The food industry is evolving as the needs of people change at specific times. Fats and oils from plant and animal sources get hydrogenated to change their natural characteristics. It may be forming semi-solid spreads like ghee or vanaspati to use directly or for making other foods like cakes, biscuits, etc. Oil hydrogenation is a process of adding hydrogen in the presence of a nickel catalyst to convert them to semi-solid things. Hydrogenation of fats and oils useful in the food industry is apart from its use in the pharmaceutical and petrochemical industries. Using advanced systems and techniques there are many hydrogenation processes like continuous, interesterification, etc.
Hence this article will discuss the different hydrogenation of oil processes to transform them into high-quality solid or semi-solid fat useful in many ways in the food industry.
What is the hydrogenation of oil?
With the changing eating habits of refined oils in solid and semi-solid forms like ghee, vanaspati and other spreads, the need for hydrogenation is increasing worldwide. Hence, it is essential to add hydrogen to oils to change the characteristics of oil into fat forms for direct or indirect use. So, hydrogenation of oil is a chemical reaction between the added molecular hydrogen with the elements in the oil before nickel or other catalysts. In a chemical reaction, it may be a simple addition of hydrogen to the double or triple bond connecting atoms called hydrogenation. The other is hydrogenolysis or destructive hydrogenation, wherein adding hydrogen breaks up or dissociates the molecules.
Hydrogenation of oils and fats at room temperature converts the oleic or linoleic acid into stearic acid or acid radicals. It is a chemical process to alter the structure of the alkene by breaking its C=C double bonds along with saturating carbons with hydrogens to make them alkanes. Hydrogen gas, high heat and metal catalysts like nickel, palladium and platinum are essential for hydrogenating fats and oils. During the hydrogenation process, the unsaturated fats in vegetable oils transform into artificial saturated fat. These saturated or partially saturated hydrogenated fats are more resistant to rancidity and heat tolerance for many direct and indirect uses in the food industry. Coconut oil, palm oil, vanaspati, ghee, etc., are a few of the hydrogenated dietary fats.
What is the different hydrogenation of oils and fats?
There are different hydrogenation of oils and fats, including interesterification, continuous hydrogenation, etc. Let us thoroughly check them to convert oils to solid and semi-solid fats.
Interesterification or partial hydrogenation
Interesterification is the alternative to partial hydrogenation, a fat modification technology to redistribute the fatty acid molecules in the triglyceride oil over its glycerol molecules. It involves rearranging the fatty ester between the triglycerides to change the physical properties of the oil or fats. The catalyst used in this partial hydrogenation is sodium methylate or ethylate to change the molecular exchange of fatty acids with glycerol as the backbone of triglycerides.
Continuous hydrogenation of oil
Unlike partial hydrogenation, the continuous hydrogenation of oil ensures its conversion to solid or semi-solid fats for many uses in the food industry. In this process, the hydrogen atom adds to the double bonds in the fatty acid chain. The hydrogenation degree directly relates to the iodine number to reduce the number of double bonds in the fatty acid chains.
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