We have tried our best to clarify the misunderstanding created by the usage of Chemicals during processing of Cooking Oil in Oil Mills. Processing of Cooking Oil Crude Oils contain impurities like:- FFA(Free Fatty Acids) Phosphatides & Gummy Matters Color Pigments Foreign Matters like dust & other matters Odoriferous Matters Processing for Cooking oil consists of three stages:- Neutralization: By this process we remove Gummy matters, Foreign Matters & Free Fatty acids. For removing gummy matters, we add a small quantity of phosphoric acid, then we add a required quantity of Sodium Hydroxide (caustic soda) solution of specific concentration during the agitation of crude at specific temperature. Sodium hydroxide react with free fatty acids(FFA) and form soap. Foreign matters are also removed with this. The soap is drained out from the bottom of the vessel. Then this neutral oil is washed with hot water to remove excessive soap. This Oil is transferred to another Vessel, which is called Bleacher. Bleaching: After neutralization, the oil is transferred to the bleacher. Here we first dry it under vacuum at 100 degree centigrade, then add Fuller’s Earth (Bleaching Earth) in a required quantity. After a certain period of interval, the bleached oil is filtered out through a filter press. This bleached oil is transferred to deodorizer. Deodorization: Bleached oil is heated up to 120 degree centigrade under vacuum (Citric Acid is added at this temperature) & live steam is purged & the temperature is raised to 200 degree centigrade. Keep it for certain period of time. Then cool that oil, live steam is closed & dropped it in a cooler for cooling, then it is filtered out through filter press. This deodorized oil is filtered in tanks from where it goes to churners. Vitamins & Flavors are added here before packing. You may have noted during processing following chemicals are used:- Sodium Hydroxide (Caustic Soda), Bleaching Earth/Fuller’s Earth, Phosphoric Acid. Though these are all injurious to health, but it does not mean that the finished Cooking Oil is injurious to health. By the addition of phosphoric acid, phosphatide & gummy matters are being settled at the bottom of the vessel & removed. In the same manner Sodium Hydroxide (Caustic Soda) react with Free Fatty Acid to make Soap, which is settled at the bottom of the vessel (In continuous refining plants phosphatides, gummy & soapy matters are removed through centrifuge. By this phosphoric acid & caustic soda are not remain in such chemical position. Bleaching Earth (Fuller’s Earth) adsorbs colour pigments as well as soap traces. After that this earth is removed by filtration. This used Fuller’s Earth is also called spent earth (Kaali Matti). This contains 25-30% oil contents. Black oil is extracted through this Spent Earth (Kaali Matti) by boiling it with water. The oil comes out on the surface of water & separate out. This oil is called black oil & is used for soap making. It is not possible to manufacture Cooking Oil or Vegetable Ghee from that black oil. You all may now understand that nothing remain left in Cooking Oil or Vegetable Ghee, which is injurious to health. If any question arises in your mind, please don’t hesitate to ask any question. FARHAT AZIM
Posted on: Fri, 30 Aug 2013 06:59:05 +0000
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