Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biotechnology > Kefir > Flashcards

Kefir Flashcards

1
Q

describe kefir grains

A

white/yellow gelantinous grains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is kefir composed of

A

symbiotic mixture of: lactic acid bacteria, yeast, acetic acid bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what kind of matrix is kefir composed of in

A

exopolysaccharide matrix called (Kefiran)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

kefir is… acidic or ?

A

acidic fermented milk product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

name 2 methods of kefir production

A
  1. russian method
  2. the pure cultures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe russian method

A

using a series fermentation process, beginning with the fermentation of the grains.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

describe the Pure Cultures method

A

Isolated from kefir grains or commercial cultures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what milks types of kefir made from

A

pasteurised cow, ewe, goat, or buffalo milk.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe the 2 commercial industrial processing uses

A

direct to vat inoculation (DVI) or
direct to vat set (DVS) kefir starter cultures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what ratio is grains to milk

A

grains usually innoculated at 1-10% w/v

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

time of fermentation

A

kefir obtained within 18-24 hr of fermentation.
kefir biomass increases and then may decrease (grains dissolve)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what temperature of kefir fermentation

A

18-30 degrees c.

exopolysaccharide production is affect by temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

fermented kefir contains

A

bioactive peptides
bacteriocins
exopolysaccharides
organic acids.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

briefly name challenges in kefir production

A

diverse microflora of kefir grain, milk type, incubation time and storage conditions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe kefir grains appearance

A

white to yellow gelantinous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what size kefir grains

A

variable. varying from 0.3–3.5 cm in diameter).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

composed of microbial symbiotic mixture of

A

lactic acid bacteria
acetic acid bacteria
yeasts
fungi

in a polysaccharide matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the 4 main groups of kefir

A
  1. homo- fermentative LAB
  2. hetero -fermentative LAB
  3. lactose assimilating yeast
  4. non-lactose assimilating yeast
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

name bacterias

A

o Lactobacillus kefiri (80%; in final beverage)
o L. paracasei ssp. paracasei, L. acidophilus, L. delbrueckii ssp. bulgaricus, L. plantarum, and L. kefiranofaciens are predominant species (20% final beverage).
o Acetobacter aceti & A.rasens.
o S.cerevisiae, S.unisporus, Candida kefyr & Kluyveromyces marxianus sub sp. Marxianus

20
Q

describe the polysaccharide in kefiran

A

heteropolysaccharide composed of equal proportions of glucose and galactose and is mainly produced by Lactobacillus kefiranfaciens

21
Q

what is heteropolysaccharide composed of

A

equal proportions of glucose and galactose produced by Lactobacillus kefiranfaciens

22
Q

what is heteropolysaccharide produced by

A

Lactobacillus kefiranfaciens

23
Q

what does kefiran improve

A

viscosity and elasticity properties of acid milk gels and aids in gel formation

24
Q

what causes the smybiotic balance of bacterias in equilibrium

A

biomass production during fermentation

25
Q

the grain outer layer contains

A

LAB & yeast

26
Q

the grain inner layer contains

A

the quantity of lactobacilli are much higher

27
Q

describe the mechanisms of grain formation

A

symbiotic community where LAB, yeasts and AAB cohabit in a specific equilibrium
o This balance between kefir microorganisms is evident by biomass production during fermentation
the outer layer of the grain: LAB & yeast
The inner layer of the grain: the quantity of lactobacilli were much higher

Initially Lactobacillus & Saccharomyces start to auto-aggregate & co-aggregated into  small granules this aggregation is enhanced when the pH drops

28
Q

what do biofilm producers adhere to in grain formation

A

the surface. they continue to co-aggregate to become a 3D micro-colony.

29
Q

list chemical % of kefir

A

90% moisture, 3.0% protein, 0.2% lipid, 6.0% sugar, 0.7% ash, 1.0% lactic acid, 0.48% alcohol and 201.7–277.0 mL/L CO2

30
Q

microbial consortium is AKA

A

proteolysis

31
Q

what role does yeast have in proteolysis

A

establishing an environment that allows for the growth of kefir bacteria, as well as the production of several key metabolites such as:
peptides, amino acids, vitamins, ethanol and CO2.

32
Q

what key metabolites does yeast contain

A

peptides, amino acids, vitamins, ethanol and CO2.

33
Q

what does lactic acid bacteria ferment/do in proteolysis

A

ferments the lactose to increase in lactic acid levels & as well as imparting the unique taste in kefir.

34
Q

what does lactic acid inhibit

A

inhibits microorganism growth owing to decrease in pH acting as a preservative.

35
Q

free fatty acids FFAs produced via… and what is it responsbile for

A

lipolysis in milk are responsible for the taste and aroma of kefir which was found to contain from 5 to 10 times more FFAs than milk.

36
Q

name amino acids in kefir and what role do they play

A

serine, threonine, alanine, lysine, valine, isoleucine, methionine, phenylalanine and
tryptophan.

major role in central nervous system

37
Q

name macro-elements in kefir and what role do they play

A

calcium, magnesium, potassium, and sodium

that aid in the: utilisation of carbohydrates, fats and proteins for cell growth, maintenance, and energy

38
Q

name micro-elements in kefir and what role do they play

A

iron, zinc, and copper

: cellular metabolism and blood production

39
Q

kefir acts against what bacteria and what does it do

A

pathogenic bacteria.

inhibits spore formation and aflatoxin B1 produced by the fungus Aspergillus flavus

40
Q

name health benefits of kefir

A
  1. antioxidant
  2. antimicrobial
  3. gastrointestinal function
  4. cholesterol lowering
  5. reduced bodyweight
  6. anti-inflammatory
  7. anticancer
  8. probiotic
  9. wound healing
41
Q

Conjugated linoleic acid (CLA)

A

native component in milk fat, can be increased in fermented milk through bioconversion of unsaturated fatty acids such as linoleic and linolenic acids by different LAB.
CLA has anti-inflammatory, anti-atherogenic, and antioxidant properties.

42
Q

Bioactive peptides

A

are specific fragments of milk proteins that are released by proteolytic activity from caseins have been described for peptides released as a result of the activity of LAB in fermented milk products.

43
Q

what role does Bacteriocins do

A

are also among the beneficial peptides intrinsically synthesised by some LAB and their usefulness in preventing growth of undesirable & pathogenic microorganisms

44
Q

role of Extracellular PolySaccharide(EPS):

A

are complex extracellular carbohydrate polymers +ve interact with colonic microbiota

45
Q
A

Biotechnology (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions