NUTRITIONAL SIGNIFICANCE OF FATS & OILS | RANCIDITY | MARGARINE

FOODS TO BOOST YOUR HEALTH-

NUTRITIONAL SIGNIFICANCE OF FATS & OILS | RANCIDITY | MARGARINE | HYDROGENATION

NUTRITIONAL SIGNIFICANCE OF FATS & OILS: Fats are present naturally in many foods they are an important component of the diet. Fats in the diet can be of two kinds the visible and the invisible fat. 

Invisible fats are:- those present inherently in foods. Example of food containing appreciable quantities of invisible
fat include dairy products, meat, poultry, fish, eggs, nuts, and seeds.

Visible fats: are those fats that are made from these products. They are salad oils, butter, cooking oils, ghee and
margarine.

NUTRITIONAL SIGNIFICANCE OF FATS & OILS:

  • They are a good source of vitamin A, D, E, and K.
  • They are a concentrated source of energy. 1 gram of fat contributes 9 kilocalories as against 4 kilocalories
    contributed by carbohydrates and protein.
  • They are also used by the body to make prostaglandins involved in a large variety of vital physiological functions.
  • They impart special flavor and texture to our foods, thus increasing palatability.
  • They provide essential fatty acids which are important components of membranes of living cells.

HYDROGENATION:

Plant oils contain a large percentage of unsaturated fatty acids and hence tend to become rancid. These unsaturated glycerides in oil can be converted to more saturated glycerides by the addition of hydrogen. This process is known as Hydrogenation. By this process, liquid fats can be converted to semi-solid and solid fats for use as shortening in the preparation of biscuits, cakes, and butter substitutes.

Hydrogenation is of great economic importance because it allows oils to be converted into fats, which have better
keeping quality. The resulting fats are odorless and colorless and blend well in several food preparations.

REFINED OILS:

Oils and fats do not occur free in nature. They occur in animal tissues and in seeds and fruits from which they are
isolated.
The extracted oils are crude and contain many constituents like free fatty acids, unsaponifiable matter, gums, waxes, mucilaginous matter, a variety of coloring matter in refining these constituents are removed by the following steps:

  • Free fatty acids are removed by alkali treatment.
  • Suspended particles are removed by filtration or centrifugation.
  • Any remaining free fatty acids are removed by neutralization.
  • The oil is finally deodorized by injecting steam through the heated fat under reduced pressure to obtain refined oil.
  • Pigments are removed by bleaching using adsorbents like activated earth or carbon.

Margarine : 

Margarine is often used as an alternate for butter. It is made from vegetable oils or a mixture of vegetable and animal
fat by hydrogenation. It is then blended with cultured skim milk and salt.

The fats most commonly used in the manufacture of margarine are cottonseed oil, soyabean oil, corn oil, groundnut oil, coconut oil, and meat fat. Additional additives may include diacetyl for butter flavor, sodium benzoate for preservation, etc.

RANCIDITY:

Rancidity refers to the development of disagreeable odor and flavor in fats and oils owing to a specified chemical reaction such as oxidation and hydrolysis. The major spoilage of fats and oils is rancidity.

Hydrolysis is the decomposition of fats into free fatty acids and glycerol by enzymes in the presence of moisture.
These free fatty acids released are responsible for the unpleasant flavor and odor.

During oxidation, oxygen is added to the unsaturated linkage and this results in the formation of peroxides. These peroxides decompose to yield aldehyde and ketones which are responsible for the pronounced off-flavor.

ROLE OF FAT / OIL IN COOKERY:

  • Fats help in leavening – in making cake, leavening occurs by incorporating air into the fat during the leavening process.
  • Fat is used as a medium of cooking in shallow and deep fat frying.
  • Fat improves the texture of food. e.g., cake, biscuit, cookies.
  • Fat increases the smoothness of the product e.g., Halwas.
  • Fat improves palatability as fats give taste and flavor to the food.
  • One of the most important functions of fat is to shorten baked products which otherwise are solid masses firmly held together by strands of gluten. They are shortening agents.

NUTRITIONAL SIGNIFICANCE OF FATS & OILS | RANCIDITY | MARGARINE


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Helthwell: To maintain good health keep sure you make a healthy approach regarding physical, mental and your own well-being.


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