What does the refined in refined oil mean? What are they refining? Why are they refining it? We all have eaten refined oil in our food at some point. It is, afterall, the most commonly used oil. Let’s find out what “refining the oil” actually means.
When seeds are oiled, the resulting oil is bound to have some colour, some scent, some flavour and even some seed particles present in it. But if we have a look at refined oils, none of these are present in it. So is the oil not made from seeds? Does it come from other sources? Are there some special colourless odorless flavourless seeds that can be used for oiling? No. The oil has just been redefined and refined to turn it into nothing more than a liquid fat that can be used in cooking.
The first step in the refining process is degumming, either hydration degumming or dry degumming. In hydration degumming, Phosphoric acid and water are added to the oil to hydrate phospholipids to form gum which is then separated from the oil. In dry degumming, dry gums are added to achieve the same result and then the gum is removed by filtration.
The second step is neutralization or deacidification. Unrefined oil contains free fatty acids that can make it taste “bad” for a particular preparation and also shorten it’s shelf life. In this step, an alkali like Sodium Hydroxide (Caustic Soda) is added to neutralize the acids form soapstock, a mixture of fatty acids and water. The soap stock is seperated through centrifuge or settling. Yes, there is soap mixed up in refined oil at one point.
In the next step, the degummed and deacidified oil is bleached or decolourized. Unrefined oil has pigments like chlorophyll which impart dark colour to the oil. Bleaching earth (absorbent clay) is mixed with oil allowing it to absorb the pigments. It is then filtered out to give decolourized oil. Yes, there is clay in the refined oil at one point.
Next, the bleached oil is deodorized. High Temperature steam and vacuum are applied to the oil in a deodorizer and the volatile components evaporate. These vapours are then condensed and collected separately leaving the oil odorless.
The oil goes through filtrations between each step. But that’s not all. Few oils have to go through a few more steps before they can make it as refined oils.
This next step is called Winterization or dewaxification of oil. This step removes waxes with the help of solvents. These waxes can cause cloudiness in oils at lower temperatures and that’s not a good look for the liquid fat that will be sold.
And the resultant oil is polished to give it further clarity and stability and we are ready with our shiny odorless flavourless nutrionless liquid fat which can now be used in daily cooking. But now, Do We Really Want to Cook With It?
