TABLE OF CONTENTS

Title Page    –         –         –         –         –         –         –         –         –         i

Certification –         –         –         –         –         –         –         –         –         ii

Dedication   –         –         –         –         –         –         –         –         –         iii

Acknowledgement –         –         –         –         –         –         –         –         iv-v

Table of Content    –         –         –         –         –         –         –         –         vi

CHAPTER ONE 

1.0     Introduction –         –         –         –         –         –         –         –         1-3

CHAPTER TWO

2.0     Overview of Food Fermentation          –         –         –         –         4-6

2.1     Types of Fermentation     –         –         –         –         –         –         7

2.2     Fermented Foods   –         –         –         –         –         –         –         8-10

2.3     Microorganism Associated in Food Fermentation    –         –         11

2.3.1  Bacteria        –         –         –         –         –         –         –         –         11-12

2.3.2  Yeast  –         –         –         –         –         –         –         –         –         12-13

2.3.3  Mould          –         –         –         –         –         –         –         –         13-14

2.4     African Fermented Foods          –         –         –         –         –         14

CHAPTER THREE: FOOD FERMENTATION

3.0     Fermentation Process       –         –         –         –         –         –         15-7

3.1     Nutritional Benefits of Food fermentation     –         –         –         17

3.1.1  Flavour Enhancement      –         –         –         –         –         –         17

3.1.2  Improvement of Nutritional Quality    –         –         –         –         17-19

3.1.3  Prevention of Toxic Effects of Mycotoxins    –         –         –         20

3.1.4  Intestinal pH Balance      –         –         –         –         –         –         21

3.2     Health Benefits of Food Fermentation –         –         –         –         21-24

3.3     Threats of Fermentation   –         –         –         –         –         –         25-28

CHAPTER FOUR

4.0     Summary and Conclusion

4.1     Summary     –         –         –         –         –         –         –         –         29

4.2     Conclusion  –         –         –         –         –         –         –         –         30

References

CHAPTER ONE

1.0 INTRODUCTION

Fermentation is one of the oldest biotechnology for the production of food products with desirable properties such as extended shelf-life and good organoleptic properties (Smid and Hugenholtz, 2010). Finished fermented foods usually have an improved microbial stability and safety and some can be stored even at ambient temperatures. Furthermore, there are several examples of fermentation processes which lead to an increase in nutritional value or digestibility of food raw materials (Jagerstad et al., 2005). Finally food fermentation processes and more precisely to link the diversity of the community of fermenting microbes and their properties to the energetics of the process and to product quality.

From a biochemical point of view, fermentation is a metabolic process of deriving energy from organic oxidizing agent. Fermentation plays different roles in food processing. Major roles attributed to fermentation are:

Preservation of food through formation of inhibitory metabolites such as organic acid (lactic acid, acetic acid, formic acid, and propionic acid), ethanol, carbon dioxide, diacetyl, reutrin, bacteriocins etc. often in combination with decrease of water activity (by drying or use of salt) (Gaggia et al., 2011).

Improving food safety through inhibition of pathogens (Adams and Nicolaides, 2008) or removal of toxic compounds (Ray and Panda, 2007).

Improving the nutritional value (Poutanen et al., 2009; van Boekel et al., 2010) and

Organoleptic quality of the food (Lacroix et al., 2010); Sicard and Legras, 2011).

The common groups of microorganisms involved in food fermentation are bacteria, yeast and moulds. The most important bacteria in the fermentation of foods are the Lactobacillaceae, which have the ability to produce lactic acid from carbohydrates. Other important bacteria are the acetic acid producing Acetobacter (mainly from fermentation of fruits and vegetables) and Bacillus (from fermentation of legumes) species. The beneficial yeast in terms of desirable food fermentation are form the saccharomyces family, especially S. cerevisiae. Yeast play an important role in the food industry as they produce enzymes that result in desirable biochemical reactions such as the production of wine, beer and ethanol and leavening of bread (Sicard and Legras, 2011). The lactic acid bacteria (LAB) are however, the most commonly found microorganisms in fermented foods (Segun and Karabiyikli, 2011). Their common occurrence in foods coupled with their long historical use contributes to their acceptance as GRAS (Generally Recognized As Safe) for human consumption (Silva et al., 2002). Thei chapter focuses briefly on the types of microorganisms involved in food fermentations, especially on the roles of LAB in fermented foods. In addition, the current research activities in the field of fermented foods are also discussed. The roles of other microorganisms such as yeast and moulds in food fermentation have been reviewed briefly.