Lipase-catalysed synthesis of modified lipids

The term sTAG was first introduced by Babayan (1987) and can be taken to include any fat or oil that has been modified in terms of its fatty acid composition by techniques like hydrogenation, blending, interesterification, directed esterification, fatty acid enrichment, genetic engineering of plants, etc. However, a stricter definition of a true sTAG includes only those fats or oils 

Reduced environmental pollution Availability of lipases with different properties (possibility of screening) Many possibilities for reaction engineering 

Ability to improve lipase properties (e.g. by genetic engineering and/or directed evolution and/or rational protein design and/or mutagenesis) Immobilized lipases can be used many times 

Despite the lack of selectivity, some structured lipid-like products have been synthesized by chemicals methods. The catalyst most often used for chemical interesterification of triacylglycerols or for alcoholysis between triacylglycerols and fatty acids is sodium methoxide, which is more active than other base, metal or acid catalysts. In general, sodium alkoxides are easy to use as catalysts. They are inexpensive, active at relatively low temperatures (50-90°C), and are effective at low concentrations. Although no regioselectivity or fatty acid selectivity occurs, the chemically synthesized commercial products listed in Table 2 contain sTAG with the desired nutritional function. 

Among low-calorie structured fats, Salatrim and Caprenin are well known because they are widely applied in food products (Auerbach et al, 

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