Description
Tom Yum soup is a hot, aromatic broth that relies on the extraction of essential oils from herbs and the controlled release of capsaicin and proteins.
Technical
The preparation involves heating lemongrass and kaffir lime leaves to 80–90 °C to volatilize essential oils such as citral and limonene, simmering chilies for 10–15 min to extract capsaicin, and acidifying the broth with lime juice to lower the pH to ~4.5, which inhibits bacterial growth. Fish sauce added at 90 °C integrates umami peptides and salt, while shrimp cooked for no more than 3 min prevents protein denaturation that would otherwise produce a rubbery texture.
Science
Primary Reaction
Extraction of essential oils, capsaicin, and aromatic compounds by heat; acidification to inhibit bacterial growth; protein denaturation at high temperatures.
Sensory Profile
Aroma ()