Fats and oils are in the category of lipids containing coarsely hydrophobic molecules (repellent from the water). They are believed to have some biological characteristics including energy saving and some chemical functions of plasma membrane.
Production of fats and oils involves reaction of three ester molecules (reactants of alcohol and acid) known as triglyceride; hydrolyzed with water to produce fatty acids and glycerol. Fatty acids maybe present in the esterification reaction or extracted from vegetable oils or animal fats.
Chemical structure of fatty acids is identified by carbon chains which are generally quantified from four to 28 carbons (even numbers of un-branched tail of carbons). Fatty acids are classified as either saturated or unsaturated forms.
Saturated fatty acids
Saturated fatty acids comprise carboxylic acids within a long chain (12 to 24 carbons) with no double bond structure; therefore they can be easily saturated with hydrogen atoms. Saturated fats are basically solid at ambient temperature and have more stability in terms of their resistance to oxygenation (rancidity).
Saturated fat content products have been widely used in food industry derived from various sources:
- Animal fats - to supply dairy products for example whole milk, butter, cheese, lard, etc. or meat products e.g. beef, lamb, pork.
- Extracted oils from some specific plants for instance coconut oil, palm kernel, cocoa butter, etc.
Unsaturated fatty acids
Chemical structure of unsaturated fats consist of molecules with carbon atoms bound together one / more than one double bond in between i.e. less bonds are available for hydrogen atoms therefore unsaturated bond would be observed at the connection point (at least one position is available). In general, unsaturated oils are originated from a specific range of vegetables and fruits which are widely used in food industry with great versatility.
The following outlines the two classifications of unsaturated fatty acids:
Polyunsaturated fatty acids; more than one double bond carbon connections are arranged. They are physically in liquid form at room and chilled temperature. They are highly prone to react with existing oxygen in the atmosphere that may lead to rancidity (oxygenation).
There are various plants rich in polyunsaturated fatty acids for instance oils from sesame, sunflower seed, safflower, seeds, soy, nuts, etc.
Monounsaturated fatty acids; are also in liquid state at ambient temperature, however they are liable to become more viscous at chilled condition.
Oils of olives, peanuts, avocados, etc are derived from plants offering a wide source of monounsaturated fatty acids.
Either type of unsaturated oils is believed to be able to reduce the blood cholesterol when it is substituted for saturated fat intakes.
[Copyright note: http://www.labreports.info] However it should be remembered that they generally contain twice as much calories as two other macronutrients (protein and carbohydrate).
Cholesterol however is considered to be as a substantial component of bile acids, hormones and some lipophilic vitamins – if it is consumed to acceptable extent. Adequate portion of cholesterol is believed to be essential in the body for properly cellular mechanism; maintaining fluidity and permeability functions of cell membrane.
Excessive or disproportional intake of cholesterol can result in developing cardiovascular disease. The most contributory factors to increasing blood cholesterol are believed to be excessive consumption of saturated fats and trans fats (carbon chains arranged at the opposite direction of the double bond).
Trans fatty acids are in the category of unsaturated fats (monounsaturated or polyunsaturated) that are produced in consequence of the chemical process of hydrogenation. This involves addition of hydrogen to cis-unsaturated oils (carbon chains arranged in the same direction across the double-bond) during food production that would undergo the saturation condition and higher melting point.
This method is extensively utilized in food industry to achieve more desirable flavour and longer shelf-life products plus the advantage of being financially economic.
However frequent use of this process may have adverse influence on human health as the cis isomers are likely to convert into trans unsaturated fats i.e. “partially hydrogenated oil” rather than fully hydrogenation outcome.
Commercial applications of trans fats are most common in bakery and confectionary (such as doughnuts, cookies and pizza dough), fast foods (like French fries) and many prepared foods in restaurants.
Results from scientific studies have implicated that trans fats are capable of raising the LDL (bad) cholesterol or ultimately contributing to developing overall cholesterol level.
They may also have the disadvantage of decreasing HDL (high density lipoprotein) bound cholesterol with consequent heart disease development. This is due to the scientific theory that HDL is able to separate cholesterol from existing atheroma from arteries in order to either send it to the liver for elimination or it is re-functioned in the body. Approximately 30% of cholesterol (in blood stream) is transferred by HDL in a healthy human body.
Current reports have suggested that a proper level of saturated fats and polyunsaturated oils is required for maintaining optimum proportion of LDL to HDL in blood stream. This has been reported to be crucial in order to obtain normal operation of lipoprotein in regulating system. [878]
