Fats and oils form an essential part of our healthy diet. Structurally glycerol esters contain three fatty acids (called triacylglycerol or triglycerides). It is these fatty acids that provide fuel performance. Chemically, they can be divided into four main types - saturated, cis-monounsaturated, cis-polyunsaturated and trans fatty acids. In broad terms, saturated fats and trans fatty acids are stable at room temperature while cis-unsaturates are liquid at room temperature. Although no natural fat is either 100% saturated or 100% saturated (but it is a mixture of the two), fats are often referred to as 'full' or 'flawless' because of the size of one or the other type of fatty acid.
Types of Oils and Fats
The 27 vegetable oil levels are set out in Section 2.2 Safety and Food Security (Food Production and Food Additives) Standards for 2011. Rates are also set for Cocoa butter, Refined Salseed oil, Mango Kernel oil, Phulwara oil, essential oils. , Vanaspati, Table Margarine and Bakery / Industrial Margarine. Animal fats include sheep / goat fat and Lard.
Preparation of Samples
Use a clear liquid of clear sediment after turning the container a few times. If the liquid sample contains sediment free it all sinks to the walls of the vessel and then spreads evenly throughout the oil to obtain moisture. For determinations where the results may interfere with the possible presence of water (eg the amount of iodine) in a dry sample by adding 1 - 2 g of Sodium Sulphate in a 10 g sample and place in the oven at 50 ° C. Stir vigorously and strain to obtain a clear filtrate.
Solid and semisolid Samples
Reduce the sample if necessary, by warming it slightly with care not to melt it. When soft enough mix well to obtain moisture and flexible matter. For some convenience, thaw in a preheated oven at a temperature of at least 10 ° C above the melting point. If it is clear, go straight ahead. If turbid or contains a test sample sediment filter inside the oven. For decisions where the results may affect the possible presence of water (e.g. amount of iodine) dry sample by adding hydrous Sodium Sulphate at a rate of 1-2 g to a sample of 10 g and then storing it (store) in the oven at 50 ° C. Stir vigorously and strain to obtain a clear filtrate. To delay rancidity keep oil and grease in a cool place and protect from light and air. \
Some of the different methods used in testing oils and fats are as follows:
1. Determination of Moisture Content
2. Determination of Color
3. Determination of Acid Value
4. Determination of Cloud Point of Palmolein (and test for presence of Palmolein in other oils)
5. Determination of presence of Cottonseed Oil (Halphen's test)
6. Method for Separation of Cholesterol by Reversed Phase Thin Layer Chromatography
7. Test for presence of animal body fat in vegetable fat based on the presence of unusual fatty acids in animal fats by gas liquid chromatography.
8. Test for presence of Castor Oil
9. Test for presence of Argemone Oil
10. Test for presence of tricresyl phosphates and determination of tri-o-cresyl phosphate in edible oils.