Question

Pectin is primarily composed of__________

• A. galactose and glucose
• B. fructose
• C. galacto-pyranosyl uronic acid
• D. amylose

Hint:

For exams, connect "Pectin" directly with "Galacturonic Acid". This is the fundamental structural unit responsible for its gelling properties.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Pectin is a complex structural polysaccharide found in the primary cell walls of plants, particularly in fruits. It is widely used in the food industry as a gelling agent, thickener, and stabilizer, most notably in jams and jellies.
Step 3: Detailed Explanation:
The main component of the pectin backbone is a linear chain of D-galacturonic acid units linked by \(\alpha\)-(1\(\rightarrow\)4) glycosidic bonds.
Galacturonic acid is a sugar acid, an oxidized form of galactose.
The term galacto-pyranosyl uronic acid is the more formal chemical name for a galacturonic acid unit when it is in its six-membered (pyranose) ring form within a polymer chain.
The other options are incorrect:
- (A) Galactose and glucose are simple sugars (monosaccharides).
- (B) Fructose is a simple sugar.
- (D) Amylose is a polysaccharide, but it is a component of starch and is made up of glucose units.
Step 4: Final Answer:
The primary building block of the pectin polymer is galacturonic acid, correctly named as galacto-pyranosyl uronic acid in its ring form. Thus, option (C) is the correct answer.