Tuesday, December 30, 2008


Whether in solid or liquid form, food fats play an important role in the diets of population all over the world. The type of fat used differs from country to country and some times localized in different parts of the same country depending on the taste perceptions of the population there. Ideal intake of fat in human beings is adequate quantity to provide 30% of the total food calories required for a normal person. If 1800 kC energy is taken as daily requirement per ca pita, total fat content, visible as well as invisible should not be more than 60 g a day. Of course there is no unanimity amongst nutrition experts some of whom justify fat consumption up to 90% of the diet calories in extremely cold conditions while it can be as low as 10% for normal persons. Fact remains that fat serves several purposes in the diet such as imparting texture and flavor to prepared foods, carrier for oil soluble ingredients and vitamins and concentrated energy storage in the body.
World wide fat consumption is estimated at 130 million tons(MT) derived from soybean, Oil Palm, Rapeseed, Sunflower seed, Peanut, Cotton seed, Olives, Maize germ, Rice bran, Safflower, Sesame, Coconut etc. In India the consumption is estimated at 13 MT per year out of which 8.5 MT is domestic production and rest imported. Though regional preferences do exist regarding the choice of cooking oil, lately Palmolein is more or less accepted nationally because of cost factors. Soybean oil is also a major commodity traded in the world market, exported from countries like the US, Brazil and others. India and China are the biggest importers of edible oils with the latter expected to overtake India in the near future. If the 30% calories level is taken as an average requirement, the global need for fat in 2050 for 10 billion people will work out to some thing like 200 million tons and achieving such a stiff target looks daunting if the past achievements are taken into consideration. India's own need will be around 30 MT.
The issues involved are: 1) the total quantity to be targeted 2) the qualitative make up of the oil pool and 3) the cost factor. Desired quantity is as worked out above and existing chemical, food and biotechnological tools may be able to achieve the target if the task is addressed collectively by all the countries. Quality is a major issue which has defied solution ever since the commercial edible oils practically wiped out the small enterprises world over using ghanies and small expellers. With the modern refining technology aiming for producing a bland oil ideal for cooking purposes, ignoring nutritional aspects, and over consumption leading to obesity epidemics in many countries, nutritional quality assumes wider significance. It is to be noted that short and medium (S/MCT) chain fatty acids are absorbed directly into the blood via intestinal capillaries and travel through the portal vein just as other nutrients do. In contrast long chain fatty acids are absorbed into the fatty walls of villi and reassembled again into triglycerides which are coated with cholesterol and protein into a compound called chylomicrons. Within the villi the chylomicrons enter a lymphatic capillary known as lacteal which merges with larger lymphatic vessels. It is transported in this format through the thoracic duct up to a location near the heart where arteries and veins are larger, getting emptied into the blood stream via the left subclavian vein. Thus fats coming under S/MCT do not need cholesterol for metabolism while LCT fats are dependent on it. Logically therefore S/MCT fats must be the preferred choice from the nutritional angle.
A larger question is the need for essential fatty acids like linolenic and linoleic acids by the human system which invariably come from liquid oils with long chain fatty acids. S/MCT fats have higher melting points being in solid or semisolid forms at room temperature. Two of the most famous S/MCT fats are coconut and palm kernel fats, both of which, paradoxically, are consumed directly to a limited extent but find extensive use as ingredients in processed food products. Though the characteristic flavor of coconut oil is not liked by many, limiting its direct use, palm kernel oil availability is rather limited as it is a by-product of palm oil industry. Ideally if these oils are available in abundance, their use could obviate many of the problems associated with fat consumption.
Synthetic fats may be an option the world has to keep in mind looking ahead but attempts so far were restricted to creating zero calorie fats or low calorie fats for use by weight watchers and over weight consumers. Sucrose fatty acid polyesters popularly known as Olestra is already in the market from the global giant Procter & Gamble containing 6-8 fatty acids but this is not digested in the body. Other companies like Nabisco, CPC International, Fritto Lay etc also have their versions of synthetic fats at different stages of evaluation. Most promising seems to be MCT, a medium Chain Triglyceride with C6-C10 fatty acids which is being readied for launch in the near future. Even if some of the synthetic fats are found to be acceptable, the moot point is from where the basic fatty acids and glycerol can be sourced in such huge quantities. Can biotechnology come to the rescue by evolving fermentation technology that can yield medium chain fatty acids? How about glycerol? Again by fermentation? Already there are bugs identified for producing both fatty acids and glycerol and further work can raise these technologies to commercial levels if sustained inputs are provided. As for essential fatty acids it is going to be a problem because the concentrated sources are fish which is not consumed by more than 25% of the population. Here again the biotechnology route can be examined.
Though synthetic fats cannot be expected to replace plant fats in the foreseeable future, a beginning has to be made and progressively more and more synthetic fats must be brought into the fat pool, sparing land for more critical crops like Rice, Wheat, Pulses and other food grains. A critical factor in the acceptability will be the cost of such fats to the consumers. If it is comparable to that of plant fats there is greater chance of gaining consumer acceptability. It is time a body like FAO takes up an inter governmental mission to prepare a route map for achieving ways and means to meet future global demand for fats without sacrificing land required for staples.

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