CSA CSA Flavor Science & Sensory Chemistry 1 — Questions and Answers
Question 1: Which chemical compound is primarily responsible for the characteristic 'green' or 'grassy' aroma found in fresh vegetables?
- Hexanal (Correct answer)
- Benzaldehyde
- Diacetyl
- Geraniol
Correct answer: Hexanal
Hexanal is a C6 aldehyde produced by the oxidation of linoleic acid and is the primary compound responsible for green/grassy aromas in fresh vegetables.
Question 2: The Maillard reaction involves a non-enzymatic browning process between which two types of compounds?
- Reducing sugars and amino acids (Correct answer)
- Fatty acids and proteins
- Polyphenols and oxygen
- Organic acids and alcohols
Correct answer: Reducing sugars and amino acids
The Maillard reaction occurs between reducing sugars and free amino acids or protein-bound amino acids, producing hundreds of flavor and color compounds during heating.
Question 3: Which taste quality is primarily mediated by the detection of glutamate ions binding to metabotropic receptors on taste cells?
- Umami (Correct answer)
- Bitter
- Sweet
- Sour
Correct answer: Umami
Umami taste is principally activated by L-glutamate (and nucleotides like IMP/GMP) binding to mGluR4 and T1R1/T1R3 receptor complexes on taste receptor cells.
Question 4: What term describes the phenomenon where a low concentration of one aroma compound significantly enhances the perceived intensity of another aroma compound?
- Synergy (Correct answer)
- Masking
- Adaptation
- Cross-modal interaction
Correct answer: Synergy
Aroma synergy occurs when two or more compounds at subthreshold or low concentrations combine to produce a perceivable or intensified aroma greater than expected by simple addition.
Question 5: Capsaicin produces the burning sensation of chili peppers by activating which receptor on sensory neurons?
- TRPV1 (Correct answer)
- TRPM8
- P2X3
- mGluR5
Correct answer: TRPV1
Capsaicin binds to and activates the TRPV1 (transient receptor potential vanilloid 1) ion channel, which is a heat-gated channel also activated by temperatures above 43°C.
Question 6: Which flavor compound is responsible for the characteristic buttery note in chardonnay wine and popcorn?
- Diacetyl (Correct answer)
- Acetaldehyde
- Ethyl acetate
- Isoamyl acetate
Correct answer: Diacetyl
Diacetyl (2,3-butanedione) is produced by lactic acid bacteria during malolactic fermentation and is the primary compound responsible for buttery, creamy aromas in wine and dairy products.
CSA CSA Flavor Science & Sensory Chemistry 1
Which chemical compound is primarily responsible for the characteristic 'green' or 'grassy' aroma found in fresh vegetables?