Fd Chem. To~:i¢. Vol, 20. pp. 231 to 236. 1982 0278-6915/82/020231-06503.00/0 Prinled in Great Britain Pergamon Press Ltd

REVIEWS OF RECENT PUBLICATIONS

Natural Colours for Food and Other Uses. Edited by J. N. Counsell. Applied Science Publishers Ltd, Lon- don, 1981. pp. x + 167. £13.00.

Despite the title, well over half of this book (the proceedings of a conference held in 1979) is devoted to general studies of the basic nature of colour, colour psychology and the importance of colour in food, pharmaceuticals and cosmetics. This unfortunately leaves a mere two chapters to deal specifically with natural colourants for foods. Whilst, to some extent, this disproportionate allocation of space can be ascribed to the relative paucity of data in this increas- ingly emotive field, the absence of even brief com- ments on certain important natural colourants, such as carmine, the extracts or oleoresins of turmeric and paprika, and the caramels, cannot similarly be explained away.

The initial chapter outlines in an interesting and readable way the physics of colour, its measurement and its perception by man, and the psychophysical theme is continued in the following presentation, con- cerned with the psychology of colour usage in foods. Reinforcing the vital and integral role of colour in man's society, three further chapters feature a dis- cussion of its importance in foods (both to consumer and manufacturer), a review of the characteristics and biological functions of colour in nature, and a con- sideration of its cosmetic use by man. In the field of pharmacy, the value of colour lies particularly in pre- venting confusion between drug preparations, in pro- moting rapid identification and in marking areas of treatment.

For readers seeking the topic implied in the title the book is saved, to some degree, by two informative chapters dealing admirably with various technological aspects of some of the natural colourants used in food. The first of these chapters introduces the reader to the carotenoids--their synthesis, their chemical, physical and biological properties and their uses. Detailed discussion of the forms available commer- cially for use in fat- or water-based foods and their practical use in virtually all types of food is followed by a section concerned with the estimation of levels of added carotenoids in food products. The next chapter forms a similarly useful reference text for the techno- logist, considering in turn the occurrence, chemistry, composition, properties and applications pertaining to riboflavin, chlorophylls, betalaines and anthocya- nins. The section on applications is particularly inter- esting, since the suitability of individual colourants for specific foods depends on a combination of the colorant characteristics (outlined in the previous sections) and the properties of the food to be col- oured. This chapter is completed by a 'quick-refer- ence' table, which clearly shows that chlorophyll and the anthocyanins (with modifications in some cases) can be adequately used in most types of food, whilst the acceptable applications of beetroot juice and the riboflavins are more restricted.

The naive and simplistic approach of the final chapter, relating to legislation, is in line with the early sections of the book, providing no more than a very brief introduction to this complex aspect of the use of natural food colourants.

This book provides useful background reading for anyone with interests involving the colours field, since it draws together information on many aspects rarely considered together in one volume.

Fragrance and Flavour Substances. Edited by R. Cro- teau, D & P S Verlag, Pattensen, FRG, 1980. pp. 200. DM 54.00.

This publication contains the papers presented at the Second International Haarmann & Reimer Sym- posium on Fragrance and Flavor Substances held in New York in September 1979. The theme of the sym- pos ium-New Products, Processes and Aspects of Product Safety--was tackled by contributors from the USA, Germany and France.

Thirteen of the eighteen papers describe develop- ments in the chemistry of perfumes and food flavours. Another (the first) is concerned particularly with the biosynthesis of terpenes (including d-camphor in sage and /-menthol in mint), while the last feur deal with some toxicological and legislative aspects of flavours, fragrances and cosmetics.

The chemical chapters feature synthetic routes (in- cluding manufacturing processes) to flavourings and fragrances (e.g. pepper alkaloids, jasmine and sandal- wood fragrances, and macrocyclic ketones) and some of their key intermediates. There are also comments on the effect structure has on odour. Thus 2-methyl- nonanal exhibits "a fatty, green note", whilst in con- trast 3-methylnonanal gives "a lively, fresh and youth- ful top note".

The toxicological contributions include a brief review of the mechanism by which some fragrances cause skin sensitization, with comments on the possi- bilities and limitations of applying structure-activity relationships to the tentative prediction of skin-con- tact hazards. The final papers discuss, from various viewpoints, the FDA's approaches to the study and control of fragrances, cosmetics and food flavourings.

Although it neglects developments in analytical methods, this book provides a succinct appraisal of current fragrance and flavour research, and should interest workers in either of these areas. The absence of any sort of index, however, lessens its value as a source of specific information.

Food Chemicals Codex. 3rd Ed. Committee on Codex Specifications, Food and Nutrition Board, Division of Biological Sciences, Assembly of Life Sciences, National Research Council. National Academy Press, Washington, DC, 1981. pp. xxxi + 735, $45.00.

The specifications in the Food Chemicals Codex are now officially recognized not only by the FDA

231