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Food Science Experiments for High School Sciences. Experiment 3 Extraction of Fats from Foods . Triglycerides. Fats (solid at room temperature) and oils (liquid at room temperature) found in foods are usually present in the form of triglycerides.
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Food Science Experiments for High School Sciences Experiment 3 Extraction of Fats from Foods
Triglycerides • Fats (solid at room temperature) and oils (liquid at room temperature) found in foods are usually present in the form of triglycerides. • Triglycerides are formed when fatty acids combine with glycerol
Fatty acids • Fatty acids are: • straight chains of carbon atoms with hydrogen atoms attached (hydrocarbons) • with a carboxylic group (COOH) attached at one end and • a methyl group (CH3) at the other end. • Fatty acids can be: • saturated (carbon chain with only single bonds) or • unsaturated (carbon chain has one or more double bonds).
Saturated fatty acids • Saturated fatty acids are straight chain molecules that can easily line up and associate with each other to form a crystalline structure, resulting in a solid fat at room temperature. • The appearance (rough, smooth, shiny), hardness, and light reflection characteristics (colour) of solid fats are influenced by how the various fatty acid chains associate.
Unsaturated Fatty Acids • Double bonds in food fats and oils are usually present in the cis conformation. • A. Hydrogen atoms attached to the carbon atoms in the double bond are on the same side. • The trans conformation is rare • B. Hydrogen atoms attached to the carbon atoms in the double bond are on opposite sides
Cis double bonds • Cis double bonds result in “kinks” in the carbon chain and therefore disrupt physical interactions with other fatty acid molecules, preventing them from packing together in a crystalline structure. • This results in a liquid structure or oil.
Solvent extraction of lipid • Fats and oils are organic substances that belong to the larger category known as lipids and are soluble in organic solvents but only sparingly soluble in water. • Solvent extraction can be used to extract lipids from foods. The amount of lipid extracted from a food will depend on: • whether the food has been sufficiently broken down to allow access of the solvent to the fats/oils held within the food • the solubility of the lipids in the solvent used