Physico chem prop of milk Flashcards

1
Q

book by Sukumar De

A

Outlines of Dairy technology

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2
Q

physical state of components of milk are all in solution

A

No
dissolved or suspended

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3
Q

Protein
Fat
Minerals
Lactose
physical state

A

Colloidal suspension
Emulsion
Solution like lactose / colloidal suspension like protein
solution

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4
Q

Physica; state of mineral salt is emulsion and solution?

A

No
Colloidal supension and solution

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5
Q

…..is used to assess perishability of milk

A

acidity

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6
Q

fresh milk is …….

A

amphoteric

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7
Q

if basic red lithmus turns

A

blue

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8
Q

what contributes to apparent accidity

A

Citrates
Acid phosphates
Casein

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9
Q

What is apparent acidity

A

Natural/ Apparent/ Titrable acidity
TAN

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10
Q

TAN is due to

A

casein
Acid phosphate
Citrate

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11
Q

Real acity is actually NAtural acidity?

A

No
real acidity= Developed acidity

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12
Q

Total acidity is expressed as percentage of ….

A

Lactic acid

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13
Q

what is the titrable acidity and pH of cow’s and
Buffaloe’s milk

A

0.13-0.14 - 6.4- 6.6
0.14-0.15 - 6.7-6.8

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14
Q

what does a lower pH than normal indicates
What does more alkaline pH indicate

A

bacterial spoilage
sub clinical mastitis

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15
Q

why pH of sub clinical mastitis cow milk is alkaline

A

Na ion seaps into mik from blood in udder

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16
Q

temperature doesn’t affect specific gravity of Milk

A

false

17
Q

the standard temp at which Specific gravity is measured in milk

A

15.6 degree celcius
60 deg fahrenheit

18
Q

Hydrostatic balance is used to measure ….. of milk for which … is also used

A

Specific gravity
Pycnometer

19
Q

principle or method used by hydrostatic balance is : determining ….. of known …..

A

weight of known vol

20
Q

principle behind pyconometer

A

determining Weight of known Vol

21
Q

working principle of Lactometer

A

determining Vol of known weight

22
Q

Sp gravity can be measured using …/…. and ….

A

pycnometer= hydrostatic balance & lactometer

23
Q

Sp gravity of cow’s milk
buffalo’s milk
skimmed milk

A

1.028- 1.030
1.030- 1.032
1.035- 1.037

24
Q

Mean value of Sp gravity of milk at market

A

1.030

25
Q

relation between fat, SNF and Sp gravity

A

fat~1/Sp gravity
SNF~ Sp gravity

26
Q

SNF and Natural acidity and why

A

SNF~ Natural acidity
SNF= casein, Citrate, acidic phosphate

27
Q

Fat and Sp gravity are inversely proportional yet buffalo with higher fat perc than cow still has higher sp gravity ….why?

A

Buffalo has Higher SNF content than cow’s

28
Q

to increase Sp gravity cream / water can be added ?

A

false
cream= fat decreases Sp gravity
water addition reduces SNF/ solute conc which also reduces Sp gravity

29
Q

dding whey/ skimmed milk …sp gravity

A

increases
skimmed milk is low in fat..lower fat means higher Sp gravity

30
Q

freezing temp of milk is > water

A

false
milk freezes at a lower temp
-5 deg celsius

31
Q

why freezing temp of milk is lower than 0 deg celsius

A

more solutes more lowering of temperature needed

32
Q

Depression in freezing point of milk indicates

A

milk freezing at a temp lower than (-5) that of water (0 deg)

33
Q

usual relation between Freezing point and Freezing point Depression is direct?

A

false
inverse

34
Q

Adding water increase / decreases fp? what about Freezing point depression

A

adding water increases Fp and Decreases FPD
adding water….. more water like so shifts from -5 to more positive or higher temp

35
Q

what all can increase FP (decrease FPD) of milk

A

increase fp means more positive
adding waterhat

36
Q

can reduce FP

A

reduce means more negative/ more cold
(more milk like)
souring
boiling (solutes increases -lowers temp)
sterillisation “