CORN OIL REFINING
Extremely nutritional corn oil also known as maize oil is extracted from the germ of the corn. It is commonly used as cooking oil but its high smoke point makes it highly valued frying oil. Apart from cooking, refined corn oil is also used in the preparation of margarine.
The refining process removes these unwanted harmful elements from the crude oil and imparts few of the most valuable qualities which include pleasant taste and resistance to smoking, discoloration, developing flavors. Let’s have a look at the refining process of corn oil.
Process of Refining Corn Oil
Crude Corn oil is refined through alkali neutralization process which is a chemical refining process and involves numerous steps. The major steps involved in refining of crude corn oil through alkali neutralization are –
- Gums conditioning Neutralization
- Bleaching
- Winterization
- Deodorization
Let’s know the each processing step in detail, one by one –
Fatty ACID Composition
Gums conditioning & Neutralization
In this process, the crude oil is first treated with acid (citric acid/ phosphoric acid) followed by treatment with alkali to neutralize the oil which is followed by soap separation. Further the soap separated oil is washed from hot water for removing the traces of soap, later dried for obtaining neutralized oil.This process further involves four steps listed below –
- Conditioning – in this step, non-hydratable phospholipids are transformed into their hydratable form by breaking down the phosphatide/metal complexes by using a strong acid.
- Neutralization – free fatty acids are neutralized by an alkali for creating the sodium salt of free fatty acids
- Washing – in this step, residual soap is removed by washing it from the hot water.
- Drying – in this step, the leftover moisture is removed from the oil under vacuum.
Bleaching
This process removes the color pigments, polycyclic aromatic compounds, dirt, trace metals, phospholipids and other impurities through the interaction of the absorbent with oil or fat in order to improve its quality. At first, the oil is heated, and then bleaching clay is added to the oil at the atmospheric condition as it helps to utilize the moisture of bleaching earth for a better outcome.
Further, the oil is heated in the separate heater which works under vacuum. After heating, the oil is sent to the bleaching reactor for decolonization & purification purpose.
This processed oil is then filtered through filtering equipment specially designed for the suitable flow of bleaching earth mixer and oil.
Winterization
In this process, the higher melting point parts such as saturated triglycerides and waxes are removed from the oil. The vegetable oil is slowly cooled and saturated glycerides are crystallized. This process consists of fractional crystallization of fats and oil which is further followed by solid-liquid separation through filter.