Fermentation Chapter 3

Front 1

3 Examples of non fermented counterparts

Back 1

Sour cream, cottage cheese, summer sausage

Front 2

Ways to initiate food fermentations

Back 2

-Reliance on indigenous microorganisms present on food material -Back slopping -Starter cultures

Front 3

Back Sloping

Back 3

Adding some of the fermented material froma batch to a new one to start fermentation

Front 4

Starter culture definition

Back 4

“…starter cultures consist of microorganisms that are inoculated directly into food materials to overwhelm the existing microflora and bring about desired changes in the finished product.”

Front 5

The changes that starter cultures generate

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Novel functionality Enhanced preservation Reduced food safety risks Improved nutritional value Improved health value Enhanced sensory qualities Increased economic value

Hint 5

Similar to funtions of fermented foods (7)

Front 6

1883 Carlsberg Brewer, Copenhagen, Denmark Relevence

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First to isolated ale and lager yeasts

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Lager yeast first name and revised name

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Saccharomyces carlbergensis later reclassified asSaccharomyces pastonatus)

Hint 7

brewery name

Front 8

Pasteur

Back 8

wine fermentations performed by yeast

Hint 8

wine...

Front 9

Hermann Muller-Thurgau

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use of select yeast strains for wine

Front 10

Christian Ditlev Ammentorp Hansen

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isolation of enzyme chymosin and production of natural coloring agents

Front 11

Charles and Max Fleischmann

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first yeast factory

Front 12

Fred Lallemand

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first yeast factory in Canada

Front 13

Storch (Denmark), Weigman (Germany), and Conn (United States)

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lactic acid bacteria starter cultures to ripen cream (cultured butter production)

Front 14

Available Formats of starter cultures

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Liquid, air-dried, freeze-dried, and frozen starter cultures

Front 15

Liquid Cultures (for dairy)

Medium-

Problem-

solution-

Back 15

Medium: Heat-sterilized milk Problems: over-acidification, loss of viability Solutions: calcium carbonate (buffer)

Front 16

Air dried cultures

Process

Problem

Back 16

Process: filter liquid cultures through cheese cloth and dehydrate (15 -18oC) Problems: culture revival issues

Front 17

Freeze dry cultures

problem

Back 17

Problems: cell viability

Front 18

Dominant culture formats today

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Frozen & freeze dried

Front 19

Starter culture Microorganisms

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Bacterial starter cultures Yeast starter cultures Mold starter cultures

Front 20

Lactic acid bacteria traits

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Gram-positive Catalase-negative Homofermentative or heterofermentative Wide temperature range for growth Variations in salt tolerance, osmotolerance, aerobiosis

Front 21

4 genera of lactic acid starter culture bacteria

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Lactococcus, Streptococcus, Leuconostoc, and Lactobacillus

Front 22

Main functions of dairy starter cultures

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-Fermentation of milk sugar (lactose) and acidification of the milk or cheese- Generation of flavor or flavor precursors -Modification of texture properties

Front 23

Main function of bread starter culture Lactobacillus sanfrancisansis

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Fermentation of maltose and lowering the dough pH

Front 24

Main function of sausage starter culturePediococcus acidilactici

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Production of lactic acid and reduction of meat pH to a level inhibitory to pathogenic microorganisms

Front 25

Main function of Oenococcus oeni

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Conversion of malic acid to lactic acid

Front 26

Propionibacterium freudenreichii subsp. shermanii used to make

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Emmenthaler and other Swiss type cheese

Front 27

Brevibacterium linens used to make

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Surface ripened cheesessuch as Limburger, Muenster, and Brick

Front 28

Micrococcus spp. used to make

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Dry fermented sausages

Front 29

Acetobacter acetii used to make

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Vinigar

Front 30

Forms of starter yeast

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Moist yeast cakes Active dry yeast packages

Front 31

Beer yeast

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Saccharomyces cerevisiae

Front 32

The blue mold cheese cultures

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Penicillum roqueforti

Front 33

White mold cheese cultures

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Penicillum camemberti

Front 34

Tempeh starter culture

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Rhizopus microsporus subsp. oligosporus

Front 35

miso starter culture

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Aspergillus sojae & Aspergillusoryzae

Front 36

Significance of accurate species/strainidentification on starterculture packaging

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-(Gras) Generaly recognised as safe status

-Knowledge of nutritional and maintenance needs- Probiotic status

Front 37

Bulk cultures

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“…is the equivalent of several intermediate cultures that traditionally have been required to build up the culture.”

Front 38

Bulk culture benefits

Back 38

-Remain viable for many hours

-can be used to innoculate production vats throught a manufacturing day

Front 39

Direct to vat cultures

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cultures added directly to the vat tank to innoculate the product without the need to make a starter or bulk culture

Front 40

direct to vat cultures advantages

Back 40

-Eliminate the labor, hardware, capital costs- Eliminate leftover or wasted bulk culture- Available in various forms- Frozen concentrates- Pourable pellets-Lyophilized powders- Less trouble with bacteriophages- Reduction of mixed strain compositional variability

Front 41

direct to vat cultures disadvantages

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Must be highly concentrated (potential viability loss from processing)

More expensive than bulk cultures

Front 42

Mixed/ Undefined cultures

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“…Blends of different organisms, representing several genera, species, or even strains…”

Front 43

Notable areas mixed cultures are used

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Parmigiano Reggiano cheese Gouda and Edam cheeses

Front 44

1 benefit & 1 detriment of using mixed cultures

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-Less prone to bacteriphage infections- Product quality may be inconsistent

Front 45

Defined cultures

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“…a single individual strain or as a blend of two or more strains…”

Must be identified for relevant metabolic and physiological properties

Front 46

Defined cultures in yogurt

Back 46

Streptococcus thermophilus Lactobacillus delbrueckii subsp. bulgaricus

Front 47

defined cultures in sour cream

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Leuconostoc sp.

