Question

The major pigments of black grape anthocyanins are ______.

• A. Pelargonidin 2-O-rutinoside
• B. Anthocyanidin 3-O-glycosides
• C. Petunidin 3-O-glucoside
• D. Delphinidin 2-O-glucoside

Hint:

In common wine grapes (*Vitis vinifera*), anthocyanins occur exclusively as 3-O-monoglucosides, unlike wild grapes which can have diglucosides.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Anthocyanins are water-soluble vacuolar pigments responsible for the red, purple, and blue colors in many fruits, including grapes.

Step 2: Detailed Explanation:
Anthocyanins chemically consist of an anthocyanidin aglycone bound to one or more sugar moieties.
In *Vitis vinifera* (black and red grapes), the main pigments are monoglucosides, specifically attached at the C-3 position of the ring.
These include the 3-O-monoglucosides of delphinidin, cyanidin, petunidin, peonidin, and malvidin.
Thus, the major class representing grape anthocyanins is anthocyanidin 3-O-glycosides (or 3-O-glucosides).
While individual pigments like petunidin 3-O-glucoside are present, the general overarching group defining the major grape pigments is the 3-O-glycosides.

Step 3: Final Answer:
Anthocyanidin 3-O-glycosides are the predominant anthocyanin pigments found in black grapes.