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Table of content
CHAPTER 1. OVERVIEW OF PROBIOTICS 1
I.History and definition of probiotics ..1
1. History of probiotics........................................................................................1
2. Definition of probiotic ...........................................................................................1
II.Microbes used as probioticS .......3
III. Charateristics of probiotics 4
1. Properties of trains of probiotics ...........................................................................4
Lactobacillus..................................................................................................4
Bifidobacterium .............................................................................................5
Streptococcus .................................................................................................6
Enterococcus ..................................................................................................7
Lactococcus lactis ..........................................................................................7
2. Technologiacal properties ......................................................................................8
IV. Effects probiotics on human health ...........................................................................9
1. Disorders associated with the gastrointestinal tract ..............................................9
1.1. Prevention of diarrhea caused by certain pathogenic bacteria and viruses...10
1.2. Helicobacter pylori infection and complications .........................................11
1.3. Inflammatory diseases and bowel syndromes ..............................................11
1.4. Cancer ..........................................................................................................12
1.5. Constipation .................................................................................................12
2. Mucosal immunity ..............................................................................................12
3. Allergy ................................................................................................................13
4. Cardiovascular disease ........................................................................................14
5. Hypocholesterolemic effect ................................................................................14
6. Urogenital tract disorder......................................................................................15
6.1. Bacterial vaginosis ...................................................................................... 15
6.2. Yeast vaginitis ..............................................................................................16
6.3. Urinary tract infections ................................................................................16
7. Use of probiotics in otherwise healthy people ................................................... 16
8. Lactose intolerance .............................................................................................17
9. Reduction of the risk associated with mutagenicity and carcinogenicity ...........18
CHAPTER 2: DRYING PROBIOTICS ..............................................................................20
I. GENERAL MECHANISM ...........................................................................................20
1. Introduction .........................................................................................................20
2.1. Freeze drying ...............................................................................................21
2.2. Spray Drying ...............................................................................................21
2.3. Fluidized Bed Drying 23
2.4. Vacuum Drying 24
2.5. Foam formation ............................................................................................24
2.6. Mixed Drying Systems ................................................................................25
II. CURRENT DRYING METHODS ..........................................................................27
1. Freeze drying 27
1.1. Mechanism and procedure: 27
Purpose 27
Mechanism ........................................................................................................28
Procedure ..........................................................................................................28
1.2. Equipments and technological parameters .................................................29
1.2.1. Equipments ........................................................................................29
1.2.2.Processing parameters .....................................................................32
1.3. Factors influence freeze drying process .....................................................33
1.3.1. Depth of product in container ............................................................33
1.3.2. Vapor pressure diferential ..................................................................33
1.3.3. Amount of solid in the product, their particle size and their thermal conductance .................................................................................................34
1.4. The influence of processing factors on quality of product .........................34
2.Spray drying ..........................................................................................................42
2.1. Mechanism and material changes ...............................................................42
2.2.Equipment and technology parameters ........................................................45
2.3. Factors influencing the spray drying ...........................................................54
2.3.1. Kind of equipment and papameters ...................................................54
2.3.2. Dry matter content in the feed ...........................................................57
2.3.3. Air temperature ..................................................................................58
2.3.4.Other factors ........................................................................................59
2.4. Products .......................................................................................................60
III. COMPARISION ......................................................................................................60
IV. ACHIEVEMENTS IMPROVE SPRAY DRYING AND QUALITY OF PRODUCT
1. Cell physiology ....................................................................................................61
1.1. Application of mild stress prior to dehydration ...........................................61
1.2. Growth phase ...............................................................................................63
1.3. Growth media ...............................................................................................63
1.3.1. Carbohydrates ....................................................................................63
1.3.2.Compatible solutes: polyols, NaCl, amino acids and
amino derivatives .........................................................................................64
1.3.3. pH .......................................................................................................64
1.4. Genetic-modification of probiotic strains ...................................................65
2. Protective agents ..................................................................................................66
2.1. Amorphous glass forming ...........................................................................66
2.2. Eutectic crystallizing salts ...........................................................................66
3. Rehydration ..........................................................................................................67
4. Storage and packaging .........................................................................................68
5. Microencapsulation ..............................................................................................70
V. PRODUCTS CONTAINED PROBIOTICS ............................................................72
1. Forms of probiotic powder ...................................................................................72
VI. Storage the products contained probiotics ...............................................................73
CHAPTER 1: OVERVIEW OF PROBIOTICS
I. History and definition of probiotics:
1. History of probiotics:
Probiotics was first conceptualized by the Russian Nobel Prize winner and father
of modern immunology, Elie Metchnikoff, at the beginning of the 20th century.
