Identify the types of methylxanthines commonly present in foods.

The types of methylxanthines commonly present in foods include:

1. Caffeine: Found in coffee, tea, chocolate, and some soft drinks.
2. Theobromine: Found in chocolate, cocoa, and tea.
3. Theophylline: Found in tea and some types of coffee.

- Caffeine is the most common methylxanthine, found in coffee, tea, chocolate, and energy drinks.
- Theobromine is found in chocolate and cocoa products.
- Theophylline is found in tea and certain medications.