Technical challenges : part 3 : cellulose and pectin

Question 1

what are the function of celluose in food

Answer 1

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

Question 2

what are the two regions of cellulose

Answer 2

paracrystalline region crystalline region

Question 3

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

Answer 3

paracrystalline

Question 4

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

Answer 4

paracrystalline

Question 5

What are the modified cellulose we saw in class

Answer 5

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

Question 6

what is the difference between the colloidal MCC and the MCC

Answer 6

in coloidal MCC the MCC is mixed with CMC

Question 7

why do we mix CMC with MCC

Answer 7

because MCC alone is not able to be suspended

Question 8

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

Answer 8

good for stabilizing not good for forming

Question 9

what is the main function of the MCC

Answer 9

to replace fat and oils in emulsion type product

Question 10

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

Answer 10

starch

Question 11

What are the function fo MCC in food products

Answer 11

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

Question 12

what is the modification done to cellulose to create CMC

Answer 12

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.

Question 13

The viscosity produced by CMC depends on :

Answer 13

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

Question 14

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

Answer 14

ionic strenght increased decreased pH

Question 15

is CMC soluble in cold water

Answer 15

yes

Question 16

what is the primary property of CMC

Answer 16

viscosity production

Question 17

are MC and HPMC soluble in hot water

Answer 17

no

Question 18

the surface activity of HPMC is ___

Answer 18

high

Question 19

why is HPMC found in fried products

Answer 19

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

Question 20

why is HPMC used in sauces

Answer 20

because it produces a high visocisty at high temperature.

Question 21

____is used to obtain hydropropyl substitution in hydroxypropyl cellulose

Answer 21

propylene oxide

Question 22

what is the main property of hydroxypropyl cellulose

Answer 22

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

Question 23

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

Answer 23

hydroxypropyl cellulose

Question 24

What are the properties of hyroxypropyl cellulose

Answer 24

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

Question 25

What are the properties of microcrytalline cellulose

Answer 25

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

Question 26

what are the properties of carboxy methyl cellulose

Answer 26

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

Question 27

what are the properties of HPMC and MC

Answer 27

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

Question 28

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

Answer 28

bacterial celllulose has much smaller fibers

Question 29

gelatin and _____ can have a synergy

Answer 29

bacterial cellulose

Question 30

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

Answer 30

1- homogalacturonan 2- rhamnogalacturonan 3- substituted galacturonans

Question 31

homogalacturonan is made of ____ units linked by ___ linkages

Answer 31

beta-galactuoronic acids beta 1-4 linkages

Question 32

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

Answer 32

1. high methylation 2. high homogalacturonan

Question 33

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

Answer 33

1. acetylation

Question 34

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

Answer 34

the apple pectin and the orange pectin

Question 35

why is potato pectin not a good gelling agent

Answer 35

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

Question 36

why is sugar beets pectin not a good gelling agent

Answer 36

because of the high level of acetylation

Question 37

pectins are used as \_\_\_\_, ___ and ___ in candies

Answer 37

thickening gelling agents stabilizer

Question 38

what are the factors that influence the properties of pectins?

Answer 38

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

Question 39

\_\_\_\_\_ 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)

Answer 39

high methoxyl pectin

Question 40

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

Answer 40

methyl substitution

Question 41

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

Answer 41

lower higher

Question 42

low methoxy pectins can form a gel upon the addition of \_\_\_\_

Answer 42

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

Question 43

acetylation prevents the gel-formation but increases :

Answer 43

the stabilizing and emulsifying effects of pectin

Question 44

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

Answer 44

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

Question 45

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

Answer 45

Sugar beet pectin

Question 46

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

Answer 46

true, at same concentration levels

Question 47

t or f : pectin can decrease the need of fat

Answer 47

true

Question 48

t or f : pectin can decrease the acrlamide formation

Answer 48

true