improves the pressure of heating. The meal is then taken via a slotted barrel. Here, the cooking oil is squeezed and it is recovered properly.
3. Solvents used to extract more oil
To attain maximum output during oil extraction, most companies normally use the solvent extraction process. Here, a volatile hydrocarbon such as hexane is usually used to dissolve the oil which is later on recovered through distillation
4. Eliminating Solvent Traces
A larger part of the solvent material that normally remains in the extracted oil during the solvent extraction process usually evaporates. It is later on collected for reuse purposes. The other part which cannot be collected is recovered by a stripping column. As the lighter and hot hexane floats on the upward position, the oil is usually heated by hot vapor. When hot hexane condenses, it is also collected easily.
5. Refining the Cooking Oil
Just after traces of solvents have been eliminated from the oil, it is then ready to be refined to eliminate bitterness, odor, and color. The oil is heated properly, and then an alkaline solution such as sodium carbonate or sodium hydroxide is added to it. Here, soap forms that can be generated from alkaline additive and unfavorable fatty acids are normally eliminated by centrifuge. Thereafter, the oil is cleaned further to eliminate soap traces and later on dried.
The gums that do exist in the oil are degummed by either acidic solution, steam or heated water. They are usually precipitated out while other dregs are eliminated by centrifuge.
The cooking oil which is heated is thereafter bleached by filtering via activated carbon or fuller’s earth so that it can effectively absorb certain pigments from the oil.
The oil is then deodorized to enhance suitability in cooking by enabling certain elements to distill from the cooking oil.
6. Packaging of Cooking Oil
Finally, the refined and fully processed cooking oil is accurately measured and later on poured into different containers for public consumption.