Technical Challenges (3) Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

what does “dietary fibers” include?

A

polymeric CHOS: cellulose, hemicellulose, pectin, gum

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

what are characteristics that fibers affect?

A
  • color and flavor
  • oil and H2O retention
  • colloidal emulsion stability (improves)
  • texture and gel formation
  • other viscometric properties (eg. thickening and mouthfeel)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are functions of cellulose in food formulations?

A
  • stabilize foams and emulsions
  • stabilize pectin and starch gels under heating
  • modify textures
  • improve adhesion
  • replace fat and oil
  • control ice crystal growth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what does cellulose not affect?

A

flavor
color
microbial contamination

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

describe the function of native cellulose powders in food pdts

A
  • does not soften on hydration and heating

- may impart rough mouthfeel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe benefits of using native cellulose in food pdts

A
  • abundant
  • cost effective
  • inert and insoluble
  • no caloric value
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

describe the production of colloidal MMC

A
  1. fibrous cellulose material is hydrolyzed to remove the paracrystalline region to form MCC
  2. add hydrocolloids (substance that forms gel in water) and CMC (carboxyl methyl cellulose) to form colloidal MMC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is MMC

A

microcrystalline cellulose

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

describe the functional properties of MCC

A
  • foam stabilizer
  • emulsion stabilier
  • heat stability w/ minimal loss of viscosity
  • textural modifier (shortens texture or adds body)
  • suspension aid of particulates
  • replace fats and oils in emulsions
  • controls ice crystal growth
  • prevents aggregation of protein and other solids
  • opacifier and whitening
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what properties of starch is improved with the addition of MCC?

A
  • improvement of heat and shear stability

- less starch thickener needed

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

what is CMC

A

carboxymethylcellulose

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

how is CMC chemically formed?

A

cellulose + alkali + chloroacetic acid = CMC

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

what requirement is needed for CMC to be water soluble?

A

degree of substitution of 0.45 or higher

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

in CMC, higher degree of polymerization = ____ (higher/lower) viscosity

A

higher

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

what differs chemically between different CMC?

A
  • degrees of polymerization
  • degrees of substitution
  • uniformity of carboxyl methyl groups
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe solubility of CMC

A

soluble in cold water

- gives clear solutions w/ neutral flavor

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

what is the primary property of CMC?

what is it commonly used for?

A
  • viscosity production

- used as a thickener and stabilizer

18
Q

what are functional properties of CMC

A
  • soluble in cold water
  • increases viscosity
  • stabilizer (b/d of anionic nature)
  • improves water retention and water binding
  • improves moistness and prolongs shelf life
  • good film forming properties
19
Q

what is HPMC

A

hydroxypropyl methyl cellulose

20
Q

what structural/chemical components is HPMC characterized by?

A
  • monomeric chain length
  • degree of substitution
  • ratios of hydroxypropyl and methyl substitution
21
Q

MC and HPMC are soluble in ___ water but not in ___ water

A

cold; hot

22
Q

what are major functional properties of HPMC?

A
  • high emulsion stability
  • extremely soluble in water
  • good water retention
  • reversible thermal gelation
  • good resistance in acidic medium
  • good film forming properties
23
Q

describe the unique reversible thermal gelation property of HPMC

A

viscosity initially decreases with rising temp but then increases until a gel is formed

processes are reversible

24
Q

describe solubility of HPC

A

water soluble (up to 40C) and organic soluble

25
Q

why is HPC used in oil-in-water emulsions and whipped products?

A
  1. it is a good surface active agent (due to low surface and interfacial tension in solution)
  2. it has a good protective colloid action
26
Q

how is bacterial or microfibrous cellulose produced?

A

by microbial fermentation of Acetobacter xylinum

27
Q

how is bacterial cellulose similar or different than plant cellulose?

A

chemically identical, but has smaller fibers bundled to form a 3D network which allows higher surface area to provide high stability to temp, pH, salts, oxidizers, shear

28
Q

what can be combined with bacterial cellulose to promote higher dispersion of a food pdt?

A

co-agents such as sucrose and CMC

29
Q

how do pectins form gels?

A

in presence of water, acid and sugar

30
Q

what are health benefits of pectin?

A
  • lower cholesterol
  • lower serum glucose
  • anti-cancer activities
31
Q

what can pectins be classified as?

A
  1. high/low ester pectins

2. high/low methoxy pectins

32
Q

what are applications of pectin?

A
  • thickening and gelling agents

- stabilizer in candies, syrups, frozen desserts, jams, jellies

33
Q

what factors determine gelling properties of pectins?

A
  • temp
  • pectin type
  • DE (degree of esterification)
  • DA( degree of acetylation)
  • pH
  • sugar
  • calcium
34
Q

with pectins, higher degree of methyl substitution of the sugar acid = ____ (higher/lower) temp of gelation

A

higher

35
Q

what requirements are needed for high methoxyl pectins to form gels?

A
  • high soluble solids contents (>55%)

- low pH (2.7-3.5)

36
Q

with pectins, higher DE = ____ (higher/lower) soluble solids required = (higher/lower) pH value at which gels can form

A

higher DE = LOWER amount of soluble solids required = HIGHER pH at which gels form

37
Q

how does the addition of divalent cations (Ca) affect the gel formation of low-methoxyl pectins?

A

forms gels at lower soluble solids and higher pH

38
Q

how does acetylation affect gel formation of pectins?

A

prevents gel formation but increases stabilizing and emulsifying effects of pectin

39
Q

how can you modify functionalities of pectins?

A

using pectinolytic enzymes

example: to create amidated pectin

40
Q

what is amidated pectin? how do they behave? what are characteristics?

A

a modified form of pectin

behaves like low-ester pectins

characteristics:

  • more tolerant of varying Ca concentrations
  • modifies hydrophilic nature of pectin to obtain a more compatible hydrocolloid
  • increases water holding capacity
41
Q

how is sugar beet pectin used? what can it substitute?

A

used for flavor oil emulsions due to its emulsifying effects

can substitute gum arabic in emulsions