Introduction

Fermentation and drying are the oldest methods of food preservation and preparation. Unlike drying, fermentation gives food a variety of avors, tastes, textures, sensory attributes, and nutritional and therapeutic values. The history of fermented foods is discussed by Prajapati and Nair (2003) and Hutkins (2006). The art of fermentation originated in the Middle East, the Indian subcontinent, and the Far East. As early as 4000 and 3000 BC, fermented bread and beer were known in Pharaonic Egypt and Babylonia. In the sacred book of the Hindus, Rigveda (ca. 1500 BC), it was mentioned that fermentation technology started to develop after observations of fermentative changes in fruits and juices (Upadhyay 1967; Prajapati and Nair 2003). Despite the long history of fermentations, the understanding of the sciences behind these arts came quite late and are not yet well achieved. In 1857, Louis Pasteur was the rst to show that bacteria is involved in milk fermentation, a rst step in elucidating the chemistry of fermentation. He described the process by the term la vie sans air, or life without air. Fermentation carried out without oxygen is an anaerobic process, and organisms that must live without air are called obligate anaerobes, while those that can live with or without air are called facultative aerobes. The understanding of the role of enzymes in fermentation reactions followed the experiments carried out in 1896 by the German chemists Hans and Eduard Buchner. In 1907, Lactobacillus was isolated from fermented milk by the Russian microbiologist Ellie Metchnikoff, and in 1930, Hans von Euler obtained the Nobel Prize for his work on the fermentation of sugars and fermentation enzymes.