Advances in Fermented Foods and Beverages

Improving Quality, Technologies and Health Benefits

Wilhelm Holzapfel

• Publisher: Woodhead Publishing
• Year: 2014
• Print ISBN: 9781782420156
• eBook ISBN: 9781782420248
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Fermentation is used in a wide range of food and beverage applications, and the technology for enhancing this process is continually evolving. This book reviews the use of fermentation in foods and beverages and key aspects of fermented food production. Part one covers the health benefits of fermented foods. Part two includes chapters on fermentation microbiology, while part three looks at ways of controlling and monitoring the quality and safety of fermented foods. Part four covers advances in fermentation technology. Finally, part five covers particular fermented food products.

Part One

Fermented foods and health

Outline

1. Probiotic fermented foods and health promotion

2. Exopolysaccharides from fermented dairy products and health promotion

3. Bioactive peptides from fermented foods and health promotion

4. Conjugated linoleic acid production in fermented foods

5. Effect of fermentation on the phytochemical contents and antioxidant properties of plant foods

6. Traditional cereal fermented foods as sources of functional microorganisms

1

Probiotic fermented foods and health promotion

A.C. Ouwehand¹, and H. Röytiö^{2 1}DuPont, Kantvik, Finland ²University of Turku, Turku, Finland

Abstract

Different types of fermented foods have been used by humans for thousands of years, and these foods have been considered to promote the health of their consumer. Fermented foods contain beneficial microbes, particularly lactic acid bacteria, some strains of which may be potential probiotics, and which, in general, are responsible for texture, flavour and better preservation of fermented foods. In the light of scientific evidence accumulated mainly since the 1990s, these microbes also have a significant impact on the wellbeing of humans. This chapter focuses on discussing probiotic microbes and their role in maintaining health and reducing the risk of various diseases of the human.

Keywords

Disease; Fermented foods; Health; Microbiota; Probiotics

1.1. Introduction

Food fermentation has, throughout much of human history, been the most common way of preserving perishable foods, thereby maintaining and in some cases even improving the nutritional value of these foods. Genesis 18:8 refers to how Abraham serves curds and milk to his guests. Not surprisingly, some of these fermented foods were perceived to be inherently healthy. The mechanism behind this preservation was not clarified until 1857, when Louis Pasteur identified “lactic yeast” as the source of lactic acid fermentation. A first “scientific” promotion of fermented food specifically as a health product came in the early 1900s with Ilya Metchnikoff, who advertised yogurt, fermented with the Bulgarian bacillus, and insisted it would contribute to longevity (Metchnikoff, 1907). In the 1930s, Minoru Shirota specifically isolated a health-promoting microbe and introduced the oldest still-existing probiotic food, Yakult.

Probiotics have been defined as “live microorganisms which when administered in adequate amounts confer a health benefit on the host” (FAO/WHO, 2002). Maintaining viability imposes some technological requirements on the manufacturing of the probiotic food product; the minimal counts should be guaranteed until the end of shelf life. The required level of these counts is likely to depend on the probiotic strain and the intended health benefit. As a rule of thumb, a minimum of 10⁹ colony-forming units (CFU)/consumption is used (Forssten, Sindelar, & Ouwehand, 2011). A correct approach would be to use a minimum dose according to that used in studies documenting the given health benefit.

Although probiotics are widely consumed as dietary supplements, the focus of the present chapter is on fermented probiotic foods. Most commercially available probiotics belong to the genera Bifidobacterium and Lactobacillus; strains from other genera are being marketed as well, but these rarely find application in fermented foods and will thus not be discussed here.

1.2. Probiotic fermented foods and health promotion

Probiotics can be included in many different foods, fermented and unfermented. The food matrix is known to have an important role in the stability of probiotics (Forssten et al., 2011). Manufacturers take this into account when developing such foods. However, which role the matrix plays in efficacy is less well understood. For some strains it does not seem to play a role, while it does for others. This topic requires further investigation and is not discussed here owing to lack of information. It is important to realise that diet is likely to be a bigger cause of variation than the matrix of one or another probiotic food (Kelly, Colgan, & Frank, 2012).

1.2.1. Different types of fermented probiotic foods

Numerous fermented foods exist, but not all of these food classes can be linked with the probiotic concept, such as alcoholic beverages and fermented meats, or foods in which the fermentations merely fulfil a technological function in the processing of the food, such as in coffee, tea and cocoa.

1.2.2. Fermented dairy foods/beverages

Fermented dairy foods are the most widely used carriers of probiotics in Western societies, in particular yogurt and yogurt-type drink products. This may have historic reasons as mentioned above, but it has also practical reasons. Most commercially available probiotics belong to the genera Bifidobacterium and Lactobacillus. Members of these genera tend to grow well in milk, and it may even be their most common habitat.

In fermented probiotic dairy products, probiotics are usually accompanied by starter cultures such as Lactobacillus delbrueckii subsp. bulgaricus and/or Staphylococcus thermophilus. There are two main reasons for the inclusion of starter cultures in a probiotic product. The first is technological: starter cultures provide structure and flavour to the product. In addition, starter cultures support functionality; some probiotics do not grow well as a pure culture in milk and grow better in symbiosis with a starter culture.

Besides fresh fermented dairy products, probiotics can be included in nonfermented milk such as the so-called “sweet acidophilus milk”. The milk is not sweet in the sense of sweet taste, but is referred to as such because it is not sour (Mcdonough, Hitchins, Wong, Wells, & Bodwell, 1987).

Furthermore, probiotics can be included in cheese. Despite the long ripening and shelf life of cheese, probiotic counts appear to be stable in cheese for months. By optimizing fermentation techniques, it is feasible to produce a good-quality cheese with high probiotic counts so that a standard portion of cheese (15 g) provides a dose of at least 10⁹ CFU (Ibrahim et al., 2010).

1.2.3. Fermented soy foods/beverages

In Asian societies, fermented soy foods are common. They are, however, not typically used to function as a delivery matrix for probiotics. Probiotic soy products most commonly designed to resemble dairy products are called “soy yogurts”. Lactic fermentation of “soy milk” may improve the bioavailability of isoflavones, improve mineral availability and increase the level of B vitamins (Rekha & Vijayalakshmi, 2010). Fermentation has the additional advantage of reducing the bean flavour of soy foods. In general, soy yogurts aim at providing a vegetarian/vegan alternative to regular (probiotic) yogurt and are not developed specifically as carriers for probiotics. Nevertheless, the stability of probiotics in a fermented soy matrix is usually good and is very similar to that in yogurt.

1.2.4. Fermented plant foods/beverages

Lactic fermented plant foods are common in Asian, African and East European societies. These are fermented vegetables such as sauerkraut and kimchi, which are mainly based on spontaneous fermentations dictated by the storage conditions and ingredients used for this fermentation (Jung et al., 2011).

Lactic fermented cereals are common, such as in sourdough, although obviously subsequent processing (baking) will not allow survival of microbes. Lactic ferm...

Table of contents

• Cover image
• Title page
• Table of Contents
• Related titles
• Copyright
• List of contributors
• Woodhead Publishing Series in Food Science, Technology and Nutrition
• Part One. Fermented foods and health
• Part Two. Fermentation microbiology
• Part Three. Quality and safety of fermented foods
• Part Four. Particular products, and approaches towards quality improvement and fermentation control
• Index