Industrial Lecture 6

8/4/2019 Industrial Lecture 6

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BIO 425BIO 425

Industrial MicrobiologyIndustrial MicrobiologyLecture 6Lecture 6

Other types of fermented milkOther types of fermented milk

productsproducts


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ContentContent outlineoutline

Type II products and examples

Yogurt

Airan Kefir


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Type II productsType II products

e.g. Bulgarian buttermilk

Present in yogurt family.

Have a high acidic pH value. Prepared from boiled cows milk.

Fermentation is carried out at 40-45C.

Monocultivation with Lactobacillusdelbrueckii spp. bulgaricus.


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Other examples to Type IIOther examples to Type II

Yakult:

In Japan-a processed milk product.

Prepared from skimmed milk-glucose-Chlorella extract dissolved in hot water.

Filtered and sterilized.

Starter:Lactobacillus casei Shirota strain;

isolated from human intestinal tract


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ProductionProduction ofof yakultyakult ((continuedcontinued))

andand otherother characteristicscharacteristics

Fermented four days, at 37 C to 2.7%

acidity, ready to serve from this point.

Its consumption increases Lactobacillus

caseiin feces and eliminates E.coli. effective against various intestinal

diseases of the enteric system.


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YogurtYogurt

Originated in:

Central Asia, Turkey,

and Balkan peninsulas traditional food.

Original yogurt: in Bulgaria.


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ProcessProcess toto makemake yogurtyogurt::

Cows or goats high solids milk boiled.

inoculated at 40-45 C with a portion ofpreviously soured milk

The pot containing inoculated milk was thoroughlywrapped,

placed for 8-10 hours in the oven.


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TodaysTodays technologicaltechnological yogurtyogurt::

End product of a culture of:

Streptococcus thermophilus and

Lactobacillus delbrueckii spp. bulgaricusgrowing at temperatures in the range of

40-45C.

Yogurt is finished at pH 4.2 - 4.3.


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Relationship of bacteria inRelationship of bacteria in

yogurtyogurt Exhibits mutualistic behavior.

Growth and acid production is greater in a

mixed culture;

as compared with monocultures.


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Relationship of bacteria inRelationship of bacteria in

yogurtyogurt Fast growth ofStreptococciat initial stage

brings out:

Lactic and acetic acids, Acetaldehyde,

Diacetyl,

Formic acid.


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RelationshipRelationship ofof bacteriabacteria inin

yogurtyogurt:: The formate present in the medium:

stimulates the red-ox potential of

Lactobacillus delbrueckii subsp.bulgaricus.

It liberates a proteolytic activity,

The liberated aminoacid triggers thegrowth ofStreptococcus thermophilus.


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Ayran (Airan)Ayran (Airan)

A traditional Turkish fermented milk

prepared from:

cows milk, goats milk,

sheeps milk,

and added water.


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Composition of ayranComposition of ayran

Milk is inoculated with Lactobacillus

delbrueckii spp. bulgaricus and

Streptococcus thermophilus

Ingredients-material balanced:

94 % water,

1.2-1.5 % fat, 0.75 lactic acid, 1.7 % protein, 2% soluble solids and

carbohydrates.


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Type IV fermented milksType IV fermented milks

In this type of milks the dominant

microflora is:

composed of lactic acid bacteria- yeastconsortia.


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ActionAction ofof thisthis consortiaconsortia::

Thermophilic and mesophilic lactic acid

bacteria

+Kluvyeromyces, Candida, Saccharomyces

Lactic acid and ethanol.

Belongs to acid alcoholic fermented milks-

widely seen in Asia and the Middle East.


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KefirKefir

Manufacture in homes for hundreds of

years in leather sacks and oak barrels

Widespread in: East Europe & Central Europe,

Former Soviet Union & Scandinavia.


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StructuralStructural aspectsaspects of kefir:of kefir:

Fermentation: Initiated by the white to yellow

grains insoluble in water,

distributed on the inner surface of the sack or

barrel,

Grains are 0.3-2 cm or more in size, irregular

form,

Large clusters are similar to cooked rice, Dry mass: consists of 10-16 % by weight,

has 30% proteins, 25-50 % carbohydrates.


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Other characteristics of kefirOther characteristics of kefir

Mass of the grain is made up of:

microbial cells,

products of their autolysis, curd of milk proteins

Carbohydrates-like mucous substances of

bacteria-as polysaccharides called kefiran.