He believed that the fermenting bacteria in milk products consumed by
Bulgarian peasants were responsible for their longevity and good health. Recent
research is now catching up with what he already knew. The actual word was
first used by Lilly and Stillwell in 1965 as a contrast to the word “antibiotics”.
By the 1970s, “probiotics” was being used in the sense that we know it today.
The use of live microorganisms in the diet has a long history and is one of the
oldest methods for producing and preserving food. Soured milks and such
cultured dairy products as kefir, koumiss, leben, and dahi were often used
therapeutically before the existence of microorganisms was recognized. Such
dairy products are mentioned in the Bible and the sacred books of Hinduism.
2. Definition of probiotic:
Probiotics are live microorganisms which, when they are administered in
adequate quantities, have beneficial effects on the health of the host. Probiotics
are products designed to deliver potentially beneficial bacterial cells to the
microbiotic ecosystem of humans and other animals.
II. Microbes used as probiotics:
Strains of lactic acid bacteria are the most common microbes employed as
probiotics, especially Lactobacillus and Bifidobacterium species, but lactococci,
some enterococci and some streptococci are also included as probiotics.
III.Charateristics of probiotics:
1. Properties of trains of probiotics:
Line Villeneuve, microbiologist among Abiasa, describes the conditions of
growth of probiotics. They are sensitive to great heat, the ideal temperature is
around 37°C, that is to say the same as the human body. Precisely, several
strains of these microoganismes referred to as probiotics are already part of the
normal flora of the intestine. The ideal pH is near the neutrality. Probiotics are
also sensitive to the oxygen and in the light.
Lactobacillus
Lactobacillus species are facultative anaerobes. They grow in the presence of
O2, however, and may convert it to H2O or H2O2. Lactobacilli normally
predominate in the small intestine, and they are known for their beneficial
effects which may antagonize potential pathogens.
Lactobacilli are sticks gram-positive, often prepared to string. More than 56
species of lactobacilli were enumerated, including 21 were found in human.
Certain strains metabolise sugars by way homofermentaire or hétérofermentaire
way.
Fig.1.2 Electron micrograph of Lactobacillus salivarius 118
adhering to Caco-2 cells (source: Neurogastroenterol Motil
2007;19:166–72).
interfacial area of the cell, possibly because the cells remain permeable throughout
storage. The accumulation of free radicals such as oxygen species within a cell
that cannot metabolize them, or actively transport them out of the cell, can result
in irreversible damaging processes occurring within the cell (Bozoglu et al., 1987).
Teixeira et al. (1995) found evidence of damage to the cell wall, cell membrane
and DNA during storage of L.delbrueckii ssp. bulgaricus. They attempted to use
an antioxidant to prolong cell viability during storage. The results showed an
increase in the death rate at –20 °C storage, but an increase in survival at 4 °C.
They believed the antioxidant ascorbic acid, could have pro-oxidant properties as
well and possibly produce hydroxyl radicals which can oxidize biological
molecules.
5. Microencapsulation
Microencapsulation helps to separate a core material from its environment until it
is released. It protects the unstable core from its environment, thereby improving
its stability, extends the core’s shelf life and provides a sustained and controlled
release (Figure 6.2). The structure formed by the micro-encapsulation agent
around the core substance is known as the wall. The properties of the wall system
are designed to protect the core and to release it at controlled rates under specific
conditions while allowing small molecules to pass in and out of the membrane
(Franjione and Vasishtha, 1995; Gibbs et al., 1999). The capsules may range from
submicron to several millimeters in size and can be of different shapes (Shahidi
and Han, 1993; Franjione and Vasishtha, 1995).