Front 48

Defined cultures in Sausage

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Lactobacillus sp. Pediococcus sp.

Front 49

Heap lawrence test

Back 49

Repeated stress testing cultures against bacteriophages in an enviorment similir to cheese making to determine if samples cultures are resistant

Front 50

Manufacturing starter culture

Back 50

1) single starter culture/colony

2) propogate in appropriate media

3) concentrate if neccecery

4) adatives if neccecery

5) package

6) freeze

7)storage

Front 51

Types of media for culture propigation

Back 51

Milk/ whey

molasses

Corn Syrup

Front 52

Addatives and purpose for growing cultures

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B Vitamins - optimal growth

tween 80- membrain stability

Front 53

What chemicals are used to nutrilize lactic acid when growing LAB

Back 53

Gaseous NH3 NH4OH Na2CO3 KOH

Front 54

How is peroxide reduced/ removed when growing cultures

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Incorporation of oxygen

Addition of catalase

Front 55

What is the typical cell dencity/ml of starter cultures

Back 55

10^9-10^10

Front 56

What phase are starter cultures harvested

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late log or early stationary phase

Front 57

Frozen liquid cultures format and storage

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-Volumes raging from 100 ml to 500 ml- Frozen in liquid nitrogen (< -196oC)- Transport and store at < -45oC

Front 58

Concentrate frozen cultures production flow

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-Grow cells to high cell densities- Concentrate cells by continuous centrifugation or cross-flow membrane filtration- Remove spent media -Resuspend in suspension solution containig stabilizing agents

-Freeze

-Package into cans or pellets

Front 59

Cryoprotectant agents

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Sucrose

Trehalose

Ascorbate

GlycerolGlutamate

Lactose

Hint 59

STAGGL

Front 60

spray drying incompatable with? due to?

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Inapplicable for lactic acid bacteria Loss in cell number Loss in cell viability

Front 61

Lyophilization other name, concentrations and storage temp

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(freeze drying) 10^9 to 10^12 cells/gram Maintain at < -20oC

Front 62

Assessment of functional properties of lactic acid bacteria

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-Acid production rates -Fermentation performance- Lag times- Bacteriophage resistance

Front 63

Assessment of functional properties of yeasts (beer, wine ,baking)

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-Rates of CO2 evolution -Flocculation or sedimentation -Growth at low temperature and produce flavorful end products (lager beer yeasts) -Attenuation -Growth at low temperature and resistance to sulfiting agents (wine yeast) -High ethanol tolerance (wine yeast) -Osmotolerance (wine yeast) -Short lag phase and rapid CO2 production (baker’s yeast) -Cryotolerance (baker’s yeast)

Front 64

Compatibility Issues within LAB starters

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Bacteriocins Peroxides Others antimicrobials

May inhibit other LAB in starter

Front 65

Compatibility Issues Yeast starter cultures

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“killer factors” may inhibit other yeasts stains in mix

Front 66

How Starter Cultures areUsed

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-Frozen and lyophilized starter cultures can be inoculated directly into the food substrate (direct To Vat)

-Used to make Bulk Cultures

Front 67

Bulk culture media is made of

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Basal medium with fermentable carbohydrate (lactose, glucose, sucrose, etc.) and nitrogen source (milk, whey, etc.)

and suplaments such as

-Vitamins -Minerals- Other nutrients (yeast extract, corn steep liquor)- Buffering agents- Carbonate, citrate, phosphate salts- Phosphate has phage inhibitory function

Front 68

How is pH controled in bulk cultures tanks

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pH probes on tank (automatic)

-Use of alkaline solution Sodium hydroxide Ammonium hydroxide Ammonia gas

Incorporation of buffer salts into the bulk culture medium

Front 69

Controling Bacteriophages

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-Sanitation- Plant design-Phage inhibitory media -Phage resistant cultures -Culture rotation

Front 70

Encapsulation of cells

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“…cells are embedded or enrobedwithin a gel-containing shell…” (innert material)

Front 71

Characteristics of encapsulated cells:

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-Metabolically active- Freely suspended in the medium or immobilized to an inert support material

Front 72

Continuous fermentation benefits

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-Increase in throughput- Reduction in overall costs -Cell recovery/reuse- Less sensitive to phage infections

Front 73

Probiotic definition

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“…live microorganisms which when administered in adequate amount confer a health benefit on the host.”

Front 74

4 probiotics

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Bifidobacterium Lactobacillus Saccharomyces Bacillus

Front 75

Applications of encapsulated or immobilized cells

Back 75

-Starter culture industry -Liquid fermentations Industrial lactic acid fermentation and other organis end products from whey, whey permetaes, corn-based-feedstocks- Exopolysaccharides -Bacteriocins -Diacetyl- Alcoholic fermentations -Kefir fermentations

Front 76

Potential advantages of adding probiotics or adjuct cultures

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Acceleration and enhancement of cheese ripening

Biopreservation

Front 77

Chemicals that assist Biopreservation

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Hydrogen peroxide Organic acids Diacetyl Bacteriocins

Front 78

Cultures that may accelerate and enhance cheese ripening

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-actobacillus helveticus -Lactobacillus casei -Citrate fermenting lactic acid bacteria

Front 79

Bacteriocins definition

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“…preteinaceous, heat-stable materials produced by a given organism that inhibits other closely related organisms.”

Front 80

potential benefits of Bactericins

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-Inhibit pathogens, spoilage organisms -Extend shelf life