Generation

• The process of hydrogenation consists of several steps. The crude oil normally contains multiple double bonds per molecule while in partially hydrogenated oil these double bonds are removed by the addition of hydrogen. Partially hydrogenated vegetable oil (PHVO) is then subjected to high temperatures in the presence of a catalyst. Hydrogen gas is bubbled through the liquid and the mixture is filtered to remove the metallic properties, leaving behind hydrogenated vegetable oil. Later, water, salt, vitamins, colourings, emulsifiers and flavorings can be added to produce margarine that tastes mostly like butter.
  
  

Process

• Hydrogenation is the process of converting the liquid vegetable oils to solid or semisolid fats. When there is change in the degree of fats present in the oil, there is also a corresponding change in other properties as the melting point which in turn helps to maintain the state of the oil stagnant at a particular temperature. Partially hydrogenated vegetable oils come at a lower cost as compared with animal fats.
  
  

Steps

• Preparation of seeds begins with heating and de-hulling; they are later subjected to chopping or grinding, which breaks the walls of the cell. This makes the penetration of the solvent in to the cells much easier. Extraction from seeds is done by pressing them mechanically or mixing with gasolinelike solvents. De-gumming is a process of treating the crude oil with water, salt solutions, dilute acids or alkalis that help in eliminating any impurities. Bleaching of oils eliminates the yellow as well as reddish pigment. Deodorization is done via pressurized steam, which distillates at the temperature range between 240 degrees and 270 degrees Celsius.
  
  

Post-generation

• Hydrogenation leaves a substantial amount of oil in the reservoir that is not sold. It is further subjected to treatment to make is usable for alternate usages. Food manufacturers prefer a solid fat that does not go rancid easily and is relatively tasteless. This facilitates the package, sale and transportation of the oil.
  
  

Dangers

• The health dangers of trans fats have been known for years. Hydrogenated oil contains a large proportion of diverse trans fatty acids, which are blamed for raising "bad" cholesterol level in the blood. A buildup of "bad" cholesterol can block arteries, resulting in stroke or coronary hearth disease.