Compared to immobilisation/entrapment techniques, micro-encapsulation has
many advantages. The microcapsule is composed of a semipermeable, spherical,
thin and strong membranous wall. Therefore the bacterial cells are retained within
the microcapsules (Jankowski et al., 1997). Moreover, compared to an entrapment
matrix, here is no solid or gelled core in the microcapsule and its small diameter
helps to reduce mass transfer limitations. The nutrients and metabolites can diffuse
through the semipermeable membrane easily. The membrane serves as a barrier to
cell release and minimises contamination. The encapsulated core material is
released by several mechanisms such as mechanical rupture of the cell wall,
dissolution of the wall, melting of the wall and diffusion through the wall
(Franjione and Vasishtha, 1995).
Figure 6.2. Principle of Encapsulation: Membrane barrier isolates cells from the
host immune system while allowing transport of metabolites and extracellular
nutrients. Membrane with size selective pores (30-70 kDa). Source: INOTECH
Encapsulation.
Microencapsulation of various bacterial cultures including probiotics has also been
used for extending their storage life (Krasaekoopt, Bhandari, & Deeth, 2003).
Several methods of micro encapsulation of probiotic bacteria have been reported
and include extrusion technique, emulsion technique, cross-linking with cationic
polymers, coating with other polymers, mixing with starch and incorporation of
additives (Krasaekoopt et al., 2003). Song, Cho, and Park (2003), Kim, Kamara,
Good, and Enders (1988) Koo, Cho, Huh, Baek, and Park (2001) observed that
both non-encapsulated and encapsulated cells stored at 4oC had comparable
stability, while encapsulation provided a greater degree of protection against
increased storage temperature. O’Riordan, Andrews, Buckle, and Conway (2001)
prepared microencapsulated Bifidobacterium PL-1 with starch by spray-drying,
however the starch-coated cells did not display any enhanced viability compared
with free PL1 cells when exposed to acid conditions for 6 h or in two dry food
preparations over 20 days storage at ambient temperature (19–24 oC). Hence, the
efficiency of microencapsulation of probiotics depends on the encapsulating
materials and techniques of micro-encapsulation.
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Table of content
CHAPTER 1. OVERVIEW OF PROBIOTICS 1
I.History and definition of probiotics ..1
1. History of probiotics........................................................................................1
2. Definition of probiotic ...........................................................................................1
II.Microbes used as probioticS .......3
III. Charateristics of probiotics 4
1. Properties of trains of probiotics ...........................................................................4
Lactobacillus..................................................................................................4
Bifidobacterium .............................................................................................5
Streptococcus .................................................................................................6
Enterococcus ..................................................................................................7
Lactococcus lactis ..........................................................................................7
2. Technologiacal properties ......................................................................................8
IV. Effects probiotics on human health ...........................................................................9
1. Disorders associated with the gastrointestinal tract ..............................................9
1.1. Prevention of diarrhea caused by certain pathogenic bacteria and viruses...10
1.2. Helicobacter pylori infection and complications .........................................11
1.3. Inflammatory diseases and bowel syndromes ..............................................11
1.4. Cancer ..........................................................................................................12
1.5. Constipation .................................................................................................12
2. Mucosal immunity ..............................................................................................12
3. Allergy ................................................................................................................13
4. Cardiovascular disease ........................................................................................14
5. Hypocholesterolemic effect ................................................................................14
6. Urogenital tract disorder......................................................................................15
6.1. Bacterial vaginosis ...................................................................................... 15
6.2. Yeast vaginitis ..............................................................................................16
6.3. Urinary tract infections ................................................................................16
7. Use of probiotics in otherwise healthy people ................................................... 16
8. Lactose intolerance .............................................................................................17
9. Reduction of the risk associated with mutagenicity and carcinogenicity ...........18
CHAPTER 2: DRYING PROBIOTICS ..............................................................................20
I. GENERAL MECHANISM ...........................................................................................20
1. Introduction .........................................................................................................20
2.1. Freeze drying ...............................................................................................21
2.2. Spray Drying ...............................................................................................21
2.3. Fluidized Bed Drying 23
2.4. Vacuum Drying 24
2.5. Foam formation ............................................................................................24
2.6. Mixed Drying Systems ................................................................................25
II. CURRENT DRYING METHODS ..........................................................................27