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Composition of kefir grainsComposition of kefir grains

Symbiotic system of Lactobacillus &

Lactococci:

in a concentration of 108

-109

bacterialcells.

For yeasts 108 / gr.


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Preparation of kefirPreparation of kefir

Add kefir grains into boiled milk,

incubate at 23-25 C overnightuntil acidity reaches 0.68-0.90 % lactic acid.

Filtration of separation of grains

cooling

ready to drink.


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M/os of kefirM/os of kefir

Lactococci,

Lactococcus lactis var. diacetylactis,

Lactococcus cremoris, Leuconostocs,

Leuconostoc mesenteroides spp.

dextranicum, Leuconostoc mesenteroides spp.

cremoris.


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M/os of kefirM/os of kefir--to be continuedto be continued

Lactobacilli

Lactobacillus brevis

Lactobacillus cellobiosus Lactobacillus acidophilus

Lactobacillus kefir

Lactobacillus casei ssp. alactosus Lactobacillus casei ssp. rhamnosus


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Lactobacillus lactis

Lactobacillus helveticus

Streptococcus thermophilus


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(yeasts)(yeasts)

Kluvyeromyces lactis

Kluvyeromyces marxianus

Torulaspora delbrueckii Saccharomyces florentinus

Saccharomyces globosus

Saccharomyces unisporus Saccharomyces carlsbergensis


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(yeasts)(yeasts)

Candida kefyr

Candida pseudotropicalis


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Koumys(Kumis, koumiss)Koumys(Kumis, koumiss)

Made from mares milk,

contains about 7% lactose.

Name comes from an Asian step tribeKumanes.


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Characteristics of koumysCharacteristics of koumys

If pieces of horse flesh or tendon or some

vegetable matter were added to the

mares milk;

and placed into bags made from lambskin;

this provides the microflora needed for

fermentation.


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Characteristics of koumysCharacteristics of koumys

Mares milk does not coagulate at the

isoelectric point of casein,

Koumys is not a curdled product.


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AccordingAccording toto RussianRussian standardsstandards

thethe majormajor endend productsproducts::

Ingredient Material balance (in 100mL,%)

Lactic acid 0.7-0.9

Ethanol 0.6-2.5

CO2 0.5-0.88


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Microflora of koumysMicroflora of koumys

Dominant m/os:

Lactobacillus bulgaricus

Lactobacillus acidophilus Lactose fermenting yeasts,

Kluvyeromyces marxianus subsp.

marxianus Candida kefyr


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Preparation of koumysPreparation of koumys

Fresh mares milk (3-10 parts by volume)

Mixed with previously finished koumys-1 part,

Place mixture in a skin bag, only used for koumys making,

Agitate milk by a special apparatus in every 1-2 hour,

After 3-8 hours when strong foam & specific sourish flavor appears

young koumys is ready for consumption


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Preparation of koumysPreparation of koumys

Incubation temperature: 20-22 C

Sometimes 25-32 C

Middle type of koumys: 24 hoursmaturation

Strong koumys: 2-4 days of maturation


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NonNon--traditional (new) fermentedtraditional (new) fermented

milksmilks

Attention is paid to the intestinal microflora

& structural ecosystem of mankind:

The most prominent cultures are:Lactobacillus acidophilus,

Bifidobacterium spp.


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NewNew strainsstrains forfor thethe beveragesbeverages of 3of 3rdrd

generationgeneration::

Bifidobacterium bifidum

Bifidobacterium longum

Lactobacillus acidophilus Lactobacillus casei

Streptococcus faecium -now

Enterobacterium faecium


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Probiotic phenomenaProbiotic phenomena

Live culture, form the production line of the

product until it reaches to the intestine and

also lives there.

Novel products come to the market as

bioyogurt-biogurt, Biodrink, Biokys.

Carry also the prefix-Sano-for health;

Jogi or Yogi relates to yoghurt.


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LITERATURE CITEDLITERATURE CITED

Forsythe, S.J. The Microbiology of Safe

Food, Blackwell Science, Cambridge,

2000.

Wood, B. J. B., Microbiology of Fermented

Foods, Vol.1 and 2, Blackie Academic and

Professional, London, Second edition,

1998.

Documents

Industrial Lecture 6