To prepare blended oil i. History at your fingertips. Transfer the whole mixture in Rotatory Vaccum Evaporator. By signing up, you agree to our Privacy Notice. Determination of the ash and mineral content of foods is important for a number of reasons: The large calorie, kilogram calorie, dietary calorie, nutritionist’s calorie, nutritional calorie, Calorie capital C ] or food calorie symbol:

The fat oxidation process, potentially resulting in rancidity, begins immediately after the animal is slaughtered and the muscle, intra-muscular, inter-muscular and surface fat becomes exposed to oxygen of the air. Keep the container in the oven with lid removed. For example, even though meat is held under refrigeration or in a frozen state, the poly-unsaturated fat will continue to oxidize and slowly become rancid. Accounting essays Architecture essays Business essays Coursework Economics essays Education essays Engineering essays English language essays English literature essays. Which of these triglycerides would you expect to find in higher amounts in oils?

Fats and Oils – Chemistry LibreTexts

In particular, short-chain fatty acidssuch as butyric acidare malodorous. A combination of water-soluble and fat-soluble antioxidants is ideal, usually in the ratio of fat to water. Monounsaturated fats 2.

essay on rancidity

Coconut oil saturated 0. Cold temperatures slow down hydrolysis reactions. Add about 1ml starch indicator into the contents in the flask, a purple colour is observed.

Triglycerides obtained from animal sources are usually solids, while those of plant origin are generally oils. As the solvent boils the vapour passes through the condenser and the pure form of the solvent drops on the sample Procedure: They provide energy for living organisms, insulate body organs, and transport fat-soluble vitamins through the blood. Inorganic Chemistry 3rd ed. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox.


Physical Properties of Fats and Oils Contrary to what you might expect, pure fats and oils are colorless, odorless, and tasteless. Crucibles Desiccators Muffle furnace Weighing machine Procedure: The end of the condenser is dipped into a solution of boric acid.

They are used esssay liquid soaps, shampoos, and shaving creams. Lovibond tintometer Cuvetts Samples Procedure: These differences in melting points reflect differences in the degree of unsaturation and number of carbon atoms in the constituent fatty acids.

It is used in chemical laboratories for the efficient and gentle removal of solvents from samples by evaporation. Fats and oils that are in contact with moist air at room temperature eventually undergo oxidation and hydrolysis reactions that cause them to turn rancid, acquiring a characteristic disagreeable odor. Word study tool of ancient languages.

17.2: Fats and Oils

When they are not attached to other molecules, they are known as “free” fatty acids. The fat oxidation process, potentially resulting in rancidity, begins immediately after the animal is slaughtered and the muscle, intra-muscular, inter-muscular and surface fat becomes exposed to oxygen of the air.

essay on rancidity

Chemically, it is essentially identical to the catalytic hydrogenation reaction described for alkenes. Ernst Abbe ‘working for Carl Zeiss AG ranciditu Jena, Germany in the late 19th century, was the first to develop a laboratory refractometer.


If the starting color of the solution is deep red orange, titrate slowly with mixing until the color lightens.

essay on rancidity

Heat the sample and note the temperature at which a thin, continuous stream of blusih smoke is given off. Antioxidants are often used as preservatives in fat-containing foods to delay the onset or slow the development of rancidity due to oxidation. Weight the pycometer completely filled with oil. Transfer and weigh 5g material to an extraction thimble, avoiding any loss.

Essay UK offers professional custom essay writing, dissertation writing and coursework writing service. Because of the nature of free-radical reactions, the reaction is catalyzed by sunlight.

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The hydrolysis of fats and oils in the presence of a base makes soap and is known as saponification. Flash and fire points are performed similarly, passing a test flame over the sample at 5degree Celcius intervals. In the Abbe’ refractometer the liquid sample is sandwiched into a thin layer between an illuminating prism and a refracting prism. Keep the crucibles containing sample in the muffle furnace for atleast 5 hours.