1. Freeze drying 27
1.1. Mechanism and procedure: 27
Purpose 27
Mechanism ........................................................................................................28
Procedure ..........................................................................................................28
1.2. Equipments and technological parameters .................................................29
1.2.1. Equipments ........................................................................................29
1.2.2.Processing parameters .....................................................................32
1.3. Factors influence freeze drying process .....................................................33
1.3.1. Depth of product in container ............................................................33
1.3.2. Vapor pressure diferential ..................................................................33
1.3.3. Amount of solid in the product, their particle size and their thermal conductance .................................................................................................34
1.4. The influence of processing factors on quality of product .........................34
2.Spray drying ..........................................................................................................42
2.1. Mechanism and material changes ...............................................................42
2.2.Equipment and technology parameters ........................................................45
2.3. Factors influencing the spray drying ...........................................................54
2.3.1. Kind of equipment and papameters ...................................................54
2.3.2. Dry matter content in the feed ...........................................................57
2.3.3. Air temperature ..................................................................................58
2.3.4.Other factors ........................................................................................59
2.4. Products .......................................................................................................60
III. COMPARISION ......................................................................................................60
IV. ACHIEVEMENTS IMPROVE SPRAY DRYING AND QUALITY OF PRODUCT
1. Cell physiology ....................................................................................................61
1.1. Application of mild stress prior to dehydration ...........................................61
1.2. Growth phase ...............................................................................................63
1.3. Growth media ...............................................................................................63
1.3.1. Carbohydrates ....................................................................................63
1.3.2.Compatible solutes: polyols, NaCl, amino acids and
amino derivatives .........................................................................................64
1.3.3. pH .......................................................................................................64
1.4. Genetic-modification of probiotic strains ...................................................65
2. Protective agents ..................................................................................................66
2.1. Amorphous glass forming ...........................................................................66
2.2. Eutectic crystallizing salts ...........................................................................66
3. Rehydration ..........................................................................................................67
4. Storage and packaging .........................................................................................68
5. Microencapsulation ..............................................................................................70
V. PRODUCTS CONTAINED PROBIOTICS ............................................................72
1. Forms of probiotic powder ...................................................................................72
VI. Storage the products contained probiotics ...............................................................73
CHAPTER 1: OVERVIEW OF PROBIOTICS
I. History and definition of probiotics:
1. History of probiotics:
Probiotics was first conceptualized by the Russian Nobel Prize winner and father
of modern immunology, Elie Metchnikoff, at the beginning of the 20th century.
He believed that the fermenting bacteria in milk products consumed by
Bulgarian peasants were responsible for their longevity and good health. Recent
research is now catching up with what he already knew. The actual word was
first used by Lilly and Stillwell in 1965 as a contrast to the word “antibiotics”.
By the 1970s, “probiotics” was being used in the sense that we know it today.
The use of live microorganisms in the diet has a long history and is one of the
oldest methods for producing and preserving food. Soured milks and such
cultured dairy products as kefir, koumiss, leben, and dahi were often used
therapeutically before the existence of microorganisms was recognized. Such
dairy products are mentioned in the Bible and the sacred books of Hinduism.
2. Definition of probiotic:
Probiotics are live microorganisms which, when they are administered in
adequate quantities, have beneficial effects on the health of the host. Probiotics
are products designed to deliver potentially beneficial bacterial cells to the
microbiotic ecosystem of humans and other animals.
II. Microbes used as probiotics:
Strains of lactic acid bacteria are the most common microbes employed as
probiotics, especially Lactobacillus and Bifidobacterium species, but lactococci,
some enterococci and some streptococci are also included as probiotics.
III.Charateristics of probiotics:
1. Properties of trains of probiotics:
Line Villeneuve, microbiologist among Abiasa, describes the conditions of
growth of probiotics. They are sensitive to great heat, the ideal temperature is
around 37°C, that is to say the same as the human body. Precisely, several
strains of these microoganismes referred to as probiotics are already part of the
normal flora of the intestine. The ideal pH is near the neutrality. Probiotics are
also sensitive to the oxygen and in the light.
