Question

In coffee, bitterness is imparted due to the presence of.......

• A. Diprophylline
• B. Xanthydrol
• C. Methylxanthines
• D. Bromotheophylline

Hint:

Always associate the alkaloid group "Methylxanthines" with caffeine in coffee, theobromine in cocoa, and theophylline in tea.
These compounds are biologically active stimulants that turally carry a bitter taste profile.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The complex flavor profile of coffee is composed of acidity, sweetness, aroma, and bitterness.
Bitterness is a key sensory attribute of coffee that is influenced by both the tural chemical compounds in green coffee beans and the chemical changes during roasting.

Step 2: Detailed Explation:
Bitterness in coffee is primarily attributed to two major classes of chemical compounds: chlorogenic acid lactones (and phenylindanes formed during roasting) and methylxanthines.
Methylxanthines are a group of purine-derived alkaloids that act as central nervous system stimulants.
The most prominent methylxanthine in coffee is caffeine (1,3,7-trimethylxanthine).
Caffeine binds directly to human bitter taste receptors (hTAS2Rs), eliciting a strong bitter sensation.
While roasting reactions produce additiol bitter compounds (like phenylindanes in dark roasts), caffeine and other methylxanthines provide the foundatiol bitterness of the beverage.
Diprophylline and Bromotheophylline are synthetic derivatives used as pharmaceuticals and are not turally present in coffee beans.
Xanthydrol is an organic compound used to test for urea and is unrelated to coffee chemistry.

Step 3: Fil Answer
The chemical group responsible for bitterness in coffee among the choices is Methylxanthines.