Bioactive Substances of Microbial Origin

The use of foods that promote a state of well-being, better health, and reduction of the risk of diseases has become popular as the consumer is becoming more and more health conscious. This has resulted in the growth of functional foods in recent years, and there is an explosion of research being conducted on the area of bioactive substances from foods. An important constituent of them comes from microbial origin, taking into consideration of the vast variety of microorganisms including bacteria, mold, and yeast, which can cause bioconversion and biotransformation of food components. Foods that improve or change the intestinal microflora are of particular interest because of increasing knowledge of the role the intestinal microflora population plays in health and disease resistance. Recent advances on the research of prebiotics, probiotics, and synbiotics have provided valuable insights on how they impact intestinal flora and thus the health of the host, but it is very complicated and much more work still needs to be carried out. In an effort to review bioactive substances produced by microorganisms, this book chapter focuses on both active compounds produced in the fermentation process and in vivo by microbes in the intestine. Currently, there is a good selection of commercial functional products from microbial origin available in the market, and in this chapter, red yeast rice, Cordyceps, and fermented ginseng are given as examples.