CFC Flavor Extraction & Isolation Techniques 3

Question 1

Microwave-assisted extraction (MAE) of flavor compounds is based primarily on which heating mechanism?

Accepted Answer

Dielectric heating of polar molecules and water within the plant matrix

Answer

Microwave energy causes rapid dielectric heating of polar molecules (especially water) inside the plant matrix, rupturing cell walls and releasing intracellular flavor compounds into the extraction solvent very quickly.

Question 2

Ultrasound-assisted extraction (UAE) of flavor compounds improves extraction efficiency primarily through:

Accepted Answer

Acoustic cavitation that disrupts cell walls and increases mass transfer

Answer

Ultrasound creates acoustic cavitation—rapid formation and collapse of microbubbles—that generates intense local pressure and temperature, physically disrupting cell walls and enhancing solvent penetration and mass transfer.

Question 3

Preparative HPLC is used to isolate pure flavor reference standards primarily because it offers:

Accepted Answer

High resolution separation with scalable throughput and fraction collection capability

Answer

Preparative HPLC uses larger-diameter columns with higher flow rates and automated fraction collectors to isolate milligram to gram quantities of pure flavor compounds that can then be used as authenticated reference standards.

Question 4

When selecting an organic solvent for extracting aroma compounds from a complex food matrix, which pair of properties is most important to evaluate first?

Accepted Answer

Selectivity for target analytes and low boiling point for easy removal

Answer

Selectivity ensures target aroma compounds are efficiently extracted with minimal co-extractants, while a low boiling point (e.g., diethyl ether, pentane) allows solvent removal by gentle evaporation without concentrating the extract thermally.

Question 5

Stir bar sorptive extraction (SBSE, e.g., Twister®) offers a significant advantage over SPME for flavor profiling because it:

Accepted Answer

Provides a much larger volume of sorptive phase, improving sensitivity for trace aroma compounds

Answer

SBSE's polydimethylsiloxane (PDMS)-coated stir bar contains 50–250 times more sorptive phase than a SPME fiber, resulting in proportionally higher analyte enrichment and lower detection limits for trace flavor aroma compounds.

CFC - Certified Flavor Chemist Practice Test

CFC - Certified Flavor Chemist Practice Test

CFC Flavor Extraction & Isolation Techniques 3