Edible oils are triglycerides with 3 moieties of fatty acids attached to a glycerol molecule through esterification. While glycerol is common in all oils, the type of fatty acids attached to it can vary in molecular weight, chain length and degree of unsaturation. As a general rule oils tend to be solids with higher melting point if the fatty acids are saturated in nature while higher the degree of unsaturation greater will be the fluidity. With Omega-3, 6, and 9 fatty acids gaining importance because of their critical biochemical role in humans, liquid oils are invariably promoted while solid fats have many desirable functional qualities desired by the food processing industry. Even amongst oils with unsaturated fatty acids in their molecules, only cis type of isomers are biologically active while trans forms are detested because of their potential for contributing to many disorders some of which can be very serious. The tendency of cis isomer to change into trans isomer during hydrogenation process and under some other processing conditions, has alerted the nutritionists regarding presence of trans fats in processed foods and compulsory declaration of extent of trans fats on the label of the package, is becoming mandatory in many countries.
There are two unique oils of commercial importance which have less of long chain fatty acids and are rich in short and medium chain length fatty acids. They are generally referred to as Lauric oils as they contain higher proportion of the lauric triglyceride compared to most other vegetable oils. Palm kernel oil and coconut oil represent most popular lauric oils which have both food and non-food uses. Coconut oil has less of oleic acid (C 18:1) and more of caprylic (C 8:0) and capric(10) acid glycerides as compared to palm kernel oil. Both contain about 45-50% lauric acid esters conferring on them some extraordinary properties which are now recognized. Process technologies like hydrogenation, fractionation, interesterification, emulsification and others have diversified the use of lauric oils to make hundreds of products of superior organoleptic quality and health attributes.
One of the striking differences between lauric oils and other edible oils is the lower calorie density in the former, about 6 kC per gm as against 9 kC per gm in the latter because of the overwhelming content of short and medium fatty acids. Lauric oils are digested by the saliva in the mouth and lipase system in the GI tract to generate fatty acids with low molecular weights which are burned by the liver for energy. They are not deposited in adipose tissues unlike the long chain fatty acids. Medium chain fats like lauric triglycerides, probably in the form of monolaurate, are believed to go to the surface cells in the skin, sinuses, digestive tract etc creating an extremely potent defensive barrier against microbial infections. It is also claimed that consumption of lauric oils increases the rate at which stored body fat is burned. Caprylic acid has the potency to kill fungus, yeasts and intestine parasites. Other beneficial properties attributed to lauric oils include their ability to increase 20% thyroid production, hasten metabolism, inactivate lipid coated viruses like HIV, Herpes, Cytomegalovirus, to kill bacteria like Listeria, Monocytogenes, Helicibacter pylori and others and to disable protozoa such as Giardia lamblia.
Compared to other major edible oils, production of lauric oils has not made any dramatic increase and it in only because of explosive growth of palm based oils that palm kernel oil was able to register a 20-25% jump in production during the last 5 years, the global out put being at 4.4 million tons(mt) with Malaysia and Indonesia leading the pack. In contrast coconut oil production slumped by 10% during the same period. India is one of the major consumers of coconut oil though it accounts for less than 15% of global production of 2.89 mt in 2007, others being Philippines and Indonesia. Importance of lauric oils has been sidelined since 1980 by the powerful lobbies representing Soybean, Raper seed, Palm oil and Sunflower seed which constitute 70% of the 110 mt world edible oil production to day. The fact that lauric oils have many beneficial properties is amply borne out by the efforts in Canada to genetically modify their canola oil production to raise the level of short and medium chain fatty acids to 40%, probably to preempt reemergence of natural lauric oils and claim their rightful place!
The strong antibiotic functions of lauric oils, confirmed by many scientific studies, make them a natural health protecting ingredient worth incorporating in many processed foods. Synthetic antibiotics that have become omnipotent in fighting infections under the allopathic system of medicine, are turning out to be ineffective against many vectors of disease and there is a case for formulating alternate therapy to fight these diseases using lauric oils. It is time old prejudices are set aside and efforts made to increase their production significantly in the coming years in preference to others with long chain saturated fats which are responsible for most of the ills mankind faces to day.