Lecture 13- Minor Components Flashcards
Waht are nutraceutials?
Product isolated or purified form food that is generally sold in medicinal forms not usually associated with food
Why d people comsume nutraceuticals?
Physiological benefit or provides protection against chronic disease
What are some examples of nutraceuticals
Ressveratrol and curcumin
What are some other properties of nutraceuticals?
Antioxidants anticarcinogenic anti-inflammatory
How are phenolic compounds detected
aromatic ring linked to one or more OH groups
What are the four major groups of nutraceuticals?
phenolic acids, flavonoids
Tannins
Stilbenes and Ligans
What is the importance of phenolic compounds?
Can positively or negatively influence food
What are some of the positive attributes of polyphenol?
Anti-aging antioxidants Sensory attributes Prevention of enzymatic browning Improve food quality Inhibit lipid oxidation
What are the negative influences of polyphenols?
Can be converted to brown pigments
Highleels are responsible to enzyme catayzed discoloration
Can bind protein carbs, reduce digestibility
What are the method of determining phenolic compounds?
- Spectrophotometric methods (Folin-Ciocalteu assay)
- Chromatographic techniques (used in separation, qualitative and quantitative analysis)
- 1 High performance liquid chromatography (HPLC)
- 2 HSCC (high counter current chromatography)
- 3 Supercritical fluid chromatography (SFC)
- 4 Other chromatographic techniques (TLC – thin layer)
- Near infrared (NIR) (FT-IR)
- Mass spectroscopy (MS)
What is the Folin Ciocalteu assay
- 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
What are the steps of hte Folin-Ciocalteau assay?
- Place 1 mL sample, a gallic acid calibration standard in 100 mL volume flask
- Add 70 mL mater
- Add 5 mL FC reagent
- Incubate 5 min at room temp
- Add 15 mL sodium carbonate
- Add water to the 100 mL line, and incubate for 2 hours
- Measure the blue solution at 765 nm
What are the chromatography techniques?
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
What do you have to do before using chromatographic techniques?
Extract phenolic compounds
What are the extraction methods?
liq-liq
solid-liq
supercritical fuid extraction
What is liq-liq extraction?
- 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
What is solid -liq transfer?
- 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
What is supercritical fluid extraction?
- 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
What are some of the other extraction methods?
enzymatic hydrolysis and ultrasound
What is important characterstic of food?
Colour
First impressions of food are based on…
Colour: immature, ripe, safe to eat
Why colour added to foods
Replace colour lost during processing
Enhance colour already present
Minimize batch variations
Colour discoloured food
What are the categories of colousr?
Nautral
Nature-identical colours
Synthetic colours
Inorganic coours
What are natural pigments
Ones that are found in nature
What are Anthocyanins?
Flavonoid copmounds that produce plant colours ranging from orange to red to various shades of blue and purple
What is anthocyanin coluble in
• Polar character of the molecule allows for its solubility in many solvents such as alcohols, acetone, dimethyl sulfoxide and water
What should the extraction method of anthocyanins maintain?
Choice of extraction method should maximize pigment recovery with a minimal amount of adjuncts and minimal degradation or alteration of the natural state
What is the analysis of anthocyanins?
- 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)
What are the extraction steps of anthocyanins?
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
What is the pruification step of anthocyanin analysis?
Water–> rid of sugars
ethyl acetate–> phenolics gone
methanol–> anthocyanins gone
How do you measure the amount of anthocyanins?
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
What happens to anthocyanins with a change in pH?
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
What are Carotenoids?
lipid soluble, yellow-orange-red pigments found in plants
What is chlorophyll?
lipid-soluble green pigment in plant (A &B)
