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FDSC 300 > Lecture 15 - Minor Components > Flashcards

Lecture 15 - Minor Components Flashcards

1
Q

what are minor components of food?

A
  • nutraceuticals

- pigments

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2
Q

what’s nutraceutical?

A

product isolated or purified from foods generally sold in medicinal forms not usually associated with food. also shows physiological benefit against chronic disease.

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3
Q

name some nutraceuticals

A
  • resveratrol
  • curcumin
  • Epigallocatechin gallate (EGCG)
  • Epicatechin gallate (ECG)
  • Epigallocatechin (EGC)
  • phenolic compounds
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4
Q

what are phenolic compounds?

A

consist of an aromatic ring linked to one or more hydroxyl groups. includes functional derivatives (esters, methyl esters, glycosides, etc)

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5
Q

how many phenolics are there out there?

A

over 8000, and counting

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6
Q

into what classes can phenolic compounds be classified?

A

1) phenolic acids
2) flavonoids
3) tannins
4) stilbenes & lignans

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7
Q

name some phenolic acids in foods

A 
hydroxycinnamic acids
- p-coumaric
- caffeic
- ferulic
- sinapic
hydroxybenzoic acids
- gallic
- protocatechuic
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8
Q

what effect do phenolic compounds have?

A 
positive:
- free radical scavengers (anti aging)
- reduce risk of coronary heart disease
- reduce some cancer types
- color
- lipid retention
negative
- undesired changes in color (enzymatic browning)
- protein and CHO binding, reducing digestibility
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9
Q

what kinds of methods can we use to determine phenols?

A
  • spectrophotometric
  • chromatographic
  • Near Infrared
  • Mass Spec
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10
Q

what spectrophotometric method is used for phenolic determination?

A

Folin-Ciocalteu assay

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11
Q

describe the Folin-Ciocalteu assay

A

based on the chemical reduction of the FC reagent by phenolic compounds, making a blue complex.

measure at 765 nm

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12
Q

what are the steps used in the Folin-Ciocalteu assay?

A
  • gallic acid calibration standard
  • FC reagent (phosphomolybdic/phosphotungstic acid)
  • sodium carbonate
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13
Q

what kinds of chromatographic methods are there for phenolic determination?

A
  • HPLC
  • HSCCC (high counter current chromatography)
  • SFC (supercritical fluid chromatography)
  • PC
  • TLC
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14
Q

true or false: you have to extract phenolic compounds before using chromatographic techniques

A

true

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15
Q

what is HSCCC?

A

high counter current chromatography

separation between 2 liquid phases by use of centrifugal or counter current during mixing of 2 liquid phases

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16
Q

what methods of extracting phenolics are there?

A
  • liquid liquid extraction
  • solid-liquid extraction (leaching)
  • supercritical fluid extraction
17
Q

describe liquid liquid extraction

A
  • mass transfer operation
  • liquid solution initially containing one or more solutes is thoroughly mixed w/immiscible liquid
  • solvent exhibits preferential affinity toward one or more the components
  • solvent containing the compound of interest is separated w/separating funnel
18
Q

describe solid-liquid extraction

A
  • mass transport

- compound contained in a solid matrix migrate into solvent

19
Q

what can enhance the mass transport phenomena during solid-liquid extraction?

A
  • changes in concentration gradients
  • diffusion coefficients
  • boundary layer
20
Q

what can solid-liquid extraction be used for?

A

recover food components

  • sucrose in cane or beets
  • lipids from oil seeds
  • proteins in oilseed meals
  • polyphenolic compounds from plants, fruits and veggies
21
Q

describe supercritical fluid extraction

A

close to its critical point, a solvent changes its properties rapidly with only slight variation in pressure

22
Q

what is the most utilized fluid for SFE?

A

supercritical carbon dioxide

23
Q

why do we analyze for pigments in food?

A
  • color impacts first impressions of food
  • quality indicator
  • safety indicator
24
Q

what are some reasons colors are added to food? (4)

A
  • replace lost color
  • enhance color already present
  • minimize batch-to-batch variations
  • color otherwise uncolored foods
25
Q

food colors are divided into what 4 categories

A

1) natural colors
2) nature-identical colors
3) synthetic colors
4) inorganic colors

26
Q

give examples of natural pigments

A
  • anthocyanins
  • carotenoids
  • chlorophyll
27
Q

how can you analyze for anthocyanins?

A

anthocyanins are polar, so you can extract the using polar solvents (alcohols, acetone, dimethyl sulfoxide, and water)

28
Q

choice of extraction method should maximize _____ _____ with a minimal amount of ______. method should also minimize _____ or alteration of natural state

A

maximize pigment recovery
minimal amount of adjuncts
degradation

29
Q

describe the analysis of anthocyanins

A

acetone extraction and chloroform partition of anthocyanins

  • acetone extracts anthocyanins
  • chloroform partitioning further isolates and partially purifies
  • adding chloroform results in phase separation
  • aq = anthocyanin, phenolics, sugars, organic acids, others
  • bulk phase = immiscible organic solvents, lipids, carotenoids, chlorophyll pigments, and others)
30
Q

give the steps of extracting anthocyanins

A

1) mix powdered plant material w/acetone
2) filter to separate anthocyanin extract and insoluble plant material
3) re extract plant material with acetone until clear/faintly colored solution is obtained
4) add chloroform in separatory funnel
5) store for a while until clear partition is obtained
6) purify using column chromatography

31
Q

what kind of columns can are used to purify anthocyanin samples?

A
  • water and HCl (separates sugars/acids)
  • ethyl acetate (separates phenolics)
  • methanol (elutes the anthocyanins)
32
Q

what method can be used to analyze for anthocyanins?

A

3-measure step: 1-UV-Vis Spectroscopy

based on structural transformation of anthocyanin chromophore as a function of pH, measured w/optical spec

33
Q

what is the 1-UV-Vis spectroscopy method also known as?

A

ph-differential method

34
Q

is the pH-differential method fast?

A

yep

35
Q

anthocyanins undergo (reversible/irreversible) structural transformation with change in pH

A

reversible

36
Q

colored oxonium form predominates at pH ___

A

1.0

37
Q

colorless hemiketal form predominates at pH ____

A

4.5

FDSC 300 (9 decks)

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