Wallerstein Laboratories Communications

From listing the steps involved in a sensory evaluation project to presenting advanced statistical methods, Sensory Evaluation Techniques, Fourth Edition covers all phases of sensory evaluation. Like its bestselling predecessors, this edition continues to detail all sensory tests currently in use, to promote the effective employment of these tests, and to describe major sensory evaluation practices. The expert authors have updated and added many areas in this informative guide. New to this edition are expanded chapters on qualitative and quantitative consumer research and the SpectrumTM method of descriptive sensory analysis that now contains full descriptive lexicons for numerous products, such as cheese, mayonnaise, spaghetti sauce, white bread, cookies, and toothpaste. Also new in this chapter is a set of revised flavor intensity scales for crispness, juiciness, and some common aromatics. The book now includes an overview of Thurstonian scaling that examines the decision processes employed by assessors during their evaluations of products. Another addition is a detailed discussion of data-relationship techniques, which link data from diverse sources that are collected on the same set of examples. With numerous examples and sample tests, Sensory Evaluation Techniques, Fourth Edition remains an essential resource that illustrates the development of sensory perception testing.

During the latter part of the last century and the early years of this century, the microbiology of beer and the brewing process played a central role in the development of modern microbiology. An important advance was Hansen's development of pure culture yeasts for brewery fermentations and the recognition of different species of brewing and wild yeasts. The discovery by Winge of the life cycles of yeasts and the possibilities of hybridization were among the first steps in yeast genetics with subsequent far-reaching consequences. Over the same period the contaminant bacteria of the fermentation industries were also studied, largely influenced by Shimwell's pioneering research and resulting in the improvement of beer quality. Towards the end of the century, the influence of brewing microbiology within the discipline as a whole is far less important, but it retains an essential role in quality assurance in the brewing industry. Brewing microbiology has gained from advances in other aspects of microbiology and has adopted many of the techniques of biotechnology. Of particular relevance are the developments in yeast genetics and strain improvement by recombinant DNA techniques which are rapidly altering the way brewers view the most important microbiological components of the process: yeast and fermentation.

Much has happened in the brewing industry since the last edition of this book was published in 1996. In particular, there has been substantial con solidation of larger brewing companies as major multinational concerns, and at the other end of the spectrum the microbrewing scene in various parts of the world has become established as a sustainable enterprise. For those involved in the scientific and technical aspects of fermented bever age production the changes have been no less daunting. The complete genome sequence of Saccharomyces cerevisiae has been determined and studies are underway in numerous laboratories throughout the world to unravel the expression of the genome (transcriptomics and proteomics) and understand exactly "how a yeast works. " This will undoubtedly con tribute to our understanding of yeast fermentation and flavor generation in a revolutionary way because it will enable the simultaneous monitor ing of all genes in the organism during the fermentation. In Chapters 2 and 3 of this volume Colin Slaughter and John Hammond bring the reader up-to-date in this rapidly moving area and cover the remarkable achievements of modern biochemistry and molecular biology. lain Campbell has also revised the systematics of culture and wild yeasts in Chapter 7. The other major technical change since the last edition of this book is the introduction of molecular characterization and detection of microor ganisms based largely, but not exclusively, on the polymerase chain reac tion (PCR) for amplification of specific DNA fragments.