Lactobacillus
Lactobacillus species are facultative anaerobes. They grow in the presence of
O2, however, and may convert it to H2O or H2O2. Lactobacilli normally
predominate in the small intestine, and they are known for their beneficial
effects which may antagonize potential pathogens.
Lactobacilli are sticks gram-positive, often prepared to string. More than 56
species of lactobacilli were enumerated, including 21 were found in human.
Certain strains metabolise sugars by way homofermentaire or hétérofermentaire
way.
Fig.1.2 Electron micrograph of Lactobacillus salivarius 118
adhering to Caco-2 cells (source: Neurogastroenterol Motil
2007;19:166–72).
interfacial area of the cell, possibly because the cells remain permeable throughout
storage. The accumulation of free radicals such as oxygen species within a cell
that cannot metabolize them, or actively transport them out of the cell, can result
in irreversible damaging processes occurring within the cell (Bozoglu et al., 1987).
Teixeira et al. (1995) found evidence of damage to the cell wall, cell membrane
and DNA during storage of L.delbrueckii ssp. bulgaricus. They attempted to use
an antioxidant to prolong cell viability during storage. The results showed an
increase in the death rate at –20 °C storage, but an increase in survival at 4 °C.
They believed the antioxidant ascorbic acid, could have pro-oxidant properties as
well and possibly produce hydroxyl radicals which can oxidize biological
molecules.
5. Microencapsulation
Microencapsulation helps to separate a core material from its environment until it
is released. It protects the unstable core from its environment, thereby improving
its stability, extends the core’s shelf life and provides a sustained and controlled
release (Figure 6.2). The structure formed by the micro-encapsulation agent
around the core substance is known as the wall. The properties of the wall system
are designed to protect the core and to release it at controlled rates under specific
conditions while allowing small molecules to pass in and out of the membrane
(Franjione and Vasishtha, 1995; Gibbs et al., 1999). The capsules may range from
submicron to several millimeters in size and can be of different shapes (Shahidi
and Han, 1993; Franjione and Vasishtha, 1995).
Compared to immobilisation/entrapment techniques, micro-encapsulation has
many advantages. The microcapsule is composed of a semipermeable, spherical,
thin and strong membranous wall. Therefore the bacterial cells are retained within
the microcapsules (Jankowski et al., 1997). Moreover, compared to an entrapment
matrix, here is no solid or gelled core in the microcapsule and its small diameter
helps to reduce mass transfer limitations. The nutrients and metabolites can diffuse
through the semipermeable membrane easily. The membrane serves as a barrier to
cell release and minimises contamination. The encapsulated core material is
released by several mechanisms such as mechanical rupture of the cell wall,
dissolution of the wall, melting of the wall and diffusion through the wall
(Franjione and Vasishtha, 1995).
Figure 6.2. Principle of Encapsulation: Membrane barrier isolates cells from the
host immune system while allowing transport of metabolites and extracellular
nutrients. Membrane with size selective pores (30-70 kDa). Source: INOTECH
Encapsulation.
Microencapsulation of various bacterial cultures including probiotics has also been
used for extending their storage life (Krasaekoopt, Bhandari, & Deeth, 2003).
Several methods of micro encapsulation of probiotic bacteria have been reported
and include extrusion technique, emulsion technique, cross-linking with cationic
polymers, coating with other polymers, mixing with starch and incorporation of
additives (Krasaekoopt et al., 2003). Song, Cho, and Park (2003), Kim, Kamara,
Good, and Enders (1988) Koo, Cho, Huh, Baek, and Park (2001) observed that
both non-encapsulated and encapsulated cells stored at 4oC had comparable
stability, while encapsulation provided a greater degree of protection against
increased storage temperature. O’Riordan, Andrews, Buckle, and Conway (2001)
prepared microencapsulated Bifidobacterium PL-1 with starch by spray-drying,
however the starch-coated cells did not display any enhanced viability compared
with free PL1 cells when exposed to acid conditions for 6 h or in two dry food
preparations over 20 days storage at ambient temperature (19–24 oC). Hence, the
efficiency of microencapsulation of probiotics depends on the encapsulating
materials and techniques of micro-encapsulation.
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