Food, Fermentation, and Micro-organisms

Charles W. Bamforth, David J. Cook

• Publisher: Wiley-Blackwell
• Year: 2019
• ISBN:
  9781119557418
• Edition: 2
• Topic: Tecnología e ingeniería
• Subtopic: Ciencia de los alimentos

Fermentation and the use of micro-organisms is one of the most important aspects of food processing – an industry that is worth billions of US dollars world-wide. Integral to the making of goods ranging from beer and wine to yogurt and bread, it is the common denominator between many of our favorite things to eat and drink.

In this updated and expanded second edition of Food, Fermentation, and Micro-organisms, all known food applications of fermentation are examined. Beginning with the science underpinning food fermentations, the author looks at the relevant aspects of microbiology and microbial physiology before covering individual foodstuffs and the role of fermentation in their production, as well as the possibilities that exist for fermentation's future development and application. Many chapters, particularly those on cheese, meat, fish, bread, and yoghurt, now feature expanded content and additional illustrations. Furthermore, a newly included chapter looks at indigenous alcoholic beverages.

Food, Fermentation, and Micro-organisms, Second Edition is a comprehensive guide for all food scientists, technologists, and microbiologists working in the food industry and academia today. The book will be an important addition to libraries in food companies, research establishments, and universities where food studies, food science, food technology and microbiology are studied and taught.

1
The Science Underpinning Food Fermentations

Use the word ‘biotechnology’ nowadays and the vast majority of people will register an image of genetic alteration of organisms in the pursuit of new applications and products, many of them pharmaceutically relevant. Even the Merriam‐WebsterDictionary tells us that biotechnology is ‘biological science when applied especially in genetic engineering and recombinant DNA technology’. Fortunately the Oxford English Dictionary gives the rather more accurate definition as ‘the branch of technology concerned with modern forms of industrial production utilising living organisms, especially microorganisms, and their biological processes’.

Accepting the truth of the second of these, then we can realise that biotechnology is far from being a modern concept. It harks back historically vastly longer than the traditional milepost for biotechnology, namely Watson and Crick's announcement in the Eagle pub in Cambridge (and later, more formally, in Nature) that they had found ‘the secret of life’.

Eight thousand years ago our ancient forebears may have been, in their own way, no less convinced that they had hit upon the essence of existence when they made the first beers and breads. The first micro‐organism was not seen until draper Anton van Leeuwenhoek peered through his microscope in 1676 and neither were such agents firmly causally implicated in food production and spoilage until the pioneering work of Needham, Spallanzani and Pasteur and Bassi de Lodi in the eighteenth and nineteenth centuries.

Without knowing the whys and wherefores, the dwellers in the Fertile Crescent were the first to make use of living organisms in fermentation processes. They truly were the first biotechnologists. And so beer, bread, cheese, wine and most of the other foodstuffs being considered in this book come from the oldest of processes. In some cases these have not changed very much in the ensuing aeons.

Unlike the output from modern biotechnologies, for the most part we are considering high volume, low value commodities. However for products such as beer, there is now a tremendous scientific understanding of the science that underpins the product, science that is none the less tempered with the pressures of tradition, art and emotion. For all of these food fermentation products, the customer expects. As has been realised by those who would apply molecular biological transformations to the organisms involved in the manufacture of foodstuffs, there is vastly more resistance to this than for applications in, say, the pharmaceutical area. You don't mess with a person's meal!

Historically, of course, the micro‐organisms employed in these fermentation processes were adventitious. Even then, however, it was realised that the addition of a part of the previous process stream to the new batch could serve to ‘kick off’ the process. In some businesses this was called ‘back slopping’. We now know that what the ancients were doing was seeding the process with a hefty dose of the preferred organism(s). Only relatively recently have the relevant microbes been added in a purified and enriched form to knowingly trigger fermentation processes.

The two key components of a fermentation system are the organism and its feedstock. For some products, such as beer, there is a radical modification of the properties of the feedstock, rendering them more palatable (in the case of beer, the grain extracts pre‐fermentation are most unpleasant in flavour; by contrast, grape juice is much more acceptable). For other products the organism is less central, albeit still important. One thinks for instance of bread, where not all styles involve yeast in their production.

For some products, such as cheese, the end product is quite distinct from the raw materials as a result of a series of unit operations. For products such as beer, wine and vinegar the product is actually the spent growth medium – the excreta of living organisms if one was to put it crudely. Only occasionally is the product th...