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FDSC 405 > Technical challenges : part 3 : cellulose and pectin > Flashcards

Technical challenges : part 3 : cellulose and pectin Flashcards

1
Q

what are the function of celluose in food

A

1- stabilize foams and emulsions 2- stabilize pectin and starch gels under heating 3- modify texture 4- improve adhesion 5-replace fat and oil 6- control ice crystal growth

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2
Q

what are the two regions of cellulose

A

paracrystalline region crystalline region

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3
Q

the ____ region of cellulose is composed of an amorphous flexible mass of cellulose chains

A

paracrystalline

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4
Q

the microcrystalline cellulose is made by removing the ____ region of the cellulose

A

paracrystalline

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5
Q

What are the modified cellulose we saw in class

A

1- Microcrystalline cellulose 2- methyl cellulose 3- carboxy methyl cellulose 4- hydroxypropyl methyl cellulose 5- hydroxypropyl cellulose

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6
Q

what is the difference between the colloidal MCC and the MCC

A

in coloidal MCC the MCC is mixed with CMC

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7
Q

why do we mix CMC with MCC

A

because MCC alone is not able to be suspended

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8
Q

MCC is good for ____ an emulsion but not good for ____ an emulsion

A

good for stabilizing not good for forming

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9
Q

what is the main function of the MCC

A

to replace fat and oils in emulsion type product

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10
Q

___ and MCC have a synergistic interaction on the thickening of a product

A

starch

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11
Q

What are the function fo MCC in food products

A

1- stabiliz emulsions 2- adds opacity 3- non-nutritive bulk filler 4- mimics mouthfeel of oil 5- opacifier 6- foam stabilizer

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12
Q

what is the modification done to cellulose to create CMC

A

substitution of the hydroxyl groups for methyl groups to improve the solubility of the cellulose. Higher is the degree of substitution and the more the CMC will be soluble.

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13
Q

The viscosity produced by CMC depends on :

A

1- the degree of polymerization because higher is the chain lenght and the more it will produce a viscosity by reudcing the solubility 2- on the degree of substitution of the OH by CH3, higher is the degree and the more soluble it will be

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14
Q

___ and ___ will decrease the viscosity as they cause the polymer of CMC to be more coiled

A

ionic strenght increased decreased pH

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15
Q

is CMC soluble in cold water

A

yes

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16
Q

what is the primary property of CMC

A

viscosity production

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17
Q

are MC and HPMC soluble in hot water

A

no

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18
Q

the surface activity of HPMC is ___

A

high

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19
Q

why is HPMC found in fried products

A

because it can form a oil insoluble gel/film and reduce the frying uptake of oil

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20
Q

why is HPMC used in sauces

A

because it produces a high visocisty at high temperature.

21
Q

____is used to obtain hydropropyl substitution in hydroxypropyl cellulose

A

propylene oxide

22
Q

what is the main property of hydroxypropyl cellulose

A

it as a high surface active properties and can be used both as an emulsifier and a stabilizer

23
Q

what is the only modified cellulose that can form and stabilize the emulsion

A

hydroxypropyl cellulose

24
Q

What are the properties of hyroxypropyl cellulose

A

1- srface active agent 2- stabilizer and emulsifier 3- stabilizer and whipping aid 4- strong, flexible and thermoplastic

25
Q

What are the properties of microcrytalline cellulose

A

1- foam stabilizer 2- emulsion stabilizer 3- opacifiers and whitening agents 4- supension aid of particulates 5- replace fats and oils in emulsion type of products

26
Q

what are the properties of carboxy methyl cellulose

A

1-viscosity production 2- an excellent stabilizer for low pH dairy beverage 3- film-forming properties 4- improve water retention and water binding

27
Q

what are the properties of HPMC and MC

A

1- extremly soluble in water and produces realtively low viscosity solutions 2- unique revesibly thermal gelation 3- good resistance in an acidic medium 4- good to very good film forming properties

28
Q

what is the difference between the plant cellulose and the bacterial cellulose

A

bacterial celllulose has much smaller fibers

29
Q

gelatin and _____ can have a synergy

A

bacterial cellulose

30
Q

what are the units you can find in pectin depending on the source

A

1- homogalacturonan 2- rhamnogalacturonan 3- substituted galacturonans

31
Q

homogalacturonan is made of ____ units linked by ___ linkages

A

beta-galactuoronic acids beta 1-4 linkages

32
Q

the high level of ___ and ___ in a pectin will increase the gel forming abilities

A
  1. high methylation 2. high homogalacturonan
33
Q

high levels of ___ and ___ in a pectin will decrease the gel forming abilities

A
  1. acetylation
34
Q

from the figure, which one will have the highest gelling abilties

A

the apple pectin and the orange pectin

35
Q

why is potato pectin not a good gelling agent

A

because of the high levels of RG and low levels of HG

36
Q

why is sugar beets pectin not a good gelling agent

A

because of the high level of acetylation

37
Q

pectins are used as ____, ___ and ___ in candies

A

thickening
gelling agents
stabilizer

38
Q

what are the factors that influence the properties of pectins?

A
  1. pH
  2. pectin type
  3. degree of esterification
  4. degree of acetylation
  5. sugar
  6. solutes and calcium
  7. temperautre
39
Q

_____ are capable of forming gels in aqueous systems with high contents of soluble solids (higher than 55%) and low pH values (2.8-3.5)

A

high methoxyl pectin

40
Q

—-The higher the degree of ______ of the pectin, the higher the temperature of gelation.

A

methyl substitution

41
Q

The higher degree of methylation the ____ the amount of soluble solids required, and the ___ pH value at which gels can be formed.

A

lower
higher

42
Q

low methoxy pectins can form a gel upon the addition of ____

A

divalent cations (ca) but can do so at lower soluble solids and higher pH

43
Q

acetylation prevents the gel-formation but increases :

A

the stabilizing and emulsifying effects of pectin

44
Q

what is the purpose of adding an amide group to the low methoxy pectins

A

to make it more resistant to mechnical properties and tolerant to varying calcium concentrations

45
Q

____ has an emulsifying effect and is mainly used for flavour oil emulsions

A

Sugar beet pectin

46
Q

t or f : sugar beet pectin is better at stabilizing emulsion than guar gum

A

true, at same concentration levels

47
Q

t or f : pectin can decrease the need of fat

A

true

48
Q

t or f : pectin can decrease the acrlamide formation

A

true

49
Q
A

FDSC 405 (14 decks)

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