ABSTRACT
Hurdles, and Achievements .........................................................................605 20.5 Viability versus Functionality ..................................................................... 611 20.6 Probiotics in Fermented Dairy Products ..................................................... 613
20.6.1 Yogurt and Fermented Milks ......................................................... 613 20.6.2 Cheese ............................................................................................ 614 20.6.3 Frozen Products ............................................................................. 614
20.7 Microencapsulation of Probiotics ............................................................... 615 20.8 Translation of Functional Effects to Other Food Matrices: Dried
Cell-Free Fractions of Fermented Milks, Possibilities for the Development of Functional Additives ......................................................... 616
20.9 The Prebiotic Concept ................................................................................. 618 20.10 Chemical Composition, Chain Length, and Sources of Prebiotics ............. 618 20.11 Production of Oligosaccharides and Technological Properties
of Oligo-and Polysaccharides .................................................................... 619 20.12 Health Bene ts Attributed to Prebiotics ..................................................... 620 20.13 Synbiotics: Their Use in Dairy Products .................................................... 621 20.14 Concluding Remarks ................................................................................... 623 References .............................................................................................................. 623
The microbiota of the large intestine are thought to account for 95% of the total cells in the human body, to have a population of approximately 1011-1012 CFU/g of intestinal contents, and to represent approximately 1012 cells/g dry weight feces. A lot of
metabolic activity is carried out by the intestinal microbiota to support the constant elimination through feces. The intestine of the human baby is sterile at birth; the composition of the intestinal microbiota is relatively simple in infants but becomes more complex in adults. The intestinal microbiota is thought to derive from the microbiota of the mother (vagina, skin, and breast milk) and from the environment. With regard to bacterial species and strains, there is a high degree of variability among human subjects, and this variability depends on age, diet, immune status, stress factors, and many other factors not yet completely known. Indeed, the normal intestinal microbiota is as yet an unexplored organ of host defense (Isolauri et al. 2004). The main genera or species found within the intestinal microbiota include Bacteroides, Eubacterium, Ruminococcus, Clostridium, and Bifi dobacterium, and, as subdominant microbiota, Escherichia coli, Veillonella, Staphylococcus, Proteus, Streptococcus, and Lactobacillus (Tannock 2003).
