پیشرفت های اخیر در شیمی و تکنولوژی چربی ها و روغن Recent Advances in Chemistry and Technology of Fats and Oils

Since we produced Fats and Oils: Chemistry and Technology in 1980, the trend we anticipated to up-date the classical texts of oils and fats has manifested itself. Bailey's famous textbook has been completely revised and a second edition of Bernardini's work has been produced. The present text is an attempt to provide some insight into the current state of the art. Chapter 1 discusses the physical properties of oils and fats with special reference to those properties which can be monitored to give an in- dication of the suitability of fats for chocolate production. The physical properties of the fats are often determined by the order in which the fatty acids are attached to the glyceride molecule. Ram Bhati, in the last article he wrote before his death, showed how mass spectrometry and chemical methods could be used to determine the sequence of fatty acids. Ram's essentially practical approach to the problem is exemplified by the section dealing with the experimental details of the techniques. Chapter 3 outlines some of the problems which can arise in industry when the lipid part of a foodstuff undergoes oxidation, whilst in Chapter 4 Patterson describes the major technique, hydrogenation, which is used to circumvent the problems caused by oxidation of the unsaturated fatty acids. In Chapter 4 the essentials of the theory are given to enable the reader to appreciate the design features of the apparatus. Chapter 5 deals with the analysis, mainly chromatographic, of lipids. Since milk fat is unique in commerce in having such a wide chain length range of fatty acids, it offers an opportunity to illustrate the special techniques needed to analyse these lipids. In Chapter 6 Barnes provides a major review of the structure of the v vi Preface wheat grain, the lipid composition and the lipid distribution within the grain. From this essential description of lipids the role of these lipids in the baking of bread is explained. The adulteration of commercial oils can be recognised by very ac- curate fatty acid analysis which is now possible by capillary gas liquid chromatography. However, the recognition of adulteration is dependent on having a standard fatty acid profile for one oil. Chapter 7 shows that there may be significant differences in the fatty acid composition from one variety to another within the same species. The review, though by no means exhaustive, attempts to bring together some results from the primary literature. Podmore shows in Chapter 8 that the naturally occurring fats such as are described in Chapter 7 need to be modified before industry can use them. The three main methods of hydrogenation, interesterification and physical processing are exemplified by showing how soya bean, lard, margarine and palm oils are affected by them. All of the chapters except one were originally presented at conferences and subsequently written up for this edition. The editors wish to thank the Royal Society of Chemistry for permis- sion to reproduce Dr Christie's article and the staff of Elsevier Applied Science for their help.