Answer: It is a dipeptide ester, and the peptide and ester bonds in it are hydrolysed by heat and moisture.
- A It reacts with atmospheric oxygen, slowly forming a non-sweet polymer that precipitates out of solution
- B It tends to sublime at the temperatures used in cooking, leaving food before it can sweeten anything
- C It is a dipeptide ester, and the peptide and ester bonds in it are hydrolysed by heat and moisture
- D Its sweetness relies on a metal-ion complex that breaks down on prolonged exposure to visible light
Correct answer: C. It is a dipeptide ester, and the peptide and ester bonds in it are hydrolysed by heat and moisture
Explanation: Aspartame is a methyl ester of a dipeptide (aspartic acid and phenylalanine), and both the peptide bond and ester bond can hydrolyse on heating or extended storage, breaking down the molecule and reducing sweetness.
The hydrophobic hydrocarbon tail of each soap/detergent molecule dissolves into an oily dirt droplet, while the hydrophilic (ionic) head stays in the surrounding water - trapping the grease inside a micelle that rinses away with water.
Concept context
Drugs and how they interact with biological targets, chemicals in food, and cleansing agents (soaps and detergents) - chemistry applied directly to daily life and healthcare.