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Introduction: fatty acids and lipid structure major sources of lipids phospholipids lipids and nutrition. Processing: extraction of lipids from natural sources refining oil storage, transport, and handling fractionation interesterification of oils and fats hydrogenation of edible oils - technology and applications. Food emulsions: butter, margarine, spread, and baking fats ice cream cream alternatives. Nonaqueous foods: ghee, vanaspati, and special applications of fats in India chocolate and confectionery fats frying oils and salad oils. Special food applications: edible coating and film barriers spray processing of fat-containing foodstuffs - spray drying and cooling low calorie fats food emulsifiers lipid emulsions for intravenous nutrition and drug delivery the role of lipids in animal feeds. Nonfood uses: anionic detergents cationic surfactants nonionic surfactants lipids - their use in personal care products the use of oils and fatty acids in paints and surface coatings lubricants epoxidized oils bio-fuels products from castor oil.

Unsaturated fatty acids contain unsaturated centres and the carboxyl group both of which can be modified to give a range of interesting and useful compounds. The former have been discussed in detail in two recent references [8, 9] and therefore this paper will be concerned with the reactions of the carboxyl group and its derivatives. Attention is directed to the lactones, alcohols and their ethoxylates and sulfates, to the preparation of cleavable surfactants (acetals, ketals, ortho esters and ester quats), Guerbet alcohols and acids, alkyl polyglycosides and to amines and other nitrogen-containing compounds.

•In considering oilseed crops with modified fatty acid composition three question have to be addressed: why is it nesessary to have oils and fats with composition different from that supplied by nature? how can such changes be accomplished? and what modified material is already available or likely to be so in the near future?•Our increased understanding of the nutritional necessary to provide healthy food and of the physical properties required for good quality spreads or frying oils allow us to write specifications for ideal oils in terms of their fatty acid composition. However, this may not be sufficient. We may need to define triacylglyderol composition and, at the same time, to manage the minor components which also have a marked influence on shelf life and on dietary properties.•Our desire to modify fatty acid composition is at least one century old and over that period of time a range of methods-some technological and some biological-have been developed. This lecture is confined to the consideration of producing modified seed oils by conventional seed breeding or by transgenic modification.•Efforts have been directed particularly to changing the levels of saturated acids, oleic acid, and linolenic acid-sometimes raising these and somtimes lowering them. Thses changes have been applied to the major oilseeds-soybean, rapeseed/sanola, and sunflower - and also to linseed. However, because of inadequqte control of triacylglycerol composition, and the minor components, the new oils have not always displayed the desired properties.

Despite the fears of Malthus, production of the major food products (grains, oilseeds, and livestock) has kept pace with population growth on a global basis, though not always on a regional basis. This claim is supported with appropriate numbers and the ways in which food supplies have been increased are discussed. It seems likely that this can continue for at least another twenty years but the situation is less clear thereafter. However, man's ingenuity continues to provide hope for a favourable outcome.

Though designed by nature to effect hydrolysis of lipids, lipases can, under appropriate reaction conditions, promote ester formation through reaction of acids and alcohols (esterification) or of esters with acids (acidolysis), alcohols (alcoholysis), or other esters (interesterification). Compared with chemical processes already carried out on an industrial scale enzymic reactions occur under milder (and ‘greener’) conditions though they may take longer. Of greater significance is the specificity shown by the enzymes which permits the formation of lipid derivatives not easily prepared by conventional laboratory procedures. This review describes the lipases and their various specificities and reports on their use in hydrolysis and in the production of phospholipids, fatty acids, alkyl esters, mono- and di-acylglycerols, triacylglycerols, other esters, and amides. Some of these have already led to marketable products but for the most part the full potential of these reactions has yet to be realised. The reactions of other enzymes promoting interesting reactions at unsaturated centres are also described. © 1999 Society of Chemical Industry