Aspartame is not used in hot drinks as a sweetener because:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → It is unstable at high temperature
Aspartame, the methyl ester of a dipeptide of aspartic acid and phenylalanine, is about 100 times as sweet as cane sugar. It is unstable at cooking temperature: on heating it breaks down and loses its sweetness. So its use is limited to cold foods and soft drinks.
Why the other options are incorrect
Option (1) It is difficult to control the sweetness — Incorrect. The sweetness of aspartame can be controlled by the amount added, as with sugar; this is not why it is kept out of hot drinks.
Option (3) It metabolises in the body — Incorrect. Being metabolised is not related to temperature, and does not stop its use in cold drinks either.
Option (4) It gives bad appearance to hot drinks — Incorrect. Aspartame is a colourless solid that dissolves without changing the look of the drink; the problem is the loss of sweetness on heating.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Artificial Sweetening Agents – …
