Lecture 13- Minor Components

Question 1

Waht are nutraceutials?

Answer 1

Product isolated or purified form food that is generally sold in medicinal forms not usually associated with food

Question 2

Why d people comsume nutraceuticals?

Answer 2

Physiological benefit or provides protection against chronic disease

Question 3

What are some examples of nutraceuticals

Answer 3

Ressveratrol and curcumin

Question 4

What are some other properties of nutraceuticals?

Answer 4

Antioxidants anticarcinogenic anti-inflammatory

Question 5

How are phenolic compounds detected

Answer 5

aromatic ring linked to one or more OH groups

Question 6

What are the four major groups of nutraceuticals?

Answer 6

phenolic acids, flavonoids
Tannins
Stilbenes and Ligans

Question 7

What is the importance of phenolic compounds?

Answer 7

Can positively or negatively influence food

Question 8

What are some of the positive attributes of polyphenol?

Answer 8

Anti-aging
antioxidants
Sensory attributes
Prevention of enzymatic browning
Improve food quality
Inhibit lipid oxidation

Question 9

What are the negative influences of polyphenols?

Answer 9

Can be converted to brown pigments
Highleels are responsible to enzyme catayzed discoloration
Can bind protein carbs, reduce digestibility

Question 10

What are the method of determining phenolic compounds?

Answer 10

1. Spectrophotometric methods (Folin-Ciocalteu assay)
2. Chromatographic techniques (used in separation, qualitative and quantitative analysis)
3. 1 High performance liquid chromatography (HPLC)
4. 2 HSCC (high counter current chromatography)
5. 3 Supercritical fluid chromatography (SFC)
6. 4 Other chromatographic techniques (TLC – thin layer)
7. Near infrared (NIR) (FT-IR)
8. Mass spectroscopy (MS)

Question 11

What is the Folin Ciocalteu assay

Answer 11

• Polyphenols react with specific redox reagents (Folin-Ciocalteu reagent - phosphomolybdic/phosphotungstic acid) to form a BLUE complex that can be quantified. FC method is based on a chemical reduction of the FC reagent by phenolic compounds
• Phenolic compounds + FC reagent –> blue complex

Question 12

What are the steps of hte Folin-Ciocalteau assay?

Answer 12

1. Place 1 mL sample, a gallic acid calibration standard in 100 mL volume flask
2. Add 70 mL mater
3. Add 5 mL FC reagent
4. Incubate 5 min at room temp
5. Add 15 mL sodium carbonate
6. Add water to the 100 mL line, and incubate for 2 hours
7. Measure the blue solution at 765 nm

Question 13

What are the chromatography techniques?

Answer 13

2.1 High performance liquid chromatography (HPLC)
2.2 HSCC (high counter current chromatography): separation between 2 liquid phases by use of centrifugal or counter current during mixing of 2 liquid phases
2.3 Supercritical fluid chromatography (SFC)
2.4 Other chromatographic techniques (TLC – thin layer, PC: paper chromatography)
• Note: you have to extract phenolic compounds before using chromatographic techniques
• Extraction is a very important step in the isolation, identification and use of phenolic compounds and there is no single and standard extraction method

Question 14

What do you have to do before using chromatographic techniques?

Answer 14

Extract phenolic compounds

Question 15

What are the extraction methods?

Answer 15

liq-liq
solid-liq
supercritical fuid extraction

Question 16

What is liq-liq extraction?

Answer 16

• Mass transfer operation in which a liquid solution (feed) initially containing one or more solutes is thoroughly mixed with an immiscible or nearly immiscible liquid (solvent)
• The solvent exhibits preferential affinity or selectivity toward one or more of the components and has different density
• Solvent containing compound of interest is later separated (separating funnel) from the feed solution

Question 17

What is solid -liq transfer?

Answer 17

• Mass transport phenomenon in which compounds contained in a solid matrix migrate into solvent brought into contact with matrix
• Can be enhanced by changes in concentration gradients, diffusion coefficients or boundary layer
• Used to recover important food components: sucrose in cane or beets, lipids from oil seeds, proteins in oil seed meals, polyphenolic compounds from plants, fruits & veggies

Question 18

What is supercritical fluid extraction?

Answer 18

• Based on the fact that, close to the critical point, the solvent changes its properties rapidly with only slight variation of pressure
• More utilized fluid has been supercritical carbon dioxide (SC-CO2)
• Automated & friends to the environment

Question 19

What are some of the other extraction methods?

Answer 19

enzymatic hydrolysis and ultrasound

Question 20

What is important characterstic of food?

Answer 20

Colour

Question 21

First impressions of food are based on…

Answer 21

Colour: immature, ripe, safe to eat

Question 22

Why colour added to foods

Answer 22

Replace colour lost during processing
Enhance colour already present
Minimize batch variations
Colour discoloured food

Question 23

What are the categories of colousr?

Answer 23

Nautral
Nature-identical colours
Synthetic colours
Inorganic coours

Question 24

What are natural pigments

Answer 24

Ones that are found in nature

Question 25

What are Anthocyanins?

Answer 25

Flavonoid copmounds that produce plant colours ranging from orange to red to various shades of blue and purple

Question 26

What is anthocyanin coluble in

Answer 26

• Polar character of the molecule allows for its solubility in many solvents such as alcohols, acetone, dimethyl sulfoxide and water

Question 27

What should the extraction method of anthocyanins maintain?

Answer 27

Choice of extraction method should maximize pigment recovery with a minimal amount of adjuncts and minimal degradation or alteration of the natural state

Question 28

What is the analysis of anthocyanins?

Answer 28

- Aqueous 2 phase system (ATPs) - Acetone extracts the anthocyanins from the plant material, and chloroform partitioning further isolates and partially purifies the pigments - Addition of chloroform results in phase separation between the aqueous portion (which contains anthocyanin, phenolics, sugars, organic acids and other water-soluble compounds) and the bulk phase (contains immiscible organic solvents, lipids, carotenoids, chlorophyll pigments, and other nonpolar compounds)

Question 29

What are the extraction steps of anthocyanins?

Answer 29

a) Mix 50 g powdered plant material with acetone b) Separate anthocyanin extract (filtrate) from insoluble plant material by filter paper c) Re-extract plant material with 70 % (v/v) aqueous acetone until a clear or faintly coloured solution is obtained Transfer filtrate to a separatory funnel, add chloroform, and gently mix by turning funnel upside down a few time e) Store sample overnight at 4 degrees C or until a clear partition between the 2 phases is obtained f) Purify the extract using column chromatography

Question 30

What is the pruification step of anthocyanin analysis?

Answer 30

Water--> rid of sugars ethyl acetate--> phenolics gone methanol--> anthocyanins gone

Question 31

How do you measure the amount of anthocyanins?

Answer 31

UV visible spectroscopy • Based on structural transformation of the anthocyanin chromophore as a function of pH, which can be measured using optical spectroscopy • Rapid and easy procedure for the quantitation of monomeric anthocyanins • Accurate & rapid measurement of the total anthocyanins, even in the presence of polymerized degraded pigments & other interfering compounds

Question 32

What happens to anthocyanins with a change in pH?

Answer 32

reversible structural transformations with a change in pH manifested by striking different asborbance spectra ---> oxonium predominates at pH 1 and colorless hemiketals at pH 4.5

Question 33

What are Carotenoids?

Answer 33

lipid soluble, yellow-orange-red pigments found in plants

Question 34

What is chlorophyll?

Answer 34

lipid-soluble green pigment in plant (A &B)